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直动式液压往复泵外文翻译.docx

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直动式液压往复泵外文翻译.docx

直动式液压往复泵外文翻译

JeffreyJ.Rudolf

HuskyEnergyInc.,

Calgary,Alberta,Canadae-mail:

jeff.rudolf@huskyenergy.ca

TedR.Heidricke-mail:

ted.heidrick@ualberta.ca

BrianA.Flecke-mail:

brian.ﬂeck@ualberta.caDepartmentofMechanicalEngineering,

UniversityofAlberta,Edmonton,AlbertaT6G2G8,Canada

V.S.V.Rajan

AlbertaResearchCouncil,

Edmonton,Alberta,Canada

e-mail:

rajan@arc.ab.caOptimumDesignParametersforReciprocatingPumpsUsedinNaturalGasWells

Experimentalandtheoreticalinvestigationofarecentlypatenteddown-holedirect-actingreciprocatingpumpsystemispresented.Thetechnology,（USPatentNo.5,860,795consistsofoperatingagaswellwithgasandliquidphasesbeingproducedseparatelybyusingthegasphasetopowerapumptobringtheliquidphasetothesurface.ThiswouldincreasethedurationofproﬁtabilityofmanygaswellsinNorthAmerica.Experimentsandmodelingwereusedtodetermineoptimumdesignparameterstomaintainﬂowataminimumreservoirpressure;anoptimumarearatioforthegas/liquidpistonsisapproxi-mately40.Theeffectoffrictioninthepumpingsystemwaspredictedtohaveasmalleffectonthisoptimumdesign.Theresultsofthisinvestigationwillnowbeusedtodesignandconstructaprototypeforﬁeldtesting.͓DOI:

10.1115/1.2000274͔

1Introduction

Liquidloadingisacommonproblemassociatedwithnaturalgasproduction.Liquidloadingoccurswhenagaswellisoperatedinatwo-phaseﬂow͑predominantlygaswithsomeliquidphase͒conﬁgurationandthegasphaselackssufﬁcientmomentumtocarrytheliquidphasetothesurface.

Astheproblemofliquidloadingingaswellsbecomesincreas-inglyimportantinNorthAmerica,arangeoftechnologieshasarisentodealwiththeproblem.ThereviewofLeaandNickens͓1͔givesanexcellentoverviewofsolutionsforliquidloadingin

gaswells.AnewtechnologyhasbeenpatentedbyRidleyetal.͓2–4͔tosolveliquidloadingproblemsingaswells.Thistechnol-ogyconsistsofoperatingthegaswellwithgasandliquidphasesbeingproducedseparatelybyusingthegasphasetopowerapumptobringtheliquidphasetothesurface.

Similarideasandtechnologicalinnovationsaresuggestedforapplicationsinoilwellsfordownholesuckerrodandprogressivecavitypumps͓5,6͔anddownholeseparators͓7͔butareessentiallyforoilproduction.Theworkpresentedhereisanoriginalinnova-tionaimedspeciﬁcallyatgaswellswithassociatedliquidproduc-tion.

Inapreviousstudy͓8͔,thefeasibilityofoperatinginthisman-nerforavarietyofNorthAmericanreservoirswasdemonstratedviatheoreticalmodeling.Intheresearchworkdescribedhere,theapplicabilityofdirect-actingreciprocatingpumps͑DARP͒wasinvestigatedforuseinthisconceptthroughbothexperimentalandtheoreticalmodeling.Theresultsobtainedwereextrapolatedtotheﬁeldtodetermineoptimumdesignparametersfora“typical”Albertagaswell.Thisisthenextlogicalstepintheprocessoftakingthisnovelconcepttowardcommercializationandpracticalimplementationwiththegoalofextendingtheproﬁtablelivesofgaswellsexperiencingliquidloadingproblemsattheendoftheirproducinglife.

2ExperimentalApparatus

Theexperimentalapparatuswasdesignedtomodeladown-holepumpsetatthebottomoftheproductiontubingwheregasandliquidenterthebottomofthewellandareseparatedbygrav-ity.Thegasdrivesthepumpwhichpumpstheliquid.Thegasandliquidphasesexituptheproductionandliquidtubingrespectivelyandﬂowtothesurface.

Adirect-actingreciprocatingtestpumpwasdesignedandmanufacturedfortesting.AschematicofthispumpisshowninFig.1.

Thetestpumpconsistsoftwoparts:

thepumpitselfandacontrollertoregulatetheﬂowofgasandthusthereciprocatingmotionofthepump.Thepiston,shownschematicallyinFig.2,hasadiameterof50.8mmandtheplungershaveadiameterof19.05mm.Thepumpingelementhasastrokelengthof111.6mm.Eachpumpingelementweighsapproximately430ganddisplaces31.7cm3perstroke.

Ineachdrivesectiontheplungerreciprocatestopumptheliq-uid.Liquidisbroughtinfromaliquidintakelinethroughacheckvalvethatisthreadedintothesideofeachliquidsection.Liquidisdischargedthroughasecondcheckvalvethatisthreadedintotheendsectionofthepump.

Theendsectionconnectstheliquidsectiontoadischargeline.Proximityprobesareusedtosensethepumpingelementwhenitreachestheendofeachpumpstroke.Theproximityprobessendsignalstoswitchtheﬂowofgasthroughthesolenoidvalve.Thetestpumpcanbeoperatedusingeitheroneorbothdrivesections.Thisisreferredtoaseithersingle-stageortwo-stageoperation.Insinglestageoperation,onlyonedrivesectioniscon-nectedtothesolenoidvalvetoprovidegaspressuretoitscorre-spondingpumpingelement.Theotherdrivesectionoperatesatambientconditionswithitspumpingelementcarriedalongasa“dummy”piston.Insinglestageoperationthepumphasanarearatioof6.11.Intwostageoperation,bothdrivesectionsarecon-nectedtothesolenoidvalveandeachpumpingelementisdrivenbygaspressure.Intwostageoperationthepumphasanarearatioof12.22.

2.1TestFacilityThefacilityusedtoexaminetheperfor-manceofthetestpumpconsistsoftwoﬂowloops:

oneforgas͑compressedair͒ﬂowandtheotherforliquid͑water͒.Forthegas

ﬂowloop,thesystemoperatesatambienttemperaturewithamaximumpressureof700kPag.Theliquidﬂowloopalsooper-atesatambienttemperatureandthemaximumoperatingpressure

ContributedbythePetroleumDivisionforpublicationintheJOURNALOFENERGY

RESOURCESTECHNOLOGY.ManuscriptreceivedbythePetroleumDivision:

September

25,2003;revisedmanuscriptreceived:

April11,2005.AssociateEditor:

A.K.

Wojtanowicz.

JournalofEnergyResourcesTechnologyDECEMBER2005,Vol.127/285

was1000kPag.

2.1.1GasFlowLoop.AdiagramofthegasﬂowloopisgiveninFig.

3.Compressedairentersthegasﬂowloopfromthecentralairsupplyandﬂowsthroughaﬁlter,regulator,andintoatank.Theairthenﬂowsfromthetanktothesolenoidandvalveanditstemperatureismeasured.Fromthesolenoidvalve,airﬂowsintothedrivesection͑s͒ofthetestpump,drivesthepumpuntilitreachestheendofastrokeandthenreturnstothesolenoidvalve.Theairdischargesfromthedrivesectionofthetestpump,throughthesolenoidvalvetoasecondtankthentoabackpressureregulator.

2.1.2LiquidFlowLoop.AdiagramoftheliquidﬂowloopisgiveninFig.4.Theﬂuidmediumiswaterwhichenterstheliquidﬂowloopfromawatersupply.Thewaterﬂowsintoa220Linlettanktosupplythepump.Thewaterﬂowsfromthetanktotheliquidsuctionheaderthenﬂowsintoeitherthetoporbottomliquidsectionoftheexperimentalpumpthroughacheckvalve.Fromtheliquidsectionthewaterispumpedthroughasecondcheckvalveandintothedischargeheaderthenthroughthereliefvalveandentersa4mtallverticalﬂowline.Thisﬂowlineisusedtogenerateadditionalbackpressureonthedischargeline.

3TheoreticalModeling

ThetheoreticalmodelingoftheperformanceofaDARPisbasedonaforcebalanceshownschematicallyinFig.2.Basedonthisforcebalance,threeimportantpumpcharacteristicswereidentiﬁed;gasutilization,pumpfrictionpressure,andthermody-namicefﬁciency.

GasutilizationrefersthevolumeofgasrequiredtodrivetheDARP.Tomodelgasutilizationthefollowingequationisused:

Qg,sc=QlAR

PINTsc

PsczTIN

͑1͒DividingEq.͑1͒bytheliquidvolumetricﬂowrateresults

inFig.1SchematicofthedirectactingreciprocatingpumpapplicationintheARCtechnology

286/Vol.127,DECEMBER2005TransactionsoftheASME

Rgl=AR

PINTscPsczTIN

͑2͒

whereRglisthegastoliquidratio.Equation͑2͒indicatesthatincreasingthepumparearatioorintakepressurewillincreasetheamountofgasrequiredtodrivethepump.Pumpfrictionpressurereferstotheﬂowlosses,slidingfriction,andotherirreversibilitiesandareexpressedasaneffectivepumpingpressureactingagainsttheplunger͓9͔

PFRICTION=⌬PGASAR−PPUMP͑3͒

whichtakesintoaccountforcesactingwhilethepumpsystemisinoperation.

ThermodynamicefﬁciencyoftheDARPisdeﬁnedastheworkdoneonthepumpedliquiddividedbytheworkdonebythedrivegasifitwereexpandedisentropicallyfromPINtoPDIS͑showninFig.2͒.Basedonthis,itcanbeshownthatthermodynamicefﬁ-ciencyofaDARP

Fig.2Schematicofthedirect-actingreciprocating

pump

Fig.3Schematicofthegasﬂowloop

JournalofEnergyResourcesTechnologyDECEMBER2005,Vol.127/287

␩=

k−1kP˜PUMP

͑1−͑1−P˜PUMP͒k−1/k͒

͑4͒

wherethenormalizedPumpingpressure,P˜PUMP,isdeﬁnedas

P˜PUMPϵ

PPUMPPINAR

͑5͒

Theeffectofnormalizedpumpingpressureonthermodynamicefﬁciencyforair͑k=1.4͒andnaturalgas͑k=1.25͒isshowninFig.5.Thesigniﬁcanceoftheseresultsisthatforagivenpump-ingpressure,thethermodynamicefﬁciencycanbeimprovedifeitherthepumparearatioorthegasintakepressureisincreased.AswellthermodynamicefﬁciencydecreaseswithP˜PUMPathigherP˜PUMPvalues.Therefore,therelativeimprovementinthermody-namicefﬁciencywithincreasedareaorgasintakepressureishigherathigherinitialvaluesofP˜PUMP.However,theefﬁciencydegradesmoreathighernormalizedpumpingpressureswhenus-ingthegastopowerthepumpduetoitslowerspeciﬁcheatratio.Toexaminetheeffectoffrictiononthermodynamicefﬁciencythefollowingtestcaseispresented.Inthissituation,pumpfrictionpressureisincreasedfrom0%to100%ofthepumpingpressurefornormalizedpressuresof0.5,0.25,0.16,and0.125.Theresultsofthistestcaseusingair͑k=1.4͒asthedrivegasarepresentedinFig.6.Theﬁgureshowsthatincreasedpumpfrictionresultsinlo

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