Anchors for Deepwater Mooring Planning & Installation Expect Moor from a Leader.
Presentation Overview • Jamie Armstrong: – – – – – –
Planning deepwater mooring systems Hazards & geophysical surveys Design for GOM hurricane season Installation calculations Mooring system approval Example field layout
• Bob Wilde: – Geotechnical investigation – Anchor types and associated seafloor footprint – Anchor installation simulations
Planning Deepwater Mooring Systems • Hazards & Geophysical Survey – – – – – – – –
Shallow Faults/Hazards Gas Seeps/Shallow Gas Slump Sediments Shallow Water Flows Hydrates Soil Borings Archeological Sites Field Infrastructure
Geophysical Analysis AUV Sub-bottom Profile
Planning Deepwater Mooring Systems
Design for GOM Hurricane Season •
New Hurricane Mooring Environmental Criteria (API 2INT-MET & Site Specific)
•
New API Guidance (API RP 2SK Hurricane Design Commentary – Appendix K)
•
New MMS Approval Process Requires an Understanding of the Risk
•
Requirement for Mooring Analysis to Estimate Probability of Failure
•
Requirement for Consequence Analysis to Estimate Consequence of Failure N 200.0 175.0
NW
150.0
NE
125.0 100.0 75.0 50.0 25.0
W
E
0.0
Semi-submersible SW
SE
S
Design for GOM Hurricane Season Regionally & Seasonally Varying Metocean Data •
West:
97.5°W to 95°W
•
West-Central: 94°W to 90.5°W
•
Central:
89.5°W to 86.5°W
•
East:
85.5°W to 82.5°W
Design for GOM Hurricane Season Regionally & Seasonally Varying Metocean Data
Design for GOM Hurricane Season MODU Mooring Strength and Reliability Joint Industry Project Location-Specific Consequence Assessment Worksheet (Based on API RP2SK Commentary) Results Assessment Results Block Area
Garden Banks
Rig Name:
Ocean Victory
Operator: Location Name: OCS Designation: Water Depth at Wellsite Rig Heading Latitude:
Callon Petroleum Garden Banks 782-Well #2 0 4,523 355 0
Longitude: UTM-N (Grid): UTM-E (Grid):
0 9,881,098.00 1,873,738.00
Overall Summary of Results (Summed over all Octants)
Component
Value
Near Surface Surfacedist Near Subsea Pipelinesdist Wellsdist Total Combined Likelihood Modified Consequence Factor
Are JIP Factor Values used throughout?
6.50 6.5 =Block Area Component 62.59 0.64 0.6 =Block Area Component 7.96 0.20 77.89
Yes
Expected Ranges: 0 to 30 Low 30 to 75 Medium Over 75 High
Anchors: Normal-loaded plate anchor (VLA) Sea Floor Component: Wire at the Anchor
Consequence Values corrected so that Worst Octant matches Combined Factor: N Near Surface Surface dist Near Subsea Pipelines dist Wellsdist Σ Subsea Σ Surface Corrected Totals
NE 1.0 0.0 0.1 1.8 0.0 1.9 1.0 2.9
1.0 0.0 0.1 1.8 0.0 1.9 1.0 2.9
E 1.0 75.0 0.1 1.8 0.0 1.9 76.0 77.9
Which produces worst results, Directional or Random Drift data?
SE 1.0 0.0 0.1 0.0 0.0 0.1 1.0 1.1
S
SW 1.0 0.0 0.1 0.0 0.0 0.1 1.0 1.1
1.0 0.0 0.1 0.0 0.0 0.1 1.0 1.1
W
NW 1.0 0.0 0.1 0.0 0.0 0.1 1.0 1.1
1.0 0.0 0.1 4.2 0.1 4.4 1.0 5.4
Random
The values in the table are corrected to represent the value for the relevant octant as if there was a 100% certainty that should the MODU break adrift it WILL drift in that relevant octant, but then factored so that the maximum value given as "Total Combined Likelihood Modified Consequence Factor" is aligned with the worst direction. Hence each octant is assigned the full near surface and subsurface values, plus the distant values for that octant multiplied by 8, but then reduced by a ratio to ensure the worst octant value is correct. It is for this reason that the numbers will not be the same as the obvious source of the data.
Design for GOM Hurricane Season Estimate Probability of Failure for Mooring Lines Minimum Mooring Line Break Strength Safety Factor vs Return Period Minimum Intact Dynamic SF
3.00
API Required Intact SF=1.67
API Required Damaged SF=1.25
2.89 2.34
2.50
1.97
2.17 Safety Facto
Minimum Damaged Dynamic SF
2.00 1.78 1.69
1.50
1.20
1.50
1.20 1.00
1.28
1.20
C at 3
C at 2
C at 1
0.50
0.00 10
20
30
40
50
60
70
80
90
100
110
120
Return Period (Years) Note: These are the extreme minima from all mooring lines and all environmental headings
130
140
150
160
170
180
190
200
Installation Calculations
Potential Mooring Configurations
Mooring System Approval •
Requirement for Equipment Inspections to Validate their Capacity
•
All above is rolled into InterMoor’s MMS Submittal for Approval
•
Requirement for “As-Built” Mooring Verification Analysis (Proof that it works) 150° Wave Heading Wave Frequency Motion RAO 20.4m Loaded Draft - Includes Viscous Roll Damping 0.90
4.50 SURGECG
0.80
SWAYCG
4.00
HEAVECG 0.70
ROLL
3.50
PITCH 3.00
0.50
2.50
0.40
2.00
FPSO
0.30
1.50
0.20
1.00
0.10
0.50
0.00 0.00
5.00
10.00
15.00 Period (seconds)
20.00
25.00
0.00 30.00
RAO (deg/m)
RAO (m/m)
0.60
YAW
Example Field Layout
Presentation Overview • Jamie Armstrong: – – – – – –
Planning deepwater mooring systems Hazards & geophysical surveys Design for GOM hurricane season Installation calculations Mooring system approval Example field layout
• Bob Wilde: – Geotechnical investigation – Anchor types and associated seafloor footprint – Anchor installation simulations
Geotechnical Analysis PCPT Test Data
Geotechnical Analysis
Suction Embedded Anchors
Red Hawk Suction Anchors
Thunder Horse PLET Anchors
Thunder Horse Manifold Piles
Pipeline Starter Anchors
ROV Interface
Driven Piles
Menck MHU-500C Hammer
High Holding Power Drag Anchors Drag Embedment
Plate Anchor Types DRAG EMBEDMENT
DIRECT EMBEDMENT (SEPLA)
Follower + SEPLA Anchor
SEPLA Anchor
Suction Pile vs Plate Anchor
SEPLA 5.75’ X 15’ 7.3 tons
SUCPILE 8’ X 25’ 24 tons
SUCPILE 8’ X 45’ 35 tons
High Holding Power Drag Anchors
Courtesy of Vryhof Anchors BV
High Holding Power Drag Anchors DeepC D4.1-02 Date: 30 Dec 2008 15:11:18
600 0
100
200
300
400
500
Local Z [m]
700
800
900
1000
1100
1200
1300
1400
Anchor line results
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Local X [m] AnchorAnalysis5.lineResult, Shackle depth Z=-14m AnchorAnalysis5.lineResult, Shackle depth Z=-6m AnchorAnalysis5.lineResult, Shackle depth Z=-0.1m
AnchorAnalysis5.lineResult, Shackle depth Z=-16m AnchorAnalysis5.lineResult, Shackle depth Z=-8m AnchorAnalysis5.lineResult, Shackle depth Z=-2m
AnchorAnalysis5.lineResult, Shackle depth Z=-18m AnchorAnalysis5.lineResult, Shackle depth Z=-10m AnchorAnalysis5.lineResult, Shackle depth Z=-4m
AnchorAnalysis5.lineResult, Shackle depth Z=-19.6m AnchorAnalysis5.lineResult, Shackle depth Z=-12m AnchorAnalysis5.lineResult, Shackle depth Z=-5m
High Holding Power Drag Anchors DeepC D4.1-02 Date: 30 Dec 2008 15:30:47
2
4
6
8
10
12
14
16
18
20
Anchor line results
-6 -8 -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10
Local Z [m]
-4
-2
0
0.
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
Local X [m] AnchorAnalysis5.lineResult, Shackle depth Z=-14m AnchorAnalysis5.lineResult, Shackle depth Z=-6m AnchorAnalysis5.lineResult, Shackle depth Z=-0.1m
AnchorAnalysis5.lineResult, Shackle depth Z=-16m AnchorAnalysis5.lineResult, Shackle depth Z=-8m AnchorAnalysis5.lineResult, Shackle depth Z=-2m
AnchorAnalysis5.lineResult, Shackle depth Z=-18m AnchorAnalysis5.lineResult, Shackle depth Z=-10m AnchorAnalysis5.lineResult, Shackle depth Z=-4m
AnchorAnalysis5.lineResult, Shackle depth Z=-19.6m AnchorAnalysis5.lineResult, Shackle depth Z=-12m AnchorAnalysis5.lineResult, Shackle depth Z=-5m
Pile Anchors DeepC D4.1-02 Date: 30 Dec 2008 17:12:16
700 600 500 0
100
200
300
400
Local Z [m]
800
900 1000 1100 1200 1300 1400
Anchor line results
0
200
400
600
AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1800kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1600kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1400kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1200kN
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
Local X [m]
Pile Anchors DeepC D4.1-02 Date: 30 Dec 2008 17:10:51
-10 -12 -24
-22
-20
-18
-16
-14
Local Z [m]
-8
-6
-4
-2
0
2
4
Anchor line results
0
5
10
15
20
25
AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1800kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1600kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1400kN AnchorAnalysis6.lineResult, Shackle depth Z=-20m, Dip down tension=1200kN
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
Local X [m]
SEPLA Anchors with Taut Leg DeepC D4.1-02 Date: 31 Dec 2008 11:43:40
700 600 500 0
100
200
300
400
Local Z [m]
800
900 1000 1100 1200 1300 1400
Anchor line results
0
100
200
300
400
AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=6000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=5000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=4000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=3000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=2000kN
500
600
700
800
900
1000
1100
1200
1300
1400
1500
Local X [m]
SEPLA Anchors with Taut Leg DeepC D4.1-02 Date: 31 Dec 2008 11:45:56
-8 -12 -10 -24 -22
-20 -18
-16 -14
Local Z [m]
-6
-4
-2
0
2
4
6
8
10
Anchor line results
-4
-2
0
2
4
6
8
AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=6000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=5000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=4000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=3000kN AnchorAnalysis7.lineResult, Shackle depth Z=-20m, Dip down tension=2000kN
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
Local X [m]
