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Study_5 (2)

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Study_5 (2)

    Study

2005Pe~oleumScience,,o1.2No.3

    ;StudyofStructuralParametersoftheInletofDownholeHydrocyclones

    ;LvFengxia,ZhangShuyanandHuChunwei

    ;(1DaqingPetroleumInstitute,Daqing,Heilong/iang163318,China)

    ;f2ChinaPetroleumPipelineEngineeringCorporation.Langfan~Hebei065000,China) ;ReceivedApril28.2005

    ;Abstract:Threedifferentinletsofhydrocyclonearestudiedincombinationwiththeconstructionofadownholesystem

    ;andhydrocyclone.Bycomparingtherelationshipbetweentheinletstructure&dimensionalparameterofhydrocyclone

    ;andseparationefficiency&pressureloss.thehighestefficiencyisobtainedfromtheinletofaninvolutecurvewith

    ;increasingdepth-widthratiofromthethreetypes,inwhichtheseparationefficiencyandpressurelossalldropsslowly,

    ;forthelengthofthechanneldecreases,whileitdropsrapidlyintheothertwo.Theflowguidingabilityoftheinletaffects

    ;theseparationefficiencygreatly,sothecorrespondinginvolutetypeofinletofhydrocyclonefitsfordownholeoil-water

    ;separationisoptimized,whichservesasabasisforthestructuraldesignofdownholehydrocyclone. ;Keywords:Downholeoil-waterseparation,hydrocyclone,inlet,separationefficiency,pressureloss ;1.Introduction

    ;Thetechnologyofdownholeoil.waterseparation&

    ;re.injectionforseparatedwaterwasputforward

    ;consideringtheactualhighwatercutinmostoilfields

    ;(Veil,eta1.,1997).W_ecarriedoutanexperimentona

    ;combinationofascrewpumpandavortexseparation

    ;deviceinviewofthewellboresituationinourcountry.

    ;Thetrialsystemismadeupofdynamicalsealing,

    ;vortexseparation,powerscrewpump,packerandsoon.

    ;Fig.1isthetechnologicflow.Thekeyequipmentisthe

    ;liquidliquidhydrocycloneforseparatingtheoilfrom

    ;waterdownhole.Consideringthetubingwithaninside

    ;diameterofl26mminmostdomesticoilfields.theinlet

    ;diameterofhydrocyclonebeingabout130mm.andthe

    ;radialdimensionoftheothervortexchamber,thelarge

    ;conicalsection.thesmallconicalsectionandthe

    ;cylindricaltailtubebeingallunder80mm.the

    ;downholeapplicationofhydrocycloneisrestricted

    ;chieflybytheradialdimensionoftheinlet.Ontheother

    ;hand,thehighpressureoftheseparatedwatertore. ;injectionfromhydrocycloneisrequired.which ;demandsthepressurelOSSonhydrocyclonetobeaslow ;aspossible.Fromtheresultofformerexperimentswe ;knowthatabout40%ofthetotalpressurelOSSof ;hydrocyclone,whichisunusedforanyactualseparation. ;iscausedbytheinlet(Wang,eta1.,2003).Therefore,it ;isnecessarytorationallyselectthestructuralstyleof ;theinletchannelandreducethepressurelOSSofthe ;inlet.Inlightoftheexperimentonthestructuralstyle ;anddimensionoftheinletchannel,therelationship ;betweenthedimensionandthepressureloss&the ;separationefficiencyoftheinletisconfirmed,which ;offersabasisforabroadapplicationofthetechnology ;ofdownholeoil-waterseparationinoilfields. ;豳千豳

    ;——

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    ;霾上缓V

    ;Fig.1Downholetechnologicflow

    ;2.Structuraltypeandtestparametersofthe ;inletofhydrocyclone

    ;2.1Basictypeofinlet(Jiang,eta1.,1998)

    ;Therearevarioustypesofinletsforhydrocyclone. ;whichcanbediholeHydrocyclonesl7

    ;showninFig.2:Beelinechanneltypewithequal ;sections,beelinechanneltypewithgraduallychanging ;sectionsandcurvechanneltype.

    ;oooabc

    ;Fig.2Threetypesofinlets

    ;a.Beelinechanneltypewithequalsections

    ;Thebeelinechannelwithequalsectionsisatypeof ;inletthatanysectionhasthesameshapeofarectangle. ;whichisthesimplestkindofarectangularsection.The ;lpealenergylOSSiSbroughtoutattheintersectionofthe ;rectanglesectionandthecolumnsection.

    ;b.Beelinechanneltypewithgraduallychanging

;sections

    ;Liketheformertype.thisinletchannelisalso ;rectangular,whileastheradialdimensionisgradually ;lessening.theaxialdepthremainsthesameandthe ;radialwidthisgraduallylessening.Theinletsection ;areaisthesmallestofthehydrocyclone.Althoughthe ;energylosscanbebroughtoutherejustliketheformer ;type,itcanenhancethekineticenergywithagradually ;shrinkingsection,sothattherotaryintensityofthefluid ;ispromoted.

    ;c.Curvedchanneltype

    ;Comparedwiththeformertwotypes,theinlet ;channelislongerandtheguiding?flowabilityisbetter, ;whichisfavorabletoformingasteadyflowrapidly ;whenthemixedliquidentersthevortexcavity,andthe ;distributionofthefluidfieldinthevortexcavityismore ;orderlyandmorerational,thentheprobabilitythatthe ;fluiddropsarefragmentedduetotheirstrikingthewall ;ofthevortexcavitywhentheyenterthehydrocyclone, ;isgreatlyreduced.

    ;2.2Testparameters

    ;Basedontheprincipalofasectionalareabeing ;minimum,acontrastexperimentontheinlet

    ;performanceiscarriedouttothreetypetestinletsthat ;havedifferentchanneldimensions.Theparametersof ;operationandthetestinletsintheexperimentare ;showninTable1.

    ;Table1Parametersofoperationandtestinlets ;Icemletno.BeelinechanneltypewithBeelinechanneltypewith ;Involutetype

    ;graduallychangingsectionequalsection

    ;l234567

    ;MinimumareaoftestDepth9.5l2.7l9.09.5l2.7l9.0l5.5 ;inletchannel,ininWidth86.0486.O44.9

    ;PressuredrivingpumpScrewpump

    ;Disposalflowrate4m3/h

    ;Splitratio(totaloverflowrate

    ;5,8,l0,l2,l3

    ;/t0talin-flowrate)

    ;3.Analysisoftestdata

    ;3.1Relationshipbetweendimensionofinletand ;separationeffieieney

    ;Fig.3isobtainedfromthisexperiment.Thetest ;inlets1.2and3havethesameminimumsectionarea

    ;andtheiraspectratios(width:depthratio)decrease ;from1to3.

    ;Thefigureshowsthattheefficiencygetsbetteralong ;withanincreaseoftheaspectratio.

    ;However,weshouldnoticethatitisalwaysgoodto ;theefficiency,astheaspectratiokeepsincreasing.The ;channelofthetestinletforthisexperimentistapered. ;thatis.themaximumsectionareabytheouterdiameter ;isdecreasinggraduallytotheminimumsectionarea ;usedtocalculatethevelocityforhydrocyclonefen

    ;theaspectratioisincrescent.theincomingliquidof ;hydrocyclonewillmovetothecentralmainstreamand ;doesworktoovercometheresistanceofpressure, ;whichenhancesthefrictionamongliquiddroplets, ;changingthedistributionofvelocitythesametime, ;strengtheningtherelativemotionamongliquidlayers, ;causingmorelocalenelOSS,andreducingthevortex ;intension.Consideringtheefficiency,theaspectratio ;shouldbeamaximumforsomehydrocycloneswhose ;

    ;l8PetroleumScience2005

    ;dimensionalparametersareknown

    ;n

    ;Fig.3Relationshipbetweensplitratioand

    ;separationefficiencyforinletdimension

    ;3.2Relationshipbetweentypeofinletandseparation ;efficiency

    ;Settingthetestinlets3,6and7,whichhavethe ;samedepth-widthratio,astheexperimentobjects,the ;relationshipbetweenthechanneltypeandseparation ;efficiencyisstudied.Therelationshipbetweenthesplit ;ratioandseparationefficiencyfromtheexperimentis ;showninFig.4.

    ;F.

    ;%

    ;Fig.4Relationshipbetweensplitratioand

    ;separationefficiencyforinlettype

    ;Thetestdatafurthervalidatestheconcluionfrom ;(Wang,eta1.,2003).Thatis,thepressurelOSSinthe ;beelinechanneltypewithagraduallychangingsection ;isthelowestofthethree.sothatwhenitentersthemain ;separationsectionofthehydrocyclone,theintensityof ;itsflowfieldisthestrongest.whichisinfavorof ;separation.Ontheotherside,thetestinletofthecurvy

    ;typemaybringagreaterloss.butitcanguidetheflow ;better.Fromthefigure,wenoticethattheseparation ;efficiencyoftheinvolutetypeisthehighestofthethree ;kinds,so,consideringthe

    ;intensityoftheflowfield

    ;twoaspectsrespectively’___——

    ;(Viz.pressureloss)andflow

    ;guidingcapacity,astrongercapacityofthetestinletfor ;flowguidingismoreusefulforseparatingaproduced ;fluid.

    ;3.3Relationshipbetweenchannellengthand

    ;pressureloss

    ;BasedonTable1.wecarryoutexperimentswiththe ;threetestinlets,whosetestnumbersare3,6and7,and ;reducetheirouterdiameterfrom135mmtol25mm. ;105mmto93mm.TheresultisshowninFig.5.

    ;

    ;-

    ;9010oll0l20130l40

    ;Inletouterdiameter,ITlln’

    ;Fig.5Relationshipbetweeninletouter

    ;diameterandpressureloss

    ;,?hentheouterdiameterofthetestinletchanges ;from135mmto125mmaccordingtotheFig.5.the ;pressurelOSSofallthethreetypesgrows.forthereason ;thatagreatlocalpressurelOSSiSbroughtoutwhenthe ;diametershrinkingonthepartofthesectionofthe ;channelinletisdisposedinviewoftheiastallationof ;thetestpiece.Thisdoesnotaffectthecontrastof ;pressurelossesgreatly.Fromthecurvewenoticethat ;thepressurelOSSofallthethreefallsgraduallywiththe ;decreaseoftheouterdiameterandthechannellengthof ;thetestinlet.ofwhichthepressurelOSSfallsrapidlyon ;testpiecesNo.3andNo.6,whilefallingslowlyonthe ;involutetypeofthetestinlet.

    ;3.4Relationshipbetweenchannellengthand ;separationefficiency

    ;Fig.6showstherelationshipbetweentheouter ;diameterofthetestinletandseparationemciency. ;,?hentheouterdiameterofthetestinletchangesfrom ;135mmto125mm.theseparationefficiencyofthethree ;typesdecreasestoacertainextentbecauseofasudden ;increaseofthepressurelOSS.,?hentheouterdiameter

    ;decreasescontinually,theseparationefficiencyofthe

;formertwotypesofthetestinletdecreasesrapidly,

    ;whilethatofthecurvedinvolutetyperises.Thereason

    ;f0rthephenomenonisthattheflowfieldintensityofthe

    ;hydrocycloneshouldbeenhancedwiththepressurelOSS

    ;

    ;Vb1.2No.3StudyofStructuralParametersoft

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    ;decreaseofthethreetypescausedbytheouter ;diameter’Sdecrease.whichiSinfavorofseparation.

    ;However,asthechannellengthdecreases,theflow ;guidingcapacityfallsdowncorrespondingly.Thisis ;anotherfactorthataffectsseparationefficiency.ThuS.it ;canbeseenthattheflowguidingcapacityofNo.3and ;No.6decreasessharplyasthechannellengthdecreases, ;butforNo.7.itsparticularcurvingchannelprovideda ;guidingcapacityforflow,SOitsseparationefficiency ;risesaliUle.

    ;

    ;n

    ;Inletouterdiameter.mm

    ;Fig.6Relationshipbetweeninletouterdiameter ;andefficiency

    ;4.Conclusions

    ;l,Theflowguidingcapacityofthetestinletaffects ;theefficiencymost;

    ;2)Fortheshortinletchannellength,thepressure ;lossinthebeelinechanneltypewithagraduallylinearly ;changingsectioniSthelowestofthethreekindsofthe ;testinlet;

    ;3)Whentheinletouterdiameterdecreases.butfor ;No.7.thecurvedchanneloftheinvoluteinletstill ;ensurestheguidingcapacityforflowanditsseparation ;efficiencyrisesmarginally.

    ;Asaresultofthesetests,afieldtrialwascarriedout ;inproductiontestingwellsintheInstituteofDaqing ;ProductionandTechnologywiththeshortchannelinlet ;ofaninvolutetype.whoseouterdiameteriS93mm.The

    ;fieldtrailprovesthefeasibilityforthetechnologyof ;downholeoilwaterseparation&reiniectionof

    ;separatedproducedwater.Acombinationscrewpump ;andvortexseparationdeviceperformedtheoilwater

    ;separation.Thedownholeapplicationofhydrocyclones ;isatateststageandtherearemanynewproblems ;worthresearchatpresent;however,thetechnique ;appearspromaslng.

    ;R-eferences

    ;Jiang,Minu;Zhao,Lixin;Li,FengandHe,Jie0998) ;ResearchontheInletPatternsofLiquidliquidHydrocyclone

    ;O/lFieldEquipment,27(2),3-6

    ;Veil,J.A.;Langhus,B.GandBelieu,S.(1999)DOWSReduce ;ProducedWaterDisposalCosts.Oil&GasJourna1. ;97(12),76?85

    ;Wang,Zunce;Gao,Ye;Lv,Fengxia;Liu,XiaominandLi, ;Feng(2003)EffectofLiquid—liquidHydrocyclone’SInlet

    ;StructureonPressureCharacteristic.FluidMachinery, ;3l(2),16-19,26

    ;Aboutthefirstauthor

    ;LVFengxia,bomin1978.

    ;receivedhermaster’Sdegreefrom

    ;DaqingPetroliumInstitutein2003.

    ;NOWsheisanassistantinthesame

    ;instituteandengagedinthe

    ;researchoffluidmachinery.E.mail:

    ;wangzunce(yahoo.corn.ca

    ;(EditedbyYangLei)

    ;

    ;

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