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

8

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

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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 PivanoLuca.pivano@dnvgl.com

Martin PoirierMartin.poirier@total.com

www.dnvgl.com www.total.com

SAFER, SMARTER, GREENER

Thanks!