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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

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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.

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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

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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