DYNAMIC POSITIONING CONFERENCE October 11-12, 2016
OPERATIONS
Planning of Drilling Operations in Extreme Ocean Currents
Luca Pivano - Marine Cybernetics/DNV GL Kristopher Eide - Marine Cybernetics/DNV GLØyvind Smogeli - Marine Cybernetics/DNV GL
Per Frederiksen - Maersk DrillingMartin Poirer - Total Exploration and Production
Planning Of Drilling Operations In Extreme Ocean Currents Experience From Time-domain Simulations and Full-scale Validation On Maersk Venturer
MTS DP conference – Houston 12th Oct 2016
Martin Poirier (TOTAL) and Luca Pivano (DNV GL)
Planning of drilling operations in extreme ocean currents - DP conference – Houston 12th Oct 2016 2
Ongoing demand for energy + decreasing supplies of traditional fossil fuels Further offshore and deeper Toward more extreme environment
Operators are facing new challenges! More operational constraints & risks Increasing operating costs
Requirements for: Improving the operating philosophy Extending equipment limits Innovative tools for operation & preparation
INTRODUCTION
Planning of drilling operations in extreme ocean currents - DP conference – Houston 12th Oct 2016 3
Raya-1 project3404m water depth (world record)Harsh Weather (wind , waves, current)Remote operationsNo O&G business in UruguayLast wells drilled offshore Uruguay in 1976 (shelf context)
Challenges:Station keepingRig motionPositioning strategy vs riser preservationCrew competencyHSECost efficient solution
Raya-1
MoooooooooCONTEXT
WELL PREPARATION – MARINE ASPECTS
Planning of drilling operations in extreme ocean currents - DP conference – Houston 12th Oct 20164
Metocean acquisition
Collection of Metocean data
(hindcasts) Calibration & interpretation
Environmental constraints
(1yr ,10yrs,100 yrs return periods )
PHASE 1 – METOCEAN ANALYSIS
PHASE 2 – RIG SELECTION
DP capability study
(and/or mooring analysis) CPY
requirements
Design review
Rig motion analysis
Rig selected
Preliminary riser study
Planning of drilling operations in extreme ocean currents - DP conference – Houston 12th Oct 2016 5
PHASE 3 – OPERABILITY STUDY
WoW & NPTTargets
Station keeping performances
Rig motion performances
Riser study
Operating limits
Time domain
simulations
PHASE 4 – PREPARATION & OPTIMZATION
Training / crew preparation
Objectives (HSE, budget)
WSOG
Operating philosophy
Spud
Risk assessment
Trials / Tests
Identification of additional
support tools
Full scale validation
DNV GL © 2016
Ungraded
27 September 2016
Full-scale trials with Maersk Venturer
Samsung 96K design (V-class series drill ship)
Advanced Thruster and Engine control
Specially designed Power Managements System
Fast blackout recovery and enhanced blackout prevention
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Description Symbol Unit ValueLength over all LOA m 228Length between perpendiculars LPP m 219Breadth B m 42
Description Symbol Unit ValueDraught T m 11Mass displacement m tonnes 88218Transverse metacenter height GMT m 3.9
6 x 5500 kW Azimuth
Thrusters
DNV GL © 2016
Ungraded
27 September 2016
Trial location – South African coast
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Goals:
– Station-keeping performance in high current (Agulhas)
– Vessel motion with medium/high waves
Measurements:
– DP control system logs (wind speed, GPS, Gyro, VRU, Thruster, Generators, etc.)
– Wave radar (Hs, wave period, Hmax)
– Wave direction measured by the crew
– ADCP: Current speed and direction once a day at 49 m
Weather: 2.11 m/s current speed, 6 m Hs, 20 m/s wind speed
Vessel location with respect to current forecast for Day 1
Vessel location with respect to current forecast for Day 3
Vessel location with respect to current forecast for Day 2
Vessel location with respect to current forecast for Day 4
DNV GL © 2016
Ungraded
27 September 2016
Summary of the trials – 31 tests
Station-keeping in DP at various heading
Significant and sudden change of heading in DP
Station-keeping in DP – worst single thruster failure and worst case single failure
Track-following in DP
Simulated power blackout tests in addition with drift off tests
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DNV GL © 2016
Ungraded
27 September 2016
Summary of the trials – 31 tests
Station-keeping in DP at various heading
Significant and sudden change of heading in DP
Station-keeping in DP – worst single thruster failure and worst case single failure
Track-following in DP
Simulated power blackout tests in addition with drift off tests
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-150 -100 -50 0 50 100 150
-200
-150
-100
-50
0
50
East Position [m]
North
Pos
ition
[m]
-100 -80 -60 -40 -20 0 20 40 60
-120
-100
-80
-60
-40
-20
0
20
40
60
East Position [m]
North
Pos
ition
[m]
DNV GL © 2016
Ungraded
27 September 2016
Summary of the trials – 31 tests
Station-keeping in DP at various heading
Significant and sudden change of heading in DP
Station-keeping in DP – worst single thruster failure and worst case single failure
Track-following in DP
Simulated power blackout tests in addition with drift off tests
10
worst single thruster failure worst case single failure Intact
DNV GL © 2016
Ungraded
27 September 2016
Summary of the trials – 31 tests
Station-keeping in DP at various heading
Significant and sudden change of heading in DP
Station-keeping in DP – worst single thruster failure and worst case single failure
Track-following in DP
Simulated power blackout tests in addition with drift off tests
11
DNV GL © 2016
Ungraded
27 September 2016
Summary of the trials – 31 tests
Station-keeping in DP at various heading
Significant and sudden change of heading in DP
Station-keeping in DP – worst single thruster failure and worst case single failure
Track-following in DP
Simulated power blackout tests in addition with drift off tests
12
DNV GL © 2016
Ungraded
27 September 2016
Station-keeping results
13
-8 -6 -4 -2 0 2 4 6 8-8
-6
-4
-2
0
2
4
6
8
East (m)
Nor
th (m
)
Wind, 18.1m/sWaves, Hs 4.0m
Current, 1.1m/s
Weather: 1.13 m/s current speed, Hs 4 m, 18 m/s wind speed
DNV GL © 2016
Ungraded
27 September 2016
Station-keeping results
14
Weather: 1.13 m/s current speed, Hs 3.2 m, 16.4 m/s wind speed
N
E
S
W Current
Trial 21-5 -4 -3 -2 -1 0 1 2 3 4 5
-5
-4
-3
-2
-1
0
1
2
3
4
5
East (m)
Nor
th (m
)
Scenario 21
Wind, 16.4m/s
Waves, Hs 3.4m
Current, 1.1m/s
DNV GL © 2016
Ungraded
27 September 2016
Station-keeping results
15
Weather: 1.13 m/s current speed, Hs 4.5 m, 17.4 m/s wind speed
N
E
S
W Current
Trial 24-5 -4 -3 -2 -1 0 1 2 3 4 5-5
-4
-3
-2
-1
0
1
2
3
4
5
East (m)
Nor
th (m
)
Scenario 24
Wind, 17.4m/sWaves, Hs 4.8m
Current, 1.1m/s
DNV GL © 2016
Ungraded
27 September 2016
Heave, Roll and Pitch
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Max heave: 5 m (top-trough)Max roll: 2.5 degreesMax pitch: 2 degrees
DNV GL © 2016
Ungraded
27 September 2016
Heave, Roll and Pitch
17
Max heave: 5 m (top-trough)Max roll: 2.5 degreesMax pitch: 2 degrees
DNV GL © 2016
Ungraded
27 September 2016
Heave, Roll and Pitch
18
Max heave: 5 m (top-trough)Max roll: 2.5 degreesMax pitch: 2 degrees
DNV GL © 2016
Ungraded
27 September 2016
Station-keeping results
19
Robustness of station-keeping with heading away from optimal heading – up to 35/40 degrees with high current
Vessel heading against current or waves?
Maersk and Total pleased with the vessel performance, both regarding station-keeping and vessel motion
N
E
S
W
Trial 11N
E
S
W Current
Trial 21N
E
S
W Current
Trial 24
DNV GL © 2016
Ungraded
27 September 2016
Time-domain simulations with DynCap
Full-motion simulator
Dynamic environmental loads
Propeller dynamics and losses
Power system dynamics
Position Refs and sensors
DP control system
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DP control system dynamics
Propeller dynamics
Vessel motion
Thrust losses
Pos-refs and sensors
Power system dynamics
Dynamic environmental loads
DNV GL © 2016
Ungraded
27 September 2016
Station-keeping comparison
22
DNV GL © 2016
Ungraded
27 September 2016
Heave, roll and pitch
Heave difference was max 60 cm for 95% of the simulations
Roll and pitch differences was always less than 1 degree
23
DNV GL © 2016
Ungraded
27 September 2016
Thruster failure tests – Transient analysis
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Trial 5:- Loss of THR 1- 1.95 m/s current speed- Hs 2.85 m- 9.4 m/s wind speed
Trial 6:- Loss of THR 1 and 4- 1.95 m/s current speed- Hs 2.66 m- 13.8 m/s wind speed
DNV GL © 2016
Ungraded
27 September 2016
Uncertainty in the results
Simulator model uncertainty
Environmental conditions uncertainty
– Current velocity and direction measured once a day
– Wave direction observed by the crew
Lengths of the simulations when comparing maxima (5 wave random seeds)
DP control system tuning and gains – Simulator vs actual vessel
DP control system steady-state before a test started
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DNV GL © 2016
Ungraded
27 September 2016
Conclusion
4 days of trials performed in harsh weather
Maersk Venturer performed very well in station-keeping, both in positioning and vessel motion
With the weather during the test there was no a clear gain on having the vessel heading toward the current or towards the waves
The vessel responded very well upon thruster failure tests
Experience was gained during the heading change trials
DynCap time-domain simulations performed for comparison
Simulation results showed satisfactory agreement for both positioning and vessel motion
Such tool could be used for operational planning (WSOG)
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Planning Of Drilling Operations In Extreme Ocean Currents Experience From Time-domain Simulations And Full-scale Validation On Maersk Venturer
Luca [email protected]
Martin [email protected]
www.dnvgl.com www.total.com
SAFER, SMARTER, GREENER
Thanks!