(BP) Flexible Riser Integrity Management Experience West ...

1 FlexibleRiserIntegrityManagementExperien ceWestofShetlandDavidKayeUKIndustrySemin ar,November20082 Contents WestofShetlandoverview Integritymanagementexperience)Bendstiffe ners)Risermonitoring)Leakdetection)Corro sion-fatigue)Marinegrowth Conclusions3 WestofShetlands4 Foinaven Located190kmWestofShetlandin330-520mwate rdepth PetrojarlFPSO,operatedbyTeekay Startup1997 Oilexportbyshuttletanker Gasexportvia20 WOSPStoSullomVoe 10flexiblerisers) production) production/test) gaslift/export)1off10 waterinjection5 Schiehallion Located175kmWestofShetlandinapprox400mwa terdepth SchiehallionFPSO Startup1998 Oilexportbyshuttletanker Gasexportvia20 WOSPStoSullomVoe 15flexiblerisers) production) production/test) gasdisposal/export) gaslift/export) waterinjection)1off11 production/test/gasstructure6 WestofShetlandsIntegrityManagement BPoperatorofsubseasystemforbothFoinavena ndSchiehallion Significantattentiontoriserintegritysinc einstallation)Monitoringandinspection)Ri sk-basedpipelineintegritymanagementsyste m,PIMS)BPIntegrityManagementStandard Keycontractors)AkerSolutions=subseaengin eeringcontractor)

2 MCS=flexibleriserengineeringcontractor)T echnip=flexiblerisers,flowlines,jumpers) Wellstream=flexibleflowlines,jumpers)Sub sea7=IRMcontractor(SubseaViking)7 SchiehallionBendStiffeners Schiehallionbendstiffenersarelarge,two-p artdesign Recentexperienceofslippageofinnerbendsti ffenerRiserInnerbendstiffenerOuterbendst iffenerBendstiffenerconnector8 StiffenerIntactPartialSlippageFullySlipp edSchiehallionBendStiffeners9 Bendstiffenerchange-outsperformed2007)6b endstiffenersreplacedonexistingrisers)1b endstiffenerinstalledwithnewriserRecover edbendstiffenersReplacementbendstiffener sSchiehallionBendStiffeners10 RiserAnchorMonitoringSystem(RAMS) Sonarsystemtomonitoranchorsystem,risersa ndbendstiffeners FieldtrialFoinaven,July2007)Sonarmonitor ingtooldevelopedbySRD)Deploymentsystemth roughspareI-tube)Deploymentsystemdevelop edbySP1 RiserMonitoring11 DeploymentsystemRiserMonitoring(RAMS)RAM S screendisplay12 SheathDamage SheathdamageonbothFoinavenandSchiehallio nrisers Annualmonitoringthroughannulusvacuumtest ing Detectionusingflourescentdyeandlaserleak detection Repairclampsdevelopedforknownbreaches Example)FoinavenR10)

3 Repairclampinstalled200713 SheathDamageLeakLocation Example)FoinavenR2)Justbelowuppertetherc lamp)Repairclampinstalled200714 Corrosion-Fatigue Fatigueofarmoursisbecomingmoreofaconcern )Historicalsheathdamageleadingtoannulusf looding)IncreasingH2 Slevels)Fatiguecriteria Keyissues)Monitoringofannuluscondition)M onitoringofprocessconditions)Protectiono fannulus)Flushingwithinhibitingfluid15 Corrosion-Fatigue FoinavenR8risercasehistory)Pre-installed 1996)Firstoperation1997)Varioussheathbre achesidentifiedandclampedbetween1997-200 3)Flushingwithinhibitorfluidinitiatedin1 997) ,000litresflushingfluidconsumedupto2003 Fatigueassessedatdesignandearly2000 Fatiguereassessedin2007/8duetoincreasing fatigueconcerns16 Corrosion-Fatigue Clampat-301m,Oct1997 Clampatseabed,May2002 Clampat-80m,Sep200317 Corrosion-Fatigue Annulusenvironment)H2 Sproductionincreasingsince2002)Permeatio ncalculationsperformedbyTechniptodetermi neH2 Sconcentrationinannulus)Predictedannulus H2 Slevels7mbar18 Corrosion-Fatigue Fatiguetesting)FI-09 SNcurvedatacurrentlyavailableforflushed( sweet)conditions)Nodataavailableforflush ed(sour)conditions)Wirefatiguetestingpro grammeinitiatedforsourserviceconditions) WorkperformedbyMarintek)

4 Wiresamples/dissectionofrepresentativest ock19 Corrosion-Fatigue Oneyearfatigueassessmentprogramme)SNcurv ederivedfromMarintektests)Globalriserana lysisperformedbyMCS)Localfatigueanalysis performedbyTechnip)Quantitativeriskasses smentperformedbyMarintek Conclusions:)Riserfatiguelifewasunaccept ableforremainingfieldlife Riserchangedoutwithspareriserin200820 MarineGrowth Foinavendynamicumbilicals)As-builtinblac k)As-found200721 BeforecleaningAftercleaningMarineGrowth2 2 MarineGrowth Specificmarinegrowth)Particularlyheavy( ))Significantlyheavierthanconsideredinde sign)Noknownindustryexperienceofthistype ofproblemonrisers)Rapid(exponential)expa nsionofgrowthoverlastfewyears Currentstatus)Extensivemarinegrowthremov alprogramresultedinre-floating)Outershea thdamageidentifiedclosetoRGBtouchdown( 08repair)23 Conclusions ExtensiveoperatingexperienceWestofShetla nd)Foinavenfield11yearsoperation)

5 Schiehallionfield10yearsoperation)Moreth an250riser-yearsoperationinbothfields Keyintegritymanagementissues)Monitoringo fbendstiffeners)Annulusmonitoringtoident ifysheathdamage)Monitoringofannulustoide ntifypotentialforcorrosion-fatigue)Fatig uepredictionandmanagement