Risk Analysis of a DP Diving Vessel Up Weather of a Platform · 2015. 1. 7. · 12 Global Maritime DP Weather Capability • Vessel had standard IMCA 1.5 knot current set and worse

1Global Maritime

Risk Management

Risk Analysis of a Dynamic Positioning Diving VesselUp Weather of a Platform and Jack Up

Doug PhillipsAmerican Global Maritime

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2Global Maritime

DP Risk AnalysisDP Risk AnalysisUp Weather DP Dive VesselUp Weather DP Dive Vessel


3Global Maritime

Presentation ContentPresentation Content••The ‘problem’ identifiedThe ‘problem’ identified••Vessel Vessel –– DP System, Capability, DP System, Capability, DPOsDPOs and and AuditAudit••Risk Picture Risk Picture –– frequency (industry and frequency (industry and vessel), exposure time, Drift of Drive off vessel), exposure time, Drift of Drive off (industry and vessel), Impact Energy ROMs (industry and vessel), Impact Energy ROMs ••Threats, Controls and MitigationThreats, Controls and Mitigation••ConclusionsConclusions


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The ProblemThe Problem


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The ProblemThe Problem••Three fixed platformsThree fixed platforms••Two Jack Up rigsTwo Jack Up rigs••Up weather DP diving vessel < 30 mUp weather DP diving vessel < 30 m••Strong prevailing currents up to 2 knotsStrong prevailing currents up to 2 knots••HAZID identified the collision riskHAZID identified the collision risk••Needed to quantify the riskNeeded to quantify the risk


6Global Maritime

The VesselThe Vessel


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Vessel’s DP SystemVessel’s DP System••Class 3Class 3••3 bow tunnels 3 bow tunnels –– 1100 kW1100 kW––18.75 tonnes18.75 tonnes••Auto Auto c’overc’over -- manual start bow thrustermanual start bow thruster••2 stern azimuths 2 stern azimuths –– 1300 kW1300 kW––21.87 tonnes21.87 tonnes••1 small 1 small skeg skeg tunnel 380 kW tunnel 380 kW –– 6.25 tonnes 6.25 tonnes ••6 Diesel 6 Diesel Gens Gens (4x1100kw, 2x 1300kW)(4x1100kw, 2x 1300kW)••Split 660VSplit 660V••Split and third 440VSplit and third 440V


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DP Control SystemDP Control System••Triple voting (Simrad)Triple voting (Simrad)••Back up (Simrad)Back up (Simrad)••Two taut wires (Alstom)Two taut wires (Alstom)••Two acoustics (Simrad & Two acoustics (Simrad & SonardyneSonardyne))••Two DGPS (Racal Multifix, Two DGPS (Racal Multifix, SatASatA, B, , B, spot beam)spot beam)••Three Gyros, VRS and Wind SensorsThree Gyros, VRS and Wind Sensors••Four UPSsFour UPSs


9Global Maritime

DP Operators & DPQADP Operators & DPQA••Four Four DPOsDPOs plus Captain (UK, Ireland, plus Captain (UK, Ireland, Poland, Italy, American)Poland, Italy, American)••One may be contract or from another vesselOne may be contract or from another vessel••12 hour on 12 hour of overlap 6 hours12 hour on 12 hour of overlap 6 hours••Senior & Junior together Senior & Junior together ••Six week rotationSix week rotation••Three week crew change (problem?)Three week crew change (problem?)••DPQA DPQA –– IMCA/IMO best industry practiceIMCA/IMO best industry practice


10Global Maritime

DP AuditDP Audit•• Failure Mode and Effect Analysis (FMEA) and Failure Mode and Effect Analysis (FMEA) and

proving trials.proving trials.•• Annual Trials. Annual Trials. •• DP Mobilization Trials.DP Mobilization Trials.•• DP Operator Training, Qualifications, DP Operator Training, Qualifications,

Familiarization and Experience.Familiarization and Experience.•• DP Operation’s Manual.DP Operation’s Manual.•• Capability Study.Capability Study.•• DP Watch keeping check lists.DP Watch keeping check lists.•• DP log books DP log books –– DP CertificatesDP Certificates.


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DP Worse Case FailuresDP Worse Case Failures••Loss of 660V swbd (short circuit) Loss of 660V swbd (short circuit) –– 1 1 Azimuth and one bow thrusterAzimuth and one bow thruster••Loss of one engine room (governor Loss of one engine room (governor 24V, fuel, cooling etc.) 24V, fuel, cooling etc.) -- samesame••Note transfers load to remaining side Note transfers load to remaining side ––doubles it.doubles it.••Loss of UPS Loss of UPS –– Stbd taut wire, DGPS 1 Stbd taut wire, DGPS 1 and both acoustics?and both acoustics?••Perfect position referencePerfect position reference


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DP Weather CapabilityDP Weather Capability•• Vessel had standard IMCA 1.5 knot current Vessel had standard IMCA 1.5 knot current set and worse case failureset and worse case failure••Performed new analysis on for 2 to 2.5 knot Performed new analysis on for 2 to 2.5 knot beam current and 20 knot head or stern windbeam current and 20 knot head or stern wind••As ran a test set to compare to 1.5 knot set As ran a test set to compare to 1.5 knot set –– large discrepancy large discrepancy –– 20 rather than 40 knots 20 rather than 40 knots concidentconcident••Tested on vessel Tested on vessel –– new analysis correctnew analysis correct


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Risk PictureRisk Picture


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Risk PictureRisk Picture••IMCA Platform Collision 93 IMCA Platform Collision 93 –– 7.13 DP yrs7.13 DP yrs••LOP 1 LOP 1 -- 7.69 months7.69 months••IMCA Shuttle Collision IMCA Shuttle Collision –– 29 DP yrs29 DP yrs••DeepStar Emergency Disconnect DeepStar Emergency Disconnect –– 11.6 yrs11.6 yrs••GM 1990 to 1998 LOP1 GM 1990 to 1998 LOP1 –– 2 yrs2 yrs••GM add 99 to 2001 GM add 99 to 2001 –– 2 + yrs2 + yrs••IMCA 2001 IMCA 2001 –– 8 well run LOP 1 8 well run LOP 1 –– 2.8 years2.8 years••Drift/Drive off Drift/Drive off –– 40:60 to 199340:60 to 1993••Drift/Drive off Drift/Drive off –– 60:40 since 60:40 since


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Risk ProfileRisk Profile•• Frequency Likely hoodFrequency Likely hoodOne or more times a year Almost certainOne or more times a year Almost certainOnce every 1 to 10Once every 1 to 10 LikelyLikelyOnce every 10 to 100Once every 10 to 100 PossiblePossibleOnce every 100 to 1000 UnlikelyOnce every 100 to 1000 UnlikelyOnce every 1000 to 10000 RareOnce every 1000 to 10000 Rare

••


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Vessel DP incidents Vessel DP incidents –– 5+yrs5+yrs••Four incidents since beginning of 1999Four incidents since beginning of 1999••Two were taut wire perfect referenceTwo were taut wire perfect reference••One was black out operator errorOne was black out operator error••One was thrusters left in fixed azimuth One was thrusters left in fixed azimuth mode mode –– operator erroroperator error••Nos of DP hours recorded Nos of DP hours recorded –– 16,92016,920••Equivalent to nearly two years DP in Equivalent to nearly two years DP in (about 40% of time)(about 40% of time)••No collisions No collisions –– No drive offsNo drive offs


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Vessel DP IncidentsVessel DP Incidents•• Four incidents in 16,920 DP hours over 5 Four incidents in 16,920 DP hours over 5 yearsyears•• One every 4,230 hours = 5.875 monthsOne every 4,230 hours = 5.875 months•• No collisions No collisions •• IMCA 93 that assumed 50% on DP here IMCA 93 that assumed 50% on DP here about 40% about 40% -- (2 years)(2 years)


18Global Maritime

DP Incident Causes IMCA 2001DP Incident Causes IMCA 2001•• Position References Position References –– 20 to 23%20 to 23%•• Computer Computer –– 20 to 23%20 to 23%•• Thrusters Thrusters –– 17%17%•• Operator Operator –– 17% (down from 25%)17% (down from 25%)•• Environment Environment –– 8% (up from 2%)8% (up from 2%)•• Rest Rest –– generators, electrical, othergenerators, electrical, other•• Looked at 90 to 2001, 90 to 95 and 95 Looked at 90 to 2001, 90 to 95 and 95 to 2001.to 2001.


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DP incident CausesDP incident Causes••Two ‘perfect’ position refs Two ‘perfect’ position refs –– refs or refs or computer or human error?computer or human error?••Two operator error Two operator error –– avoidableavoidable•• One would not have happened with divers One would not have happened with divers down down


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IMPACT ENERGIESIMPACT ENERGIES(consequences)(consequences)


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STANDARDSSTANDARDS••Impact Energy Impact Energy –– DnVDnV, LR, NORSOK, , LR, NORSOK, UKOOAUKOOA UK, UK, -- 5000 Tonnes at 2 m/s (10MJ)5000 Tonnes at 2 m/s (10MJ)••API API –– 1000T at 0.5 m/s (0.125 MJ)1000T at 0.5 m/s (0.125 MJ)


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Vessel Impact Energy ROMsVessel Impact Energy ROMs••10000, 10000, displdispl, 4000 added mass, environment , 4000 added mass, environment –– bows at 33%, azis 50%, no dragbows at 33%, azis 50%, no drag••Drift off 10 m 40 T environment Drift off 10 m 40 T environment –– 3.77 MJ3.77 MJ••Drift off 20 m 40 T environment < 6.52 MJDrift off 20 m 40 T environment < 6.52 MJ••Drift off 30 m 40 T environment < 8.56 MJDrift off 30 m 40 T environment < 8.56 MJ••Drive off 10 m 80 T (40:40) < 7.51 MJ Drive off 10 m 80 T (40:40) < 7.51 MJ ••Drive off 20 m 80 T (40:40) < 13.09 MJDrive off 20 m 80 T (40:40) < 13.09 MJ••Drive off 30 m 80 T (40:40) < 17.45 MJDrive off 30 m 80 T (40:40) < 17.45 MJ••Further off greater the energyFurther off greater the energy••Better chance of recovery or missBetter chance of recovery or missReturn to Session Directory

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What is a Mega Joule?What is a Mega Joule?

••5800 lb SUV with 800 lb pay load (3 5800 lb SUV with 800 lb pay load (3 TonneTonne) ) at 30 mph at 30 mph ••0.25 MJ0.25 MJ


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¼ of a Mega Joule?¼ of a Mega Joule?


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Impact Energy?Impact Energy?••DNV DNV –– 66% vessel and 33% rig66% vessel and 33% rig••HSE HSE –– 65% vessel and 35% rig (14 to 4 ratio)65% vessel and 35% rig (14 to 4 ratio)

••1.25 MJ (10m drift off)1.25 MJ (10m drift off)•• to 5.81MJ (30m drive off)to 5.81MJ (30m drive off)

••Consequences Consequences ------------------••Jack Up 1 Jack Up 1 –– 14 MJ 14 MJ –– Minor to ModerateMinor to Moderate••Jack Up 2 Jack Up 2 –– 5 MJ 5 MJ –– Minor to ExtremeMinor to ExtremeReturn to Session Directory

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Quantifying the RiskQuantifying the Risk

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Exposure TimeExposure Time••9 days in position of critical exposure time 9 days in position of critical exposure time assumed 10 daysassumed 10 days••2 days two and 5 days at the other2 days two and 5 days at the other••Of that 10 hours with heading totally restricted Of that 10 hours with heading totally restricted and beam to current and beam to current –– assumed 12 hoursassumed 12 hours


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Risk ProfileRisk Profile

High100

High30

Moderate10

Low3

Low1

1Rare1000 to 10000

Extreme300

High90

Moderate30

Low 9

Low3

3Unlikely100 to 1000

Extreme1000

Extreme300

High100

Moderate

30

Low 10

10Possible10 to 100 yrs

Extreme3000

Extreme900

High300

High90

Moderate 30

30Likely1 to 10 yrs

Extreme10000

Extreme3000

Extreme1000

High300

High100

100Almost Certain

<1yr

ExtremeMajorModerateMinorLowFactorLikelihood

100301031Factor

Consequences


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Risk ProfileRisk Profile

3 to 1003 to 10Rare (IMCA (93 and 12 hour exposure

9 to 3009 to 30Unlikely (IMCA 2001)

30 to 100030 to 100Possible – IMCA 93 – 10 days exposure

Jack Up 2(minor to extreme)

Jack Up 1(minor to moderate)

Consequences______________________________________________________________

_

Likelihood


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Threats Threats -- ProblemsProblems••Unknown DP system faultsUnknown DP system faults••Operator ErrorOperator Error••Systematic FaultsSystematic Faults••Unexpected change in the weatherUnexpected change in the weather••Fast change in the currentFast change in the current


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Mitigation/ControlsMitigation/Controls••Op Class 3 Op Class 3 -- 660V, fuel, cooling, 440V split660V, fuel, cooling, 440V split••DP Control System limitations known, DP Control System limitations known, researched and researched and DPOs DPOs trainedtrained••Capability CheckedCapability Checked••Manned ECRManned ECR••Main pumps on correct side of boardMain pumps on correct side of board••Back ups check at mobilizationBack ups check at mobilization••Attend Annual Trials and UKOOA AuditAttend Annual Trials and UKOOA Audit••Test loss of swbd and transfer of loadTest loss of swbd and transfer of load


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Mitigation/ControlsMitigation/Controls••Test all DGs and thrusters to full loadTest all DGs and thrusters to full load••Power Limits Power Limits –– 33% thrust Bow, 50% azis, 33% thrust Bow, 50% azis, 50% each swbd 50% each swbd –– 40 T pull off40 T pull off••Independent measurement and alarm of Independent measurement and alarm of distance to closest point (fan beam)distance to closest point (fan beam)••Control of DP shift after crew change Control of DP shift after crew change ••Accurate weather forecastsAccurate weather forecasts••Weather fronts watched forWeather fronts watched for••Accurate current informationAccurate current information


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Mitigation/ControlsMitigation/Controls••Worse heading Worse heading –– got choice of most got choice of most favorable conditionsfavorable conditions••Consequence analysis selectedConsequence analysis selected••Fast Current updateFast Current update••Back up tests Back up tests –– pumps, batteries, diodespumps, batteries, diodes••Survey to show vessel, rig and platform at Survey to show vessel, rig and platform at DP position DP position


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CONCLUSIONSCONCLUSIONS


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CONCLUSIONSCONCLUSIONS••Initial assessment was Initial assessment was ‘likely’‘likely’ but given but given the exposure time this was reassessed as the exposure time this was reassessed as ‘unlikely’‘unlikely’ and for the critical work as and for the critical work as ‘rare’‘rare’••Vessel capable of operating in the Vessel capable of operating in the prevailing conditions (2 knots beam and prevailing conditions (2 knots beam and head wind head wind –– 20 knots)20 knots)••Vessel well operated and limitations knownVessel well operated and limitations known••Risk ALARP provided all risk reduction Risk ALARP provided all risk reduction measures identified were implemented prior measures identified were implemented prior to the start of the operation. to the start of the operation.


36Global Maritime

DP Risk AnalysisDP Risk AnalysisUp Weather DP Dive VesselUp Weather DP Dive Vessel


Documents

Risk Analysis of a DP Diving Vessel Up Weather of a Platform · 2015. 1. 7. · 12 Global Maritime DP Weather Capability • Vessel had standard IMCA 1.5 knot current set and worse