Drilling Bits CASING
Objectives At the end of this training session, you will be able to: List the different type of bits Describe the different rock failure mechanism Describe the IADC (International Association of Drilling Contractors) bit coding and dull bit grading Describe the effect of change in weight on bit, rpm, hole size, mud weight and solids content on bit performance
Introduction Drilling bits selection is crucial to the performance of all drilling projects. Understanding the different types of bits and their respective applications is a pre-requisite to bit selection. Not only the right bit in the right application but also running it with the right operating parameters. Well engineers must stay abreast of the latest developments to ensure optimum bit selection.
Bit Types
Bit Types Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Roller Bearing
Insert
Journal Bearing
PDC (Polycrystalline Diamond Compact) Use artificially made diamonds
Drill Bits
Run successfully with downhole motors
Fixed Cutter
PDC
Natural Diamond Courtesy of
Diamond
TSP
Impregnated
Diamond
Roller Cone
Mill Tooth
Roller Bearing
Insert
Journal Bearing
PDC bit: Elements 5 1
2
1. synthetic diamond cutters 2
3
2. support structures for the cutters 3. gauge protection inserts 4. Depth of cut limiters 5. nozzles.
Steel / Tungsten Carbide Courtesy of
PDC bit: Body Material Steel body in one piece ⇒ High precision ⇒ simple repair ⇒ no weld
Tungsten Carbide matrix on steel shell ⇒ Erosion resistant
PDC bit: Cutting Elements 19 mm
BLADE PDC CUTTER
γ Courtesy of
16 mm
13 mm
11 mm
8 mm
Natural Diamond Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Diamond
TSP
Impregnated
Diamond
Roller Cone
Mill Tooth
Roller Bearing
Insert
Journal Bearing
Diamond Bit Profiles Taper or Double cone
Soft formation=>
Parabolic
=>
=>
=>
Shallow cone
=> Hard formation (More diamond coverage) Low ROP
Diamond bit : Design Size and spacing of diamonds determines its use
Widely spaced diamonds : large pieces of soft sand and shale Medium spacing of large diamonds: wide range of sand, shale , limestone Smaller diamonds set in close pattern: hard formations
Natural Diamond bit: Elements
Natural Diamonds = hardest mineral But brittle and Temp dependant
Fluid circulation important
No cone , operates like a single unit Sensitive to shock and variation
Courtesy of
TSP (Thermally Stable Polycrystalline) Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Diamond
TSP
Impregnated
Diamond
Roller Cone
Mill Tooth
Roller Bearing
Insert
Journal Bearing
Cutting Elements - TSP TSP
Courtesy of
Impregnated Diamond Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Diamond
TSP
Impregnated
Diamond
Roller Cone
Mill Tooth
Roller Bearing
Insert
Journal Bearing
Impregnated Diamond: Blades Bit Blade Matrix
Diamond Grit Courtesy of
Formation: medium hard to very hard, ABRASIVE! Impregnated cutting element. Distributed in a tungsten carbide matrix. During heating (furnace) the Segments are bonded to the bit body.
Cutting Elements - Impregnated Impregnated Diamond Blades
Courtesy of
ROLLER CONE Drill Bits
Alternative Names Fixed Cutter
Rock Bit Tri-Cone™
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Roller Bearing
Insert
Journal Bearing
Basic Types Of Roller Cone Bits
Tooth Bits Mill Tooth Bits
Insert Bits Tungsten Carbide Bits Button Bits
Roller Cone Components Nose Cone #3 Gauge Row
Cone #1 Inner Row
Heel Row
Cone #2
Shirttail
Lug
Nozzle Pin
Bit Body
Roller cone bits: Nozzles SHROUDED TYPE
STANDARD TYPE
Mill Tooth Bits Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Insert
Roller Bearing
Journal Bearing
Cutting Elements – Mill Tooth Teeth and Hardfacing
Courtesy of
Insert Bits Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Insert
Roller Bearing
Journal Bearing
Cutting Elements - Insert Tungsten Carbide Inserts
Courtesy of
Tricone Bit - Roller Bearing Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Insert
Roller Bearing
Journal Bearing
Roller Cone Bearing Systems Main Bearings
Roller Bearing Bit
Retention Bearings
Seals
Journal Bearing Bit
Tricone Bit - Roller Bearing
Main Bearing Retention Bearing Thrust Bearing Pin Bearing
Courtesy of
Tricone Bit - Journal Bearing Drill Bits
Fixed Cutter
PDC
Natural Diamond Courtesy of
Roller Cone
Diamond
TSP
Impregnated
Diamond
Mill Tooth
Insert
Roller Bearing
Journal Bearing
Tricone Bit - Journal Bearing
Main Bearing Retention Bearing Thrust Bearing Pin Bearing
Rock Failure Mechanisms
Failure Mechanisms Failure Mechanisms
Shear Failure
PDC BIT CONTINUOUS SHEARING
Compressive Failure
ROLLER CONE BIT CYCLIC COMPRESSION
Courtesy of
Drilling Mechanisms Shear/Compressive Failure
NATURAL DIAMOND OR IMPREG BIT CONTINUOUS CRUSHING & ABRASION
Courtesy of
Drilling Mechanisms vs Bit Type
Scraping
Mill Tooth
Chipping and Crushing Insert Shearing
PDC
Ploughing / Grinding
Natural/Impregnated Diamond
Courtesy of
IADC Bit Classification
IADC Classification – Roller Cone 517G Cutting Structure Series
8-1/2” EHP 51
Soft Formations w ith Low Compressive Strength and High Drillability STEEL Medium to Medium TOOTH Hard Formations w ith BITS High Compressive Strength Hard Semi-Abrasive and Abrasive Formations Soft Formations w ith Low Compressive Strength and High Drillability Soft to Medium Formations w ith Low Compressive Strength INSERT Medium Hard BITS Formations w ith High Compressive Strength Hard Semi-Abrasive and Abrasive Formations Extremely Hard and Abrasive Formations
1 2 3
Cutting Structure Type (1 to 4) 1 refers to the softest formation in a particular Series and 4 refers to the hardest formation within the Series
4 5 6 7 8
Ref: SPE 23937 The IADC Roller Bit Classification System
Bearing/Gauge Description Standard Roller Bearing Roller Bearing Air Cooled Roller Bearing Gauge Protected Sealed Roller Bearing Sealed Roller Brg Gauge Protected Sealed Friction Bearing Sealed Frction Brg Gauge Protected
1 2 3 4 5 6 7
Features Available (Optional) A - Air Application B - Special Bearing Seal C - Center Jet D - Deviation Control E - Extended Nozzles G - Gauge/Body Protection H - Horizontal Steering Appl. J - Jet Deflection L - Lug Pads M - Motor Application S - Standard Steel Tooth T - Two Cone Bit W - Enhanced Cutting Structure X - Predominantly Chisel Tooth Insert Y - Conical Tooth Insert Z - Other Shape Insert
IADC Classification – Fixed Cutter M432 Body Material Steel or Matrix. Cutter Density PDC: 1 to 4, diamond bits: 6 to 8 (the lower the number, the lighter set the bit). 12-1/4” DS66H
Cutter Size/Type For PDC cutter, 1 indicates >24 mm, 2 is between 14 and 24 mm, 3 is between 8 and 14 mm and 4 is smaller than 8. For diamond bits, 1 represents natural diamond, 2 is for TSP, 3 is a combination of natural diamond and TSP and 4 is for impregnated. Profile The final digit indicates the general body style and varies from 1 (flat profile) to 4 (long flanked turbine style).
Fixed cutter IADC codes are intended only to provide a means for characterizing the general physical appearance of fixed cutter drill bits. Unlike the IADC classification for roller bits, these codes do not represent an application guideline. Ref: SPE 23940 Development of a New IADC Fixed Cutter Drill Bit Classification System
IADC Codes Tooth 1-1
Soft 1
2
1-3
3
2-1 Hard
IADC Codes Tooth Soft 1
2 3
Insert
4-1
4 5 6 7
Hard
8
8-3
IADC Codes Tooth
PDC
Soft 1 Insert 2
4
3
5 6 7
Hard
8
IADC Codes Tooth
PDC
Soft 1 Insert 2
4
3
5 6 7
Hard
8
Diamond
IADC Codes Tooth
PDC
Soft 1 Insert 2 3
4 5 6 7
Hard
8
Impregnated Diamond Diamond
IADC Bit Dull Grading Code
IADC Bit Dull Grading Code The International Association of Drilling Contractors has developed a standard methodology for describing used bits. This information is essential for detailed bit performance analysis. The methodology is composed of an 8 character code that describes bit wear and the reason why the bit was pulled. Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
Remarks
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
The cutting structure is graded from 0 to 8 depending on the proportion of cutting structure lost (0 = Intact, 8 = 100% worn). Fixed Cutter Bits
Roller Cone Bits 0
1
2
3
4
Inner Cutting Structure (All Inner Rows)
Outer Cutting Structure (Gauge Row Only)
Cone 3 Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
5
6
7
8
Cone 1
Cone 2
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
Roller Cone Bits *BC - Broken Cone BF - Bond Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Note that this is for the Primary dull characteristics.
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Fixed Cutter – Main Wear Characteristics POST OR STUD CUTTERS NO WEAR (NO)
CYLINDER CUTTERS
Courtesy of
NO WEAR (NO)
WORN CUTTER (WT)
WORN CUTTER (WT)
BROKEN CUTTER (BT)
BROKEN CUTTER (BT)
LOST CUTTER (LT)
BOND FAILURE (BF)
LOST CUTTER (LT)
EROSION (ER)
BOND FAILURE (BF)
Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
BU - Balled Up
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
BU – Balled Up Bit (primary) CD – Cone Dragged (secondary)
Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
CT – Chipped Cutter
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
LT – Lost Cutter
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
BT – Broken Teeth/Cutters
Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
RO – Ring Out
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
JD – Junk Damage
Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
WT – Worn Cutters
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
SD - Shirttail Damage
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
TR - Tracking
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
SS – Self Sharpening Wear
Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : IADC Drilling Manual – Eleventh Edition
ER – Erosion
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Fixed Cutter Bits
Remarks OTHER CHAR
REASON PULLED
Roller Cone Bits N - Nose Row M - Middle Row G - Gauge Row A - All Rows
C - Cone N - Nose T - Taper S - Shoulder G - Gauge Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Cone 1, 2 or 3
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
Fixed Cutter Bits This box is for roller cone bits. Fixed cutter bits will always be designated by "X".
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
Roller Cone Bits Non Sealed Bearings A linear scale estimating bearing life used. (0 -No life used, 8 - All life used, i.e., no bearing life remaining.) Sealed Bearings E - Seals Effective F - Seals Failed N - Not Able to Grade
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
For all Bits The letter “I” is used to designate bits that are in gauge. If the bit is under gauge, the amount is recorded to the nearest 1/16” of an inch. For example, if the bit is 1/8” under gauge, this is reported as 2/16 or often only as 2.
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
This is for the Secondary dull char. and it uses the same codes as for the Primary dull char.
Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics
Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone
LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
IADC Bit Dull Grading Code Cutting Structure INNER ROWS
OUTER ROWS
DULL CHAR
LOCATION
B
G
BRNG/ SEALS
GAUGE 1/16”
Remarks OTHER CHAR
REASON PULLED
For All Bits BHA - Change Bottom Hole Assembly DMF - Down hole Motor Failure DSF - Drill String Failure DST - Drill Stem Test DTF - Down hole Tool Failure RIG - Rig Repair CM - Condition Mud CP - Core Point DP - Drill Plug FM - Formation Change
HP - Hole Problems HR - Hours PP - Pump Pressure PR - Penetration Rate TD - Total Depth/Casing Point TQ - Torque TW - Twist Off WC - Weather Conditions WO - Washout -DrillString
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Key to Dull Bit Grading: Grade a Lot of Dulls !
Photo courtesy of
BIT RECORD To be filled up at wellsite
BIT RECORD
Well : Date : Bit Data
Run Data
BHA Bit Size Bit type Serial IADC Nozzles Depth Depth Drilling ROP Bit krevs WOB No. No. (inch) & maker Number Code (1/32") IN (m)OUT (m) Time (m/hr)(drilling) (Klbs) 3 x 18, 1 1 1 16 T11C L15264 115 15 420 18.04 22.45 151.50 10-25 x 16 2 2RR 12 1/4 DSX113 204556 PDC 8 x 13 420 422 0.50 4.00 1.22 2-10 4 2RR2 12 1/4 DSX113 204556 PDC 8 x 13 1408 1714 16.54 18.50 119.09 25-35
Bit life
Grading
Rot Flow Press Inc Mud Total Total Total (RPM) (GPM) (psi) (deg) SG mtr hrs krevs I 0
O
D
Dull L B
G O
R
120
820
1450
1.07
405
18.04
152
0
1 WT A
E
I NO TD
60 120
680 820
1000 0.00 1.15 1900 1.00 1.19
2 308
0.50 17.04
1 120
0 1
1 WT S 3 WT A
X X
I CTBHA I PN TD
•BHA nb does not always = bit nb •Drilling time = bit time on bottom (← ← Mud loggers) •Krevs = 1000 bit revolution (← ← Mud loggers)
Drilling Parameters vs Bit Performance
Bit performance Main function: ROP and longevity Drilling fluid is circulated through passageways in the bit to remove cuttings and apply hydraulic power to improve ROP ROP is a function of WOB, RPM, mud properties and hydraulic efficiency
Chip Formation Tooth load overcomes rock compressive strength, generates crater Scraping helps to remove chips from craters.
Cutter Borehole pressure causes chip hold down effect
Formation Courtesy of
ROP vs Overbalance Data based on 7-7/8” bit with 30 klbs at 60 RPM
Courtesy of
Chip Removal Removal of chips is required to allow for new chip formation Hydraulics help to remove chips
Cutter
Formation 72
Courtesy of
WOB (Weight on Bit) Response
ROP
CHIP CREATION
0 0 Courtesy of
WEIGHT on BIT
CHIP REMOVAL
RPM Response
CHIP CREATION
ROP
CHIP REMOVAL
0 0 Courtesy of
RPM
Effects of Offset or Skew
Reduced Offset
Increased Offset
– 0º - 2º – Reduced Gage Scraping – More Durable – Slower Drilling – Abrasive / Hard Formations
– – – – –
Courtesy of
3º - 5º Increased Gage Scraping Less Durable Faster Drilling Soft / Sticky Formations
Cone Profiles
Flat Cone Profile – – – –
Minimum Bottom Scraping More Durable Slower Drilling Abrasive / Hard Formations
Round Cone Profile – – – –
Increased Bottom Scraping Less Durable Faster Drilling Soft / Sticky Formations
Tooth Cutter Design
Faster Drilling Less Durable
Slower Drilling More Durable
Insert Cutter Design HP51
Faster Drilling Less Durable
HP83
Slower Drilling More Durable
Cutting Structure Comparisons EHP41H
Faster Drilling Less Durable
HP83
Slower Drilling More Durable
Tooth & Insert Cutter Designs • • • • • •
Soft Formation
Hard Formation
Fewer Teeth Longer Teeth Bigger Teeth Sharper Teeth Sharp Profile Fracture-Resistant Tooth Material
• • • • • • •
• Faster Drilling • Less Durable
• •
More Teeth Shorter Teeth Smaller Teeth Duller Teeth Rounded teeth Flat Profile Wear-Resistant Tooth Material Slower Drilling More Durable
Bit Selection
Bit Application Spectrum
Penetration Rate
PDC
Mill Tooth Insert
Impreg & Natural Diamond
Formation Compressive Strength Courtesy of DP
Bit Selection Process
Which One ?
Courtesy of
Bit Selection - PDC Advantages Very Fast ROP Long Life Potential
Considerations Impact Damage Abrasiveness Stability
Courtesy of
Bit Selection – Tooth Bit Advantages Fast ROP Good Stability Economic
Considerations Tooth Wear Rate Bearing Life
Courtesy of
Bit Selection – Insert Bits Advantages Cutting Structure Durability Range of Formations Interbed Tolerance Steerability and Stability
Considerations Slower ROP Bearing Life Courtesy of
Bit Selection – Natural & Impreg Diamond Bits Advantages Very Durable Hard Rock Capability Low Junk-in-Hole Risk
Considerations Slower ROP RPM Sensitivity High Cost Applications Courtesy of
Gauging Procedures for 3-Cone Bits Smith 3-Cone Bits are designed to have minimum gauge contact. By use of suitable gauge cutting structure design and materials, the “minimum gauge” configuration improves penetration rates whilst maintaining full size hole. Only the cutting elements (teeth or inserts) contact, while the cone shell steel is held away from the hole wall. This means that unless the gauge cutting elements are “lined up” with the gauge contact point on any gauge ring, the bit will measure slightly smaller than it actually is. This is particularly true of aggressive insert bits which have a lighter set gauge and large offset. Gauging a 3-cone bit, either sharp or dull, requires some care and should be carried out as follows: Gap
1. Only use a calibrated 3-cone gauge ring measuring the nominal bit size. 2. Turn the bit on its pin and rotate all the cones to their “maximum gauge point” so that a gauge tooth or insert lines up at this point. 3. Place the gauge ring over the bit at the maximum gauge points. 4. Pull the ring gauge tight against the gauge elements on two cones. 5. Measure any gap at the free cone. This is not the the correct value for gauge wear. 6. To calculate the actual gauge wear you must multiply the gap distance by 2/3 (‘two thirds’). For example: if measured gap is 3/16” then multiply by 2/3 giving 2/16” under-gauge. 7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to use an “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an I and a 1. Important points to note: A 3-Cone bit can be built larger than nominal size because of the plus tolerance allowed, but a new bit can never be undergauge (due to the required cutting structure clearances).
Maximum gauge point API Sizes for New Bits Bit Size
To gauge a new bit you must use a 3-cone ring gauge that measures the nominal bit size plus API tolerance (see table). You CANNOT use a PDC ring gauge to gauge a 3-cone bit and vice versa. On those Smith 3-Cone bits that feature the ‘OD’ diamond enhanced heel row inserts (e.g. MSDGHOD), these bits are designed and built so that these inserts actively cut gauge at the maximum gauge point. Therefore, if the gauge cutting elements are worn and undergauge, then regauge the bit on the heel row inserts. The manufacturing locations of Smith 3-Cone bits are all ISO Certified (ISO 9001).
API Roller Cone Bit Tolerances
Actual Size
Bit Size
Tolerance
26.094”
3-3/8” to 13-3/4”
+1/32”, -0”
23.000”
23.094”
14” to 17.5”
+1/16”, -0”
17.5”
17.500”
17.562”
17-5/8” and larger
+3/32”, -0”
16”
16.000”
16.062”
12.25”
12.250”
12.281”
8.5”
8.500”
8.531”
6”
6.000”
6.031”
Min.
Max.
26”
26.000”
23”
Gauging Procedures for PDC Bits Gauging a PDC bit, either sharp or dull, requires some care and should be carried out as follows: 1. Only use a calibrated PDC “No-Go” gauge ring. 2. Turn the bit on its pin. 3. Place the No-Go gauge ring over the bit - it should stop at the gauge skimmer/gauge pads 4. If the No-Go PDC gauge ring will not pass over the entire gauge area of the bit then the bit is in gauge. 5. If the No-Go gauge ring will pass then place the ring gauge at the gauge pads and pull hard to one side. 6. Measure the gap in 1/16” at the point opposite the point of contact between ring gauge and gauge pad. 7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to use an “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an I and a 1.
No-Go gauge ring pulled hard against gauge pad.
PDC Bit No-Go ring gauge
Measure the gap here in 1/16” and record
Important points to note: A PDC bit can be built slightly smaller than nominal size because of the negative tolerance allowed, but a new bit should never be overgauge. To gauge a bit you must use a PDC “No-Go” ring gauge that measures the nominal bit size minus API tolerance (see table). You CANNOT use a 3-cone ring gauge to gauge a PDC bit and vice versa.
API PDC Bit Tolerances Bit Size
Tolerance
6 3/4” and smaller
-0.015” to + 0”
6 25/32” and including 9”
-0.020” to + 0”
9 1/32” and including 13 3/4”
-0.030” to + 0”
13 25/32” and including 17 1/2” -0.045” to + 0”
The manufacturing locations of Smith PDC bits are all ISO Certified (ISO 9001).
17 17/32” and larger
-0.063 to + 0”
Bi-center Bit Casing / Drift Diameter Bit Center
Bit Center Hole Center Drill Diameter
Pilot Diameter
Tripping through Casing / During Drill out
Drilling Ahead
Drill Out Mode During drill out, drift & drill bits rotate around the drift axis The drift axis is at the geometric center of the reamer
Drilling Ahead When drilling ahead, drift & drill bits rotate around the drill axis The drill axis is defined as the center of the pilot section, and is also the center of the bit connection / shank
Quad-D Nomenclature 12 1/4” x 14 3/4” QDS41PX Drift Diameter Drill Diameter
QDS: QUAD-D Steel Bit QDM: QUAD-D Matrix Bit QDG: QUAD-D Reamer
Enhanced Gage Protection (standard on all steel bits)
Number Range Cutter Size 02-07 6mm 08-27 9mm 28X 11mm 29-59 13mm 60-81 16mm 82-97 19mm 98X 22mm 99X 25mm
9 7/8”
8 1/2”
Drill Diameter Drift Diameter
Dual Diameter Reamer Geometry Pilot Conditioning Section Diameter
6 1/2”
Pilot Bit Diameter
8 1/2” x 9 7/8” QDG76 example Pilot Bit = 6 1/2” Diameter
= 6 3/4”