ProMAX Seismic manual

ProMAX VSP User Training Manual copyright © 1999 by Landmark Graphics Corporation

Part No. 625321 Rev. B

June 1999

Copyright © 1999 Landmark Graphics Corporation All Rights Reserved Worldwide This publication has been provided pursuant to an agreement containing restrictions on its use. The publication is also protected by Federal copyright law. No part of this publication may be copied or distributed, transmitted, transcribed, stored in a retrieval system, or translated into any human or computer language, in any form or by any means, electronic, magnetic, manual, or otherwise, or disclosed to third parties without the express written permission of: Landmark Graphics Corporation 15150 Memorial Drive, Houston, TX 77079, U.S.A. Phone: 281-560-1000 FAX: 281-560-1410

Trademark Notices Landmark, OpenWorks, SeisWorks, ZAP!, PetroWorks, and StratWorks are registered trademarks of Landmark Graphics Corporation. Pointing Dispatcher, Log Edit, Fast Track, SynTool, Contouring Assistant, TDQ, RAVE, 3DVI, SurfCube, SeisCube, VoxCube, Z-MAP Plus, ProMAX, ProMAX Prospector, ProMAX VSP, MicroMAX, and Landmark Geo-dataWorks are trademarks of Landmark Graphics Corporation. ORACLE is a registered trademark of Oracle Corporation. IBM is a registered trademark of International Business Machines, Inc. AIMS is a trademark of GX Technology. Motif, OSF, and OSF/Motif are trademarks of Open Software Corporation. UNIX is a registered trademark in the United States and other countries, licensed exclusively through X/Open Company, Ltd. SPARC and SPARCstation are registered trademarks of SPARC International. Solaris, Sun, and NFS are trademarks of SUN Microsystems. X Window System is a registered trademark of X/Open Company, Ltd. SGI is a trademark of Silicon Graphics Incorporated. All other brand or product names are trademarks or registered trademarks of their respective companies or organizations.

Note The information contained in this document is subject to change without notice and should not be construed as a commitment by Landmark Graphics Corporation. Landmark Graphics Corporation assumes no responsibility for any error that may appear in this manual. Some states or jurisdictions do not allow disclaimer of expressed or implied warranties in certain transactions; therefore, this statement may not apply to you.

Contents

Agenda

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Agenda - Day 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Agenda Day 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Agenda Day 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v About The Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v How To Use The Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

ProMAX VSP System and Database Parameters . . . . . . . . . . 1-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 Directory Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ProMAX Data Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8 Ordered Parameter Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15 Parameter Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20 Disk Datasets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24 Tape Datasets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28 Tape Catalog System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30

Flow Building and Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 Landmark

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Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 ProMAX Menu Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 Building and Executing a Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Interactivity of Trace Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-1

Topics to be covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Trace Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Create and Apply a Parameter Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Parameter Selection and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Parameter Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 IF/ENDIF Conditional Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 Interactive Spectral Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Real Dataset Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 VSP Real Dataset Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Geometry Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

View Input Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Display the Input Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 Write Dataset To Disk in Your Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

VSP Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Assign VSP Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2 Quality Control Plots using the XDB database tool . . . . . . . . . . . . . . . . . . . . . 7-7 Load Geometry to the trace headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8

Keep Vertical Component Traces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 Trap Vertical Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2 Output a file with vertical traces only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

First Break Picks on Vertical Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 Pick First Breaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2 QC the First Breaks in the Database using XDB . . . . . . . . . . . . . . . . . . . . . . . . 9-4

VSP Velocity Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1

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Generate Average Velocity vs. Depth and Smooth . . . . . . . . . . . . . . . . . . . . . 10-2

VSP True Amplitude Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1 True Amplitude Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 Compute an RMS Velocity Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 Test TAR Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7

VSP Wave Field Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1 Flatten the Downgoing with F-B Picks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 Flatten with F-B Picks and Event Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4 Compare Flattening Iterations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7 Wavefield Separation with Median Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9 F-K Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-13 Wavefield Separation with F-K Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-16 Wavefield Separation with Eigenvector (K-L) Filter . . . . . . . . . . . . . . . . . . 12-18 Wavefield Separation Comparison Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-22 Save the Upgoing Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-24 Wavefield Separation to Keep Downgoing . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-26 Save the Downgoing Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-28 QC plot of Separated Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-30

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VSP Deconvolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1 Picking the Decon Design Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 Apply the mute for QC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3 Deconvolution Filter Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4 Deconvolution Filter QC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-6 Deconvolution - Application to UpGoing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7 Spectral Analysis Before and After Decon . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-9

VSP Corridor Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1 Picking Corridor Mutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2 Apply the Corridor Mutes for QC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 Produce the Corridor Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5 Splice the Corridor Stack into a Surface Stack. . . . . . . . . . . . . . . . . . . . . . . . . 14-8

Generate Intv-Dpth Velocity Function . . . . . . . . . . . . . . . . . . . . . . . 15-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1 Compute Interval Velocity vs. Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-2

VSP CDP Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1

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VSP CDP Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2

VSP Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1 VSP Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2 Display the VSP Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3

VSP Corkscrew Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1 Assign VSP Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2 Quality Control Plots from the database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-8

Pre Vertical Stack Dataset Information . . . . . . . . . . . . . . . . . . . . .

19-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1 VSP Prevertical Stack Dataset Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2

VSP Level Statics and Vertical Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1 Plot the Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-2 VSP Level Statics Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-5 Compute and Apply the Level Statics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-7

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Vertically Stack Shots by Common Header Entry . . . . . . . . . . . . . . . . . . . . . 20-10 Compare Stacks With and Without Level Statics . . . . . . . . . . . . . . . . . . . . . 20-11

Synthetic Dataset Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1 VSP Synthetic Dataset Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2

Level Stat and Vertical Stack for Multi Component / Multi Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1 Plot the Traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2 Determine Level Statics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-3 Vertically Stack Shots for Common Depth Levels . . . . . . . . . . . . . . . . . . . . . 22-7 Examine Headers for Common Header Entry . . . . . . . . . . . . . . . . . . . . . . . . . 22-9 Vertically Stack Shots by Common Header Entry . . . . . . . . . . . . . . . . . . . . . 22-10 Compare Stacks With and Without Level Statics . . . . . . . . . . . . . . . . . . . . . 22-11

3-Component Transform and First Break Picking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1 Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1 3-Component Transform and First Arrival Picking . . . . . . . . . . . . . . . . . . . . . 23-2 Copying Picks from one Trace to the Others . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4 QC the Copied Picks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-6 Landmark


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VSP 3-Component Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1 3 Component Hodogram Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2 Example Hodogram Analysis Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-4 Example of Hodogram Output Trace Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-7

Prepare Input Data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1 Preparing the Input Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2

Archival Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1 SEG-Y Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2 Tape Data Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-4 UNIX tar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-7 Archive to Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-8

UNIX Workstation Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27-1

Topics covered in this chapter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1 Text Editors in ProMAX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2 UNIX Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-5 Examples of UNIX Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-15

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Agenda Agenda - Day 1 Introductions, Course Agenda ProMAX User Interface Overview Trace Display Functionality

• Exercises to familiarize ourselves with Trace Display System Overview Discussion

• Discussion of the ProMAX system architecture Parameter Testing Viewing the Input Data Geometry

• Building the geometry database for VSP data

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Keep Vertical Traces First Break Picking Velocity Function Generation Velocity Function Manipulation True Amplitude Recovery Testing True Amplitude Recovery Wavefield Separation Testing

• Median Filter - FK Filter - Eigen Vector Filters

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Agenda Day 2 Isolate the Upgoing Energy

• After choosing the desired wavefield separation technique we will isolate the upgoing energy Isolate the Downgoing Energy

• After choosing the desired wavefield separation technique we will isolate the upgoing energy Deconvolution

• Source signature removal filter design and application Corridor Stack Splicing the Corridor Stack into a Surface Stack VSP-CDP Transform VSP Migration Single channel vertical stack

• Preprocessing exercise for vertically stacking multiple shots at the same receiver locations Look at Synthetic Data Level Statics Level Summing (vertical stack)

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ProMAX VSP User Traiining Manual

iii

Agenda Day 3 3-Component Transforms and first break picking 3-Component Hodogram Analysis Dataset Preparation VSP Modelling Cross Well Tomography Demonstration Archive Methods Generation of CGM Plots

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Preface About The Manual This manual is intended to accompany the instruction given during the standard ProMAX VSP User Training course. Because of the power and flexibility of ProMAX VSP, it is unreasonable to attempt to cover all possible features and applications in this manual. Instead, we try to provide key examples and descriptions, using exercises which are directed toward common uses of the system. The manual is designed to be flexible for both you and the trainer. Trainers can choose which topics, and in what order to present material to best meet your needs. You will find it easy to use the manual as a reference document for identifying a topic of interest and moving directly into the associated exercise or reference.

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How To Use The Manual This manual is divided into chapters that discuss the key aspects of the ProMAX VSP system. In general, chapters conform to the following outline: •

Introduction: A brief discussion of the important points of the topic and exercise(s) contained within the topic.

•

Topics Covered in Chapter: Brief list of skills or processes, in the order that they are covered in the exercise.

•

Topic Description: More detail about the individual skills or processes covered in the chapter.

•

Exercise: Details pertaining to each skill in an exercise, along with diagrams and explanations. Examples and diagrams will assist you during the course by minimizing note taking requirements, and providing guidance through specific exercises.

This format allows you to glance at the topic description to either quickly reference an implementation, or simply as a means of refreshing your memory on a previously covered topic. If you need more information, see the Exercise sections of each topic.

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Conventions Mouse Button Help This manual does not refer to using mouse buttons unless they are specific to an operation. MB1 is used for most selections. The mouse buttons are numbered from left to right so: MB1 refers to an operation using the left mouse button. MB2 is the middle mouse button. MB3 is the right mouse button. Actions that can be applied to any mouse button include: •

Click: Briefly depress the mouse button.

•

Double Click: Quickly depress the mouse button twice.

•

Shift-Click: Hold the shift key while depressing the mouse button.

•

Drag: Hold down the mouse button while moving the mouse.

Mouse buttons will not work properly if either Caps Lock or Nums Lock are on.

Exercise Organization Each exercise consists of a series of steps that will build a flow, help with parameter selection, execute the flow, and analyze the results. Many of the steps give a detailed explanation of how to correctly pick parameters or use the functionality of interactive processes. The editing flow examples list key parameters for each process of the exercise. As you progress through the exercises, familiar parameters will not always be listed in the flow example. The exercises are organized such that your dataset is used throughout the training session. Carefully follow the instructor’s direction when assigning geometry and checking the results of your flow. An improperly generated dataset or database may cause a subsequent exercise to fail.

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Chapter 1

ProMAX VSP System and Database Parameters In this chapter we discuss some of the behind-the-scenes program operation, as well as basic ProMAX framework. Understanding the ProMAX framework and its relationship to the UNIX directory structure can be useful. The ability to manipulate the various components of the line database, such as ordered parameter files, from the User Interface is critical to smooth operation of the software.

Topics covered in this chapter: ❏ Directory Structure ❏ Program Execution ❏ Ordered Parameter Files ❏ Parameter Tables ❏ Disk Datasets ❏ Tape Datasets

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Chapter 1: ProMAX VSP System and Database Parameters

Directory Structure /advance (or $PROMAX_HOME) The directory structure begins at a subdirectory set by the $PROMAX_HOME environmental variable. This variable defaults to / advance, and is used in all the following examples. Set the $PROMAX_HOME environment variable to /my_disk/my_world/ advance to have your Advance directory tree begin below the /my_disk/ my_world subdirectory.

/advance/sys /advance/sys is actually a symbolic link to subdirectories unique to a given hardware platform, such as: /advance/rs6000 for IBM RS6000 workstations, /advance/sparc for Sun Microsystems Sparcstations running SunOS, /advance/solaris for Sun Microsystems Sparcstations and Cray 6400 workstations running Sun Solaris OS, /advance/sgimips for Silicon Graphics Indigo workstations using the 32 bit operating system and /advance/sgimips4 for Silicon Graphics Indigo and Power Challenge workstations using the 64 bit operating system. This link facilitates a single file server containing executable programs and libraries for all machine types owned by a client. Machine specific executables are invoked from the UNIX command line, located in / advance/sys/bin. Operating System specific executables and libraries, called from ProMAX, are located under /advance/sys/exe. These machinedependent directories are named after machine type, not manufacturer, to permit accommodation of different architectures from the same vendor. Accommodating future hardware architectures will simply involve addition of new subdirectories. Unlike menus, help and miscellaneous files, a single set of executables is capable of running all Advance products, provided the proper product specific license identification number is in place.

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ProMAX Directory Structure $PROMAX_HOME (default=/advance)

/exe exec.exe super_exec.exe *.exe

/sys

/frame /sdi /3rd party software

/bin promax promax3d promaxvsp /lib lib*.a

/port

/plot /help

/promax *.lok - Frame help *.help -ASCII help /promax3d /promaxvsp /promax *.menu Processes /promax3d /promaxvsp

/menu

/misc *_stat_math *.rgb-colormaps ProMax_defaults /etc config_file product install.doc pvmhosts qconfig license.dat

/scratch /queues /area

/data

/line

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Third party software distributed by Advance will now be distributed in a subdirectory of /advance/sys/exe using the company’s name, thus avoiding conflicts where two vendors use identical file names. For example, SDI’s CGM Viewer software would be in /advance/sys/exe/ sdi and Frame Technology’s FrameViewer would be in /advance/sys/ exe/frame.

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ProMAX Directory Structure $PROMAX_HOME (default=/advance)

/sys

/exe exec.exe super_exec.exe *.exe

/frame /sdi /3rd party software

/bin promax promax3d promaxvsp /lib lib*.a

/port

/plot /help

/promax *.lok - Frame help *.help -ASCII help

/promax3d /promaxvsp /promax *.menu Processes /promax3d /promaxvsp

/menu

/misc *_stat_math *.rgb-colormaps ProMax_defaults /etc config_file product install.doc pvmhosts qconfig license.dat

/scratch /queues /data

/area

/line

(or $PROMAX_DATA_HOME)

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/advance/port Software that is portable across all platforms is grouped under a single subdirectory /advance/port. This includes menus and Processes (/ advance/port/menu), helpfiles(/advance/port/help), miscellaneous files (/advance/port/misc). Under the menu and help subdirectories are additional subdirectories for each ProMAX software product. For instance, under /advance/port/menu, you will find subdirectories for ProMAX 2D (promax), ProMAX 3D (promax3d), and ProMAX VSP (promaxvsp). Menus for additional products are added as new subdirectories under /advance/port/menu.

/advance/etc Files unique to a particular machine are located in the /advance/etc subdirectory. Examples of such files are the config_file, which contains peripheral setup information for all products running on a particular machine, and the product file, which assigns unique pathnames for various products located on the machine.

/advance/scratch The scratch area defaults to /advance/scratch. This location can be overridden with the environmental variable, PROMAX_SCRATCH_HOME. All ProMAX development tools are included within the following subdirectories: /advance/sys/lib, /advance/sys/obj, /advance/port/src, / advance/port/bin, /advance/port/include and /advance/port/man.

/advance/data (or $PROMAX_DATA_HOME) The primary data partition defaults to /advance/data, with new areas being added as subdirectories beneath this subdirectory. This default location is specified using the entry: — primary disk storage partition: /advance/data 20 in the /advance/etc/config_file. This location can also be set with the environmental variable $PROMAX_DATA_HOME.

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ProMAX Data Directories PROMAX_DATA_HOME

or /Data /Area DescName Project

Area subdirectory and its files

/Line DescName 17968042TVEL 31790267TGAT 36247238TMUT 12345678CIND 12345678CMAP

Parameter Table files

Index and Map Dataset files

/12345678 HDR1 HDR2 TRC1 TRC2

Dataset subdirectory and Header and Trace Dataset files

/Flow1 DescName TypeName job.output packet.job

A Flow subdirectory and its files

/OPF.SIN OPF60_SIN.GEOMETRY.ELEV

/OPF.SIN Database subdirectory and a non-spanned file

/OPF.SRF #s0_OPF60_SRF.GEOMETRY.ELEV

/OPF.SRF Database subdirectory and a span file

Each region identifies a collection of files and directories which can be summarized as the Area, Line, Parameter Tables, Flow, Trace Headers, and Ordered Parameter Files database.

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Program Execution User Interface ($PROMAX_HOME/sys/bin/promax) Interaction with ProMAX is handled through the User Interface. As you categorize your data into Areas and Lines, the User Interface automatically creates the necessary UNIX subdirectories and provides an easy means of traversing this data structure. However, the primary function of the User Interface is to create, modify, and execute processing flows. A flow is a sequence of processes that you perform on seismic data. Flows are built by selecting processes from a list, and then selecting parameters for each process. A typical flow contains an input process, one or more data manipulation processes, and a display and/or output process. All information, needed to execute a flow, is held within a Packet File (packet.job) within each Flow subdirectory. This Packet File provides the primary means of communication between the User Interface and the Super Executive program. See next section, Super Executive Program. In addition, the User Interface provides utility functions for copying, deleting and archiving Areas, Lines, Flows, and seismic datasets; accessing and manipulating ordered database files and parameter tables; displaying processing histories for your flows; and providing information about currently running jobs. The User Interface is

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primarily mouse-driven and provides point-and-click access to the functions.

Program Execution

Super Executive Program (super_exec.exe) Execution of a flow is handled by the Super Executive, which is launched as a separate task by the User Interface. The Super Executive is a high level driver program that examines processes in your flow by reading packet.job and determines which executables to use. The majority of the processes are subroutines linked together to form the Executive. Since this is the processing kernel for ProMAX, many of your processing flows, although they contain several processes, are handled by a single execution of the Executive. Several of the processes

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are stand-alone programs. These processes cannot operate under the control of the Executive, and handle their own data input and output by directly accessing external datasets. In these instances, the Super Executive is responsible for invoking the stand-alone programs and, if necessary, multiple calls to the Executive in the proper sequence. The Packet File, packet.job, defines the processes and their type for execution. The Super Executive concerns itself with only two types of processes: •

Executive processes

•

Stand-alone processes

Executive processes are actually subroutines operating in a pipeline, meaning they accept input data and write output data at the driver level. However, stand-alone processes cannot be executed within a pipeline, but rather must obtain input and/or produce output by directly accessing external datasets. The Super Executive sequentially gathers all Executive-type processes until a stand-alone is encountered. At that point, the Packet File information for the Executive processes is passed to the Executive routine (exec.exe) for processing. Once this is completed, the Super Executive invokes the stand-alone program for processing, and then another group of Executive processes, or another stand-alone process. This continues until all processes in the flow have been completed.

Executive Program (exec.exe) The Executive program is the primary processing executable for ProMAX. The majority of the processes available under ProMAX are contained in this one executable program. The Executive features a pipeline architecture that allows multiple seismic processes to operate on the data before it is displayed or written to a dataset. Special processes, known as input and output tools, handle the tasks of reading and writing the seismic data, removing this burdensome task from the individual processes. This results in processes that are easier to develop and maintain.

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The basic flow of data through the Executive pipeline is shown below:

Each individual process will not operate until it has accumulated the necessary traces. Single trace processes will run on each trace as the traces come down the pipe. Multi channel processes will wait until an entire ensemble is available. For example in the example flow the FK

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filter will not run until one ensemble of traces has passed through the DDI and AGC. If we specify for the Trace Display to display 2 ensembles, it will not make a display until two shots have been processed through the DDI, AGC and FK filter. No additional traces will be processed until Trace Display is instructed to release the traces that it has displayed and is holding in memory by clicking on the traffic light icon or terminating its execution (but continuing the flow). Note: All the processes shown are Executive processes and thus operate in the pipeline. An intermediate dataset and an additional input tool process is needed if a stand-alone process were included in this flow. A pipeline process must accept seismic traces from the Executive, process them, and return the processed data to the Executive. The table below describes the four types of processes defined for use in the Executive.

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Disk Data Input, Tape Data Input and standalone tools always start new pipes within a single flow

Disk Data Input

AGC F-K Filter

Decon Disk Data Input

Disk Data Output

NMO

CDP Stack

Bandpass Filter

Disk Data Output One pipe must complete successfully before a new pipe will start processing

Multiple Pipes in One Flow

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Types of Executive Processes The table below describes the four types of processes defined for use in the Executive. Table 1: ProMAX Executive Process Types Process Type

Description

simple tools

Accepts and returns a single seismic trace.

ensemble tools

Accepts and returns a gather of seismic traces

complex tools

Accepts and returns a variable number of seismic traces such as, stack. This type of process actually controls the flow of seismic data.

panel tools

Accepts and returns overlapping panels of traces to accommodate a group of traces too large to fit into memory. Overlapping panels are processed and then merged along their seams.

Stand-Alone Processes and Socket Tools Some seismic processing tools are not well suited to a pipeline architecture. Typically, these are tools making multiple passes through the data or requiring self-directed input. These tools can be run inline in a ProMAX job flow and appear as ordinary tools, but in reality are launched as separate processes. The current version of ProMAX does not provide the ability to output datasets from a stand-alone process. Socket tools start a new process and then communicates with the Executive via UNIX interprocess communications. Socket tools have the singular advantage of being able to accept and output traces in an asynchronous manner.

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Ordered Parameter Files Click to jump to the section

This section discusses the following issues relating to the Ordered Parameter Files database: •

Organization

•

Database Structure

•

File Naming Conventions

The Ordered Parameter Files database serves as a central repository of information that you or the various tools can rapidly access. Collectively, the ordered database files store large classes of data, including acquisition parameters, geometry, statics and other surface consistent information, and pointers between the source, receiver and CDP domains. The design of the Orders is tailored for seismic data, and provides a compact format without duplication of information. The Ordered Parameter Files database is primarily used to obtain a list of traces to process, such as traces for a shot or CDP. This list of traces is then used to locate the index to actual trace data and headers in the MAP file of the dataset. Once determined, the index is used to extract the trace and trace header data from their files.

Organization The Ordered Parameter Files contain information applying to a line and its datasets. For this reason, there can be many datasets for a single set of Ordered Database Files. Ordered Parameter Files, unique to a line, reside in the Area/Line subdirectory. The Ordered Parameter Files database stores information in structured categories, known as Orders, representing unique sets of information. In each Order, there are N slots available for storage of information, where N is the number of elements in the order, such as the number of sources, number of surface locations, or number of CDPs. Each slot contains various attributes in various formats for one

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particular element of the Order. The Orders are organized as shown in the table below. Table 2: Organization of Ordered Parameter Files LIN (Line)

Contains constant line information, such as final datum, type of units, source type, total number of shots.

TRC (Trace)

Contains information varying by trace, such as FB Picks, trim statics, source-receiver offsets.

SRF (Surface location)

Contains information varying by surface receiver location, such as surface location x,y coordinates, surface location elevations, surface location statics, number of traces received at each surface location, and receiver fold.

SIN (Source Index #)

Contains information varying by source point, such as source x,y coordinates, source elevations, source uphole times, nearest surface location to source, source statics.

CDP (Common Depth Point)

Contains information varying by CDP location, such as CDP x,y coordinates, CDP elevation, CDP fold, nearest surface location.

CHN (Channel)

Contains information varying by channel number, such as Channel gain constants, channel statics

OFB (Offset Bin)

Contains information varying by offset bin number, such as surface consistent amplitude analysis. OFB is created when certain processes are run, such as surface consistent amplitude analysis.

PAT (Pattern)

Contains information describing the recording patterns.

Table 3: Additional Parameter Files for 3D ILN (Inline)

Contains information, constant within a 3D inline.(Number of traces per line)

XLN (Crossline)

Contains information constant within a 3D crossline. (Number of traces per crossline)

OPF Matrices The OPF database files can be considered to be matrices. Each OPF is indexed against the OPF counter and there are various single numbers per index. Note the relative size of the TRC OPF to the other OPF files. The TRC is by far the largest contributor to the size of the database on disk

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SIN (Sources) Database

SRF (Receivers) Database

OPF Maftrices

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Database Structure The ProMAX database was restructured for the 6.0 release to handle large 3D land and marine surveys. The features of the new database structure are listed below: Each order is contained within a subdirectory under Area and Line. For example, the TRC is in the subdirectory OPF.TRC. There are two types of files contained in the OPF subdirectories: •

Parameter: Contain attribute values. There may be any number of attribute files associated with an OPF.

•

Index: Holds the list of parameters and their formats. There is only one index file in each OPF subdirectory. The exception to this is the LIN OPF. The LIN information is managed by just two files, one index and one parameter, named LIN.NDX and LIN.REC.

OPF files are of two types: •

Span: These files are denoted by the prefix, #s. Non-span files lack this prefix. The TRC, CDP, SIN, and SRF OPF parameters are span files. The first span for each parameter is always written to primary storage. Span files are created in the secondary storage partitions listed in the config_file as denoted with the OPF keyword. Span files may be moved to any disk partition within the secondary storage list for read purposes. Newly created spans are written in the OPF denoted secondary storage partitions. All subsequent spans are written to the secondary storage partitions denoted by the OPF keyword in a round robin fashion until the secondary storage is full. Then, subsequent spans are created in primary storage. Span file size is currently fixed at 10 megabytes, or approximately 2.5 million 4 byte values per span file.

•

Non-span: All other OPFs are non-span.

Given the fact that each parameter is managed by a file, it may be necessary to increase the “maximum number of files open” limit on some systems, specifically, SUN, Solaris and SGI. From the csh, the following command increases the file limit to 255 files open, “limit de 255”. The geometry spreadsheet is a ProMAX database editor. Modifying information within a spreadsheet editor and saving the changes will automatically update the database.

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There is no longer an import or export from the geometry database to the ProMAX database files as was required prior to the 6.0 release. Database append is allowed. Data can be added to the database via the OPF Extract tool or the geometry spreadsheet. This allows for the database to be constructed incrementally as the data arrives. There is improved network access to the database. Database I/O across the network is optimized to an NFS default packet size of 4K. All database reads and writes are in 4K pages. Existing and restored 5.X databases are automatically converted to the 6.0 (and later) database format.

File Naming Conventions Parameter file names consist of information type and parameter name, preceded by a prefix denoting the Order of the parameter. For example, the x coordinate for a shot in the SIN has the following name: #s0_OPF60_SIN.GEOMETRY.X_COORD. Where #s0_OPF60 indicates a first span file for the parameter, _SIN denotes the Order, GEOMETRY describes the information type of the parameter, and X_COORD is the parameter name. 0. Index file names contain the three letter Order name. For example, the index file for the TRC is called OPF60_TRC. NOTE:

The index file for each Order must remain in the primary storage partition. Span parameter files may be moved and distributed anywhere within primary and secondary storage.

Within each Order, there are often multiple attributes, with each attribute being given a unique name.

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Parameter Tables Parameter Tables are files used to store lists of information in a very generalized structure. To increase access speed and reduce storage requirements, parameter tables are stored in binary format. They are stored in the Area/Line subdirectory along with seismic datasets, the Ordered Parameter Files database files (those not in separate directories), and Flow subdirectories. Parameter Tables are often referred to as part of the database. Parameter tables differ from the OPF database in OPF files contain many attributes that are 1 number per something. Parameter tables contain more than one number per something. For example a velocity function contains multiple velocity-time pairs at 1 CDP.

Creating a Parameter Table Parameter tables are typically created in three ways: •

Processes store parameters to a table for later use by other processes.

•

Parameter tables can be imported from ASCII files that were created by other software packages or hand-edited by you.

•

Parameter tables can be created by hand using the Parameter Table Editor which is opened by the Create option on the parameter table list screen.

An example is the interactive picking of time gates within the Trace Display process. After seismic data is displayed on the screen, you pull down the Picking Menu and choose the type of table to create. The end result of your work is a parameter table. If you were to pick a top mute, you would generate a parameter table ending in TMUT. If you were picking a time horizon, you would generate a table ending in THOR. These picks are stored in tabular format, where they can be edited, used by other processes in later processing, or exported to ASCII files for use by other software packages. Remember, you name and store the parameter tables in their specific Area/Line subdirectory. Therefore, you can inadvertently overwrite an existing parameter table by editing a parameter table in a different processing flow.

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ASCII File Export to Parameter Table Editor Export writes either ASCII or EBCDIC formatted files with fixed columnar data from a spreadsheet editor. In the following exercise, a velocity table is exported to an ASCII file.

Exercise 1. In a flow-building window, add the Access Parameter Tables process to a flow and view the parameter menu with MB2. Find the line: VEL: RMS (stacking) velocity and click on Invalid. The list of parameter tables for RMS Velocity appear. 2. Click on Edit and select the name of the file to export. A Parameter Table spreadsheet appears with CDP, TIME, and SEMB_VEL columns. 3. Click on File and select Export. An ASCII File Export window appears with export information for quality control before actually creating the ASCII file. 4. Click on File. A new window appears with the path to your working directory. 5. Enter a filename after the last / and click OK. The window disappears and a dashed line appears in the ASCII File Export window. 6. Click on Format. An Export Definition Selection window appears. 7. Type in a selection name and click on OK. The Column Export Definition window appears. 8. Fill the Column Export Definition with starting and ending column numbers, then click on Save. When you fill in the start and end columns for a particular column definition, the contents of the column appear in the ASCII File

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Export window. Be sure the column definitions are wide enough to accommodate all the significant figures, as well as complete column titles. If they are not, edit the Column Export Definition window until the information is correct. 9. When the ASCII File Export window is correct, click on Apply. An Apply Export window appears. You may choose to overwrite or append new information to the ASCII file. You may also add a single line description of your work that will be internal to the file. 10. Click on OK. This creates the ASCII file in the directory you specified. You may now Quit the Column Export Definition window, Cancel the ASCII file Export Window, and pull down the File menu in the Parameter Table window and exit this window and continue working.

ASCII File Import to a Parameter Table File Import reads either ASCII or EBCDIC formatted files with fixed columnar data into the spreadsheet editor.

Exercise 1. In a flow-building window, add the Access Parameter Tables process and view the parameter menu with MB2. Find the line: VEL: RMS (stacking) velocity and click on Invalid. The list of Parameter Files(tables) for RMS velocity appear. 2. Click on Create. The cursor will move to the top of the table name column, enter a new velocity file name. After typing a name, press Return. A Parameter Table spreadsheet appears with CDP, TIME, and VEL_RMS columns. 3. Click on File and choose Import. Two new windows appear: ASCII/EBCDIC File Import and File Import Selection. In the File Import Selection window, choose the path to the file containing velocity information to import and click on OK. The import information appears in the ASCII/EBCDIC File Import window.

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4. Click on Format in the ASCII/EBCDIC File Import window. The Import Definition Selection window appears. 5. Type in a selection name and click on OK. The Column Import Definition window appears. 6. Blank rows that will not be imported into the new velocity file. To blank the rows, click MB1 in the first row to ignore and click MB2 in the last row to ignore. Press Ctrl-d, the rows to ignore are labeled Ignore Record for Import. 7. Fill the Column Import Definition window. Begin filling the Column Import Definition window by choosing a definition parameter by clicking on the parameter name. The parameter box will be highlighted in white. Next, move the cursor into the ASCII/EBCDIC File Import window to the values defining the definition parameter. Hold down MB1 as you drag it from left to right across the import parameter values. The chosen columns should highlight in black in the ASCII/EBCDIC File Import window and the Start Col and End Col boxes in the Column Import Definition window should contain the appropriate column numbers. Repeat this process with the other two parameters and save the definition. 8. When the Column Import Definition window is correct, click on Apply in the ASCII/EBCDIC File Import window. The Apply Import window appears. You may choose to overwrite or append new information to the spreadsheet. 9. Click OK. This fills in the spreadsheet with selected numbers. Also, the Import windows disappear from the screen. You may now continue working and apply these velocities to your data.

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Disk Datasets ProMAX uses a proprietary disk dataset format that is tailored for interactive processing and random disk access. Disk dataset files can span multiple filesystems, allowing for unlimited filesize datasets. A typical set of files might look like this: — /advance/data/usertutorials/landexample/12345678CIND /advance/data/usertutorials/landexample/12345678CMAP /advance/data/usertutorials/landexample/12345678/TRC1 /advance/data/usertutorials/landexample/12345678/HDR1 These files are described in more detail in the table below. Table 4: Composition of a Seismic Dataset

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File Name

Contents

Trace (...TRCx)

File containing actual sample values for data trace.

Trace Header (....HDRx)

File containing trace header entries corresponding to data samples for traces in the trace file. This file may vary in length, growing as new header entries are added. Keep trace headers in a separate file so trace headers can be sorted without needing to skip past the seismic data samples.

Map (....CMAP)

File keeps track of trace locations. Given a particular trace number, it will find the sequential trace number within the dataset. This rapidly accesses traces during processing. The map file is a separate file, as it may grow during processing.

Index (....CIND)

File has free-form format information relating to the entire dataset, including sample interval, number of samples per trace, processing history, and names of trace header entries. This file may grow during processing.


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CIND

CMAP

HDRx

TRCx

Disk Dataset Components - Relative Sizes

Secondary Storage In a default ProMAX configuration, all seismic dataset files reside on a single disk partition. The location of this disk partition is set in the $PROMAX_HOME/etc/config_file with the entry: — primary disk storage partition: /advance/promax/data 20 In addition to the actual trace data files, the primary storage partition will always contain your flow subdirectories, parameter tables, ordered parameter files, and various miscellaneous files. The ...CIND and ...CMAP files which comprise an integral part of any seismic dataset are always written to primary storage. Since the primary storage file system is of finite size, ProMAX provides the capability to have some of the disk datasets, such as the ...TRCx and ...HDRx files, and some of the ordered parameter files span multiple disk partitions. Disk partitions other than the primary disk storage partition are referred to as secondary storage. All secondary storage disk partitions must be declared in the appropriate $PROMAX_HOME/etc/config_file. Samples entries are:

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secondary disk storage partition: /advance/promax/data2 20 TRC OPF secondary disk storage partition: /advance/promax/data3 20 TRC secondary disk storage partition: /advance/promax/data4 20 OPF secondary disk storage partition: /advance/promax/data5 20 Refer to the ProMAX System Administration guide for a complete description of the config_file entries for primary and secondary disk storage. Under the default configuration, the initial TRC1 and HDR1 files are written to the primary storage partition. It is possible to override this behavior by setting the appropriate parameter in Disk Data Output. If the parameter Skip primary disk partition? is set to Yes, then no TRC or HDR files will be written to the primary disk partition. This can be useful as a means of maintaining space on the primary storage partition. (To make this the default situation for all users, have your ProMAX system administrator edit the diskwrite.menu file, setting the value for Alstore to ‘t’ instead of ‘nil’). A typical set of data files might look like this: — /advance/data/usertutorials/landexample/12345678CIND /advance/data/usertutorials/landexample/12345678CMAP /advance/data/usertutorials/landexample/12345678/TRC1 /advance/data/usertutorials/landexample/12345678/HDR1 /advance/data/usertutorials/landexample/12345678/TRC4 /advance/data/usertutorials/landexample/12345678/HDR4 /advance/data/usertutorials/landexample/12345678/TRC7 /advance/data/usertutorials/landexample/12345678/HDR7 /advance/data2/usertutorials/landexample/12345678/TRC2 /advance/data2/usertutorials/landexample/12345678/HDR2 /advance/data2/usertutorials/landexample/12345678/TRC5 /advance/data2/usertutorials/landexample/12345678/HDR5 /advance/data2/usertutorials/landexample/12345678/TRC8 /advance/data2/usertutorials/landexample/12345678/HDR8 /advance/data3/usertutorials/landexample/12345678/TRC3 /advance/data3/usertutorials/landexample/12345678/HDR3 /advance/data3/usertutorials/landexample/12345678/TRC6 /advance/data3/usertutorials/landexample/12345678/HDR6

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Secondary storage is used in a “as listed and available” fashion. As an attempt to minimize data loss due to disk hardware failure, ProMAX tries to write a dataset to as few physical disks as possible. If the primary storage partition is skipped by setting the appropriate parameter in Disk Data Output, the CIND and CMAP files are still written to the primary storage partition, but the TRCx or HDRx files will not be found there.

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Tape Datasets Tape datasets are stored in a proprietary format, similar to the disk dataset format, but incorporating required structures for tape input and output. Tape input/output operates either in conjunction with a tape catalog system, or without reference to the tape catalog. The tape devices used for the Tape Data Input, Tape Data Insert, and Tape Data Output processes are declared in the ProMAX device configuration window. This allows access to tape drives anywhere on a network. The machines that the tape drives are attached to do not need to be licensed for ProMAX, but the fclient.exe program must be installed.

Tape Trace Datasets A ProMAX tape dataset is similar to a disk dataset in that the index file (...CIND) and map file (...CMAP) still reside on disk in the Line/survey database. Refer to the documentation in the Disk Datasets portion of this helpfile for a discussion of these files. Having the index and map files available on disk provides you with immediate access to information about the dataset, without needing to access any tapes. It also provides all the information necessary to access traces in a non-sequential manner. Although the index and map files still reside on disk, copies of them are also placed on tape(s), so that the tape(s) can serve as a self-contained unit(s). If the index and map files are removed from disk, or never existed, as in the case where a dataset is shipped to another site, the tapes can be read without them. However, access to datasets through the index and map files residing solely on tape must be purely sequential. Tape datasets are written by the Tape Data Output process, and can be read using the Tape Data Input or Tape Data Insert processes. These input processes include the capability to input tapes by reel, ensemble number, or trace number. Refer to the relevant helpfile for a complete description of the parameters used in these processes. The use or non-use of the tape catalog in conjunction with the tape I/O processes is determined by the tape catalog type entry in the appropriate $PROMAX_HOME/etc/config_file. Setting this variable to full activates catalog access, while an entry of none deactivates catalog access. An entry of external is used to indicate that an external tape catalog, such as the Cray Reel Librarian, will be used. You can override the setting provided in the config_file by setting the environment

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variable for BYPASS_CATALOG to ‘t’, in which case the catalog will not be used. The actual tape devices to use for tape I/O must also appear as entries in the config_file, under the tape device: stanza.

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Tape Catalog System Tape Catalog Overview The fundamental strategy of the tape catalog is that a group of tapes are introduced or logged into the tape catalog, which then works in conjunction with the Tape Input, Tape Insert, and Tape Output processes to provide access to those tapes from within the ProMAX system. Before being introduced to the catalog, an ANSI label is written to each tape using the catalog utilities outlined below. The catalog system knows the label and status (initially SCRATCH) of every tape, and can monitor and validate the tape catalog resources accordingly. For example, when a request for an output dataset is made, the catalog can decide which tape to use, and can verify that the correct tape is mounted. When a dataset overflows a tape, the catalog can decide which tape to use next, and can again verify that the correct tape is mounted. When a request for an input dataset is made, the catalog knows which tapes belong to the dataset, and can verify that the correct tapes are mounted in the correct order.

Getting Started The first step in using the Advance tape catalog is to create some labeled tapes. The program $PROMAX_HOME/sys/bin/tcat is used for tape labelling, catalog creation and maintenance, and for listing current catalog information. The program is run from the UNIX command line. The following steps are required to successfully access the tape catalog: 1. Label tapes 1. Read and Display tape labels 1. Add labeled tapes to a totally new catalog Before adding the tapes to a new catalog, it is a good idea to visually inspect the contents of the label information file for duplicate or missing entries. The contents typically look like: 0 AAAAAA 0 1 4 1 AAAAAB 0 1 4

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2 AAAAAC 0 1 4 3 AAAAAD 0 1 4 4 AAAAAE 0 1 4 The fields are: volume serial number (digital form), volume serial number (character form), tape rack slot number, site number, and media type, respectively. You can manually edit these fields. 1. Write a label information file from the existing catalog 1. Add labeled tapes (and datasets) to the existing catalog 1. Merge an additional catalog into the existing catalog 2. Delete a dataset from the catalog

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Chapter 2

Flow Building and Execution This chapter is designed to get you started processing with ProMAX. You will learn how to set up a work space with the ProMAX User Interface and subsequently build and execute data processing flows.

Topics covered in this chapter: ❏ Getting Started ❏ Building and Executing a Flow

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Chapter 2: Flow Building and Execution

ProMAX Menu Map

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Getting Started ProMAX is built upon a three level organizational model referred to as Area/Line/Flow. When entering ProMAX for the first time, you will build your own Area/Line/Flow workspace. As you add your own Area, you may want to name it with reference to a geographic area that indicates where the data were collected, such as Onshore Texas, or use your name, such as daves area. Line is a subdirectory of Area which contains a list of 2D lines from an area or a 3D survey name. After choosing a line from the Line menu or adding a new line, the Flow window will appear. Name your flows according to the processing taking place, such as brute stack. Look at the Menu Map figure on the previous page. This figure refers to other menus you can use to access your datasets, database entries and parameter tables. These features will be discussed later.

Exercise In this exercise, you will build a workspace and look at some of the available options. Initiating a ProMAX session can be done in a variety of ways. Typically your system administrator will create a start-up script or make a UNIX alias, and set certain variables within your shell start-up script to make this easy. This topic is discussed in the system overview chapter. 1. Type promax. A product name window should pop up followed by the Area window. The window, as shown below displays a list of all available Areas. Other information is listed, such as owner, date and UNIX name.

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Global Commands

Area Menu

Mouse Button Help

Configuration Options

Processing Queues Window Exit Promax Job Notification and Control

The black horizontal band below the menu is called mouse button helps. Mouse button helps describe the possible actions at the current location of the cursor. Below the mouse button helps are options to Exit ProMAX, configure the queues and user interface, as well as check on the status of jobs. These options will be discussed at length later. The list of options running across the top of this menu: Select, Add, Delete, Rename, and Permission are called global options. To use these, you must first click on the option followed by clicking the line on your screen with your Area name. The Copy option works differently by providing popup menus to choose Areas not displayed in this window.

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2. Click on Add from the Area Menu with MB1. At this point you are building your work space. Adding an Area creates a UNIX directory. 3. Before moving the mouse, enter an Area name You can choose the area name. 4. Press return, or move the mouse to register your selection. The Line Menu appears with the same global options to choose from as the Area Menu. (Pressing return or moving the mouse to register a selection depends on whether the ‘Popups remain after mouse leaves’ option is toggled on or off. This option is listed under the Configuration Options.)

Global Commands

Area Name Available Seismic Lines Active Command

Line Menu

Mouse Button Help

Configuration Options

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Processing Queues Window Exit Promax Job Notification and Control


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5. Add a Line using the same steps as you did for adding an Area. The Flow window appears with the following new global options:

6.

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Datasets: Lists all your datasets for that particular line.

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Database: Allows you to view your Ordered Parameter Files.

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Product: Changes from ProMAX 2D to ProMAX 3D or VSP.

Add a Flow and name it Display Shots.

Global Commands

Available Flows Active Command Access Datasets

Change Products Access Database

Flows Menu

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Building and Executing a Flow Now it is time to process data. In order to perform this task, you will need to tell ProMAX which processes you want to invoke as well as provide specific details for each of these steps. Finally, there are different options available for executing a flow.

Exercise Upon completion of the previous exercise, you are in the ProMAX flow building menu (see below). From here, you will construct your flows by ordering processes and selecting the necessary parameter information. Once the flow is ready, you will execute it and look at the results. 1. Look at the flow building menu.

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The screen is split into two sides: a list of processes on the right and a blank tablet below the global options on the left. You will select from the processes on the right and add them to the left. The list of available processes is very long. This list is ordered from top to bottom into a general processing sequence with I/O processes at the top and poststack migration tools further down on the list. There is a scroll bar to help you look at the list. There are also options available to hide processes in the secondary or More list (use the mouse button helps). You can customize the list to have only the processes you use most often displayed. 2. Move your cursor into different areas of the display, such as into the processes list, the blank tablet and the various options. The mouse button helps are sensitive to the current cursor location. 3. Global Options for flow editing are as follows. •

Add: This is the default. When highlighted in blue, a process can be selected from either the list of processes or a text search menu.

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Delete: When selected with MB1, the highlighted process is removed from the flow. This process is actually stored in a buffer and can be accessed by selecting Delete with MB3. Selecting Delete with MB2 appends a newly deleted process to the existing delete buffer. MB3 is also used to paste the contents of this buffer into the current flow. The memory of the buffer is maintained even after exiting a flow menu, so the contents may be pasted into another flow.

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Execute: When selected, the job is executed. There are two methods available to execute a flow using the Trace Display process: MB1 and MB2 will Execute suppressing pause for display. These options allow the display to immediately take over the monitor when the job has finished running. MB3 indicates Execute via Queue. This option enables the use of the two types of queues. When using MB3, a new menu pops up allowing the use of either the general batch queues or the

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small job batch queues. In order for this option to work your system administrator should have enabled the queues when ProMAX VSP was installed. Note: When using Screen Display, the mouse button helps are correct and MB1 will Execute With Normal Wait on display. When this option is used, the Notification window first shows the job has started and is then waiting for display. By clicking on the Notification window, a new Processing Jobs window appears where it waits for your response. Clicking on Wait for Display, prompts the display to come to the foreground of the monitor. This option is useful if you want to work on something else and do not want to be interrupted by the display taking over the monitor. •

View: Accesses the view (job.output) file. This file includes important job information such as error statements.

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Exit: Brings you back to the menu listing of all your flows.

4. Move your cursor into the Data Input/Output portion of the processes list, and select the process SEG-Y Input with MB1. You have just added your first process to a flow. 5. Move your cursor back into the processes list (but not on a category heading) and type “trace d” and press return. This acts as a text search. Click on Trace Display to add it to the flow. 6. Parameterize the flow. Editing Flow: 00- Display data Add

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SEG-Y Input----------instructor provided MAX traces per ensemble---------------------------------3 ----Default all remaining parameters for this process----

Trace Display Number of ENSEMBLES/screen-----------------------10 ----Default all remaining parameters for this process---7. Select SEG-Y Input parameters.

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Click on SEG-Y Input with MB2 to bring up the parameter selection window. Now you can select the parameters for this process. To get a helpfile for a process, click on the red highlighted question mark. 8. In the SEG-Y Input menu, select the dataset as directed by your instructor. There are 3 traces per shot ensemble in this SEGY dataset. All of the remaining parameters may be defaulted. 9. Select the Trace Display parameters. For now, do not change any of the values except that we want to display 10 ensembles. We will discuss many of the other options in the next chapter. 10. Run the flow by clicking on the global command, Execute. Execution results in a trace display on the screen. Eight icons appear in a column to the left of the traces, and pulldown menus appear above the traces. 11. Click on the page forward icon a few times and watch as we move from one group of shots to the next. 12. You may elect to change the primary annotation from Source to FFID using the VIEW/Trace Annotation pull down menu. 13. Click on File and then Exit/Stop flow in the pulldown menu. This interrupts the job and brings you back to the flow builder.

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Exercise- output a file to disk 1. Using the same flow as before deactivate the Trace Display using MB3 and add in a Disk Data Output at the end of the flow. Editing Flow: 00- Display data Add

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SEG-Y Input >Trace Display< Disk Data Output 2. Add a dataset to the datasets list in the Disk Data Output menu. We will use this dataset in the next few exercises instead of reading the SEGY file again. 3. Execute the flow 4. When complete, go to the datasets list and press MB2 on the file name you just created. You should see a summary print that shows that you have a data set with 80 ensembles and 240 traces.

Exercise- Disk Data Input Sort Options 5. Using the same flow toggle the SEG-Y Input inactive and add a Disk Data Input to the Flow. Editing Flow: 00- Display data Add

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>SEG-Y Input< Disk Data Input Trace read option-------------------------------------------------Sort Select primary trace header entry------------------------FFID Sort order list for dataset--------------------------------1-80(2)/

Trace Display Primary trace LABELING header entry-----------------FFID

>Disk Data Output<

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6. Toggle the Trace Display active and the Disk Data Output inactive using MB3. 7. Select new Disk Data Input parameters. Your first look at the executed job was all of the shots with all channels. After clicking the Page Forward icon, you saw the next set of shots. What if you wanted to look at a every other shot? What if you only wanted to look at a single channel for each shot? These options, and many more, are available in Disk Data Input. 8. Click on the Get All for Trace Read Option. This toggles to Sort and the menu will automatically add three new options: •

Select Primary trace header entry: Allows you to resort to another domain, such as CDP, or remain in the same sort order, which sets you up for trace limiting.

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Select Secondary trace header entry: Same as above.

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Sort order for dataset: Allows you to restrict the amount of data brought into the flow, such as channels 1-60.

Let’s try one. 9. Set the Primary trace header entry to FFID (Field file ID number) 10. Click on Sort order for dataset. An Emacs Widget Window appears for specifying input traces. A format and example are given at the bottom of this window. Emacs Help is discussed later in the training class. 11. In the Widget Window delete existing values and type 1-80 (2) /. 12. Move your cursor out of the Widget Window. 13. Click on Execute. You will see FFID’s 1- 19 by 2. 14. You may want to change the primary trace annotation again to FFID instead of SOURCE using the pull down menu.

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15. Click on the Page Forward icon. This will be Live Source Numbers 21-39 by 2. When the last available data is displayed, the Page Forward triangle becomes grayed out and is inactive. To exit this display, click on File and choose Exit/Stop Flow. Lets make the exercise a little bit more complicated and try to display all the shots but only with channel 1. 16. Select the parameters for Disk Data Input. . Editing Flow: 00- Display data Add

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>SEG-Y Input< Disk Data Input Trace read option-------------------------------------------------Sort Select primary trace header entry----------------------CHAN Select secondary trace header entry-------------------FFID Sort order list for dataset--------------------------------1:*/

Trace Display Primary trace LABELING header entry--------------CHAN Secondary trace LABELING header entry-------------FFID >Disk Data Output< Choose CHAN from the popup menu for primary trace header entry and FFID for secondary. 17. Change the Sort order for dataset to 1:*. This format specifies to build ensembles of recording channel number and have the traces within this ensemble ordered by FFID. Check the formats and examples for hints. 18. Execute the flow. You will only see the trace from channel 1 for all the shots displayed as a single ensemble

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In this case you may elect to set the primary annotation to CHAN and the secondary to FFID. This is a typical sort type for VSP data. 19. Select to Exit/Stop the flow.

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Chapter 3

Interactivity of Trace Display Trace Display provides general trace display and analysis capabilities. In addition, it allows for interactive definition of parameter tables. Interaction with the data is accomplished using a series of icons and pulldown menus presented upon execution of a flow with Trace Display. Icon or menu choice allow you the ability to: •

Obtain information about the traces in the display window.

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Modify the presentation.

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Define processing parameter information.

Topics to be covered in this chapter: ❏ Trace Display ❏ Create and Apply a Parameter Table

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Chapter 3: Interactivity of Trace Display

Trace Display When you execute your job, the following display appears: Trace Display Window Icon Bar

Active Icon

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Menu Bar

Mouse Help


Trace Header Plot

Data Display

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Icon Bar The following is a brief description of the Trace Display icons, located along the side border:

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Next ensemble: Show the next ensemble. When there is no more data in the flow, the icon will turn gray and become inactive. In ProMax, an ensemble is a collection of traces, such as a shot record or CDP gather. Each ensemble is flagged with an end of ensemble mark in the trace header (END_ENS).

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Previous ensemble: Show the previous ensemble. When at the beginning of the flow, this icon is gray and inactive.

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Rewind: Return to the first ensemble.

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Save Image: Save the current screen image. Annotation and picked events are saved with the trace data.

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Animation: Brings up the Animation dialog box to review the saved images. This button is active only when there are at least two saved screen images. You have the option to cycle through the selected screens at a chosen rate. These are just screen images, you cannot edit parameter files using the saved image.

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Paintbrush: Allows you to "paint" trace kills, reversals and mutes interactively on the screen after they have been picked.

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Zoom Tool: Click and drag using MB1 to select an area to zoom. If you release MB1 outside the window, the zoom operation is canceled. If you just click MB1 without dragging, this tool will unzoom. You can use the zoom tool in the axis area to zoom in one direction only.

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Velocity Tool: Displays linear or hyperbolic velocities. For a linear velocity, click MB1 at one end of a waveform and drag the red vector out along the event. A velocity is displayed at the bottom of the screen. Use MB2 to display a hyperbolic velocity by anchoring the cursor at the approximate zero offset position of the displayed shot or CDP. Drag the red line along the event and read the velocity at the bottom. New events can be measured with either velocity option by reclicking the mouse on a new reflector and re-anchoring ProMAX VSP User Traiining Manual

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the starting point. Velocities can be labeled by using MB3 on the current velocity. Geometry must be assigned to successfully use this icon. •

Header Tool: Displays detailed information about trace headers and their values for each individual trace. Click MB1 on any trace to call up the header template. If the header template is in the way of the traces being viewed, you can move the template by dragging the window. To remove the template click on the header icon or on any other icon.

•

Annotation Tool: When active you can add, change, and delete text annotation in the trace and header plot areas. The pointer changes to a circle when it is over text annotation. You can move an annotation by clicking and dragging MB1, or add new annotation by clicking MB1 when the pointer is not over an existing annotation. When the pointer is over an existing annotation, click MB2 to delete the text or MB3 to edit the text or change its color.

Menu bar

File has five options available in a pulldown menu. You can save your picks, move to the next screen, make a hardcopy plot or exit Trace Display. You have two choices when you exit. You can exit and stop the flow, or you can exit and let the flow continue without Trace Display. Note: Use caution when using the stop option. For example, you use Disk Data Input to read in ten ensembles with a Disk Data Output and a Trace Display. If you execute this flow and use the Exit/Stop Flow option after clicking through the first five ensembles, then you will actually output five ensembles in the output dataset as opposed to writing out ten ensembles. View has five options in a pulldown menu. You can control the trace display, the trace scaling, and trace annotation parameters. You can also choose to plot a trace header above the trace display and edit the color map used for color displays.

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Animation saves screens, or displays previously saved screens in any order and different swap speeds .

Picking for Parameter Tables Picking inputs values into one or more of the parameter tables. You can store the primary and secondary header values into a kill trace or reverse trace table. You can pick any kind of mute, horizons, gates, or autostatics horizons. You can also edit database or header values.

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For example, to create a parameter table file with a list of traces to kill, click on Picking and a menu of parameter table choices appears. Click on Kill traces. Another window appears for selecting a previous kill parameter file or creating a new file.

When you create a new file, another window appears listing trace headers to choose from for a secondary key.

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In this case, an appropriate key for killing traces would be CHAN, allowing selection of each individual trace within each shot record. Depending upon the parameter table you are using, the most appropriate secondary header should appear at the top of the list. At this time a Picking Tool icon will appear on the side of the Trace Display screen below the other icons. •

Picking Tool: This appears when one or more pick objects from the Picking menu are selected. A small window with the file name will appear on the right hand side of the screen. This means the file is open and ready to be filled with the primary and secondary key values of killed traces. When active, click on MB1 to pick a point on a trace or click and drag to pick a range of traces. When the mouse is over a picked point, the pointer shape changes into a circle. Click and drag using MB1 to move a picked point. Use MB2 to click on a single point to delete it, or click and drag over a range of points to delete them. Click MB3 for additional picking options. Holding MB1 down and dragging it across several traces allows for a consecutive number of traces to be added. To select traces from the next shot use the Traffic light icon. The created Kill traces file remains open and waiting for more traces to be added to the file.

To create a new parameter table such as a reverse traces file, use the Pick icon again and select Reverse traces from the menu. After creating a new file with a new name, choose a secondary key of CHAN. The new file name appears in the small window on the right hand side of the screen below the kill traces file name. The kill traces file is no longer highlighted, meaning that it is inactive and the reverse traces file is highlighted. If you have chosen traces to kill and reverse on the screen, the active parameter file will have the chosen traces overplotted with a red line. The traces chosen for the inactive table(s) will be overplotted in blue. This helps you distinguish which file is active and which file is inactive. Traces are only added to the active file. Select or delete traces in the same manner using the mouse button helps at the bottom. To go back to adding to the kill traces file, click on the kill file and use MB1 to toggle that file to active. The reverse traces file table is no longer highlighted in black and any reverse traces picked on the screen are overplotted in blue. Some parameters require a top and a bottom pick, such as a surgical mute. Once you have picked the top of the mute zone, click MB3 anywhere inside the trace portion of Trace Display. A new menu appears allowing you to pick an associated layer (New Layer). You can also snap your pick to the nearest amplitude peak, trough or zero crossing.

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Miscellaneous time gates are parameter tables used for such procedures as picking a window for a deconvolution operator design gate or windows for time variant filtering or scaling. For this exercise pick a decon design gate with a secondary key of AOFFSET. Picking a miscellaneous time gate is also done in two steps. First, pick the top of the gate by selecting points to be connected with MB1. Because AOFFSET is the secondary key, the picks at the corresponding offset on the opposite side of the shot will be displayed if you click MB3 in the display field and choose Project from the popup menu. Then use MB3 to select an associated layer for the bottom half of the gate. In order to pick another time gate, below or overlapping the previous, continue to use MB3 to pick tops and bottoms. Time gates must always be picked in pairs, otherwise your job may fail. Each time gate pair is also shown in the legend box.

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Create and Apply a Parameter Table Parameter tables are generated when you interactively define lists or tables of information. These files are stored in binary format and are intended for use in subsequent processing flows. Interactivity of Trace Display allows you to generate files, such as first break mutes, decon design time gates, lists for zeroing or reversing traces in a record. You make a parameter selection while viewing the data.

Exercise This exercise describes the way to pick a top mute. Other parameter tables may be picked in the same fashion. Trace kills, trace reversals and miscellaneous time gates were discussed in the previous section. 1. Build this flow: Editing Flow: 01- Pick Parameter Tables Add

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Disk Data Input Automatic Gain Control Trace Display Number of ENSEMBLES(line segments)/screen--------80 Primary trace LABELING header entry-----------------FFID‘

2. Read the file we created in the last exercise. This file should exist in your own line. 3. Insert an Automatic Gain Control process for cosmetics. 4. Parameterize Trace Display to display 80 ensembles per screen. This VSP data has 3 traces per shot and there are a total of 80 shots in this project. 5. Set the primary annotation to be FFID instead of SOURCE. 6. Click on Execute.

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The interactive Trace Display window appears. 7. Click the Picking pulldown menu and choose Pick Top Mute. Since you have not previously created a top mute table, enter a new table name called Top Mute. A select Secondary key window appears. 8. For this dataset, select FFID for the trace header entry. The mute times that you pick will be interpolated as a function of FFID. This is a relatively unique relationship for VSP data that differs from surface seismic. 9. Pick a mute. Turn on the Picking tool icon and pick a top mute to remove the energy above the first arrivals. Select only a few traces on the record because points will be connected and interpolated as well as extrapolated. Click MB3 in the display field and choose Project from the popup menu to display the picks at the intermediate FFIDS that were not explicitly picked. NOTE: all of the traces at the same FFID will get "X"’ed as the project interpolates the points. You may also elect to press the "Paintbrush" icon and interactively apply the mute on the display. 10. Exit and Stop the flow. To exit, click on File pulldown menu and select Exit/Stop Flow. If you choose to exit, you are prompted to save or not save the work you have completed. Save this mute so that we can re-apply it via the Trace Muting Process.

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11. Edit your previous flow by inserting Trace Muting. Editing Flow: Display Gathers Add

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Disk Data Input Trace Muting Type of Mute:------------------------------------------------------- Top SELECT mute parameter file: --------Your mute file name

Automatic Gain Control Trace Display 12. Click on Invalid to select the type of mute to apply (Top) and the mute parameter file (Top Mute). In ProMAX, each type of parameter table has its own separate list, such as mute tables, kill trace tables, velocity tables. When selecting the mute parameter file, you are taken to a list of parameter files for Mute Gates. 13. Click on Execute. Notice the effect Trace Muting has on your data. Also, be aware that this effect is not permanent since you have not created a new disk data file with Disk Data Output.

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Chapter 4

Parameter Selection and Analysis ProMAX contains a suite of processing modules which provide the user with convenient, yet flexible parameter testing and data analysis capabilities. The modules developed to facilitate parameter selection are found in the process list category called Flow Control. Parameter testing is broken down by type: manual and automatic. Manual parameter testing refers to the use of IF-ELSEIF-ENDIF conditional processing sequences to define a particular test scenario, whereas automatic parameter testing refers to using the Parameter Test module.

Topics covered in this chapter: ❏ Parameter Test ❏ IF/ENDIF Conditional Processing ❏ Interactive Spectral Analysis

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Chapter 4: Parameter Selection and Analysis

Parameter Test The Parameter Test process provides a mechanism for testing simple numeric parameters by creating multiple copies of input traces and replacing a key parameter in the next process in the flow with specified test values. It automatically expands the processing flow, creating IF conditional branches for each test value. The output consists of copies of the input data with a different test value applied to each copy. Parameter Test creates two header words. The first is called REPEAT. This is the data copy number and is used to distinguish each of the identical copies of input data. The second is called PARMTEST and is an ASCII string, uniquely interpreted by the Trace Display processes as a label for the traces.

Exercise In this exercise, you will use Parameter Test to compare shot gathers with different AGC operator lengths. 1. Build the following flow: Editing Flow: 02- Parameter Test Example Add

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Disk Data Input Select primary trace header entry----------------------CHAN Select secondary trace header entry---------------------FFID Sort order list for dataset -------------------CHAN:FFID 1:*/

Parameter Test Enter Parameter Values: ---------------------250|500|1000 Trace Grouping to Reproduce: ----------------------Ensemble

Automatic Gain Control AGC operator length: ----------------------------------------99999

Trace Display 2. Read the file that we wrote to your line after reading the SEGY file. Sort the input to have a primary sort order of CHAN and a secondary of FFID. Get channel 1 only for all FFID’s

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3. Specify Parameter Test test values. Type in a list of parameter values for AGC operator lengths, each separated by a vertical bar ( | ). To determine the format (real, integer, sequence) and a realistic range of test values, look at the default value in the AGC process, in this example the AGC operator length. (Try values of 250, 500 and 1000 ms.). We will reproduce by ensembles. 4. Replace the AGC operator length default value with five nines (99999). 99999 is a flag telling Parameter Test which parameter you are testing. 5. Use Trace Display to present the results from the test to the screen. We will have 3 original ensembles each copied 4 times. This gives a total of 12 ensembles. 6. Execute the flow. After the Trace Display appears, you can use the zooming and scrolling capabilities to move through the ensembles. 7. Exit and Stop the flow. 8. Select View from the flow builder menu to look at the processes that were executed in your flow. Near the bottom of the job.output file is a listing of the executed processes as shown below. There are some additional processes in the flow and Parameter Test is absent because Parameter Test is a macro, built from other processes. DISKREAD2 REPEAT FLOW_IF AGC THDRMATH FLOW_ELSEIF

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Chapter 4: Parameter Selection and Analysis AGC THDRMATH FLOW_ELSEIF AGC THDRMATH FLOW_ELSEIF THDRMATH FLOW_ENDIF ST_TRACE_DISPLAY

In the next exercise we will build a flow similar to this manually to see how these components communicate with one another.

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IF/ENDIF Conditional Processing Automatic parameter testing is not always an option. It can only be used when the testing parameter is a simple numeric value, such as the automatic gain control operator length, or a sequence of numerics, as in the case of corner frequencies used to define a bandpass filter. When your testing requires evaluating multi-level tests, or comparing nonnumeric parameters, such as a fan filter option instead of a polygon filter option in FK Filter, then manual testing must be used. In order to manually test parameters you must: •

generate multiple copies of the data

•

split or branch your processing stream so that each copy of the data may be processed with different parameters.

One method of generating multiple data copies is to use the Reproduce Traces process. This process is included in the Parameter Test macro. Reproduce Traces generates a specified total number of copies and appends a header word to each trace, allowing you to distinguish between the multiple versions of data. This header word is known as Repeated Data Copy Number or REPEAT for short. It is a numeric value from 1-N, where N is the total number of generated copies. You should consider placing Reproduce Traces after any processing which is common to all copies of the data, but prior to the processes you wish to compare. Splitting or branching the flow is a conceptual term for controlling the processes your dataset utilizes. In other words, you do not actually break up any single flow into separate flows, rather utilize the capability of the IF, ELSEIF, and ENDIF processes to select and direct traces for processing. This is handled automatically by the Parameter Test process, as you saw if you looked at the View information when you executed the previous flow. More specifically, each copy of the data is passed to a different process, or the same process with different parameter selection using a series of IF, ELSEIF and ELSE processes in the flow. For example, if the data copy number (REPEAT) is 1, then pass that copy of the data to the next process. If the data copy number is 2, pass that copy to a different process, and so on until all copies of the data have been passed to unique processes. The series of conditions is ended with ENDIF. Landmark


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Finally, you may use a process called Trace Display Label to generate a header word for posting a label on the display.

Exercise Incorporate Reproduce Traces with IF and ENDIF to compare processed and unprocessed data. In this exercise, we will compare the first shot of the AGC dataset to a version with true amplitude recovery. It is always a good idea to have a control copy, the original input, for further comparison. This flow illustrates how to compare these three copies. 1. Build the following flow: Editing Flow: 03 - IF/ELSEIF Conditional Add

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Disk Data Input Select primary trace header entry----------------------CHAN Select secondary trace header entry---------------------FFID Sort order list for dataset -------------------CHAN:FFID 1:*/

Reproduce Traces Trace grouping to reproduce: ----------------------Ensembles Total Number of datasets: ----------------------------------------3

IF SELECT Primary trace header word:-----------------Repeat SPECIFY trace list:----------------------------------------------------1

Automatic Gain Control Trace Display Label:-------------- AGC ELSEIF SELECT Primary trace header word:-----------------Repeat SPECIFY trace list:----------------------------------------------------2

Trace Equalization Trace Display Label:--------------- EQ ELSE Trace Display Label:-------- Original Input ENDIF Trace Display 2. Read the file that we wrote to your line after reading the SEGY file.

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Sort the input to have a primary sort order of CHAN and a secondary of FFID. Get channel 1 only for all FFID’s 3. In Reproduce Traces, enter 3 for the total number of datasets. You will generate two additional copies, one ensemble (record) at a time. 4. Select Repeat for Select Primary trace header word in IF and ELSEIF. IF acts as the gate keeper, providing the mechanism for selecting or restricting traces which will be passed into a particular branch of the flow. Header words are used (just as in Disk Data Input) to uniquely identify the traces to include or exclude in a particular branch. In the first IF conditional, select REPEAT as the primary trace header and 1 (copy number) as the trace list entry. Data copy 1 is passed to AGC in this example. The ELSEIF condition passes the second data copy number (REPEAT=2) to Trace Equalization. The ELSE process selects all traces, not previously selected with IF or ELSEIF. In our case, having selected two of the three copies of data for filtering, leaves only the third data copy (REPEAT=3) for the ELSE branch. In this example, no additional processing is applied to this copy. It is the control copy. 5. Use Trace Display Label to create labels for each copy. Label the copies according to their unique processing. For example, label the first copy with AGC, the second with EQ and the final copy with Original Input. 6. Select to use a hand input design gate for the Trace Equalization and use the default parameters. 7. Modify Trace Display to do each of the following in two different executions:

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•

each copy on different screens and use screen swapping

•

all records on same screen.


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Interactive Spectral Analysis Interactive Spectral Analysis computes and displays power, phase and F-X spectra estimates for interactively selected subsets of traces. These displays can be configured both interactively and from the ProMAX menu. There are three modes of data selection: •

Simple Selection: Analyzes only the displayed traces. During the interactive session you may analyze new traces by choosing Next Data from the Data menu.

•

Single Subset Selection: Enables you to interactively select a rectangular subset of the data for spectral displays. The spectral displays are automatically updated for each new rectangle selection.

•

Multiple Subset Selection: Displays at least two windows: a Data Selection Window and one or more Spectral Analysis windows. Subsets for Spectral Analysis are chosen from the Data Selection Window, using the selection tool from the toolbox. A Spectral Analysis window for the current selection is made by selecting Spectral Analysis from the Data Analysis menu. By default, the Spectral Analysis window updates itself for each new selection. You can freeze the subset in the Spectral Analysis window so that it does not update with new selections. This allows spectra from different subsets to be compared.

Exercise In this exercise you will run Interactive Spectral Analysis in the simple mode.

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1. Build this flow. Editing Flow: interactive spectral analysis Add

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Disk Data Input Select primary trace header entry----------------------CHAN Select secondary trace header entry---------------------FFID Sort order list for dataset ------------------------------------ 1:*/

Automatic Gain Control Interactive Spectral Analysis Data selection method?:------------------------------------Simple Display data by traces or ensembles?:--------Ensembles Number of ensembles per analysis location?:-------------1 Primary header for sorting and trace label?:-------CHAN Secondary header for sorting and trace label?:-----FFID 2. Read the file that we wrote to your line after reading the SEGY file. Sort the input to have a primary sort order of CHAN and a secondary of FFID. This yields only channel 1 for all FFID’s. 3. Select Interactive Spectral Analysis parameters. Select the Simple mode and bring in traces by ensemble. Select to process 1 ensemble per analysis location Also set the primary annotation to Recording Channel Number and the secondary annotation to FFID so that the traces do not overlay one another. 4. Click on Execute. A Simple Spectral Analysis window appears, displaying your data in T-X, F-X representation, power and phase spectra. Now we will look at the choices available across the top of the menu: File, Data, Options and Window. 5. Select View/Visibility and select Data window.

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There are many different displays that you can interactively turn on and off. Remember that you have control of your display when you are selecting parameters. 6. Select Options/PreFFT Time Window, and turn on the Boxcar. You have a lot of control from within the interactive session to modify your analysis. 7. Activate the Zoom icon to enlarge the trace data. In this case, your F-X spectrum is zoomed as well. 8. From the File pull down select to Exit and Stop the flow.

Exercise 1. Rerun the flow after changing to Single Subset mode. Editing Flow: interactive spectral analysis Add

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Disk Data Input Select primary trace header entry----------------------CHAN Select secondary trace header entry---------------------FFID Sort order list for dataset ------------------------------------ 1:*/

Automatic Gain Control Interactive Spectral Analysis Data selection method?:-------------------------Single Subset DIsplay data by traces or ensembles?:--------Ensembles Number of ensembles per analysis location?:-------------1 Primary header for sorting and trace label?:-------CHAN Secondary header for sorting and trace label?:-----FFID

2. Click on the Select Rectangular Region icon to window the data on the leftmost (large) shot display. 3. Select a range of data from the left hand window over which to do the analysis. Use MB1 to start the rectangle and MB1 again to end the window.

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Now the trace data in the top middle of the screen is the subset of data you just defined with the corresponding spectra also displayed. 4. Click on the Select Rectangular Region again. 5. Click MB2 inside the zoom window on the left data display window to drag the box to another location and click MB2 again to redisplay the zoom window. 6. Try resizing the selection window with the other mouse button options. 7. From the File pulldown select to Exit and Stop the flow.

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Exercise 1. Rerun the flow after changing to the Multiple Subset mode. Editing Flow: interactive spectral analysis Add

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Disk Data Input Automatic Gain Control Interactive Spectral Analysis Your 80 traces will appear in a window. You may find that iconifying the ProMAX User Interface makes it easier for you to manage the windows you create in this session. 2. Activate the Select Rectangular Region icon to window the data on display. Choose an analysis region by drawing a rectangle beginning and ending with MB1 clicks. 3. Select Analysis Options and then Spectral Analysis. This produces a Spectral Analysis window. 4. Choose another window on the data display. This changes what is displayed in the Spectral Analysis window. 5. Select Data and Freeze selection from within the Spectral Analysis window. 6. Choose a new window on the data display and select Analysis Options and Spectral Analysis. This will use your last rectangular region to create a second Spectral Analysis window. This capability enables you to compare spectra from different windows. 7. From the File pulldown select to Exit and Stop the flow.

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Chapter 5

Real Dataset Information Most of the exercises in this manual will use a real dataset. This dataset has already been vertically stacked so that there is only 1 shot for each depth position. The following information provides you with the needed information to build the geometry spreadsheet and database, and prepare the job flows in the exercises.

Topics covered in this chapter: ❏ VSP Real Dataset Geometry

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Chapter 5: Real Dataset Information

VSP Real Dataset Geometry Source type: Vibrator Number of Sweeps per receiver location: 1 Number of Receivers: 1 Number of components: 3 •

channel 1: vertical component

•

channel 2: primary horizontal

•

channel 3: secondary horizontal

Number of recording levels: 80 Depth of first record: 12100 ft. Depth of last record: 8150 ft. Depth increment: 50 ft. Source offset from hole: 500 ft. The bore hole is vertical with no deviation Source elevation: 0 ft. Datum elevation: 0 ft. Assume the Kelly Bushing is also at 0 ft. for simplicity Source is at station 1 Receivers are at stations 2-81

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Geometry Diagram

source location 500 ft east of the well

surface elevation and Kelly Bushing elevation = 0 ft

8150 ft

recording level increment = 50 ft

1 2 each level has a three component recording tool 3

12100 ft

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Chapter 6

View Input Data This is our first look at the input data. There are 80 FFIDs, each consisting of 3 channels. Channel 1 is the vertical trace, channels 2 and 3 are the two horizontal traces situated orthogonal to one another. The traces are approximately 3400 ms in length.

Topics covered in this chapter: ❏ Display the Input Data ❏ Write Dataset To Disk in Your Area

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Chapter 6: View Input Data

Display the Input Data Exercise In this exercise we will simply view the traces and look at the trace headers to familiarize ourselves with the data. 1. Build the following flow to look at the input data and trace headers: Editing Flow: display the input data Add

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SEGY Input Type of storage to use: ----------------------------- Disk Image Enter DISK file path name: ----------------------------------------------------------------------/misc_files/vsp/vsp_segy MAX traces per ensemble: ----------------------------------------3 Remap SEGY header values -----------------------------------No

Automatic Gain Control Trace Display Number of ENSEMBLES /screen -----------------------------80 Primary trace LABELING ------------------------------------ FFID Secondary trace LABELING ------------------------------- Chan 2. You will read a SEGY file as described by the instructor. Read all available traces. There are 3 traces per shot ensemble and 80 ensembles. 3. Apply an AGC scaler for cosmetics. 4. Display the data and view the trace headers. Set the Trace Display to plot 80 ensembles and annotate each FFID and channel. Which trace headers have values?

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Write Dataset To Disk in Your Area Exercise 1. Expand the previous flow to write the dataset to disk in your own area for future processing. Editing Flow: display the input data Add

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SEGY Input Type of storage to use: ----------------------------- Disk Image Enter DISK file path name: ----------------------------------------------------------------------/misc_files/vsp/vsp_segy MAX traces per ensemble: ----------------------------------------3 Remap SEGY header values -----------------------------------No

>Automatic Gain Control< >Trace Display< Disk Data Output Output Dataset -------------------------------shots - input data 2. Write the file to disk in your own area. 3. Make sure you toggle the AGC and the Trace Display inactive. 4. After the flow is complete go to the datasets list and press MB2 on the dataset name that you just created. It should have 80 ensembles and a total of 240 traces.

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Chapter 7

VSP Geometry VSP Geometry Assignment takes advantage of the simplicity of the spatial relationship between the source and receiver positions in VSP data. This helps to minimize the input required to describe the geometry. Some VSP data is very complex and incorporates a lot of varied information to describe the geometry. Some holes are deviated (crooked) and you may have inclination and azimuth information at all recorded depth levels. In these cases you may also have two sets of depth information: log depth and vertical depth. The Spreadsheets have been written to handle all such information. Our case is very simple, using a non-deviated hole.

Topics covered in this chapter: ❏ Assign VSP Geometry ❏ Quality Control Plots from the database ❏ Load Geometry to the trace headers

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Chapter 7: VSP Geometry

Assign VSP Geometry In this exercise you will describe the source and receiver coordinate and depth information, define the field recording channel geometry, and describe the shot to receiver group relationships using the spreadsheets.

Exercise 1. Build a flow to Assign VSP Geometry. Editing Flow: Spreadsheet / Geometry Add

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VSP Geometry Spreadsheet* 2. Execute the flow. The following window will appear:

Fill in each of the Borehole, Patterns, and Sources spreadsheets in this order. The Borehole spreadsheet describes the X, Y and Z information of the borehole. The Patterns spreadsheet describes how many channels were recorded and the orientation of these channels. The Sources spreadsheet describes the X, Y and Z information for all of the source locations and relates the recorded FFID information with a given source and spread reference position.

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3. Open the Borehole spreadsheet by clicking on “Borehole” on the main menu. In this case we have a straight, vertical borehole. The log depths are the same as the elevations, except that they are all positive numbers. All x,y values will be defined at 0.0 and 0.0. 4. Define the borehole with two sets of X,Y, and Z coordinates.

5. Exit from the Borehole Spreadsheet. 6. Open the Patterns Spreadsheet by clicking on “Patterns” on the main menu. There is only one pattern for this geometry. The Grp Int column specifies the separation between the specified recording channels in the borehole. The Offset column specifies a shift to apply to the “chan from” channel relative to the depth listed in the sources spreadsheet. In this case we have three channels all at the same depth. You will define the exact depth for the receivers for each shot.

7. Exit from the Patterns Spreadsheet.

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8. Open the Sources Spreadsheet by clicking on “Sources” on the main window. 9. We have a total of 80 shots in this VSP, so the first thing to do is expand the sources spreadsheet to 80 rows. Mark the last card as a block with MB1 and MB2 and then use the edit pull down to insert the required number of cards. 10. Number the Sources and FFIDs starting at 1 and incrementing by 1. 11. All shots are at shot station number 1 and at an elevation of 0.0 ft. 12. X,Y values are defined at 500.0 and 0.0 respectively. 13. All shots use the same pattern (1) and have 3 channels. 14. The pattern reference depths start at 12100 and decrement by 50 ft. for each shot. NOTE: For documentation purposes, the columns have been re-ordered slightly. All additional columns are filled with 0.0

15. Exit from the Sources Spreadsheet The next steps in the geometry definition process are to define the pseudo CDP binning and to finalize the database.

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This is a 3 step process. 16. Open the Bin menu and select to Assign trace geometry by pattern information. 17.

18. With the Assign option selected, click on the OK button. You should see several window related to Assigning VSP geometry based on patterns flash by fairly quickly. The last window will say that the geometry has been successfully assigned. 19. Dismiss the Status window by clicking on OK. 20. Compute the Pseudo Common Depth points. Bin starting at CDP 1, starting at 0.0 ft. and ending at 12100 ft. incrementing by 50 ft. per bin.

21. Click on the OK button. Again you should see several window flash by ending with a window indicating that the binning was completed successfully. 22. Dismiss this window by clicking on the OK button. 23. Finalize the database.

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This step completes building the look up tables and other database finalization functions.

24. Select the Finalize Database option and click on the OK button. You should see a window indicating that the VSP geometry finalization has completed successfully. 25. Dismiss the Status window by clicking on OK. 26. Click on the Cancel button in the binning dialog box to dismiss this window.

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Quality Control Plots using the XDB database tool 2D plot of TRC vs. Receiver elevation and log depth

• used to check depth assigned to each trace 2D plot of SRF vs. elevation

• used to check depth assigned to each receiver station 2D plot of TRC vs. various other values

• used to check additional information for each trace

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Load Geometry to the trace headers Exercise 1. Build the following flow to install the Geometry information into the trace headers: Editing Flow: load geometry to headers Add

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Disk Data Input Select dataset----------------------------------shots - input data Trace Read Option--------------------------------------------Get All

VSP Inline Geom Header Load Primary header to match database --------------------- FFID Secondary header to match database ---------------- None Match by valid trace number?---------------------------------No Verbose Diagnostics?----------------------------------------------No

Trace Header Math Select Mode ------------------------------- Fixed equation mode Define trace header equation ------------- geo_comp=chan

Disk Data Output Output Dataset Filename-------------- “shots - with geom” New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No 2. Input the file that we previously wrote to your own areas after reading the SEGY data. 3. Select VSP Inline Geom Header Load parameters. Since you did not use the Extract Database Files process you must assign the geometry to the trace headers by referencing the FFID and default of recording channel. You do not have valid trace numbers.

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4. Create the GEO_COMP trace header word. In Trace Header Math, create a trace header word called GEO_COMP, which is equivalent to recording channel number. For multi component VSP processing we need to be able to distinguish between the vertical and two horizontal components by a geophone component header word. Component 1 is the vertical trace. Component 2 is the primary horizontal and component 3 is the other horizontal. By convention horizontal 2 is 90 degrees clockwise from horizontal 1 looking from the top. 5. In Disk Data Output, output a new file. Since there are no valid trace numbers, we cannot do trace header only processing in an overwrite mode.

Exercise This exercise QCs the headers. 1. Build a new flow to re-read the data and plot it to check the new values in the trace headers Editing Flow: qc geometry load Add

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Disk Data Input Select dataset----------------------------------shots - input data Trace Read Option--------------------------------------------Get All

Trace Display Number of ENSEMBLES per screen --------------- 80 Primary trace LABELING ------------------------------------ FFID Secondary trace LABELING ----------------------- REC_ELEV INCREMENT for Secondary annotation ------------------- 12 2. Input the traces with the new geometry and check the headers with the Header Dump capabilities in Trace Display. Plot 80 ensembles and annotate each FFID and every 12th receiver elevation. Landmark


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You should see the correct shot X value, and receiver elevation values. . NOTE: The receiver depths go into receiver elevation not receiver depth.

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Chapter 8

Keep Vertical Component Traces Although most VSPs are recorded using multi-component instruments, in the majority of cases only the vertical component traces are actually used. In order to minimize our disk requirements, we only want to keep the traces that we are actually going to process. In this exercise we will run a job that will keep only the vertical traces for further processing. We will keep the original data (with all 3 components) for some other exercises later in the class. A good question to ask here is: “What is the best sort order to build the most efficient ensemble for future processing?”

Topics covered in this chapter: ❏ Create Vertical Component Dataset

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Chapter 8: Keep Vertical Component Traces

Trap Vertical Traces Exercise 1. Build the following flow to keep only the vertical traces. Editing Flow: 03 - trap vertical traces Add

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Disk Data Input Select dataset----------------------------------shots - input data Trace Read Option-------------------------------------------- SORT Interactive Data Access ----------------------------------------- No Select primary trace header ----------------------------- CHAN Select secondary trace header ---------------------------- FFID Select tertiary trace header ------------------------------ NONE Sort order list for dataset ------------------------------------ 1:*/ Presort in memory or on disk? ------------------------ Memory

Trace Length New trace length ----------------------------------------------- 2000

>Disk Data Output< Trace Display Number of ENSEMBLES per screen -------------------------- 1 Primary trace LABELING ---------------------------------- CHAN Secondary trace LABELING ----------------------- REC_ELEV Sort the input data on CHAN/FFID and only keep channel 1 for all of the shots. If we make an ensemble of only channel 1, then we can always default the Trace Display to plot all traces in 1 ensemble instead of having to change it to 80 and worry about ensemble gaps and display label issues. 2. In Trace Length, limit the amount of data to be processed to 2000 ms. 3. Display the resulting dataset and if satisfied, write the output to disk.

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Plot 1 ensemble. You also may want to change the annotation to be CHAN and then Receiver Elevation.

If you are successful, the Trace Display plot should look as follows:

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Output a file with vertical traces only 1. Modify the flow to output a file that contains only the vertical traces. Editing Flow: 03 - trap vertical traces Add

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Disk Data Input Select dataset----------------------------------shots - input data Trace Read Option-------------------------------------------- SORT Interactive Data Access ----------------------------------------- No Select primary trace header ----------------------------- CHAN Select secondary trace header ---------------------------- FFID Select tertiary trace header ------------------------------ NONE Sort order list for dataset ------------------------------------ 1:*/ Presort in memory or on disk? ------------------------ Memory

Trace Length New trace length ----------------------------------------------- 2000

Disk Data Output Output Dataset Filename------------ “vertical traces only” New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No

>Trace Display<

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Chapter 9

First Break Picks on Vertical Traces First Break times are an integral part of the processing of VSP data. In this exercise we will pick the first arrival times on the vertical component traces for use in future processing steps. In the processing of VSP data, first arrival times are used for a variety of different purposes. These times are used to compute velocity functions which are then used by other processes. The first arrival times are also used as flattening statics for wavefield separation. They are also used to convert the VSP data to two way travel time in preparation for Corridor Stack. With all of these uses in mind, it is apparent that the first arrivals must be accurate.

Topics covered in this chapter: ❏ Pick First Breaks

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Chapter 9: First Break Picks on Vertical Traces

Pick First Breaks Exercise In this exercise, we will build a flow to display the vertical traces and pick the first arrivals. 1. Build the following flow:. Editing Flow: pick first arrivals Add

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Disk Data Input Select dataset--------------------------------vertical traces only Trace Read Option--------------------------------------------Get All

Trace Display Number of ENSEMBLES per screen -------------------------- 1 Primary trace LABELING ---------------------------------- CHAN Secondary trace LABELING ----------------------- REC_ELEV INCREMENT for Secondary annotation ------------------- 12 2. In Disk Data Input, input the previously created file containing the vertical trace. This file is one ensemble of all traces from channel 1 3. In Trace Display, plot 1 ensemble. You may also want to set the annotation heading to be CHAN on the first line and then plot every 12th receiver elevation on the second. 4. Execute the Flow. 5. Select the Picking pulldown menu, and choose to edit the first arrivals in the database. You will be prompted to select a type of attribute. You will write these first break times to an attribute of type GEOMETRY in the TRC database called FB_PICK.

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6. The Pick editing icon on the left side of the plot will automatically be selected for you. 7. Pick the arrivals with the rubber-band and then snap to the desired phase with MB3. It is suggested to pick the first strong, continuous peak. 8. Edit any picks as you see fit. 9. Exit the program to save the picks to the database.

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QC the First Breaks in the Database using XDB 1. Click on Database in the flow menu. From the resulting DBTools dialog, click on the Database pulldown and select XDB Database Display. Plot the first arrival times from the TRC database and edit any bad picks. Reposition any picks that appear out of line and then save the edited picks back to the database. This is accomplished using the Database/ Save buttons. Be sure not to move the pick off of the selected trace. 2. If you want, you can re-execute the pick job and then replot the edited picks on the traces for further QC.

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Chapter 10

VSP Velocity Functions VSP datasets can provide additional velocity information to aid in the processing of surface seismic data and provide comparisons with well log information. Additionally, some processes that can be applied to VSP data require some velocity information. VSP data provides a direct measurement of average velocity as a function of depth. The Velocity Manipulation process allows you to generate other types of velocity fields from this average velocity function which in turn permits you to generate VSP-CDP transforms and/or migrations of the VSP data.

Topics covered in this chapter: ❏ Generate Average Velocity vs. Depth ❏ QC using Velocity Viewer/Point Editor ❏ Velocity function manipulation ❏ Velocity function smoothing

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Chapter 10: VSP Velocity Functions

Generate Average Velocity vs. Depth and Smooth The first arrival times are a direct measure of travel time as a function of source to receiver distance. This gives a direct measurement of the average velocity between the source and receiver.

Exercise 1. Build the following flow to compute the average velocity: Editing Flow: generate avg.velocity function Add

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Vel Table From VSP* Specify a datum elevation---------------------------------------- 0 Limit source-receiver horizontal offsets ------------------- No Limit source elevations ------------------------------------------ No Limit receiver elevations ---------------------------------------- No Select output AVERAGE velocity file -------------------------------------------------------------- from raw first break pick times Table overwrite options ---------- Overwrite existing table Time pick Parameter ---------- TRC GEOMETRY FB_PICK

Velocity Viewer / Point Editor* Select the type of field you wish to edit ---------------------------------------------------------- Average Velocity in Depth Do you wish to edit an existing table --------------------- Yes Select the input velocity database entry --------- ---------------------------------------------- from raw first break pick times Do you wish to specify the bounds of the field -------- No Select output velocity database entry ------------------------------------------------------------------------- smoothed version Minimum depth (or time) of velocity field ------------------- 0 Maximum depth (or time) of velocity field ------------------ 0 2. Parameterize Vel Table From VSP.

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Using a reference datum of 0 ft., generate an average velocity vs. depth velocity table. Do not impose any limits. Input the set of first breaks that was picked from the vertical traces and then edited from the database. 3. View the output function using Velocity Viewer/ Point Editor. Select parameters to input the average velocity vs. depth table created from the first arrivals, and output to a new velocity table that is generated by smoothing the computed function over a depth range of 250 ft. (or 5 receiver levels). In the interactive smoothing parameters, set to output a function every 1000 CDPs to ensure that only one function is output. Also set the depth sampling interval to 50 ft. to match the original input sampling interval. The CDP smoothing value can be defaulted and set the depth smoothing level to 250 ft.

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The following diagram shows the difference between the original, or raw average velocity vs. the smoothed version.

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Chapter 11

VSP True Amplitude Recovery VSP data is similar to surface seismic data in that it also suffers from amplitude loss due to spherical divergence and inelastic attenuation. However, one difference is that VSP data generally only travels half of the distance relative to surface data because the data we are interested in is recorded directly above the reflecting horizon. This difference is compensated for in the True Amplitude Recovery process. Spherical divergence requires accurate first arrival times in the header and both the spherical divergence and inelastic attenuation corrections require a velocity function. Therefore, TAR cannot be applied until after the first arrivals have been picked, loaded to the trace headers, and an RMS velocity function has been generated. As an alternative to spherical divergence and dB/sec gain recovery, you may elect to test various time power curves.

Topics covered in this chapter: ❏ RMS Velocity Function generation ❏ True Amplitude recovery tests ❏ Application of True Amplitude Recovery correction.

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Chapter 11: VSP True Amplitude Recovery

True Amplitude Recovery In this exercise, you will test the True Amplitude Recovery process for an appropriate dB/sec correction combined with spherical divergence. The spherical divergence correction requires a velocity function which is generated by converting your average velocity function into an RMS function.

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Compute an RMS Velocity Function 1. Build the following flow. Editing Flow: 06- compute RMS from AVG vel Add

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Velocity Manipulation* Type of velocity table to input ----- Average Vel in Depth Get velocity table from database entry ------------------ Yes Select input velocity database entry --------------------------------------------------from raw first break pick times Combine a second velocity table ---------------------------- No Resample the input velocity table? ------------------------- No Shift or stretch the input velocity table ------------------- No Type of parameter table to output ---------------------------------------------------------------- Stacking (RMS) Velocity Select output velocity database entry ------------------------------------------------------------------- from raw average Spatially resample the velocity table ---------------------- No Output a single average velocity table -------------------- No Smooth velocity field --------------------------------------------- No Vertically resample the output velocity table ----------- No Adjust Output velocity by percentage --------------------- No

Velocity Viewer / Point Editor* Select the type of field you wish to edit ------------------------------------------------------------- Stacking (RMS) Velocity Do you wish to edit an existing table --------------------- Yes Select the input velocity database entry --------- ----------------------------------------------------------------- from raw average Do you wish to specify the bounds of the field -------- No Select output velocity database entry --------------------------------------------------------------------------from raw average Minimum depth (or time) of velocity field ------------------- 0 Maximum depth (or time) of velocity field ------------------ 0

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2. Input the average velocity function that was computed from the first arrival times before smoothing and convert it to an RMS function. You might want to name the output table “from raw average”. 3. Display the output function using the point editor. 4. Rerun the same flow using the smoothed average function that you created earlier. Convert it to an RMS function using the option: from smoothed average. Editing Flow: 06- compute RMS from AVG vel Add

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Velocity Manipulation* Select input velocity database entry ---------------------------------------------------------------------smoothed version Select output velocity database entry ----------------------------------------------------------- from smoothed average

Velocity Viewer / Point Editor* Select the input velocity database entry --------- --------------------------------------------------------- from smoothed average Select output velocity database entry -----------------------------------------------------------------from smoothed average 5. Compare the results and look at the values of the RMS function in the Velocity table editor.

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If you zoom in around a single output point on either plot, you will see that there are actually two points at each time knee separated by only a couple of ms.

From Raw Average ----------- From Smoothed Average Comparison of RMS Velocity Functions

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6. Edit the Velocity Manipulation* menu to vertically resample the output RMS from the smoothed average at a new sample interval of 48 ms. Editing Flow: 06- compute RMS from AVG vel Add

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Velocity Manipulation* Select input velocity database entry ---------------------------------------------------------------------smoothed version Select output velocity database entry ------------------------------------------------------- from smoothed average Spatially resample the velocity table ---------------------- No Output a single average velocity table -------------------- No Smooth velocity field --------------------------------------------- No Vertically resample the output table ----------------- Yes Time step sizes for the output table ------------------- 48 Adjust Output velocity by percentage --------------------- No

Velocity Viewer / Point Editor* Select the type of field you wish to edit ------------------------------------------------------------- Stacking (RMS) Velocity Do you wish to edit an existing table --------------------- Yes Select the input velocity database entry --------- --------------------------------------------------------- from smoothed average Do you wish to specify the bounds of the field -------- No Select output velocity database entry -----------------------------------------------------------------from smoothed average Minimum depth (or time) of velocity field ------------------- 0 Maximum depth (or time) of velocity field ------------------ 0 Input the smoothed average function and output a new table and view the results using the Point editor.

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Test TAR Parameters 1. Build a flow to test various dB/Sec corrections combined with spherical divergence. Editing Flow: 07 - true amp recovery (test) Add

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Database/Header Transfer Direction of transfer -- Load TO trace headers FROM db Number of parameters -------------------------------------------- 1 First database parameter --- TRC GEOMETRY FB_PICK First header entry --------(FB_PICK) First break pick time

Parameter Test Enter parameter VALUES ----------------- 2|4|6|8|10|12 Trace grouping to reproduce ---------------------- Ensembles

VSP True Amplitude Recovery Apply spherical divergence corrections ---------------- YES Basis for spherical divergence -------------------------- 1/dist Apply inelastic attenuation correction --------------------- No Get TAR velocity from database ---------------------------- Yes Should the vel be treated as space variable ------------ No Select the velocity parameter table -------------------------------------------------------------- from smoothed average Apply dB/sec correction --------------------------------------- Yes dB/sec correction constant ------------------------------ 99999 Apply time raised to a power correction ------------------ No APPLY or REMOVE ------------------------------------------- Apply Maximum application time --------------------------------- 2000

Trace Display Number of ENSEMBLES per screen -------------------------- 7 2. Input the file with only the vertical traces and process all traces. Landmark


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3. Transfer the first break times to the trace headers. 4. Produce a comparison of 2,4, 6, 8, 10 and 12 dB/Sec combined with a 1/dist spherical divergence correction. Use the RMS velocity function that you generated from the smoothed average and then resampled to every 48 ms. 5. Parameterize Trace Display for the test panels. We are generating 6 panels plus the control panel, so we will have a total of 7 ensembles. We may also elect to set the minimum time of the display to 500 msec instead of 0 for the comparison to avoid a lot of dead samples at the top of the display. Since we are looking for relative amplitude on these traces, we may find that using entire screen scaling will be a better choice than individual trace scaling. 6. Produce a second set of test panels varying the time power value from 1.4 to 2.2 by .2 and turning off the SPHDIV and dB/sec corrections. You must reset the dB/sec correction back to a single number other than 99999 and don’t forget to reset the number of ensembles to display in Trace Display if you are using this option.

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7. After selecting a set of TAR parameters (suggested SPHDIV and 6 dB/sec to 2000 ms), process the traces and output a new data file with TAR applied. Editing Flow: 07 - true amp recovery (test) Add

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Database/Header Transfer Direction of transfer -- Load TO trace headers FROM db Number of parameters -------------------------------------------- 1 First database parameter --- TRC GEOMETRY FB_PICK First header entry --------(FB_PICK) First break pick time

>Parameter Test< VSP True Amplitude Recovery Final Selected Parameters

Trace Display Label Trace Label --------------------------- vertical traces with TAR

Disk Data Output Output Dataset Filename-------- vertical traces with TAR New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No

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Chapter 12

VSP Wave Field Separation Corridor Stacks, VSP-CDP transforms and/or migrations are the final products from most VSP processing exercises. These products usually consist of only upgoing reflected energy. The downgoing energy must be removed from the total wavefield to uncover the reflected energy. It is also necessary to isolate the downgoing energy to aid in the deconvolution process. There are three basic techniques available to separate the downgoing and upgoing wavefields from the total wave field. These are Median, FK and Eigenvector Filters.

Topics covered in this chapter: ❏ Flattening the downgoing using the first arrivals ❏ Wavefield Separation using a Median Filter ❏ Wavefield Separation using an F-K filter ❏ Wavefield Separation using an EigenVector Filter. ❏ Wavefield Separation Test Comparisons ❏ Saving the Upgoing to Disk ❏ Saving the Downgoing to Disk

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Chapter 12: VSP Wave Field Separation

Flatten the Downgoing with F-B Picks Wavefield separation requires flattening on the downgoing energy. This is accomplished by applying first arrival times as static values followed by some trim statics. Therefore, as a prerequisite to wavefield separation, first arrival times must be in the database and in the trace headers.

Exercise 1. Build the following flow to apply the first break pick times as a static to flatten the down going energy. Editing Flow: 08- wavefield separation Add

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Disk Data Input Select dataset-------------------------vertical traces with TAR Trace Read Option--------------------------------------------Get All

Header Statics Bulk shift Static -------------------------------------------------- 100 What about previous statics ---- Add to previous statics Apply how many static header entries --------------------- 1 First header word to apply --------------------------- FB_PICK How to apply header statics ------------------------- Subtract

Apply Fractional Statics Trace Display 2. Input the file containing only the vertical component traces after tar has been applied and process all traces. Remember that we transferred the first arrival times from the database to the headers prior to applying True Amplitude Recovery. 3. Select Header Statics parameters. Apply a positive 100 ms Bulk Shift to all the traces and Subtract the first arrival time from the trace header as a static.

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4. In Apply Fractional Statics, apply the non-sample period portion of the static. 5. Plot the output traces on the screen and check to see that the first arrivals are approximately flat at about 100 ms. Set the maximum time of the display to 500 msec.

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Flatten with F-B Picks and Event Alignment Because the first arrival pick times can be somewhat contaminated by noise, we can estimate trim statics via a cross correlation technique and apply them for additional flattening. 1. Expand the previous flow to add one iteration of event alignment. Editing Flow: 08- wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics -----------Event Alignment in Window Maximum allowable static shift ----------------------------- 10 Allowable percentage of hard zeros ------------------------ 55 Method of building model trace ------------ Selective Stack Ignore end of ensembles? ------------------------------------- Yes Seek and report reversed traces ---------------------------- No Accumulate statics in TOT_ALIN ---------------------------- No Get analysis window parms from Database? --------- No SELECT Primary header word ---------------------------- FFID SELECT secondary header word ---------------------- NONE SPECIFY window analysis parameters ------ 1:50-150/

Header Statics Bulk shift Static ------------------------------------------------------ 0 What about previous statics ---- Add to previous statics Apply how many static header entries --------------------- 1 First header word to apply ------------------------------alinstat How to apply header statics -------------------------------- Add

Apply Fractional Statics -----------Trace Display 2. Select Event Alignment in a Window parameters.

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Use a 55 trace Selective Stack model, ignoring end of ensemble issues to estimate static shifts up to 10 ms on a Hand Input window 100 ms wide centered on the first breaks [1:50-150/]. Use a primary header word of FFID with no secondary header. 3. Read the Event Alignment helpfile to find the name of the attribute to apply in Header Statics and also how to set the yes/no switch for Accumulate Statics in TOT_ALIN. Set to No for this flow. 4. In Header Statics, ADD a user defined attribute called ALINSTAT to any previous statics and apply any remaining fractional statics. 5. Plot the output traces on the screen and check to see that the first arrivals are flatter than those from the previous exercise.

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6. Expand the previous flow to add in a second iteration of event alignment. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics -------------Event Alignment in Window Allowable percentage of hard zeros ------------------------ 30 Accumulate statics in TOT_ALIN ----------------------------Yes

Header Statics Bulk shift Static ------------------------------------------------------ 0 What about previous statics ---- Add to previous statics Apply how many static header entries --------------------- 1 First header word to apply ------------------------------alinstat How to apply header statics -------------------------------- Add

Apply Fractional Statics -------------Trace Display 7. In Event Alignment in Window, use a 30 trace Selective Stack model, again Ignoring end of ensemble issues. Use the same gate as the previous execution. Make sure you properly set the yes/no switch for Accumulate Statics in TOT_ALIN. Yes in this case. 8. Add the new ALINSTAT statics to any previous statics and apply any fractional remainder. 9. Plot the output traces on the screen and check to see that the first arrivals are even flatter than those from the previous exercise.

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Compare Flattening Iterations 1. COPY the previous flow to a new flow to compare all three datasets. Editing Flow: 09- compare flattening Add

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Disk Data Input Header Statics Apply Fractional Statics Reproduce Traces IF Trace Display Label ELSEIF Event Alignment in Window Header Statics Apply Fractional Statics Trace Display Label ELSEIF Event Alignment in Window Header Statics Apply Fractional Static Event Alignment in Window Header Statics Apply Fractional Statics Trace Display Label ENDIF Trace Display Specify Display END time ------------------------------------ 500 2. Using flow editing techniques, rearrange and expand the existing flow to generate the comparison displays of:

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First Arrivals only

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1 loop of Event Alignment

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2 loops of Event Alignment


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3. Display the results using Trace Display. The three comparison displays should resemble the following examples:

You may find that setting the trace display to display 3 vertical panels will help you do this comparison.

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Wavefield Separation with Median Filter The median filter has proven to be a very effective means of estimating the flattened event amplitudes by computing the median amplitude over a series of traces at constant time samples. If the input data is well flattened and the waveforms are stable, then the median filter should perform well. Typically, the amplitudes of consistent events are estimated and then this component is subtracted from the input.

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Exercise 1. Expand the previous flow to do 2D spatial filtering to estimate and subtract the downgoing energy. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics --------------Parameter Test Enter parameter VALUES ------ 3|5|7|9|11|13|15|19 Trace grouping to reproduce ---------------------- Ensembles

2-D Spatial Filtering Type of 2-D filter --------------------------- Simple 2-D Median Number of SAMPLES for 2-D filter ---------------------------- 1 Number of TRACES for 2-D Filter ---------------------- 99999 Type of trace edge taper --------------------- Fold edge back Application mode for 2-D filter ------------------ Subtraction Minimum number of traces for subtraction ---------------- 3 Steer filters along a vertical dip? ---------------------------- No Re-apply mutes after filtering ------------------------------- Yes

Bandpass Filter Default all parameters EXCEPT Ormsby filter frequency values ------------- 8-12-100-125

>Trace Display Label< --------------Trace Display Number of ENSEMBLES per screen ------------------------ 10 2. In Parameter Test, test a series of different length median filters.

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Test values of 3 |5| 7 |9| 11 |13| 15 | 19 for the number of traces in the filter. 3. In 2D Spatial Filtering, apply a Single Sample, Simple 2D Median Filter to Subtract the downgoing energy from the total flattened wavefield. In the Minimum Number of traces for Subtraction parameter, use a minimum of 3 traces in the filter and fold live traces back over the edge to make sure that there are always enough traces for the filter. 4. Apply a fairly wide open zero phase Ormsby Band Pass filter to suppress any adverse side effects of the median filter. For this data at a 4 ms sample rate, apply a filter of 8-12-100-125. 5. Display the results using Trace Display. You may find that setting the maximum time to display to 700 ms prior to display may save you some time in the zooming process. You may also find that setting the display to plot 5 horizontal panels will be helpful. You may also want to reset the Trace Display to do one vertical panel with 1 ensemble per screen and use the screen swapping capabilities within Trace Display to compare the different results. 6. After selecting the length of filter that works best, rerun the flow to QC the output section. Toggle the Parameter Test inactive and input the proper filter length (11) in the 2D Spatial Filter process instead of the 99999 for the parm test.

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7. Add a Trace Display Label after the Median Filter to annotate these data for future reference.

Upgoing Energy Separated by Median Filter

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F-K Analysis Using an F-K filter to separate the input data into various dip components is another very effective means of separating the flattened downgoing energy from the dipping upgoing energy, thus separating the upgoing from the downgoing. We can plot the flattened data in the F-K plane and estimate various fan filters and/or polygonal filters to isolate one of the dip components. Using the Interactive F-K Analysis process, you can interactively test various reject and accept F-K polygons to keep the upgoing and downgoing.

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Exercise 1. Expand the previous flow to add an F-K Analysis to pick the fan filter, or polygon filters to apply. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Static >Parameter Test< >2-D Spatial Filtering< >Bandpass Filter< --------------F-K Analysis DEFAULT all parameters EXCEPT Panel width in traces -------------------------------------------- 80 Distance between input traces ------------------------------- 50 Select mute polygon table -- reject poly to keep upgoing Mode of F-K filter windowing ------------------------- REJECT

-------------->Trace Display< Note: Toggle the median filter, bandpass filter, and Trace Display steps inactive. 2. Select F-K Analysis parameters. There are 80 traces per panel and the traces are separated by 50 ft. Add a Parameter Table name for the FK-Polygon. We may elect to use polygon editing or we may just measure velocities to use a fan function in the F-K filter process.

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3. Use the dx/dt tool to measure the apparent velocity of the up-going energy in flattened space on the F-K Analysis section. The velocity should be about 6700 ft./sec. 4. Pick a positive and negative velocity cut to apply as a fan filter in FK Filter. Numbers like -4000 and + 20000 are good choices for a reject filter to keep the upgoing. You may choose numbers like -20000 and +20000 as an accept filter to keep the downgoing. Note: If you are working with polygons, be careful about how you set the Accept and Reject options. 5. Generate the Filtered Output panel to QC the polygon and parameters.

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Wavefield Separation with F-K Filter Experiment with different accept and reject fan filters and polygons looking at the output in F-K Analysis and Trace Display. 1. Expand the previous flow to add an F-K Filter to estimate and reject the downgoing energy. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Static >Parameter Test< >2-D Spatial Filtering< >Bandpass Filter< --------------F-K Filter Type of F-K filter ----------------------------- Arbitrary Polygon Distance between input traces ------------------------------- 50 Panel Width on Traces ------------------------------------------ 80 Select mute parameter file - reject poly to keep upgoing Mode of F-K filter operation --------------------------- REJECT

F-K Analysis -------------->Trace Length< >Trace Display< 2. Input your velocities as a fan filter and/or try any picked polygons to Reject the downgoing and keep only the upgoing. Use the defaults for padding and tapering.

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Suggested parameters are to use a fan filter of -4000 and + 20000 ft./ sec in reject mode. With this velocity the K-space wrap parameter should be set to No. QC the output with F-K analysis.

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Wavefield Separation with Eigenvector (K-L) Filter An Eigenvector Filter essentially decomposes a group of traces into dip components where the number of dip components is related to the number of traces in the transform. These dip components are accessed by selecting eigenvector percentages from 0 to 100 percent where the low percentages are the flatter components. The option exists to either keep the selected percentage or to subtract the selected percentage from the input. Three sets of times are required depending on what options are selected: •

a design gate from which the dip component matrix weights are computed

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an application time gate

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an optional subtraction time gate.

In general the application and subtraction gates are the entire time range of the data. The design gates should be restricted to a good data zone. For VSP data, this is the area near the first arrivals. When operating on data that has been flattened on the first arrivals, the low percentage eigenvectors are the flattened downgoing energy and the high percentages are the dipping upgoing. In this exercise you will design the eigenvectors over a time window around the first arrivals using a fairly short spatial window and then subtract the low percentage values from the input to extract the upgoing energy.

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Exercise 1. Alter the existing flow to use the Eigenvector Filter to separate the wavefields. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Static >Parameter Test< >2D Spatial Filtering< >Bandpass Filter< >F-K Analysis< >F-K Filter< --------------Parameter Test Eigenvector Filter --------------Trace Display Parameters for Parameter Test and Eigenvector Filter are on the next page.....

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. Editing Flow: wavefield separation Add

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--------------Parameter Test Enter parameter VALUES ------------------- 3|7|11|15|19 Trace grouping to reproduce ---------------------- Ensembles

Eigenvector Filter Mode ----------------------------- Subtract Eigenimage of Zone Get matrix design gates from DATABASE --------------- No SELECT Primary header word ---------------------------- FFID SPECIFY design time gate ---------------------------- 1:0-500/ Get application gates from DATABASE ------------------- No SELECT Primary header word ---------------------------- FFID SPECIFY application gate -------------------------- 1:0-2000/ Get Subtraction gate from DATABASE -------------------- No SELECT Primary header word ---------------------------- FFID SPECIFY subtraction gate -------------------------- 1:0-2000/ Type of Computation ------------------------------------------ Real Horizontal window width -------------------------------- 99999 Start percent of eigenimage range ---------------------------- 0 End percent of eigen image range -------------------------- 10 Re-apply trace mutes after filter --------------------------- Yes

--------------Trace Display Note: Toggle the F-K filter and F-K Analysis inactive in the flow 1. Design a test of the Eigenvector filter over the first arrivals Use a constant design window for all FFID’s from 0-500 ms and apply a filter over the entire time range (0-2000 ms). Also, subtract over the entire time range from 0-2000 ms. Test values of 3, 7, 11, 15, and 19 for the trace window width and subtract the first 10 percent of the Eigen images.

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2. You may want to test various panel widths, design gates, and Eigen image percentage ranges. Note that you cannot use the “Parameter Test” sequence to test the percentage ranges. 3. Try various Trace Display configurations: 1) Each output ensemble individually and then swap the screens. 2) All ensembles on the same screen. Note that the Eigen Filter is very difficult to test because the percentage to keep range varies as a function of the length of the filter.

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12-21


Wavefield Separation Comparison Test Exercise 1. Expand the previous flow to reproduce the traces and add IF ELSEIF - ENDIF statements around the various separation programs. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics >Parameter Test< Reproduce Traces IF 2D Spatial Filtering Trace Display Label Bandpass Filter ELSEIF F-K Filter >F-K Analysis< Trace Display label ELSEIF Eigenvector Filter Trace Display Label ENDIF >Trace Length< Trace Display 2. Based on the value of the Repeat header word, apply all three types of separation possibilities and compare the results using Trace

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Display. 3. If desired, an AGC or other type of gain function may be applied. 4. Experiment with various display options to compare the results from the different separation techniques. •

Display each 80 trace ensemble on the screen independently and scroll through them.

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Display all three 80 trace ensembles on the screen at the same time.

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Display all three 80 trace ensembles on the screen in 3 vertical and then 3 horizontal display panels.

5. Select the method that produces the best results.

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Save the Upgoing Energy Exercise 1. Select the method that best isolates the upgoing and then remove the flattening statics, and trim statics and save the upgoing data. Editing Flow: wavefield separation Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics >Reproduce Traces< >Parameter Test< >IF< >2D Spatial Filtering< >Trace Display Label< >Bandpass Filter< >ELSEIF< >F-K Analysis< F-K Filter Trace Display label >ELSEIF< >Eigenvector Filter< >Trace Display Label< >ENDIF< -------------Header Statics Disk Data Output ------------->Trace Display<

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2. Suppose that the F-K Filter was selected as the best option to isolate the upgoing energy. 3. Comment out all other processes and Add in a Header Statics to Remove the previous statics. Set the number of header statics to apply to “0”. 4. Add in a Disk Data Output to save the upgoing energy in a file for later processing. Editing Flow: wavefield separation Add

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-------------Header Statics Bulk shift static ------------------------------------------------------ 0 What about previous statics -- Remove previous statics Apply how many static header entries --------------------- 0 HOW to apply header statics ------------------------------- Add

Disk Data Output Output Dataset Filename------------------- isolated upgoing New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No

-------------Note: You may want to toggle the Trace Display inactive for this exercise to ensure that all traces get processed. If you leave the Trace Display turned on you will find that the display is not very good because we have returned the data to original recorded time but the display is set for the first 700 msec only.

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Wavefield Separation to Keep Downgoing Exercise 1. The same job can be used to determine the best approach to use to separate the downgoing energy only. Copy the Wavefield separation flow to a new flow to test the different techniques for isolating the downgoing data. Editing Flow: 10 - test/keep downgoing Add

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Disk Data Input Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Reproduce Traces >Parameter Test< IF 2D Spatial Filtering Trace Display Label Bandpass Filter ELSEIF F-K Filter >F-K Analysis< Trace Display label ELSEIF Eigenvector Filter Trace Display Label ENDIF >Header Statics< >Disk Data Output< Trace Display

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2. In 2D Spatial Filtering, select to run in Normal mode, the Eigenvector Filter to Output the eigenvector filtered zone, and the F-K filter to run in an Accept mode. Note: You may want to change the fan filter velocities for this exercise. Values of -20000 to 20000 ft./sec in an accept mode are reasonable. 3. Repeat the various comparison displays and select the method which gives the desired results.

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•

Display 3 vertical panels limiting the time on each panel to 1100 ms.

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Display 3 ensembles on one screen to 2000 ms.


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Save the Downgoing Energy Exercise 1. Select one of the separation techniques and leave the flattening statics applied. Save the downgoing data to disk. Editing Flow: test/keep downgoing Add

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Disk Data Input Database/Header Transfer Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics Event Alignment in Window Header Statics Apply Fractional Statics >Reproduce Traces< >IF< >2-D Spatial Filtering< >Trace Display Label< >Bandpass Filter< >ELSEIF< >F-K Analysis< >F-K Filter< >Trace Display label< >ELSEIF< Eigenvector Filter Trace Display Label >ENDIF< Disk Data Output ------------->Trace Display< 2. Comment out all other processes.

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3. Change the dataset name in Disk Data Output to save the down going energy for later processing. 4. In this case, also make sure that the Header Statics process is toggled inactive. Why do we leave the statics applied to the downgoing data?

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QC plot of Separated Data Exercise 1. Reread the input, the isolated upgoing data file and the isolated downgoing data files and plot them together on the screen. Editing Flow: QC Wavefield Separation Add

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Disk Data Input Select dataset-------------------------vertical traces with TAR Trace Read Option--------------------------------------------Get All

Disk Data Insert Select dataset------------------------------------isolated upgoing Trace Read Option--------------------------------------------Get All

Disk Data Insert Select dataset-------------------------------isolated downgoing Trace Read Option--------------------------------------------Get All

Trace Display Number of ENSEMBLES per screen -------------------------- 3 In the Disk Data Input and Insert processes, get three input files: the original input, the separated upgoing with statics removed, and the separated downgoing with the statics still applied. 2. In Trace Display, select to plot three ensembles. 3. Plot the first break picks on the traces. They should plot at about the start of the reflection data on the upgoing. Note: This is meaningless on the downgoing.

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Chapter 13

VSP Deconvolution Deconvolution of VSP data involves the generation of an inverse filter designed to compress an input wavelet to a zero phase wavelet. The input wavelet is commonly extracted from the separated downgoing energy. A filter is designed to compress this energy into a zero-phase wavelet centered on the first arrival time. This filter is then applied to the upgoing data to remove the source signature from the reflection energy and output a zero phase wavelet at the actual time of the reflection generation interface. Some design gate determination is commonly performed to isolate the wavelet from which the inverse filter is designed. This design gate generally starts at zero time, envelopes the first arrivals and progresses in time for a couple of hundred milliseconds. The maximum time of the gate typically comes immediately after the last consistent reverberation of the first arrival.

Topics covered in this chapter: ❏ Picking a design gate ❏ Designing the inverse filter on the downgoing data ❏ Applying the filter to the down-going for Quality Control ❏ Applying the filter to the upgoing data

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Chapter 13: VSP Deconvolution

Picking the Decon Design Gate Exercise 1. Build a flow to plot the downgoing data and pick a design gate. Editing Flow: 12 - VSP Decon Add

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Disk Data Input Select dataset-------------------------------isolated downgoing Trace Read Option--------------------------------------------Get All

Trace Display 2. Input the separated, flattened downgoing data. 3. All of the Trace Display parameters may be defaulted. 4. Using the Pick pulldown menu, select to pick a Bottom Mute to be applied prior to inverse filter design. When prompted for a header entry to use for the mute function, select FFID as the header entry over which to vary the mute start times. Set the bottom mute to start at about 400 ms. 5. Exit the program to save the mute parameter table.

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Apply the mute for QC Exercise 1. Expand the previous flow to apply the mute for QC. Editing Flow: 12 - VSP Decon Add

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Disk Data Input Select dataset-------------------------------isolated downgoing Trace Read Option--------------------------------------------Get All

Trace Muting Reapply previous mutes --------------------------------------- NO Mute time reference ---------------------------------------- Time 0 Type of mute -------------------------------------------------- bottom ending ramp --------------------------------------------------------- 30 EXTRAPOLATE mute times --------------------------------- YES get mute file from the database ---------------------------- Yes Select mute parameter file -- decon design bottom mute

Trace Display 2. Apply the mute that was just picked as a Bottom Mute. 3. Display the result.

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Deconvolution Filter Design Exercise 1. Build a flow to design the decon filter traces. Editing Flow: 12 - VSP decon Add

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Disk Data Input Trace Muting Filter Generation Filter type ------------------------------------------------------ Inverse Type of operator ------------------------------------ Time Domain Percent additive noise factor ------------------------------------ 3 Trace length for the filter trace --------------------------- 1000 Time on input trace representing time zero ----------- 100 Apply taper to input wavelet AND output -------------- Yes Taper type --------------------------------------------------- Hanning Percent flat for time window ramping ----------------------- 0 Output filter or filtered wavelet -------------------------- Filter Spectral plot --------------------------------------------------------- No Write filter trace to disk ---------------------------------------- Yes Output dataset name ------------------------------ decon filters

Trace Display 2. Input the separated, flattened downgoing data and apply the bottom mute to limit the design gate. 3. Select Filter Generation parameters. After applying a Hanning Window taper over 100% of the input wavelets (zero percent flat), design and output to disk 1000 ms inverse filters where time zero on the input trace is 100 ms and use 3% white noise. 4. Plot the output from Filter Generation. The plotted traces are the actual filters to be applied.

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5. In Filter Generation, output the filter traces to a disk file. Where did the 100 ms in the filter generation come from?

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Deconvolution Filter QC Exercise 1. Expand the previous flow to apply the filters and QC the results on the down going data. Editing Flow: 12 - VSP decon Add

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Disk Data Input >Trace Muting< >Filter Generation< VSP Deconvolution Dataset where filters are stored -------------- decon filters Mode of mixing filters -------------------------------------- Mixing Select header on which to match traces -------------- FFID Bin Radius ------------------------------------------------------------- 5 Exclude filters at edge of image ----------------------------- No Time of input filter that represents zero time --------- 500 Reapply mutes after deconvolution ----------------------- Yes

Trace Display Label Trace Label ----------------------------- downgoing - decon QC

Trace Display 2. Input the separated, flattened downgoing data. 3. Select VSP Deconvolution parameters. Apply filters that have been mixed over 5 FFIDs and exclude 1 filter trace on each end. Make sure that the zero reference time of the filter is correct. This should be set to 500 ms. which is the center time of the filter traces. 4. Add a label for display Is the peak of the zero phase wavelet at the correct time?

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Deconvolution - Application to UpGoing Once the filter traces have been generated and checked, they can be applied to the upgoing data to produce a zero phase wavelet at the time of the reflection events.

Exercise 1. Build a flow to apply the decon filters to the upgoing data. Editing Flow: 12 - VSP decon Add

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>Disk Data Input< Disk Data Input Select dataset------------------------------------isolated upgoing Trace Read Option--------------------------------------------Get All

>Trace Muting< >Filter Generation< VSP Deconvolution Trace Display Label Trace Label --------------------------------- upgoing with decon

Disk Data Output Output Dataset Filename---------------upgoing with decon New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No

Disk Data Input Select dataset------------------------------------isolated upgoing Trace Read Option--------------------------------------------Get All

Disk Data Insert Select dataset-------------------------------upgoing with decon Trace Read Option--------------------------------------------Get All

Trace Display Number of ENSEMBLES per screen -------------------------- 2 2. Input the separated upgoing data at original recorded time. Landmark


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3. In VSP Deconvolution, apply the filters that were previously generated. Mix the filters over 5 FFIDs and exclude 1 filter trace on each end. Make sure that the zero reference time of the filter is correct. This should be set to 500 ms or the center of the filter traces. 4. In Trace Display Label, label this data as being upgoing energy with decon applied. 5. In Disk Data Output, write the deconvolved data to disk. 6. Read the before and after decon files in a Disk Data Input and compare them with Trace Display.

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Spectral Analysis Before and After Decon Once the deconvolution has been applied we can generate a comparison spectral analysis of the data before and after decon.

Exercise 1. Expand the previous flow to read two files from disk and then do a spectral analysis on each. Editing Flow: 13 - spectral analysis Add

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Disk Data Input Select dataset------------------------------------isolated upgoing Trace Read Option--------------------------------------------Get All

Disk Data Insert Select dataset-------------------------------upgoing with decon Trace Read Option--------------------------------------------Get All

Interactive Spectral Analysis Data Selection method ---------------------- Multiple subsets Freeze the selected subset ----------------------------------- Yes Display data by traces or ensembles --------- Ensembles Number of ensembles per analysis location -------------- 1 Number of ensembles between analysis locs ------------ 1 Primary header for sorting and label ----------------- CHAN Secondary header for sorting and label ----- REC_ELEV Default all remaining parameters-------------------------------Run a Multiple Subset analysis on one ensemble at a time. Use Recording Channel and FFID as the primary and secondary annotation levels.

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Chapter 14

VSP Corridor Stack The Corridor stack is one of the common final products from VSP data processing for zero (or near) offset surveys. This stack can be tied to surface seismic stack sections to help the processors and interpreters identify key geologic horizons at known depths to events seen on the seismic section. The corridor stack can also be used to help the drillers predict what is coming up deeper in the borehole by what is called “looking ahead of the bit”. There is scope for discussion about how the processing sequence for the corridor stack is put together. We will first present the sequence using the prepared ProMAX macros for simplicity and then we can discuss variations on the processing sequence.

Topics covered in this chapter: ❏ Picking Corridor Mutes ❏ Apply the Corridor Mutes for QC ❏ Produce the Corridor Stack ❏ Splice the Corridor Stack into a Surface Stack

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Chapter 14: VSP Corridor Stack

Picking Corridor Mutes Two mutes are required to define the top and bottom of the corridor.

Exercise 1. Build a flow to pick the top and bottom mute to define the corridor to stack. Editing Flow: corridor stack Add

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Disk Data Input Select dataset------------------------isolated upgoing - decon Trace read option---------------------------------------------Get All

Trace Display 2. In Disk Data Input, input the deconvolved upgoing data file. 3. Use Trace Display to plot the trace. You may find that adjusting the minimum and maximum display time will help you position your mutes. 4. From the picking pulldown menu, select to define a top mute. Define the mute to set the Top of the corridor. When prompted, select FFID as the header entry over which to vary the mute start times. Note: This mute should be about the same time as the first arrivals. 5. From the picking pulldown menu, select to define a bottom mute. Define the mute to set the Bottom of the corridor. It is normal to make the corridor about 100 ms wide.

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Apply the Corridor Mutes for QC As a second check of the mutes, apply the mutes to the data and display the result.

Exercise 1. Expand the existing flow to add in two Trace Muting processes. Editing Flow: corridor stack Add

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Disk Data Input --------Trace Muting Re-apply previous mutes-----------------------------------------No Mute time reference------------------------------------------Time 0 TYPE of mute--------------------------------------------------------Top Starting ramp--------------------------------------------30. EXTRAPOLATE mute times?----------------------------------Yes Get mute file from the DATABASE?-------------------------Yes SELECT mute parameter file-----corridor stack top mute

Trace Muting Re-apply previous mutes-----------------------------------------No Mute time reference------------------------------------------Time 0 TYPE of mute---------------------------------------------------Bottom Starting ramp--------------------------------------------30. EXTRAPOLATE mute times?-----------------------Yes Get mute file from the DATABASE?-------------------------Yes SELECT mute parameter file--------------------------------------------------------------------corridor stack bottom mute

--------Trace Display 2. In Disk Data Input, input the deconvolved upgoing data file. 3. In Trace Muting, apply the Top and Bottom mutes.

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Do not forget that one is a Top mute and the other is a Bottom mute. 4. Display the result with Trace Display.

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Produce the Corridor Stack In this exercise you will use the VSP Corridor Stack macro to apply the mutes and the first arrival times as a positive static. This will shift the data to two way time. You will then stack the traces. This stack trace will be copied a number of times to produce the final Corridor Stack dataset.

Exercise 1. Expand the existing flow to add in the processes associated with VSP Corridor Stack and optional enhancement programs. Editing Flow: 14 -corridor stack Add

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Disk Data Input >Trace Muting< >Trace Muting< >Trace Display< --------One Way Normal Moveout Correction VSP Corridor Stack Trace Display Label Disk Data Output Automatic Gain Control Bandpass Filter Trace Display Parameters for One Way NMO and VSP Corridor Stack are on the next page.

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. Editing Flow: 14 -corridor stack Add

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One Way Normal Moveout Correction CDP number for velocity--------------------------------------------1 Direction for NMO application----------------------FORWARD Stretch mute percentage-----------------------------30. Apply any remaining static during NMO?----------------Yes Get velocities from the database?---------------------------Yes Select velocity parameter file----from smoothed average

VSP Corridor Stack Ramp time for top mute (ms)-----------------------------------30. EXTRAPOLATE top mute times?-----------------------------Yes Get top mute file from the DATABASE---------------------Yes Select top mute parameter file---corridor stack top mute Ramp time for bottom mute (ms)-----------------------------30. EXTRAPOLATE bottom mute times?-----------------------Yes Get bottom mute file from the DATABASE?--------------Yes Select bottom mute parameter file-------------------------------------------------------------corridor stack bottom mute Bulk shift static-------------------------------------------------- -900 What about previous statics?----Add to previous statics Apply how many static header entries?---------------------1 First header word to apply-----------First break pick time Header statics application mode---------------------------Add Method for trace summing----------------------------------Mean Root power scalar for stack normalization---------------0.5 Number of copies------------------------------------------------------5 2. Comment out the two trace mutes since they are applied in the Corridor Stack Macro. Also comment out the Screen Display. MB3 will toggle the processes inactive.

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3. Apply the One Way NMO correction using the RMS velocity function that was generated earlier for the Spherical Divergence Correction. Use the resampled RMS from the smoothed average. 4. In VSP Corridor Stack, apply the Top and Bottom mutes and add the first arrival times from the header as a static. Make 5 copies of a mean stack trace. For display purposes, apply a bulk shift static correction of -900 ms. 5. Write the Corridor Stack traces to a disk dataset. 6. If desired, add in the AGC and/or Bandpass Filter before and/or after stack to help with the cosmetic appearance of the stack traces. 7. Add a new Trace Display to plot the corridor stack.

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Splice the Corridor Stack into a Surface Stack One of the main purposes for generating VSP data is to produce the corridor stack. This stack is a direct measurement of geologic reflection times and depths at the borehole. By tieing the VSP Corridor Stack to surface seismic, interpreters can identify seismic reflections against known geologic interfaces in the borehole. In this exercise you will splice the corridor stack into a surface seismic stack.

Exercise 1. Build the following flow: Editing Flow: splice corr stk into stack Add

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Disk Data Input Trace Display Label Splice Datasets Select a trace data file to be spliced -------------------------------------------------- your area - your line corr stack Primary header word ------------------------------------------ CDP Input a primary header value ------------------------------ 820 Secondary header word ----------------------------------- NONE Number of dead padding traces ------------------------------- 3

Bandpass Filter Default all parameters

Automatic Gain Control Default all parameters

Trace Display 2. In Disk Data Input, input the Final Stack file. 3. In Trace Label, add a label called Stack. 4. In Splice Datasets, splice in the Corridor Stack at CDP Bin Number 820 and pad with 3 dead traces. 5. Apply a bandpass filter and amplitude scaler (AGC) for cosmetic purposes.

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6. Plot the combined display with Trace Display Note: The stack and VSP are from completely different areas. When the corridor stack was generated, a time shift is applied to approximately tie the stack and the corridor stack.

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Chapter 15

Generate Intv-Dpth Velocity Function Two products from VSP data processing require an Interval Velocity vs. Depth velocity function. These are the VSP-CDP transform and the VSP Migration. In this exercise, we will build INTV-DPTH velocity fields from the average velocity functions that we derived from the first arrival times before and after smoothing. Some additional editing will be required to ensure that the velocity field spans the entire desired depth image area for the VSP migration.

Topics covered in this chapter: ❏ Compute Interval Velocity vs. Depth ❏ QC of the function using the Velocity Viewer/Point Editor

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Chapter 15: Generate Intv-Dpth Velocity Function

Compute Interval Velocity vs. Depth The average velocity vs. depth function in itself is not very useful but we can convert this function to an interval velocity vs. depth function for future processing. As you will see, typically some smoothing must occur while generating the interval velocity function.

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1. Build the following flow: Editing Flow: 16- generate intv-dpth function Add

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Velocity Manipulation* Type of velocity table to input ----- Average Vel in Depth Get velocity table from database entry ------------------ Yes Select input velocity database entry --------------------------------------------------from raw first break pick times Combine a second velocity table ---------------------------- No Resample the input velocity table? ------------------------- No Shift or stretch the input velocity table -------------------- No Type of parameter table to output --------------------------------------------------------------------- Interval Vel in Depth Select output velocity database entry ------------------------------------------------------------------- from raw average Spatially resample the velocity table ---------------------- No Output a single average velocity table -------------------- No Smooth velocity field --------------------------------------------- No Vertically resample the output velocity table ----------- No Adjust Output velocity by percentage --------------------- No

Velocity Viewer / Point Editor* Select the type of field you wish to edit ------------------------------------------------------------Interval Vel in Depth Do you wish to edit an existing table --------------------- Yes Select the input velocity database entry --------- ----------------------------------------------------------------- from raw average Do you wish to specify the bounds of the field -------- No Select output velocity database entry --------------------------------------------------------------------------from raw average Minimum depth (or time) of velocity field ------------------- 0 Maximum depth (or time) of velocity field ------------------ 0 2. Input the average velocity function computed from the first arrival times and output an interval velocity vs. depth function. 3. View the output intv-dpth function. Landmark


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We will not do any editing, so you can output to the same table as you are reading from. Are there any problems with this interval velocity function?

Exercise 1. Expand the flow to generate a new interval velocity vs. depth function from the smoothed average velocity vs. depth function. Editing Flow: 16- generate intv-depth function Add

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>Velocity Manipulation*< >Velocity Viewer/Point Editor*< Velocity Manipulation* Select input velocity database entry ---------------------------------------------------------------------smoothed version Select output velocity database entry ----------------------------------------------------------- from smoothed average Vertically resample the output table ----------------- Yes Time step sizes for the output table ------------------- 48

Velocity Viewer / Point Editor* Select the input velocity database entry --------- --------------------------------------------------------- from smoothed average Select output velocity database entry ----------------------------------------------------------------- from smoothed average 2. Input the smoothed average velocity function computed from the first arrival times and output a new intv-depth table. 3. View the output table for QC.

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You may elect to run each of these simultaneously for comparison.

------- from raw avg ------- from smoothed avg ----Note: There are two points very close together on both functions so you can elect to resample the function in Velocity Manipulation prior to output.

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Exercise One of the requirements for the VSP migration is that the velocity field span the entire range of the output image area. Since we may want to image events recorded below the bottom of the well, we must expand the velocity field in depth to cover the proposed image area. We will also resample the output intv-depth function to the original sample period of 50 ft. 1. Edit the existing flow. Editing Flow: 16- generate intv-depth function Add

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>Velocity Manipulation*< >Velocity Viewer/Point Editor*< Velocity Manipulation* Select input velocity database entry ---------------------------------------------------------------------smoothed version Select output velocity database entry ----------------------------------------------------------- from smoothed average Vertically resample the output table ----------------- Yes Time step sizes for the output table ------------------- 50

Velocity Viewer / Point Editor* Select the input velocity database entry --------- --------------------------------------------------------- from smoothed average Select output velocity database entry ----------------------------------------------------------------- from smoothed average Minimum depth (or time) of vel field -------------------------- 0 Maximum depth (or time) of vel field ----------------- 15000 2. Input the smoothed average velocity function computed from the first arrival times and output a new intv-depth table. 3. In Velocity Manipulation, resample the output function to a depth increment of 50 ft. 4. View the output table for QC. Specify an output maximum depth of 15000 ft.

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5. Remember to go into edit mode and you may elect to edit the velocity function in preparation for migration. Edit the smoothed version and output a Velocity Function for VSPCDP transform and Migration.

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Chapter 16

VSP CDP Transform For VSP surveys where the source is offset from the well location, a standard final product is the VSP to CDP transform. The VSP to CDP transform is a high spatial and temporal resolution seismic section that allows you to image reflection events near the borehole in the direction toward the shot location. This may help identify faults and/or the attitude of dipping reflected events.

Topics covered in this chapter: ❏ Generation of the VSP CDP transform

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Chapter 16: VSP CDP Transform

VSP CDP Transform Exercise 1. Build a flow to generate the VSP-CDP transform. Editing Flow: 17 - VSP-CDP transform Add

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Disk Data Input Select dataset-------------------------------upgoing with decon Trace Read Option--------------------------------------------Get All

VSP/CDP Transform Horizontal binning interval -------------------------------------- 5 CDP at which to extract vel function --------------------- 100 Specify trace length of output trace in msec -------- 3000 Select how velocity is to be specified ------------ Database Select a velocity file ---------------- from smoothed average Ray trace interval ------------------------------------------------- 20 Datum elevation ----------------------------------------------------- 0 Allowable percentage of moveout stretch ---------------- 50

Trace Display Label Trace Label --------------------------------- VSP-CDP transform

Disk Data Output Output Dataset Filename-------------VSP - CDP transform New, or Existing, File?------------------------------------------New Record length to output--------------------------------------------0. Trace sample format------------------------------------------16 bit Skip primary disk Storage?-------------------------------------No

Trace Display Primary trace LABELING header ----------------------- NONE Secondary trace LABELING header ---------------- RBIN_X 2. In Disk Data Input, input the upgoing data with decon applied. 3. Select the VSP/CDP Transform parameters.

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Use the interval velocity function that was created from the smoothed average function and edited. Build a trace every 5 ft. to 3 sec, and ray trace every 20 ft. 4. Use Trace Label to label the traces as the VSP-CDP transform. In Disk Data Output, output the file. 5. Plot the output traces using Trace Display. Plot 1 ensemble. You will probably want to make the display window smaller in order to see the traces more clearly. 6. Look at the headers of the traces and find the new header word that you can use to best annotate above the traces

Exercise 1. Expand the existing flow to redisplay the VSP-CDP transform. Editing Flow: VSP-CDP transform Add

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>Disk Data Input< >VSP/CDP Transform< >Trace Display Label< >Disk Data Output< Disk Data Input Select dataset----------------------------------shots - input data Trace Read Option--------------------------------------------Get All

Bandpass Filter Default all parameters

Automatic Gain Control Default all parameters

Trace Display 2. In Disk Data Input, input the VSP-CDP transform. 3. Apply a bandpass filter and AGC for cosmetic appearance. 4. Display the traces using Trace Display.

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Plot the traces by annotating the RBIN_X header word above the traces. This will plot a value representing the distance from the borehole above the traces. Note: This is a user-defined attribute. You may want to enhance the appearance of the transform by applying a trace mix and/or adjusting the scaling and/or bandpass filter parameters.

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Chapter 17

VSP Migration For VSP surveys where the source is offset from the well location, it is possible to migrate the recorded data. The migration produces a high spatial resolution seismic section that allows you to image reflection events in the vicinity of the bore-hole looking in then plane defined by the well bore and the shot location. Unlike the VSP-CDP transform, the migration can look on the opposite side of the borehole. This may help identify faults and/or the attitude of dipping reflected events. The migration differs from the VSP-CDP transform in that the transform is a simple mapping function that takes a point on a shot to receiver trace and maps that point to a single reflection point in the subsurface. The migration operation is similar to that for surface seismic data, where it attempts to place a data point at all locations from which it could have originated. The migration can be a time consuming process depending on the size of the output image area, the selected algorithm and the size of the dataset.

Topics covered in this chapter: ❏ VSP Migration

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Chapter 17: VSP Migration

VSP Migration Exercise 1. Build the following flow to migrate the VSP data: Editing Flow: VSP migration Add

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Disk Data Input VSP Kirchhoff Migration Trace Display Label Disk Data Output 2. In Disk Data Input, input the upgoing data with decon applied. 3. Select the following VSP Kirchhoff Mig. parameters:

4. In Trace Label, label the traces as the migration. In Disk Data Output, output the file to disk.

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Display the VSP Migration Exercise 1. Expand the flow to reread the migrated data and add an AGC prior to display. Editing Flow: Add

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>Disk Data Input< >Trace Header Math< >VSP Kirchhoff Migration< >Trace Display Label< >Disk Data Output< ------------------Disk Data Input Automatic Gain Control ------------------Trace Display 2. In Disk Data Input, input the migration file. 3. Scale the data to improve its cosmetic appearance. Use a value of about 2000 ft. for the AGC gate length. 4. In Trace Display, plot the migrated data and annotate CDP number above the traces.

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Chapter 18

VSP Corkscrew Geometry VSP Geometry can as simple as a straight borehole or it may become more complex when working with deviated boreholes. In this exercise we will look at a synthetic VSP which was recorded in a borehole that resembles a corkscrew.

Topics covered in this chapter: ❏ Assign VSP Geometry ❏ Quality Control Plots from the database

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Chapter 18: VSP Corkscrew Geometry

Assign VSP Geometry In this exercise you will describe the source and receiver coordinate and depth information, define the field recording channel geometry, and describe the shot to receiver group relationships using the spreadsheets.

Exercise 1. Build a flow to Assign VSP Geometry. Editing Flow: Spreadsheet / Geometry Add

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VSP Geometry Spreadsheet* 2. Execute the flow. The following window will appear:

Fill in each of the Borehole, Patterns, and Sources spreadsheets in this order. The Borehole spreadsheet describes the X, Y and Z information of the borehole. The Patterns spreadsheet describes how many channels were recorded and the orientation of these channels. The Sources spreadsheet describes the X, Y and Z information for all of the source locations and relates the recorded FFID information with a given source and spread reference position.

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Y-Coordinate 1100 1000

1100


100

929.92

1050,1050

929.92

1000

1100

1070.71

X-Coordinate 100 on the surface 1-3 50

1000 log depth difference

995 true vertical depth difference

maximum log depth of 7000 ft

4-6 7-9 10-12 13-15

Synthetic Corkscrew VSP Geometry Diagram

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3. Open the Borehole spreadsheet by clicking on “Borehole” on the main menu. In this case we have a curved borehole. We have 8 control points. The log depths differ from the elevations. 4. Define the borehole with six sets of X,Y, and Z coordinates.

5. Exit from the Borehole Spreadsheet. 6. Open the Patterns Spreadsheet by clicking on “Patterns” on the main menu. There is only one pattern for this geometry. The Grp Int column specifies the separation between the specified recording channels in the borehole. The Offset column specifies a shift to apply to the “chan from” channel relative to the depth listed in the sources spreadsheet. In this case we have fifteen channels with a set of three at the same depth. We will simulate a 5 level multi component tool where the individual levels are 50 apart. You will define the exact depth for the first receiver for each shot.

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7. Exit from the Patterns Spreadsheet. 8. Open the Sources Spreadsheet by clicking on “Sources” on the main window. 9. We have a total of 28 shots in this VSP, so the first thing to do is expand the sources spreadsheet to 28 rows. Mark the last card as a block with MB1 and MB2 and then use the edit pull down to insert the required number of cards. 10. Number the Sources and FFIDs starting at 1 and incrementing by 1. 11. All shots are at shot station number 1 and at an elevation of 0.0 ft. 12. X,Y values are defined at 1050.0 and 1050.0 respectively. 13. All shots use the same pattern (1) and each has 15 channels. 14. The pattern reference depths start at 6800 and decrement by 250 ft. for each shot. Note: For documentation purposes, the columns have been reordered slightly. All additional columns are filled with 0.0.

15. Exit from the Sources Spreadsheet The next steps in the geometry definition process are to define the pseudo CDP binning and to finalize the database. This is a 3 step process. Landmark


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16. Open the Bin menu and select to Assign trace geometry by pattern information.

17. With the Assign option selected, click on the OK button. You should see several windows related to Assigning VSP geometry based on patterns flash by fairly quickly. The last window will say that the geometry has been successfully assigned. 18. Dismiss the Status window by clicking on OK. 19. Compute the Pseudo Common Depth points. Bin starting at CDP 1, starting at 0.0 ft. and ending at 7000 ft. incrementing by 50 ft. per bin.

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20. Click on the OK button. Again you should see several windows flash by ending with a window indicating that the binning was completed successfully. 21. Dismiss this window by clicking on the OK button. 22. Finalize the database. This step completes building the look up tables and other database finalization functions. 23. Select the Finalize Database option and click on the OK button. You should see a window indicating that the VSP geometry finalization has completed successfully. 24. Dismiss the Status window by clicking on OK. 25. Click on the Cancel button in the binning dialog box to dismiss this window.

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Quality Control Plots from the database 2D plot of TRC vs. Receiver elevation and log depth •

used to check depth assigned to each trace

2D plot of SRF vs. elevation •

used to check depth assigned to each receiver station

2D plot of TRC vs. various other values •

used to check additional information for each trace

From the Traces Spreadsheet generate a pointcloud of log depth vs X and Y.

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Chapter 19

Pre Vertical Stack Dataset Information A dataset was generated to illustrate some of the capabilities of ProMAX VSP. This dataset will be used for an exercise to demonstrate vertically stacking multiple shots where the receiver(s) were at common depth positions.

Topics covered in this chapter: ❏ VSP Pre Vertical Stack Dataset Geometry

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Chapter 19: Pre Vertical Stack Dataset Information

VSP Prevertical Stack Dataset Geometry Source type: surface Number of Sweeps per receiver location: 5 Number of Receivers / receiver string: 1 Number of components: 1 •

Channel 1: vertical component first receiver

Number of recording levels: 80 Depth of first record: 12100 ft. Depth of last record: 8150 ft. Depth increment: 50 Source offset from hole: N/A The bore hole is vertical with no deviation Source elevation: 0 ft. Datum elevation: 0 ft. Assume the Kelly Bushing is also at 0 ft. for simplicity Source is at station 1 Receivers are at stations 2-81

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Chapter 20

VSP Level Statics and Vertical Stack When collecting VSP data, it is common to acquire multiple records with the sources and receivers at the same location. This helps attenuate random noise and builds up the signal to noise ratio of the data. Each time the source and recording system are activated, there can be small time differences in the records relative to one another. In order to optimize the vertical stack of these records, these time differences can be measured, normalized and applied prior to vertically stacking the records. There are some fairly complex issues associated with these processes such as: •

What information is available in the incoming trace headers?

•

What information do I have on observers notes?

•

What are the best primary and secondary sort orders for picking analysis time gates?

•

Do I need to do some trace header manipulation to build special ensembles?

•

How many traces and recording levels per shot do I have per shot record?

Topics covered in this chapter: ❏ Plot the Traces ❏ VSP Level Statics Parameters ❏ Compute and Apply the Level Statics ❏ Vertically Stack Shots by Common Header Entry

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ProMAX 3D User Training Manual

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Chapter 20: VSP Level Statics and Vertical Stack

Plot the Traces In this exercise you will plot the synthetic data to familiarize yourself with it.

Exercise 1. Build a flow to plot the input data. Editing Flow: level statics - vertical stack Add

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Disk Data Input Trace Display 2. In Disk Data Input, input the prevertical stack traces file. 3. Use Trace Display to plot 400 ensembles. There are 80 levels and 5 sweeps per level. Each trace is a separate shot ensemble. Because each trace is a separate ensemble, we will want to set the gap between ensembles to “0” for the display. Notice that there are 5 traces per depth level and these traces differ slightly due to variations in random noise on each trace. 4. Look at the trace headers and see what values exist and are common for all traces at the same depth level. There are two header words that can be used to identify all traces at the same depth level, these are: •

Receiver Elevation

•

SHT_GRP

If these header words did not already exist, how could you build them?

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Exercise In this exercise, we will pick the level statics correlation time gate. 1. Edit the flow to toggle the VSP level Statics process inactive.. Editing Flow: level statics- vertical stack Add

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Disk Data Input Trace Display The parameter table we need to pick will be a miscellaneous time gate which has certain requirements. We need to think about how we should sort the input data for presentation to Trace Display and how to determine the secondary sort order for the parameter table itself. We want a table that has constant values for all traces with the same receiver elevation, but varies linearly between receivers. We will pick a miscellaneous time gate where we will pick times and interpolate the times as a function of receiver elevation. What is the best ensemble to build? There are actually two choices here. •

We could combine all of the traces into one ensemble and then pick the times as a function of receiver elevation

•

We could make ensembles of all traces of common receiver elevation and also interpolate the times a function of receiver elevation.

2. In Disk Data Input, sort the input with a primary sort key of CHAN and a secondary of REC_ELEV. This will combine all traces into one ensemble with the traces ordered as a function of the receiver elevation. 3. Pick a miscellaneous time gate with a secondary key of “rec_elev” and select times on the first trace and last trace about 50 ms before the first arrivals. 4. Using MB3, Project the pick times to all of the other traces. Landmark

ProMAX 3D User Traiining Manual

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You should see that all traces recorded at the same receiver elevation have the same time. 5. Add a New Layer using MB3 to this table. Pick the bottom time of the correlation gate about 100 ms below the top time. 6. Use MB3 to Project the times to the other traces. Exit the Trace Display program and save the table to disk.

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VSP Level Statics Parameters In this exercise we will estimate and apply normalized time shifts to rectify any small shot to shot time variations in the data.

Exercise 1. Expand the flow to add the VSP level Statics process: Editing Flow: level statics - vertical stack Add

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Disk Data Input -------------------VSP Level Statics -------------------Trace Display 2. Shots will be identified by their FFIDs, that is all traces with the same FFID belong to the same shot. There are two methods for identifying groups of shots to be operated on as groups: •

By hand listing the respective FFIDs

•

By reading all traces with a common header word

In our case we have two header words to choose from, the Receiver Elevation and the SHT_GRP. We will use the SHT_GRP header word for this exercise. There are a maximum of 5 shots in a group. 3. The maximum separation between groups of SHT_GRP must be set to a value less than 1. 4. Analyze the vertical Recording Channel Number from each shot [channel 1]. 5. You can expect a maximum static shift of about 5 ms.

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6. Select to use the analysis window picked in the previous exercise.

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Compute and Apply the Level Statics In this exercise we will run the VSP Level Statics process to estimate the time shifts and then apply the normalized time shifts using Header Statics and Apply Fractional Statics. Actually on this data, there are no time shifts, just random noise variation, so the values we get will be very small.

Exercise 1. Expand the flow to add the Header Statics, Apply Fractional Statics and the Trace Display: Editing Flow: level statics - vertical stack Add

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Disk Data Input -------------------VSP Level Statics Header Statics Apply Fractional Statics Trace Display Label -------------------Trace Display 2. In VSP Level Statics, select the time gate that was previously picked. 3. In Header Statics, add the value in trace header word LVL_SHFT as a static. 4. Complete the static shift using the Apply Fractional Statics process 5. Add a label to the headers and display the results. 6. You may want to produce a Header Plot of the LVL_SHFT values.

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Exercise With a little rearranging we can produce a comparison plot to look at the data before and after the level statics application. 1. Expand the flow to compare the traces before and after level statics application. Editing Flow: level statics - vertical stack Add

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Disk Data Input Reproduce Traces <2 copies ALL DATA> IF VSP Level Statics Header Statics Apply Fractional Statics Trace Display Label ELSEIF Trace Display Label ENDIF Inline Sort Trace Display 2. Add the Reproduce Traces and IF-ELSEIF-ENDIF processes. 3. Add the Inline Sort to resort the data by Repeat number and FFID for display. There are 400 traces per ensemble and a total of 800 traces in the sort buffer. 4. In the Trace Display select to plot 1 ensemble per screen and plot 2 vertical panels. You may also select to generate a header plot of the LVL_SHFT header values.

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Comparison of with and without level statics including a header plot of the Level Statics Values for a subset of the data.

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Vertically Stack Shots by Common Header Entry Exercise 1. Rearrange the flow to vertically stack based on a common header entry. Editing Flow: level statics - vertical stack Add

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Disk Data Input >Reproduce Traces< >IF< VSP Level Statics Header Statics Apply Fractional Statics VSP Level Summing Trace Display Label >ELSEIF< >Trace Display Label< >ENDIF< >In-line Sort< Trace Display 2. Toggle the Comparison processes inactive. 3. Add VSP Level Sum after the statics application. In VSP Level Sum, select to identify shot groups by header word SHT_GRP. There will be a maximum of 5 shots in a group. 4. Plot the results. You should have 80 traces. (80 ensembles) You can do an Inline Sort prior to the Trace Display with a primary ensemble of CHAN and secondary sort of FFID and then you will have a single ensemble for the Trace Display.

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Compare Stacks With and Without Level Statics Exercise 1. Rearrange the flow to compare a vertical stack with and without the level sum. Editing Flow: level statics - vertical stack Add

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Disk Data Input Reproduce Traces IF VSP Level Statics Header Statics Apply Fractional Statics VSP Level Summing Trace Display Label ELSEIF VSP Level Summing Trace Display Label ENDIF Inline Sort Trace Display 2. Using the screen swapping in Trace Display, compare the results with and without the level summing. Display 1 ensemble per screen and then set the window size and zoom parameters. Save one screen and then go to the next. Save it and compare the two plots. The differences in this example will be minimal. 3. You may also try to use two vertical (or horizontal) panels and plot both results simultaneously.

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Chapter 21

Synthetic Dataset Information A synthetic dataset was generated to illustrate some of the capabilities of ProMAX VSP. This dataset will be used for a couple of exercises showing some ways of compensating for shot to shot time variations and also to demonstrate vertically stacking multiple shots where the receiver(s) were at common depth positions. This data set shows a multi level / multi component example.

Topics covered in this chapter: ❏ VSP Synthetic Dataset Geometry

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Chapter 21: Synthetic Dataset Information

VSP Synthetic Dataset Geometry Source type: surface Number of Sweeps per receiver location: 5 Number of Receivers / receiver string: 2 Number of components: 3 •

channel 1: vertical component first receiver

•

channel 2: one horizontal component first receiver

•

channel 3: second horizontal component first receiver

•

channel 4: vertical component second receiver

•

channel 5: one horizontal component second receiver

•

channel 6: second horizontal component second receiver

Number of recording levels: 4 Depth of first record: 1200 - 1100 ft. Depth of last record: 1000 - 900 ft. Depth increment: 100 Source offset from hole: N/A The borehole is vertical with no deviation Source elevation: 0 ft. Datum elevation: 0 ft. Assume the Kelly Bushing is also at 0 ft. for simplicity Source is at station 1 Receivers are at stations 2-5

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Chapter 22

Level Stat and Vertical Stack for Multi Component / Multi Level When collecting VSP data, it is common to acquire multiple records with the sources and receivers at the same location. This helps attenuate random noise and build up the signal to noise ratio of the data. Each time the source and recording system are activated, there can be very small time differences in the records relative to one another. In order to optimize the vertical stack of these records, these time differences can be measured, normalized, and applied prior to vertically stacking the records. In this set of exercises we will use a synthetic dataset simulating the Multi Component - Multi Level situation.

Topics covered in this chapter: ❏ Determine Level Statics ❏ Vertically Stack Shots for Common Depth Levels ❏ Examine Headers for Common Header Entry

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Chapter 22: Level Stat and Vertical Stack for Multi Component / Multi Level

Plot the Traces In this exercise we will simply view the traces and look at the trace headers to familiarize ourselves with the data.

Exercise 1. Build the following flow to plot the input data: Editing Flow: level statics Add

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Disk Data Input Select dataset------------------------------Synthetic input data Trace read option---------------------------------------------Get All

Trace Display Specify display END time-------------------------------400 Number of ensembles(line segments)/screen------------10 2. In Disk Data Input, input the synthetic shot record dataset. This dataset can be found in the VSP tutorials area. 3. In Trace Display, plot 10 ensembles. 4. Estimate the time of the first arrivals for each set of shots. In the next exercise we will need some time gate information. At approximately what time are the first arrivals on this dataset for each set of 5 shots?

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•

Shots 1-5 __________

•

Shots 6-10 _________


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Determine Level Statics In this exercise we will estimate and apply normalized time shifts to rectify any small shot to shot time variations in the data.

Exercise 1. Expand the flow to compute and apply level_statics. Editing Flow: level statics Add

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Disk Data Input Select dataset------------------------------Synthetic input data

VSP Level Statics Shot header name:----------------------------------------------FFID How will shot groups be identified?:-----------Hand input Shot grouping:---------------------------------------------1,5/6,10/ Analysis receivers:------------------------------------------------1,4 Maximum static shift (in ms):-------------------------------------5 Basis for analysis window:-----------------------Hand input Select primary header word:--------------------------------FFID Specify window analysis parameters:------------------------1:100-200/5:100-200/6:50-150/10:50-150/

Header Statics First header word to apply:--------------------------LVL_SHFT

Apply Fractional Statics Trace Display 2. Select VSP Level Statics parameters. Shots will be identified by their FFIDs and instead of grouping them by a header word, you will hand input the common shot groups. The first five are one group and the second five are another group. There are a maximum of 5 shots in a group. Analyze the two vertical traces from each shot. [traces (1 and 4)] You can expect a maximum static shift of about 5 ms. Use a hand input window about 100 ms wide centered at the approximate time

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of the first arrivals. This analysis window will be constant for the first 5 FFIDs and change to a new constant for the second 5. 1:100-200/5:100-200/6:50-150/10:50-150

3. Read the VSP Level Statics helpfile to determine the name of the Header Attribute to apply as a static in Header Statics. 4. After applying the LVL_SHFT statics using the Headers, apply the fractional remainder with Apply Fractional Statics.

Exercise With a little rearranging we can produce a comparison plot to look at the data before and after the level statics application.

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1. Modify the flow to compare the traces before and after level statics application. Editing Flow: level statics Add

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Disk Data Input Select dataset------------------------------Synthetic input data

Reproduce Traces Total number of datasets------------------------------------------2

IF SELECT Primary trace header word:------------REPEATED SPECITY trace list:----------------------------------------------------1

Trace Display Label Trace label--------------------------------------------Original Input

ELSEIF Trace selection MODE:-------------------------------------Include SELECT Primary trace header word:-----------REPEATED SPECIFY trace list:----------------------------------------------------2

VSP Level Statics Header Statics Apply Fractional Statics Trace Display Label Trace label------------------------------------------------w/hdr stat

ENDIF In-line Sort Select new PRIMARY sort key:----------------------- REPEAT Select new SECONDARY sort key:------------------------FFID Max. traces per output ensemble:----------------------------60 Number of traces in buffer:------------------------------------120

Ensemble Redefine Mode of application:-------------------------------------Sequence Max traces per output ensemble:-------------------------------6

Trace Display Number of ensembles(line segments)/screen------------10 2. Add Reproduce Traces and IF-ELSEIF-ENDIF.

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3. In Inline Sort, resort the data by Repeat number and FFID for display. We have a total of 60 traces per ensemble and a total of 120 traces in the sort buffer. 4. Split the Repeat ensembles back into individual shot ensembles using Ensemble Redefine. We will take each sequence of 6 consecutive traces as one output ensemble. 5. In Trace Display, plot 10 ensembles per screen and use the screen swap functionality to compare the data before and after level static adjustment.

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Vertically Stack Shots for Common Depth Levels After the level statics have been computed and applied, the traces can be vertically stacked for common shot and receiver locations.

Exercise 1. Modify the previous flow to vertically stack shots by hand input shot groups for common receiver depth levels. Editing Flow: vertical stack Add

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Disk Data Input >Reproduce Traces< >IF< >Trace Display Label< >ELSEIF< VSP Level Statics Header Statics Apply Fractional Statics >Trace Display Label< >ENDIF< >In-line Sort< VSP Level Summing Shot header name:----------------------------------------------FFID Header name for secondary key:-----------------------CHAN How will shot groups be identified?:-----------Hand input Shot grouping:---------------------------------------------1,5/6,10/

Trace Display Label Trace Display 2. Select VSP Level Summing parameters. In this exercise, individual shot records will be identified by their FFID. We will sum common channels for Hand Input sets of shots where the first 5 FFIDs are grouped together and then the second 5. 3. Add a Trace Display Label.

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4. In Trace Display, plot the result. You should now have only 12 traces, 3 traces for each depth level. Use the Header Dump icon to look at a few trace headers.

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Examine Headers for Common Header Entry Plot the original input data and examine the trace headers.

Exercise 1. Rearrange the flow to input the data and plot it via Trace Display. Editing Flow: vertical stack Add

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Disk Data Input >Reproduce Traces< >IF< >Trace Display Label< >ELSEIF< >VSP Level Statics< >Header Statics< >Apply Fractional Statics< >Trace Display Label< >ENDIF< >In-line Sort< >VSP Level Summing< >Trace Display Label< Trace Display 2. Plot the traces using Trace Display. Examine the headers to see if there is a header word that is common to all traces in a group of shots that should be vertically stacked together. In this case there is a header entry called SHT_GRP. We can use this header entry in VSP Level Summing as an alternative to hand inputting the shot groups.

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Vertically Stack Shots by Common Header Entry Exercise 1. Rearrange the flow to vertically stack based on a common header entry. Editing Flow: vertical stack Add

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Disk Data Input >Reproduce Traces< >IF< >Trace Display Label< >ELSEIF< VSP Level Statics Header Statics Apply Fractional Statics >Trace Display Label< >ENDIF< >In-line Sort< VSP Level Summing Trace Display Label Trace Display 2. Toggle the level statics, static application and level summing processes back to active. 3. Review the parameters of VSP level summing. In the VSP Level Summing process, select to identify shot groups by header word SHT_GRP. Plot the results. Again you should have 12 traces, 3 from each depth level.

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Compare Stacks With and Without Level Statics Exercise 1. Copy the flow and rearrange it to compare a vertical stack with and without the level sum. Editing Flow: compare level statics Add

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Disk Data Input Reproduce Traces IF VSP Level Summing Trace Display Label ELSEIF VSP Level Statics Header Statics Apply Fractional Statics VSP Level Summing Trace Display Label ENDIF Inline Sort Trace Display 2. Using the screen swapping in Trace Display, compare the results with and without the level summing. Display 1 ensemble per screen and then set the window size and zoom parameters. Save one screen and then go to the next. Save it and compare the two plots. There are some very subtle differences.

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Chapter 23

3-Component Transform and First Break Picking In some cases it may be advantageous to generate a trace that represents the total power of all three component traces in order to help in the first break picking process. Here we will generate a trace that is the RMS amplitude of the three component traces and look at a couple of different techniques for picking the first arrivals.

Topics covered in this chapter: ❏ 3 Component Transform to generate an RMS amplitude trace and First arrival picking ❏ Setting the first arrival times identical on all three components ❏ QC the copied picks

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Chapter 23: 3-Component Transform and First Break Picking

3-Component Transform and First Arrival Picking In this exercise you will input the three component traces and recompute new traces based on the amplitudes of all three inputs.

Exercise 1. Build a flow to construct an RMS trace and display the results. Editing Flow: three component transform Add

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Disk Data Input Trace read option:--------------------------------------------Get All

3-Component Transforms Header word for selecting replacement trace:----Geophone component (x,y,z) Value of replacement trace header ---------------------------2 Select 3-component transform to apply:-----------------Sum Squares Stack Maximum time to calculate transform (ms):----------1500

In Line Sort Select new PRIMARY sort key:-----------------------Geophone component (x,y,z) Select new SECONDARY sort key:------------------------FFID Maximum traces per output ensemble:--------------------80 Number of traces in buffer:----------------------------240

Trace Display Number of ENSEMBLES(line segments)/screen:---------1 Number of display panels:--------------------------------3 Trace Orientation:---------------------------------------Horizontal 2. In Disk Data Input, read the real data with the correct geometry in the headers. This file still has 3 traces per shot and has a primary sort order of FFID. 3. Select 3-Component Transform parameters.

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Replace header entry geophone component (x,y,z) number 2 and process to 1500 ms using a sum squares stack. 4. Sort the data with a primary sort of Geophone Component (x,y,z) and secondary of FFID. There are 80 traces per ensemble and a total of 240 traces in the sort buffer. 5. In Trace Display, display the three component traces. Use 1 ensemble per screen and 3 horizontal panels. You may also want to try 3 vertical panels. 6. Identify the first arrivals on the display of the RMS trace. 7. Create a new First Break entry of the type GEOMETRY in the database using the Picking pulldown menu. Select to edit database values (first breaks) and give these FB Picks a name that describes them as being picks from the RMS trace. 8. After “rubber-banding” the first arrivals on one of the panels, snap them to the nearest peak. Notice that each panel is picked completely independently from the others. In this case only pick the one panel that contains the RMS trace. 9. Compare the picks by plotting them from the database. We should have two sets of first break picks in the TRC database. The picks from the vertical traces that we picked earlier and these new picks from the RMS traces.

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Copying Picks from one Trace to the Others For 3-Component rotation and/or Hodogram Analysis, it is required that all traces at a common receiver position have the same first arrival time. This exercise will demonstrate how this can be accomplished given one good first arrival per receiver depth level.

Exercise 1. Build a flow to copy the time pick from 1 component to the other components. Editing Flow: copy first break picks Add

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Disk Data Input Database/Header Transfer Assign Common Ensemble Value Database/Header Transfer Disk Data Output 2. In the first Disk Data Input, read the file with all three traces per shot with the geometry installed in the headers. 3. In Database/Header Transfer, move the database resident first break pick that was picked from the single vertical trace to the fb_pick word in the trace header. This is the first break pick that was picked earlier on the vertical traces only and then edited in the database.

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4. In Assign Common Ensemble Value, copy the first break pick time from channel 1 to the other 2 channels of each shot.

5. Transfer the copied first break times from the trace header back to the database. Each trace has a first arrival time in the trace header, but there is no attribute in the database that has a first break time for all traces that is correct. For future reference it would be advisable to make a copy of the copied arrival times in the database. 6. Write the output data to a new file.

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QC the Copied Picks As a final QC of the copied picks, plot them over the traces to see if all three traces at a receiver depth level are constant.

Exercise 1. Display the picks in the database. Exit from the flow. Click on the global Database button. Use the Database display tool to graph the various picks and compare the results. 2. Expand the flow to reread the new data file and plot the first breaks. Editing Flow: copy first break picks Add

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>Disk Data Input< >Database/Header Transfer< >Assign Common Ensemble Value< >Database/Header Transfer< >Disk Data Output< ---------------------Disk Data Input Trace Display 3. Toggle all of the previous processes inactive. 4. In Disk Data Input, read in the file that was written in the previous exercise that has the copied picks in the header. 5. In Trace Display, plot the traces Plot 80 ensembles. 6. Execute the flow. 7. Overlay the picks from the headers and/or the database on the traces.

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Use the Picking pulldown menu to select the first breaks from the trace headers, or the database. All three traces per FFID should have the same pick time. Check the values by using the header dump facility.

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Chapter 24

VSP 3-Component Orientation Most modern down-hole seismic recording tools consist of one or more sets of geophones in a string. Each of these sets is typically a group of three geophones, (occasionally you may find four component tools). For the three component tool there will be one vertical geophone and two horizontal geophones which are oriented perpendicular to one another. Sometimes, in processing, the energy recorded on the horizontal phones is of interest. This data may contain a lot of shear wave energy which can yield valuable information if this is the goal. Quite often, this horizontally recorded energy is ignored and only the vertical traces are used in processing. In this chapter we will look at the interactive Hodogram Analysis 3 component orientation process which can be used to build new horizontal traces from the recorded traces that represent what are called transverse and radial components. These correspond to the traces that would have been recorded had the horizontal phones been perpendicular and parallel, to the line defined by the shot and receiver positions on the surface. Additionally, given the vertical and oriented (radial) horizontal traces, two new traces can be built representing the maximum and medium traces where the maximum trace is that which would have been recorded had one geophone been aligned pointing directly toward the source position. Once the geophone orientation is known, additional processing of the oriented horizontal traces is possible for both p and shear wave energy.

Topics covered in this chapter: ❏ 3 Component Hodogram Analysis

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Chapter 24: VSP 3-Component Orientation

3 Component Hodogram Analysis Exercise In this exercise we will work with the two horizontal traces and build two new horizontal traces: one Radial and one Transverse. Watch the polarity of the output (watch the vertical orientation plot as well) in order to get the output traces all the correct polarity. 1. Build a flow to compute the radial and transverse traces from two horizontally recorded input traces of unknown orientation. Editing Flow: 3 comp hodogram analysis Add

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Disk Data Input Bandpass Filter Hodogram Analysis Disk Data Output 2. In Disk Data Input, read the traces with constant first arrival times for each trace at each receiver level in the headers. 3. Apply a bandpass filter. Default values are ok. In general you would not want to apply any trace by trace amplitude corrections for this process. 4. Select Hodogram Analysis parameters.

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Plot the first arrival times, and use the arrival times as a basis for the analysis window. Do not output the analysis window to a time gate file. Write the orientation values to the trace headers.

5. Write the output data to disk. 6. Execute the Flow. You should see a display similar to the following after zooming in around the first arrivals.

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Example Hodogram Analysis Plot The Hodogram plot has three basic sections: •

the trace data area

•

the horizontal hodogram

•

the vertical hodogram

Hodogram of Two Horizontal Traces

Original Vertical and Two Horizontal Traces

Original Vertical and Radial and Transverse Horizontal Traces

Oriented Vertical, Transverse Vertical and Transverse Horizontal Traces

Hodogram of Oriented Horizontal and Original Vertical

Example Hodogram Analysis Product Display

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1. Click on the Hodogram editing icon. This enables us to alter the orientation angle that the program computed automatically if desired. Normally we will only want to watch the polarity of the oriented traces and we may need to rotate the trace by 180 degrees to get the proper polarity. 2. Look at the second and third trace of the middle trace display. The second trace should be maximized at the same polarity as the first trace and the third trace should be minimized. 3. Press MB2 in the top hodogram window to rotate the oriented traces by 180 degrees to change it’s polarity. Change it back again with another MB2 Click. This trace has the correct polarity. 4. Press MB2 in the bottom hodogram window to rotate the oriented vertical trace by 180 degrees. After rotation this trace now has the proper orientation. 5. Fine tune the orientation to minimize the third trace on the second set of traces and the second trace on the third set of traces by using MB1 and rotating the orientation axes. In general you will find that the fine tuning is not required. 6. Press the Next Screen icon to go to the next set of three traces for the next depth level. Repeat the orientation procedures where the goal is to: •

1) maximize the second trace on the second panel of traces at the same polarity as the original vertical trace

•

2) maximize the first trace on the third panel of traces at the same polarity as the original vertical trace.

7. Continue until all 80 levels have been oriented.

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8. Expand the flow to display the output data. Editing Flow: 3 comp hodogram analysis Add

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>Disk Data Input< >Bandpass Filter< >Hodogram Analysis< >Disk Data Output< Disk Data Input Select primary trace header entry------------------hodo_typ Select secondary trace header entry---------------------FFID

Trace Display 9. Read the file that was just created. You will want to sort the input with a primary ensemble sort order of hodo_typ and sort the traces within these ensembles to increase by FFID. 10. You may want to experiment with different display options. A best first guess would be to use Trace Display and plot 5 ensembles. You may also want to try 1 ensemble per screen and 5 horizontal panels.

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Example of Hodogram Output Trace Data Given three input traces, there will be 5 output traces •

the original vertical traces

•

the oriented (radial) horizontal traces

•

the transverse horizontal traces

•

the oriented (maximum) vertical traces

•

the orthogonal to maximum (medium) traces

--- 1 ---------------- 2 ----------------- 3 -------------- 4 ------------------5 ----

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Chapter 25

Prepare Input Data There was a minor limitation with the tutorial dataset whereby in the original file, all of the shot records had the same FFID and the geophone component header word was not set. In order to process these data, we had to assign different FFID numbers to each record and set the geophone component value. Additional header words were also zeroed so that you could follow the header updates as the processing progressed.

Topics covered in this chapter: ❏ Preparing the Input Data

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Chapter 25: Prepare Input Data

Preparing the Input Data This is an exercise in trace header manipulation. There may be cases where you may want to alter trace headers before starting to process a dataset. Here is one example.

Exercise 1. Build a flow to look at the trace headers. Editing Flow: prepare input data Add

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Disk Data Input Trace Display 2. In Disk Data Input, read a file from another area. This dataset can be found in: •

Area: VSP tutorials

•

Line: VSP tutorials

•

Data File: Wtexas_VSP

3. In Trace Display, plot the data and view the trace headers to identify the header values that may need to be altered prior to the start of processing. Since we have no idea how this data is organized, use all defaults for Trace Display except specify to plot 100 ensembles. This will help you identify what an ensemble is and then how to deal with the data. 4. Derive an equation to use to assign the FFIDs from 1 to 80. Also note that the Geophone (x,y,z) header word does not exist and must be set equal to the channel number.

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Exercise 1. Expand the previous flow to rebuild the trace headers and write the file to your own line directory. Editing Flow: Add

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Disk Data Input Trace Header Math Trace Header Math Trace Header Math Trace Header Math Trace Header Math Trace Header Math Trace Header Math In-line Sort >Disk Data Output< Trace Display 2. In the first Trace Header Math, compute FFID=(12100-CDP)/50+1. 3. In the second Trace Header Math, compute GEO_COMP=chan. 4. In the remaining Trace Header Math processes, set SOU_X=0.0, REC_ELEV=0.0, CDP=0, TR_FOLD=0.0, and LINE_NO=0 one at a time. Note: Some are integer others are floating point. 5. Sort the data back to FFID/CHAN. There are 3 traces per FFID ensemble and a total of 240 traces in the dataset. 6. Check the output headers using Trace display. 7. In Disk Data Output, write the data to disk when satisfied that the data is OK.

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Chapter 26

Archival Methods Archiving your data protects your work from system failure and may allow you to bring data into other software packages. The archiving methods can be run from both inside and outside the ProMAX User Interface. In this chapter, we will discuss options for archiving your data.

Topics covered in this chapter: ❏ SEG-Y Output ❏ Tape Data Output ❏ UNIX tar ❏ Archive to Tape

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Chapter 26: Archival Methods

SEG-Y Output ProMAX offers a variety of industry standard and individual company output formats. Of these, SEG-Y is the most common. This process can write out industry standard SEG-Y tapes as well as frequently requested non-standard variations of SEG-Y and IEEE format. SEG-Y Output is a good choice for archiving a dataset that will later be loaded to a third party software package. This process will successfully archive data spanning over multiple disks. One downfall to this archival method is that it will not automatically map all the ProMAX trace headers. However, SEG-Y Output provides you the capability of mapping these non-standard trace headers.

Exercise In this exercise, you will write a SEG-Y formatted tape, mapping some non-standard SEG-Y headers. We will check to make sure the headers were mapped correctly by using SEG-Y Input and Screen Display. Depending on the availability of a tape drive on the system, this exercise may be modified to write a SEG-Y disk image. 1. Build the following flow: Editing Flow: SEG-Y Output Add

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Disk Data Input SEG-Y Output Remap SEGY header values: Yes Use defaults for remapping.

>SEG-Y Input< >Trace Display< 2. Select Disk Data Input parameters. Select two shots from your Raw Shots with Geometry dataset. Limit the dataset size for efficiency. 3. Select SEG-Y Output parameters.

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Enter the tape drive device name. Select Yes to Remap SEG-Y headers. Map the defaulted header values, sou_sloc, rec_sloc, and cdp_sloc. The SEG-Y format reserves bytes 181-240 for optional use. The *_sloc trace headers are important to ProMAX so we typically write them to the extended headers. These header values must be present in order to automatically rebuild the database files with the Extract Database Files process. 4. Put tape in tape drive. 5. Execute the flow. 6. Once the job is completed, build the following flow to QC the headers. Editing Flow: SEG-Y Out Add

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>Disk Data Input< >SEG-Y Output< SEG-Y Input Remap SEGY header values: Yes Use defaults for remapping.

Trace Display 7. Select SEG-Y Input parameters. Make sure the formats are consistent with those specified in SEG-Y output. 8. Select Yes to Remap SEGY headers. This loads the extended headers that you mapped with SEG-Y output. 9. Execute the flow. 10. Click on the Header icon in Trace Display to QC the headers. The extended header values should be preserved (rec_sloc and sou_sloc).

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Tape Data Output Tape Data Output writes seismic traces to tape in ProMAX format. This process is ideal for archiving a dataset to use later since it automatically preserves all trace headers, the CIND and the CMAP file. Like SEG-Y output, Tape Data Output will archive datasets spanning multiple disks.

Exercise In this exercise, you will view trace headers in the dataset, write a ProMAX formatted tape and read the tape back in to make sure the headers are preserved. 1. Exit out of ProMAX by selecting the Exit at the bottom of the User Interface. 2. Set the environment variable BYPASS_CATALOG = t in your ProMAX start-up script or your .cshrc file, by including the line setenv BYPASS_CATALOG t (for the c shell). This will deactivate the tape cataloging system. Information about this system is located in the helpfile index under seismic datasets and tape datasets. 3. If you set the environment variable in your .cshrc file, type source .cshrc. This will reinitialize your .cshrc file. 4. Type promax. 5. Build the following flow: Editing Flow: Tape Data Output Add

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Disk Data Input >Tape Data Output< >Tape Data Input< Trace Display

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6. Select Disk Data Input parameters. Select two shots from your Raw Shots with Geometry dataset. Limit the dataset size for efficiency. 7. Execute the flow. 8. Click on the Header icon in Trace Display to view the trace headers. 9. Exit out of Trace Display 10. Toggle off Trace Display and toggle on Tape Data Output using MB3. Editing Flow: Tape Data Output Add

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Disk Data Input Tape Data Output >Tape Data Input< >Trace Display< 11. Select Tape Data Output parameters. Enter an output file name and tape drive device path name. The Pre-geometry Database Initialization option is the same one found in Disk Data Output. This initializes the database, creating the TRC, SIN, and CHN ordered database files. Since we already applied our geometry, leave the question defaulted to No. 12. Put tape in tape drive. 13. Execute the flow. Choose to continue when the popup menu appears. 14. Enter your datasets menu and click MB2 on your tape dataset. You can view your tape dataset filename under the same menu as your disk dataset. Click MB2 to see information about your dataset. Your new tape dataset will have a Media type of Tape.

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15. Build the following flow to QC the headers: Editing Flow: Tape Data Output Add

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>Disk Data Input< >Tape Data Output< Tape Data Input Trace Display 16. Select Tape Data Input parameters. Select your tape dataset created in Tape Data Output, and specify the tape device path name. 17. Execute the flow. Choose to continue when the popup menu appears. 18. Click on the Header icon in Trace Display to QC the headers. You should see that all of your header values are preserved.

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UNIX tar The UNIX tar command is handy for archiving files, such as datasets, flows, and OPFs residing on one disk such as your primary disk data storage.

Exercise 1. Put a tape in the tape drive. 2. In an X-window, change directories to your line directory using the cd command. 3. Type ls. This lists all the files in your line directory 4. Select the flow that you want to archive. 5. Type tar -cvf /dev/(tape drive device name;rmt0) ./(flowname). This command copies your flow directory and the files contained underneath that directory to tape. 6. When files are copied, type tar -tvf /dev/ (tape drive device name) at the prompt. This command types the files contained on your tape to screen. This step should always be done when you are using tar to archive files to make sure the archive worked. You can also redirect the output to a file by typing: tar -tvf /dev/(tape drive device name) > (file name with tape list)

If you wanted to place archived files back to disk, you would type the following command: tar -xvf /dev/(tape drive device name) ./(flowname).

The x in -xvf indicates that you want to extract data.

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Archive to Tape The UNIX tar command was discussed in the previous section. Although this works fine in many situations, ProMAX also includes an inline archive program, Archive to Tape (sometimes referred to as ctar), designed specifically for seismic datasets. The program ctar has some advantages over the UNIX tar commands such as the ability to span tape volumes on all platforms, flexible use of ProMAX’s secondary storage for seismic trace datasets and checking for available disk space before writing files during restore operations. Also, you may use this functionality in conjunction with the Advance Tape Catalog. The related process, List/Restore from Tape reads ProMAX archive tapes and restores the data to disk.

Exercise In this exercise, you will archive your ProMAX Area to tape, list the tape contents and restore your Area back to disk. 1. Add an Area/Line called archive/archive with permissions of 775 or 777. You may not need to do this in the classroom or, for that matter, at your workplace if this Area/Line has already been created. The purpose of creating this new Area/Line is to prevent you from archiving a line by executing a flow from within the line to be archived. 2. Build the following flow: Editing Flow: ARCHIVE Add

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Archive to Tape >List/Restore from Tape< 3. Select Archive to Tape parameters. 4. Click on Invalid to select an Area.

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5. Click on Invalid to select a tape drive device path. 6. Execute the flow. Choose to continue when the popup menu appears. 7. Build the following flow: Editing Flow: ARCHIVE Add

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View

Exit

>Archive to Tape< List/Restore from Tape 8. Select List/Restore from Tape parameters. Select Simple List for Type of operation. 9. Select Catalog is Bypassed for Select Archive. 10. Click on Invalid to select a tape drive device path. 11. Execute the flow. Choose to continue when the popup menu appears. Verify that your Area exists on the archive tape by looking at your job.output file. 12. From the ProMAX user interface, delete the Area you just archived. You can remove the files from within the process after archiving. 13. Select Restore to Change Type of operation. 14. Execute the flow. Choose to continue when the popup menu appears. If you view your job.output file, you will see that the files were written to disk. 15. Exit out of ProMAX using the Exit button at the bottom and then get back into ProMAX by typing promax. 16. Verify that your Area is restored.

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Chapter 27

UNIX Workstation Basics This chapter serves as a quick reference to you for some basic workstation operations.

Topics covered in this chapter: ❏ Text Editors in ProMAX ❏ UNIX Commands ❏ Examples of UNIX Commands

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Chapter 27: UNIX Workstation Basics

Text Editors in ProMAX There are three text editors used with ProMAX: •

Emacs Editor

•

Emacs Editor Widget

•

Emacs View Widget

The Emacs Editor is a general-purpose, full-function editor. It can be operated outside of ProMAX or in the processes: Config File Edit and the Emacs Editor process. To start the Emacs editor outside of ProMAX, exit ProMAX and type emacs filename at the UNIX prompt. The Emacs Editor Widget is a subset of the full-function editor and is used within ProMAX when a single line editor is insufficient but a fullfunction editor is unnecessary. It supports cursor movement commands and a small set of editing commands. The Emacs View Widget is similar to Emacs Widget in cursor movement, but does not allow any modification of text. The Emacs View Widget only displays text. It is used by ProMAX to view help files and the flow execution output listings (view job.output). Since all the editors listed above are variations on the Emacs Editor, they operate similarly. Of course, the View Widget, which does not actually modify text, has no need for editing commands. Since the Editor Widget is a subset of the full Emacs Editor, it does not have all the commands in the Emacs Editor (Search and Replace, for example). Note: The implementation of the editors is slightly different for each of the ProMAX supported hardware platforms. One reason for the differences is the fact that the keyboards are not the same on each platform. The main difference is the designation of the Meta key. This is the diamond key on either side of the space bar on the keyboard of SUN SPARCstations, Compose Character key on DECstations and the Alt key on IBM RS/6000 workstations. In the following instructions, replace the Meta key with the equivalent key stroke depending on your platform.

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Cursor movement: Use the 4 cursor arrow keys Point the mouse cursor and click button 1 Ctrl-A Move the cursor to the beginning of the current line Ctrl-E Move the cursor to the end of the current line Ctrl-V Scroll the screen forward (down) one screen ”Meta”-V Scroll the screen backward (up) one screen “Meta”-Shift- Jump to the end of the file Ctrl-S Search forward for a string; (start entering ‘string’) Ctrl-R Search backward for a string; (start entering ‘string’)

Editing: All keyboard entry is in insert mode Delete key Delete one character to the left of the cursor (“Backspace” for DEC) Ctrl-D Delete one character to the right of the cursor Ctrl-K Kill to the end of the line (from the cursor) Ctrl-Y Yank back the contents of the kill buffer (created by Ctrl-K or Ctrl-W); “cut and paste”; (can move the cursor first) “Meta”-X, then type “repl s” Search and replace; (follow prompts) Ctrl-X, Ctrl-W Write new Emacs file; (enter path & filename) Ctrl-X, Ctrl-S Save current Emacs file Ctrl-X, Ctrl-F Find another Emacs file Ctrl-X, I Insert a file at current cursor location Ctrl-X, Ctrl-C Exit Emacs

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Exiting Emacs: Ctrl-X, Ctrl-C; (then respond Y or N to saving)

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UNIX Commands Alphabetical summary of general purpose UNIX commands used in conjunction with ProMAX.

cat Concatenate and Display Files UNIX$ cat [options] [files]

Option: -n print output line numbers with each line

cd Change Directory $ cd [directory]

chmod Change Access Modes $ chmod [options] mode names

Option: -r recursively change directory tree Mode can be numeric or symbolic The symbolic case is of the form [agou][+-=][rstwx] where: a group, other and user, access permissions g group access permissions o other access permissions u user access permissions + add the permission to current status of files - remove the permission from status of files Landmark


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= set the permission of files to specified value r read permission s set owner -ID or group -ID on execution (usable only with g or u) t save text mode w write permission x execute permission

cp copy files $ cp [options] file 1 file 2

make a copy of file 1 named file 2 $ cp [options] files directory

make copies of specified files in directory Options: -i prompt user before overwriting file -p copies have same modification times and modes as source files -r recursive copy of directory (with subdirectories)

df Report Free Block Count $ df [options][filesys][file]

Options: -i print number of modes free and in use files df reports on file system containing files filesys is a list of device names or mounted directory names to report (default = all mounted)

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du Summarize Disk Usage $ du [options][names]

Options: -a generate entry for each file -s only display a grand total summary (default is entry for each directory) names directory names or filenames

grep Search File for Pattern $ grep [options]expr [files]

stdin read if no files specified Options: -b precede line with block number -c print count of matching lines only -e expr useful if the expr start with a -i ignore case of letters in search -l print only names of files with matching lines -n print line numbers -s print error messages only -v print non-matching lines -w search for expression as a word expr expression or pattern

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kill Terminate Process $ kill -l

list signal names $ kill [signal]process-ids

Options: signal send signal instead of terminate 0 for process-id implies all processes resulting from current login

ln Make Links to File $ ln [option] file1 file2

make a link to file1 named file2 $ ln [option] files directory

make links of specified files in directory $ ln [option] pathname

make link with same name in current directory Option: -s make symbolic link (hard link default)

login Sign On to System $ login [option][user]

login as user, logout if no user specified

ls List Contents of Directories $ ls [options][names]

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names can be files of directories current working directory used if no name specified Options: -1 print listing of one entry per line -a list all entries (including ones starting with.) -d list only name (not contents) of directory -l long list (mode, links, owner, size, mod. time) -r reverse sort order -R recursively print subdirectories -s print file size in kilobytes

man Print Manual Entries $ man -k keywords

print 1 line synopsis for each section containing keywords $ man -f files

print 1 line synopsis for sections related to files $ man [options][section] cmds

print manual sections for each cmd specified Options: - pipe output through more (default on terminals) -M path to search for entries (/usr/man/default) -t troff output to raster device path list of directories to search, separated by colons section Arabic section number, followed by optional letter signifying type of command

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dir Create Specified Directories $ mkdir directories

more View file by Screenful or by Line $ more [options][files]

Options: -c redraw page one line at a time -d prompt after each screenful -f count by newlines instead of screen lines -l treat formfeed (L) as ordinary character -n window size (default set with stty) +n start viewing file at line n -s reduce multiple blank lines to one -u suppress terminal underlining or enhancing +/pat start two lines before line containing pat Enter h when more pauses for interactive options

mv Move Files (See CP) $ mv [options] file1 file2

rename (or move) file1 file2 $ mv [options] files directory

rename (or move) specified files to directory

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Options: - following arguments are filenames -f force overwriting of existing files -i interactive mode

ps Report Process Status $ ps [keys][-t list][process-id]

Keys: a print all processes involving terminals c print internally stored command name e print both environment and arguments g print all processes k use/vmcore in place of /dev/kmem and /dev/mem for debugging l long listing n process number (must be last key) s add size of kernel stack of process to output tn list processes associated with terminals; n is terminal number (must be last key) u include fields of interest to user U update namelist database (for speed) v print virtual memory statistics w 132 column output format ww arbitrarily wide output x include processes with no terminal

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pwd Print Working Directory Name $ pwd

rcp Copy Files Between Machines $ rcp [option] file1 file2

copy file1 file2 $ [options] files directory

copy files to specified directory Options: -p copies have same modification times and modes as source files -r recursive copy of directories

rlogin Login on Remote Terminal $ [rlogin] remote [options]

Options: -8 allow 8 bit data path -ec specify new escape character c -l user user is login name on remote system -L run remote session in litout mode remote remote host system rlogin is optional if /usr/hosts in search path

rm Remove Files $ rm [options] files

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Options: - treat all following arguments as filenames -i ask for confirmation before each delete -r recursively delete directories

rmdir Remove Empty Directories (See RM) $ rmdir directories

su Become Another User (Set User) $ su [options][user]

user defaults to root Options: - act like full login -f if csh, don’t execute .cshrc

tar Tape file Archiver $ tar [key][option][files]

stdin read if no files specified Keys: format: letter [modifiers] Function Letters: c create new tape and record files t tell when files found, all entries if no files x extract files, entire tape if no files

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Function Modifiers: 0...9 specify which tape drive to use (0 default) b next arg is blocking factor (20 default, 20 max) B force I/O blocking at 20 blocks per record f arch arch is the file to be used for input/output to archives (if-then stdin read) h follow symbolic links l complain if all file links not found m update file modification times v verbose mode w wait for confirmation after reporting filename (y causes action to be performed) Option: -C dir change directory to dir

who Who is on the System $ who [file][am i]

Arguments: file read instead of /etc/utmp for login information am i output who you are logged in as

whoami Print Effective User-Id $ whoami

works even if you have become another user with su.

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Examples of UNIX Commands Most of the following commands apply to Berkeley UNIX. Some of the commands will be different or even unavailable, depending on which shell you are using. The following examples refer to the C shell, and do not necessarily work with the Bourne or Korn shells.

alias promax /advance/sys/bin/promax& The alias command is used to substitute a short, convenient command in place of a longer command. In this case, promax is the new (alias) command. From this point on, typing promax will be equivalent to typing the full /advance/sys/bin/promax&. Note: This alias will only be effective until you log out. If you want it to be available each time you log in, place this line in your .cshrc file. This is a C shell command.

cp -r /advance/data/offshore . cp is the copy command. The -r tells the system that you want to copy recursively (useful for copying directories trees). The directory from which you are copying in this case is /advance/data/offshore. Note the final ., which denotes the target directory. The single . means the current directory. Be careful about how you specify the target directory. If you told the system to copy the files to a directory offshore and this directory already exists, then the files will end up in offshore/offshore.

df df shows the amount of free space on all the currently mounted file systems, including remotely mounted file systems. The listing will show you which of the file systems are remotely mounted. It is possible to specify one file system and see the amount of free space in only that file system. If you do not specify a file system, then df will default to showing all the mounted file systems. There are many other options for df which you may find useful.

du -s offshore The du command summarizes disk usage. It can show disk usage file by file. When the -s option is given, only a grand total summary of disk Landmark


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usage is produced. Specifying offshore requests a disk usage report for that directory.

grep -i STAT elev_stat_math | grep -i CDP grep is the search command. This command will search for the lines within the file elev_stat_math which contain the string STAT. The -i causes the search to ignore upper or lower case differences. Without this option, it would look for STAT exactly, in upper case. The | or pipe redirects the output from the search into another grep command. This again performs a case-insensitive search for CDP. Because the output from the first search contains only lines with the string STAT, the result of the piped search will contain only lines with both STAT and CDP.

grep STAT header.list static_hdrs This grep will search the file header.list for lines containing the string source in upper case letters only, and then will direct the output of the search to a file called static_hdrs.

kill -9 2367 The kill command will stop a current process by sending a signal. The process number in this case is number 2367, which was found by using the ps command. There are many modifiers for this command, but one which you should know is the -9. This makes it impossible for the process to ignore the signal. You might use this when a process is locked up and there is no other way to stop it.

ln -s /advance/data2/oswork offshore The ln command means link. The -s denotes a symbolic link. This can be used to link files on different file systems. A normal link, sometimes known as a hard link, specified as ln without the -s, cannot link between file systems. This symbolic link will cause the directory /advance/data2/oswork to appear in the current directory under the name offshore. It is not a new directory, or a copy of the oswork directory in /advance/data2. When you access a file in your directory called offshore, you are actually accessing the original file in the directory /advance/data2/oswork.

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Therefore any changes made in offshore will be made to in /advance/ data2/os work. You should be aware that certain commands act differently when applied to a linked file. For example, if you delete the linked file using rm applied to the linked file in your directory, only the link is removed. The original file is intact. But if you copy the linked file with cp applied to the file in your directory, the system will make a copy of the original file.

ps -ax The ps (process status) command shows all of the processes currently running on the system. The -a tells the system to display all processes except process group leaders and processes not started from terminals. The x shows processes without control terminals. If you do not specify the x, then you may not see the process for which you are looking. The -ax on Berkeley UNIX changes to -elf on System V UNIX. The l provides a long form of the listing, -f provides a full listing of the processes, and -e asks for every process on the system.

rcp -r neptune:/usr/disk2/offshore . rcp is the remote copy command. The -r, as with the cp command, is the recursive form of copy. It will copy the /usr/disk2/offshore directory and its subdirectories from the named server. The destination directory is ., the current working directory.

rmdir offshore The rmdir command removes directories. In this example the rmdir command will remove the directory offshore. rmdir will only remove an empty directory. If you still have entries in the directory, this command will fail. You can check the contents of the directory, to see if it contains files you meant to keep. Or you can use the rm -r command, at your own risk.

tar c /advance/data/offshore The tar command (tape archive) is used for moving files to or from tape. The c means create, so a new tape will be created. The directory to be copied to tape is /advance/data/offshore. To copy more directories to tape, just list them after the first directory, separated by spaces. x in place of the c will extract files from the tape and copy them to the disk.

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tar x with no files listed will read everything off the tape. tar x followed by a file name, directory or path will only read the data if it exists on the tape. This is a safe way to get back a specific dataset from the tape. The v option is verbose, so that you can see what the process is doing. Otherwise, like most UNIX processes, it is silent. You may wish to investigate cpio as a more versatile alternative to tar.

tar c ./offshore This tar command copies to tape the directory offshore and the files which belong to the directory offshore. The ./ preceding ‘offshore’ indicates that offshore is a subdirectory of the current working directory. It is generally best to use relative path names (rather than full path names) when you are using tar.

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ProMAX Seismic manual

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