wp lifecycle cost reduction while improving well … word - wp lifecycle cost reduction while...
TRANSCRIPT
Copyright©PetroleumTechnologyCompany2016
LifecycleCostReductionwhileImprovingWellIntegrityandReliabilityonGasVentedESPWellsAllrightsreservedPetroleumTechnologyCompany(hereinafterPTC)2016.Reproduction,distributionorstorageofanykindwithoutthewrittenconsentfromPTCisprohibited.AbstractThepracticeofventinggasvia theTubingCasingAnnulus (TCA) iscommon inmanyESP liftedwells.However, tocomply with double barrier well integrity policies, until now, it has been necessary to install a vent packer anddownholeannulussafetyvalve(DHASV).Thiswhite paper describes a newuse for field proven technologies,which can eliminates this requirement. As aresultworkoversaresimplified,welllifecyclecostsarereduced,wellintegrityisenhanced,ESPsystemreliabilityisimprovedandinsomecasesproductionwillbeincreased.DoublebarrierIntegrityonGasVentedESPliftedWells?TheNorsokD10‘WellIntegrityforDrillingandWellOperationsGuidelines’describes‘MultiPurposeWells’as“wellsthathastransportofmediatoorfromaformationintervalviatheAAnnulusinadditiontoviathetubing”. Italsostates: “allmulti purposewells shall have two barriers to prevent release of the A Annulusmedia”. Typically theprimarybarrier toannulus flowhasbeenaventpacker,and thesecondarybarrier theproductioncasingand thewellheadanditsassociatedvalvesandseals.DownsidesofusingaVentPacker?Ventpackers require tobe replacedduring the frequentworkovers thatarean inevitabilitywhenESP lift isused.This incursCAPEX, their installationandremovalalsocomplicatesand therefore increases theworkovercosts.Anelectricalpenetratoralsohastobedeployedtopassthepowercablethroughtheventpacker.Thesealsoaddtothecost and complexity and are common system failure locations. Finally, the vent packer can sometimes pose arestrictiontogasventrate.Thiscanreducegas/liquidseparationefficiencyupstreamoftheESPcausingimpairedESPperformanceandlowerproduction.VRSenseandMSASThese technologies are now widely used in gas lifted wells, to provide a double barrier vs the escape of highpressureliftgasfromtheAAnnulus(amorechallengingdutythanagasventedESPwell).TheyarenowalsobeingusedasanalternativetoVentPackersandDHASV’singasventedESPwells.
Theyare installed in the threadedprofiles (VRprofiles),whicharemachined intobothsideoutletsonallwellheads.Specifically,aPressure/Temperaturesensor‘VRSense’[1]is installed in one of theVR profiles, and a ‘Master SurfaceAnnulus Safety’ (MSASG)valve(withsimilarfailsafeclosedfunctionalitytoasub-surfacesafetyvalve)isinstalledintheother,whereitiscontrolledviathewellheadhydrauliccontrolpanel.They,alongwiththewellheadandproductioncasing,combinetoformaprimarybarrierenvelopearoundtheAorTCAnnulus.Theoutercasingstringandassociatedwellheadand valves in the first casing / casing annulus (CCA1), forms the secondary barrierenvelope.
VRSenseandMSASBenefitsonGasVentedESPWellsBecausetheMSASandVRSensearelocatedinthewellheadVRprofiles,ESPcompletioncanbesimplified(noventpackers/packerpenetrators)reducingtheCAPEX,thelikelihoodofESPsystemfailureandsimplifyingworkovers.Well Integrity is also improvedandmoreeasily verified. TheMSAS valve canalsobe replacedwithoutworkover.FinallybecauseofthelargeflowareaoftheMSASvalvethelikelihoodofESPgaslockingisreduced.[1]PTCWhitePaper:AnewApproachtoAnnulusPressureMonitoring:ImprovingDataReliabilityandWellIntegrity,whileReducingLifecycleCosts
MSASG
VRSense
Copyright©PetroleumTechnologyCompany2016
www.ptc.as 1
Well Integrity Assurance: Double Barrier Policy Implementation ( base case non vented ESP lifted wells)
Secondary Barrier Envelope
Prevents flow if the Primary Barrier fails
P Primary Barrier Envelope
• This is the first barrier that prevents flow from a source.
www.ptc.as 4
Well Integrity Assurance: Double Barrier Policy Implementation ( gas vent ESP lifted wells)
Secondary Barrier Envelope
No change from base case
P Primary Barrier Envelope
• Add Vent Packer as annulus flow primary barrier
www.ptc.as 5
Well Integrity Assurance: Alternative Double Barrier Policy Implementation ( gas vent ESP lifted wells)
Secondary Barrier Envelope
Outer Casing / Wellhead becomes secondary barrier
Primary Barrier Envelope • No need for vent packer and
associated penetrator / control line.
• MSAS and VR Sense in wellhead VR Profile replace it as primary barrier
P P