(海洋油气专业外语课件)C-Well-Control

Unit6WellControlDefinitionProcessandEquipmentforkickdetectionandcontrolUnit6WellControlDefinition1Wellcontrol

Wellcontrolreferstothecontrolofdownholeformationpressurespenetratedbythewell.Therearethreedistinctwellcontrollevelsthatmayoccurduringdrillingoperations.

Primarycontrol.Primarycontrolisgivenbymaintainingthedensityofthedrillingfluidsuchthathydrostaticpressureatalldepthswhereformationsareexposedexceedsformationporepressures.

Mudhydrostaticpressure>formationporepressureWellcontrolWellcont2PrimarycontrolTherearefourmainreasons,ingeneral,whyprimarycontrolmightbelostduringdrillingoperations:1.Thewellpenetratesanoverpressuredzonewithahigherformationpressurethanmudhydrostatic.2.Aweakdownholeformation

allowssufficientmudtoleavethewellboresothatthelevelofmudintheannulusdrops.3.Failuretofilltheholeproperlywhenpullingoutofthehole.4.Swabbing.Ifthedrillstringispulledupwithsufficientspeed,thereductioninpressureatthebottomcanbeenoughtoallowformationfluidstoenterthewell.PrimarycontrolTherearefour3(海洋油气专业外语课件)C-Well-Control4(海洋油气专业外语课件)C-Well-Control5BOPstackTheprimaryfunctionoftheBOPistoformarapidandreliablesealaroundthedrillstringoracrosstheemptyhole(ifnopipeisinthehole)tocontaindownholepressures.Therearecurrentlytwotypesofpreventersavailablethatallowthissealtobeformed.MostBOPscontainatleastoneofeachtypeasthedifferentcharacteristicsofeachareusefulfordifferentoperations.Annularpreventer/bagtypepreventerFixedpiperamVariableborepiperamBlind-shearramDetectionequipmentPit-volumetotalizerFlowindicatorBOPstackTheprimaryfunction6Bagtypepreventer

(annularpreventer)Functions:SealingonirregularshapedtubularsAllowingpipesmoveinoroutofthewellunderpressure(stripping)Bagtypepreventer

(annularp7Ramtypepreventer

Fixedpiperam.ThesealissizedtofitoneoutsidediameteronlyRamtypepreventerFixedpipe8VariableborepiperamThesealelementcanaccommodateanarrowrangeofdiameters,forexample3-1/2"to7".Itcanonlysealonroundpipe,notsquareorhexagonalshapesVariableborepiperamThe9BlindramsDesignedtosealontheopenhole.Blind-shearramshavebladesincorporatedthatcancutthroughdrillpipe(thoughnotthroughdrillcollarsorcasing)BlindramsDesignedtosealon10BOPstackaBOPstackwouldhaveatleastonebagpreventerandtworampreventers.BOPstacksfordeeperwellsmighthaveuptofourrampreventersandtwoAnnularpreventers.Therampreventersgenerallyhaveahigherpressureratingandarealwaysinstalledbelowthebagpreventers.Ifonlytworampreventersareused,thebottomsetwillnormallybeblind-shearramsandtheuppersetwillbepiperams.Onereasonforplacingtheblindramsonthebottomisthatifthepiperamsleak,itispossibletoclosetheblindramsbelowandsafelyopenuptheupperpreventertochangetherams.BOPstackaBOPstackwouldhav11BOPcontrolsystemsAhydrauliccontrolsystemisusedtomoveBOPunitsusinghydraulicfluidunderpressure.BOPcontrolsystemsAhydraulic12BOPcontrolsystems1.Areservehydraulicfluidtankholdingfluidatatmosphericpressure.2.Asetofbottlesholdingfluidunderhighpressure(usually3,000psi)withpressurizednitrogen.3.Ahighpressuremanifoldconnectedtothebottlesystem.4.Alowpressuremanifoldthatcontainsfluidattheworkingpressureoftherampreventers(usually1,500psi).5.Apressureregulatorthatfeedsfluidfromthehighpressuremanifoldtothelowpressuremanifold,whichreducestheunregulatedpressuretotheworkingpressure.Asetofvalvesattachedtothelowpressuremanifoldthatcandirectworkingpressurefluidtotherams(toopenortoclosethem)andthatdirectsexhaustfluidbacktothereservehydraulicfluidtank.BOPcontrolsystems1.Areserv13BOPcontrolsystems7.Avalvethatcontrolstheopeningandclosingofthebagpreventer.8.Apressureregulatorthatfeedsfluidfromthelowpressuremanifoldtothebagpreventercontrolvalve.Bagpreventersoperateatalowerpressurethanrampreventers,butasthesealelementgetsworn,higherpressureisrequiredtomakethebagsealaroundthepipe.Thisregulatorisalsousedtolowertheclosingpressuretothebagpreventerifitisdesiredtostrippipeinthroughthepreventerortoincreasetheclosingpressureonawornelement.9.Twosetsofpumpstomaintainsystempressure.Onesetisdrivenbycompressedairfromtherigairsystem,theotherispoweredbyelectricityThisprovidessomebackupintheeventofeithertherig'sairorelectricalsystemfailing.Theairdrivenpumpsgiveahigherflowrateandpressurethesystemtoaround2,800psi.Theelectricpumptopsthesystemtothefullpressureof3,000psiatalowerflowrate.BOPcontrolsystems7.Avalve14KickDetectionEquipment1.Thepit-volumetotalizerprovidesareadoutshowingthetotalvolumeofdrillingfluidheldonthesurfaceintheactivesystem~tanks.Ifthistotalincreases,andiftheincreaseisnotduetothemudengineeraddingchemicalsorfreshmudtothesystem,thenakickisoccurring.2.Theflowindicatorisaninstrumentattachedtoapaddlethatsitsintheflowlinefromtheannulus.Thispaddleispushedupbythereturningmudstream--theamountitispusheddependsontheflowrate,amongotherthings.Iftheflowrateshouldincreaseanalarmwillsound.Iftheflowrateoutincreases,butthemudpumpspeedhasnotbeenincreased,itispossiblethattheextraflowoutisduetoaninfluxenteringthewellbore.Generally,theflowindicatorwillgivethefirstpositiveindicationofakick.However,thepaddletypeflowindicatorispronetofalsealarmsbecauseofcuttingsandotherdebristhatmaysticktothepaddleorbuildupunderneathit.KickDetectionEquipment1.The15SignsofakickDrillingbreakMudpitgainFlowingwellShowsofgas,oilorsaltwaterDecreaseincirculatingpressure(flowrateincrease)PumpstrokeincreaseImproperholefill-upStringweightchange(buoyancyeffectdecreases,andstringbecomesheavier)SignsofakickDrillingbreak16KillingthewellIfthesurfaceinstrumentsindicatethatakickisinprogresswhiledrilling,normallythedrillerwillstopdrilling,pickupthedrillstringsothatthebitisabovethebottomoftheholeandstopthepumps.Avisualcheckisthenmadebylookingdownthroughtherotarytable,intothebellnipple,atthelevelofmudintheannulus.Ifthewellisinfactkicking,thenthemudintheannuluswillstillbemovingupwardseventhoughthepumpsareshutdown.Havingconfirmedakick,thedrillerwillclosetheBOPasquicklyaspossibleandnotifythetoolpusheranddrillingsupervisorinchargeoftherig.Ifthepermeabilityoftheflowingformationishigh,thekickcandevelopveryquickly.Alargerdrilledholewillalsoallowinfluxtoflowinfasterbutthisiscompensatedfor(toanextent)becausethecapacityoftheholeisgreaterinalargerhole.Itisalsopossiblethatifpermeabilityisverylow,littleornoinfluxentersthewellboreeventhoughmudhydrostaticislessthantheformationporepressure.KillingthewellIfthesurface17WellcontrolproceduresShutwellinPullkellyupOpenhydraulicclosingram(HCR)valvebutnotsuperchokeorchokemanifold.CloseannularpreventerRecordpressureRecordshut-indrillpipepressure(SIDPP)Recordshut-incasingpressure(SICP).WellcontrolproceduresShutwe18KillmethodsDrillersmethodWait-and-weightmethod(engineersmethod)CirculateandweightmethodKillmethodsDrillersmethod19Unit6WellControlDefinitionProcessandEquipmentforkickdetectionandcontrolUnit6WellControlDefinition20Wellcontrol

Wellcontrolreferstothecontrolofdownholeformationpressurespenetratedbythewell.Therearethreedistinctwellcontrollevelsthatmayoccurduringdrillingoperations.

Primarycontrol.Primarycontrolisgivenbymaintainingthedensityofthedrillingfluidsuchthathydrostaticpressureatalldepthswhereformationsareexposedexceedsformationporepressures.

Mudhydrostaticpressure>formationporepressureWellcontrolWellcont21PrimarycontrolTherearefourmainreasons,ingeneral,whyprimarycontrolmightbelostduringdrillingoperations:1.Thewellpenetratesanoverpressuredzonewithahigherformationpressurethanmudhydrostatic.2.Aweakdownholeformation

allowssufficientmudtoleavethewellboresothatthelevelofmudintheannulusdrops.3.Failuretofilltheholeproperlywhenpullingoutofthehole.4.Swabbing.Ifthedrillstringispulledupwithsufficientspeed,thereductioninpressureatthebottomcanbeenoughtoallowformationfluidstoenterthewell.PrimarycontrolTherearefour22(海洋油气专业外语课件)C-Well-Control23(海洋油气专业外语课件)C-Well-Control24BOPstackTheprimaryfunctionoftheBOPistoformarapidandreliablesealaroundthedrillstringoracrosstheemptyhole(ifnopipeisinthehole)tocontaindownholepressures.Therearecurrentlytwotypesofpreventersavailablethatallowthissealtobeformed.MostBOPscontainatleastoneofeachtypeasthedifferentcharacteristicsofeachareusefulfordifferentoperations.Annularpreventer/bagtypepreventerFixedpiperamVariableborepiperamBlind-shearramDetectionequipmentPit-volumetotalizerFlowindicatorBOPstackTheprimaryfunction25Bagtypepreventer

(annularpreventer)Functions:SealingonirregularshapedtubularsAllowingpipesmoveinoroutofthewellunderpressure(stripping)Bagtypepreventer

(annularp26Ramtypepreventer

Fixedpiperam.ThesealissizedtofitoneoutsidediameteronlyRamtypepreventerFixedpipe27VariableborepiperamThesealelementcanaccommodateanarrowrangeofdiameters,forexample3-1/2"to7".Itcanonlysealonroundpipe,notsquareorhexagonalshapesVariableborepiperamThe28BlindramsDesignedtosealontheopenhole.Blind-shearramshavebladesincorporatedthatcancutthroughdrillpipe(thoughnotthroughdrillcollarsorcasing)BlindramsDesignedtosealon29BOPstackaBOPstackwouldhaveatleastonebagpreventerandtworampreventers.BOPstacksfordeeperwellsmighthaveuptofourrampreventersandtwoAnnularpreventers.Therampreventersgenerallyhaveahigherpressureratingandarealwaysinstalledbelowthebagpreventers.Ifonlytworampreventersareused,thebottomsetwillnormallybeblind-shearramsandtheuppersetwillbepiperams.Onereasonforplacingtheblindramsonthebottomisthatifthepiperamsleak,itispossibletoclosetheblindramsbelowandsafelyopenuptheupperpreventertochangetherams.BOPstackaBOPstackwouldhav30BOPcontrolsystemsAhydrauliccontrolsystemisusedtomoveBOPunitsusinghydraulicfluidunderpressure.BOPcontrolsystemsAhydraulic31BOPcontrolsystems1.Areservehydraulicfluidtankholdingfluidatatmosphericpressure.2.Asetofbottlesholdingfluidunderhighpressure(usually3,000psi)withpressurizednitrogen.3.Ahighpressuremanifoldconnectedtothebottlesystem.4.Alowpressuremanifoldthatcontainsfluidattheworkingpressureoftherampreventers(usually1,500psi).5.Apressureregulatorthatfeedsfluidfromthehighpressuremanifoldtothelowpressuremanifold,whichreducestheunregulatedpressuretotheworkingpressure.Asetofvalvesattachedtothelowpressuremanifoldthatcandirectworkingpressurefluidtotherams(toopenortoclosethem)andthatdirectsexhaustfluidbacktothereservehydraulicfluidtank.BOPcontrolsystems1.Areserv32BOPcontrolsystems7.Avalvethatcontrolstheopeningandclosingofthebagpreventer.8.Apressureregulatorthatfeedsfluidfromthelowpressuremanifoldtothebagpreventercontrolvalve.Bagpreventersoperateatalowerpressurethanrampreventers,butasthesealelementgetsworn,higherpressureisrequiredtomakethebagsealaroundthepipe.Thisregulatorisalsousedtolowertheclosingpressuretothebagpreventerifitisdesiredtostrippipeinthroughthepreventerortoincreasetheclosingpressureonawornelement.9.Twosetsofpumpstomaintainsystempressure.Onesetisdrivenbycompressedairfromtherigairsystem,theotherispoweredbyelectricityThisprovidessomebackupintheeventofeithertherig'sairorelectricalsystemfailing.Theairdrivenpumpsgiveahigherflowrateandpressurethesystemtoaround2,800psi.Theelectricpumptopsthesystemtothefullpressureof3,000psiatalowerflowrate.BOPcontrolsystems7.Avalve33KickDetectionEquipment1.Thepit-volumetotalizerprovidesareadoutshowingthetotalvolumeofdrillingfluidheldonthesurfaceintheactivesystem~tanks.Ifthistotalincreases,andiftheincreaseisnotduetothemudengineeraddingchemicalsorfreshmudtothesystem,thenakickisoccurring.2.Theflowindicatorisaninstrumentattachedtoapaddlethatsitsintheflowlinefromtheannulus.Thispaddleispushedupbythereturningmudstream--theamountitispusheddependsontheflowrate,amongotherthings.Iftheflowrateshouldincreaseanalarmwillsound.Iftheflowrateoutincreases,butthemudpumpspeedhasnotbeenincreased,itispossiblethattheextraflowoutisduetoaninfluxenteringthewellbore.Generally,theflowindicatorwillgivethefirstpositiveindicationofakick.However,thepaddletypeflowindicatorispronetofalsealarmsbecauseofcuttingsandotherdebristhatmaysticktothepaddleorbuildupunderneathit.KickDetectionEquipment1.The34SignsofakickDrillingbreakMudpitgainFlowingwellShowsofgas,oilorsaltwaterDecreaseincirculatingpressure(flowrateincrease)PumpstrokeincreaseImproperholefill-up