improving subsurface safety valve reliability_ a problem_solution approach - offshore

10/08/2015 Improvingsubsurfacesafetyvalvereliability:aproblem/solutionapproachOffshorehttp://www.offshoremag.com/articles/print/volume57/issue11/news/generalinterest/improvingsubsurfacesafetyvalvereliabilityaproblemsolutiona 1/8HomeImprovingsubsurfacesafetyvalvereliability:aproblem/solutionapproach11/01/1997SafetyreliabilityrequiresongoingimprovementsDonAldridgeBakerOilToolsInthissafetyvalvedesign,thelockopensleeveisremovedandinitsplaceisaradialpunchcommunicationssystem,providingasmoothID.[16,430bytes]Conventionally,wirelineconveyedshiftingtoolsseekamatchingprofilewhengoingintothewellandwilloftenactivatethelockopensleeveandcausethedownholevalvetofail.[7,678bytes]Surfacecontrolled,subsurfacesafetyvalves(SCSSVs)arebecomingmoreandmorecommoninonshoreaswellasoffshoreoperationsthroughouttheworldbecauseoftheirabilitytoprotectlives,theenvironment,andoperators'investmentsifthewellheadbecomesdamaged.TheUSGovernmentnowrequiressafetyvalvesformostGulfofMexicooperations,andothercountries'governmentsarefollowingsuit.Inadditiontobeingnecessarytopreventunwantedflowduringcatastrophicevents,safetyvalvereliabilitycanleadtolongercompletionlifeandcurbunwantedworkovers,thusreducinglifecyclecostsforwellsandfields.TheimportanceofthisissuewasemphasizedseveralyearsagoinanindependentstudyonSCSSVsafetyandreliability,conductedbytheFoundationforScientificandIndustrialResearch(SINTEF)attheNorwegianInstituteofTechnology.Insuggestingthatpurchasingdepartmentslookmoretowardthelifecyclecostforwellsratherthanfocusingstrictlyontrialpurchasingcost,SINTEFaddressedtheimportanceofconsideringSCSSVreliability,forbothsafetyandproductionregularity.Atthetimeofthereport,thereliabilityofallvalveclasseshadimprovedsignificantlysincethefoundation'spreviousreport.However,opportunitiesforfurtherimprovementexisted.HOME MOREOILPRODUCTIONNEWS IMPROVINGSUBSURFACESAFETYVALVERELIABILITY:APROBLEM/SOLUTIONAPPROACHIndependentsgalvanizemarginalTunisianfielddevelopments|PreviousArticleNextArticle|NorwayimprovingtaxconditionsforFPSOleasingHOMEREGIONALREPORTSDRILLING&COMPLETIONFIELDDEVELOPMENTSUBSEAGEOSCIENCESPIPELINESPRODUCTIONRIGS/VESSELSDEEPWATERBUSINESSBRIEFS10/08/2015 Improvingsubsurfacesafetyvalvereliability:aproblem/solutionapproachOffshorehttp://www.offshoremag.com/articles/print/volume57/issue11/news/generalinterest/improvingsubsurfacesafetyvalvereliabilityaproblemsolutiona 2/8WhyvalvesfailWhilesomedownholeequipmentremainsstaticthroughoutthelifeofthecompletion,safetyvalvesareroutinelyopened,closed,andtestedtoensurethattheyarereadyandworkingproperlyintheeventofacatastrophe.However,thevalvessometimesfailduringnormalproductionoperationsduetoelastomerfailure,failureofpressfitplugs,orprematureactivationoflockoutfeatures.Ifavalvefailsduringoneoftheseprocedures,itgenerallynecessitatesanunscheduledworkoverwhichinterruptsproductionand,particularlyindeepwaters,canbeveryexpensive.Or,itmayrequiretheinstallationofaninsertsafetyvalvewithrestrictiveinternaldiameters.Failureofthecontrolfluidcommunicationsystemhasbeenshowntobetheprimarycauseofsafetyvalvefailures.Infact,theSINTEFstudyrevealedthatmorethan25%offailuresinconventional,normallyclosed,tubingretrievablesubsurfacesafetyvalveswerelinkeddirectlytoleakagebetweenthehydrauliccontrollinechamberandthetubingwellbore,throughthewirelineinsertvalvecommunicationfeature.Inmostfailures,theleakagewascausedbyprematureorinadvertentactivationofthelockopensleeveintheIDofthevalve.Anewsafetyvalvedesignedaroundapatentedcontrolfluidcommunicationfeatureprovidesanuninterruptedcontrolfluidpathtothepistonandpreventsaccidentalactivationoflockopensleeves.FailureanalysisIndependenttestingandfieldexperienceconfirmthataccidentalactivationofsubsurfacesafetyvalvesislinkedtolinearmotionsleevedesignsthatareintegraltomanysafetyvalves.WhenroutineinterventionmethodsareperformedsuchasusingashiftingtooltooperateaslidingsleeveandbringanewzoneonproductionthewirelineorcoiledtubingthatconveysthetoolmustpassthroughtheIDofthevalve.Unfortunately,theprofileofthevalve'slinearmotionlockopensleeveisverysimilartothatofothertubingmountedaccessories,suchasnipplesandslidingsleeves.Thewirelineorcoiledtubingconveyedtoolsautomaticallyseekamatchingprofilewhentheyaregoinginthewell.Thus,iftheyhitonanyoftheshouldersorprofilesinthelockopensleeve,theywilllikelyactivateit,causingthecontrolfluidtoleakandthevalvetofail.Thiscallsforexpensive,correctivewellreentryprocedures.EliminatingvulnerabilityThepreviouslydescribed,newlydesignedtubingretrievablesafetyvalveremovesthelockopensleevefromthevalveandsubstituteslinearlockopenmotionwithapatented,radialpunchcommunicationsystem.ThesedesignchangesleavethesafetyvalvewithasmoothID,freeofsleevesorotherdevicesthatmovelinearlyandcanhangupwirelineorcoiledtubingconveyedtools.Controlfluidcommunicationtothelockopensleeveisachievedonlybyradialmotionofaonetrip,jardownwirelinetool.Asaresult,thereisnopossibilityforothertoolstoaccidentallyactivatethelockopenfeaturewhilepassingthroughtheIDofthevalve.Intheeventthatifbecomesnecessarytopuncturethevalve,onlythecylindersubispunctured.Therestofthevalveremainsintact.Thenewradialpunchdesignhascompiledafieldhistoryandhasdisplayedalevelofdependabilitythathasgainedoperatoracceptance.After2300installations,therehavebeennovalvefailuresduetoprematurelockopen.10/08/2015 Improvingsubsurfacesafetyvalvereliability:aproblem/solutionapproachOffshorehttp://www.offshoremag.com/articles/print/volume57/issue11/news/generalinterest/improvingsubsurfacesafetyvalvereliabilityaproblemsolutiona 3/8PerformanceimproversInadditiontoradialpunchcommunication,othersafelyvalvedesignfeaturecanfurtherenhanceperformanceintegrity.Outerhousingthreadseals:Thesealsusedintheouterhousingsofsafetyvalvesarecriticaltosafetysystemreliability.Failureinthesesealscanleadtoatubingtoannulusleak,andpossiblyaworkover.Metaltometalhousingconnectionscaneliminateexplosivedecompression,chemicalandthermaldegradation,andotherproblemsassociatedwithelastomericsealingsystems.Atwostepthreaddesigncanfurtherextendthevalve'sservicelifebydistributingloadingonthethreadmoreefficiently,andprovidingsignificantlygreaterstrengthforagivensectionthicknessthanasinglestepdesign.Closuremechanism:Astrongclosuremechanismcanprotectthevalveseatfromstressinduceddamagetoensurecontinuouslyreliablesealing.Athick,wedgeshapedflapperclosuremechanismhasbeenproventobeparticularlyeffectiveforthispurpose.Thewedgedesignmovesthefirstpointofcontactwiththeflowtubeawayfromthehingepintominimizeloadingonthehingeandflapperpin.Aspecialhingedesignvitallyeliminatesflapperpinbending.Selfequalizingmechanism:Anintegralequalizingmechanismeliminatestheneedtoequalizedifferentialpressureacrosstheflapper.Byventingshutinpressurefrombelowthesafetyvalvetothetubingabovetheflapper,avalvecanbeequalizedandcanreturnthewelltoproductionquicker,safer,andmoreefficientlythanwhenpumpsandfluidsmustbeused.Particularlyeffectiveisathroughtheflapper,metaltometalselfequalizingsystemthateliminatesvalvefailurecausedbyerosionproblemsorbuildupoffluiddebrisinthevalveannulus.SlamtestingGasslamtestsareanexcellentindicationofthereliabilityofasubsurfacesafetyvalve.Toeffectivelyevaluatethevalve,thesetestsmustduplicateorexceedreallifedownholeconditionspresentwhenthewellisflowing,thecontrollineisbledoff,andthesafetyvalvecloseswiththeflowagainsttheflapper.Thefollowinglistrepresentssuggestedminimumrequirements:Twentyslams,ofwhich15are:200ft/sec(41MMscfd)for23/8in.valves200ft/sec(58.5MMscfd)for27/8in.valves200ft/sec(102.7MMscfd)for3l/2in.valves150ft/sec(146.0MMscfd)for4l/2in.valves125ft/sec(120.7MMscfd)for51/2in.valvesand80ft/sec(146MMscfd)for7in.valves.Theseflowratesareashighas10timesthoserequiredbytheAPI.Continuedtechnologicaladvancements,suchasthosedescribedhere,whichcansubstantiallyimprovesafetyvalvereliability,willbekeytomeetingthecombinedeconomic,environmental,andhumansafetystandardsthatwilldrive21stCenturyenergydevelopmentandutilization.References"ReliabilityofSurfaceControlledSubsurfaceSafelyValvesPhaseIV",FoundationforScientificandIndustrialResearch,NorwegianInstituteofTechnology,ReportNo.STF75R91038,1992.Copyright1997Oil&GasJournal.AllRightsReserved.10/08/2015 Improvingsubsurfacesafetyvalvereliability:aproblem/solutionapproachOffshorehttp://www.offshoremag.com/articles/print/volume57/issue11/news/generalinterest/improvingsubsurfacesafetyvalvereliabilityaproblemsolutiona 4/8SPSOverlayprovidessideimpactprotectiononthreeFPSOsDec17,2014SPSOverlayhasprovidedsideimpactprotectionforthreeFPSOs.TheworkwascarriedoutatEnseadadoParaguauSAShipyards(EEP)inBrazilandattheCOSCO(Dalian)ShipyardinChina.EnicompletesproductiontestonwelloffshoreCongoDec15,2014EnihascompletedtheproductiontestontheMinsalaMarine1NFW,locatedintheMarineXIIblockoffshoreCongo.BlueOceansetsdeepwatersubseainterventionrecordDec15,2014BlueOceanTechnologieshassetanotherrecordfordeepwatersubseainterventions.BlueOceansInterchangeableriserlessinterventionsystem(IRIS)recentlyintervenedonadeepwaterproductionwe...LiuhuagasfieldgoesonstreamoffshoreChinaDec15,2014CNOOChasstartedproductionfromtheLiuhua342gasfieldintheeasternSouthChinaSea,wherewaterdepthsrangefrom8501,250m(2,7894,101ft).NorthSeaHuntingtonstilloutofactionDec15,2014NorecosaysproductionfromtheE.ONRuhrgasoperatedHuntingtonfieldintheUKcentralNorthSearemainsshutin,duetoanincidentthataroseduringrestartoftheCATSriserplatform.MoreOffshoreIssueArticlesOffshoreArticlesArchivesRELATEDARTICLESIndependentsgalvanizemarginalTunisianfielddevelopments|PreviousArticleNextArticle|NorwayimprovingtaxconditionsforFPSOleasing10/08/2015 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5/8OffshorephotoofthedayMexicorevisesrulesforsecondphaseofRoundOneauctionAug7,2015MexicosoilregulatorhasunveiledmoreattractiverulesforthesecondphaseofthecountrysRoundOneoilauction,accordingtoareportintheLatinAmericanHeraldTribune.HorizonGeosciencesaddsnewvesselAug7,2015HorizonGeoscienceshasaddedtheKommandorStuartvesseltoitsfleet.BechtelreceivesFEEDcontractforPortDelfinFLNGvesselAug7,2015DelfinLNGhaschosenBechteltoprovidefrontendengineeringanddesignforwhatwouldbethefirstUSbasedFLNGvesseltogoontheproposeddeepwaterport50mi(80km)offshoreCameronParish,Louisiana.Phase1MexicoSPANfasttrackdataavailablefromIONGeophysicalAug7,2015IONGeophysicalhasavailablethefasttrackprestacktimemigrateddatafromPhase1ofitsMexicoSPANprogram.OFFSHORETOPICSDrilling&CompletionFieldDevelopmentSubseaGeosciencesPipelinesProductionRigs/VesselsDeepwaterBusinessBriefsREGIONALREPORTSTRENDINGNEWS10/08/2015 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