FACILIDADES DE AGUA DE INYECCIÓN EN LA UNIDAD DEL CAMPO WEBSTER

7/28/2019 FACILIDADES DE AGUA DE INYECCIN EN LA UNIDAD DEL CAMPO WEBSTER

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SPESPE6880

WEBSTERI ELBUNI TWATERFLOODACI LI TI ESby B. L. Moore, Jr., M@m~@rPE-AIMESxxonco S*AC

@ Copyr i gh t 1977 , Ameri can Institute ot Mining, Metsllurg@, and Petroleum Engineers. Inc.This psper wss presentti, al the 52nd Annual Fzll TechnicalConferenceandExhibition of the Society of Pet r ol eum Eng ineer s o f A IM E, he ld I nDenve r , Co l or ado , Ot t 9 . 12, 1977 . The m al e ri a l I s subj ac t t ocorrechon by the autho! Permission to copy Is restricted to an abstract of n ot m or e t h an 3 00 w o rd s. Wr i t% 6 2KI N. Ce nt r al Ex py , Da ll ss , T ex as 7 52 (W

ABSTRACT of the field. It was froma requi rement to cont rolthemovementof thegas-oiland oil-watercontacteThe WebsterFieldin HarrisCounty,Texasis in thelargestfaultsegmentthattheWebsterWater-one of thelargerreservesoperatedby EwconCompany, floodProjectwas conceived.U.S.A.,and is currentlybeingwaterfloodedat ratesin excessof 50,000barrelsof waterper day. Pre- Thispaperdescribesthebasicdesignof theMminary reservoirstudiesindicateda need for waterfloodsystem,and a revi- of the firstthreewaterinjectionto controlthemovementof the oil yearsof operations,A schematicof thewaterfloodcolumnin thisFriosandreservoirand thereby stationis ehownin Figure2. The systmuconsisteincreaeeultimaterecovery. Basedon resultsof of the followingmajarpiecesof equipment:more detailedstudies,includingreservoirsimula-tion,the fieldwas unitizedanda waterfloodsystem (1)Four10,000barrelinletwatersertlingwas designedand builtduringthe threeyear period tankswith accompanyingtransferpumps.1972-75. The system,whichprovidedforuse of bothsourceand producedwaters,includedsourcewater (2)Sevenup-flowrapidsand filters.wellsand relatedfacilities,waterclarificationfacilities,injectionpumps,an injectionwater (3)Four2,800barrelcleanwatersurgetanks.distributionsystem,and injectionwells. The

facilitieswere automatedthroughutilizationof an (4)Threesevenstagehorizontalsplit-caseexistingfield-wideComputerProductionControl centrifugalpumpseachdrivenby a 1,400HPSystma. naturalgas fueledinternalcombustionengine.Thispaperdescribesthe planningeffortasso-ciatedwiththe designof theproject,designconsi- (5)A distributionsystemconsistingof morederations,operationalresults,and currentsurveLl- thsn11 milesof internallyand externallylanceactivities.Thissurveillanceprogramincludas coatedinjectionlateralsvaryingin sizewater qualityanalysis,corroeioncontrol,and from2 7/8OD to 8 5/8OD connectingcomputerizedpreventivemaintenanceschedulingfor about20 injectionwellewith thewater-theplantfacilities. floodplant. Mexiunsmwrking pressureonthissystemiS 2160 PSi~.INTRODUCTION completesystemis closedto excludeoxygenThe WebsterFieldis locatedapproximately20 and theentireplantpipingsystemis designedt omilessoutheastof downtownHouston,Texas,as indi- allowuse of both producedsaltwaterandwaterfromcatedin Figure1. The fieldwas discoveredin 1937 sourcewellswithoutixingthewaters. Peripheralby Humble011 & RefiningCompany(nowExxonCompany, equipmentincludesa completesupplygas system,skimU.S.A.),and containsa majoroil ras :J e, overlain oil recovery, storageand disposalsystems,filterby a largegascap and underlainby water. Since backwashpumpsandcontrolsystem,and a backwashdiscovery.developmenthas progressedsuchthatthe waterrecoveryand storagesystemconsistingoffieldnow contains144wells,producingapproximately storagetanksand a naturalgas de-aerationCOIUZZI.60,000barrelsof oil par day. Priorto unitizationin 1973,theproductivelimitsof the fieldencom- Therewere threesignificantfeaturesof thepassed52 individualleases.representingore than WebsterWaterfloodStation:660mineralroyaltyinterests.The majorproducinghorizonis theFriosendoccurringat approximately (1)The designof the inletwatersettlingtanks.6,000feet. Majorfaultingin thearea reeulteinvariedproductiondriv?mechanismsin variousparte (2)Ahigh levelof automationincorporat~intoIllustrationst endof paper. thewaterflood y s t em .

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(3)The relativelyehorttimeperiodfrom the From the dataobtainedin the abovestudiesandcompletionof the unitizationto the ini- basedon reviewof otherExxonwaterfloodplantstiationof waterinjection. performance,thebasicdesignfor thisprojectwasdeveloped.Bastedesignfeaturesincluded:Theeefeatureswillbe discussedin detaillat-erin the paper. 1. Bothproducedwater fromthe WebsterFieldandsourcewaterwouldbe used forinjection.DESIGNAND CONSTRUCTION Economiceindicatedthatthe sourcewellsshouldbe producedby submergiblepump.Beforediscussingthemoreuniqueaspectsof this~aterflood,thispaparwill addressseveralcritical 2. Due to potentialcomparabilityroblems,designconsiderationshatwere evaluatedpriorto the entirewaterfloodsystemwouldba re-construction.Severalstudieswerecompletedin order signedto proces~sourcewater and producedtoacquirenecessarydesigninformation.Thesastudiec waterseparately.Each tank,vessel,andincluded: pumpwouldbe pipedso thattheycouldprocesseithertypewater. Thisdesign1. Alternatesourcesof injectionwater. Salt- providedcompleteflexibilityin caseofwaterbearingsandswithinthe surfaceboun- changeain watersupplies.dariesof theWebsterField.producedwaterfromtheWebsterField,and producedwaters 3. The entiresystem,fromwatersupplytofromtwo fieldsin thegeneralvicinitywera injectionwell,wouldbe closedso thatevaluuted. Capacitiesand computabilities oxygenintrusioncouldbe held to a minimum.of thesesourcesweredeteznrined,s well asthe economicsof deliveringthesewatersto 4. Primaryremovalof entrainedoil andheavieran injectionsiteat thedesiredrates. suspendedeolidswouldbe accomplishedbydesigningthe inletsettlingtanksfora2. Sourcewaterwellproductivitytesting. 12 hourretentiontime.Thie studyinvolvedthe recompletionof anabandonedoilwell intotheprospective 5. Remainingeuspendedsolidswouldbe removedwaterbearingsandand thetestingof the to acceptablelimitsby filtration.The sizewell to determineproductivecharacteristics. and amountof euspendedsolidsto be removedThewellwas equippedwith gas liftequipment indicatedthatup-flowtypefilterswithandproducedforan adequatetime to achieve throughputratesof approximately gallonsstabilizedflow. Shut-inand flowingbottom- perminuteper squarefootof cross-sectionalholepressuredatawere obtainedfor the areawouldoperatesatisfactorily.calculationof a productivityiz.dex.Thesedatawere essentialin theevaluationof the 6. Centrifugalunitswouldbe used. A comparisoreservoirand ultimatedesignof sourcewater of primemoversindicatedthatnaturalgaswell completionsand gatheringsystems. fueledinternalcombustionengineswcdd bemore economicthanusingelectricpower.3. &oloRic eval=_t~onof the Prospectivesourcewatersand. The productivehorizonwas geo- 7. Pipingin thewaterfloodplantwouldbe sizedlogicallymappadco establisharealextent to limitfluidvelocitiesto less than6 feet

and reservoirvolumedataand to verifythat per secondsincevelocitiesin excessof 10the reservoircouldsustainanticipatedwith- feetper secondhad been foundto acceleratedrawalratesand volumes. internalcorrosionin baresteelpiping. Aa4. Corrosivitytestingof potentialsourceand additionalsafeguard,all tanksand filtervesselswouldbe internallycoatedto preventprod;lcedaters. Thewaterswere tested corrosion.underfialdconditionsto evaluatecorrosiontendencies.Oxygancontentsurveyswere 8. In orderto takeadvantageof the talentstakenat varicvspointsin the fieldto and sktllsof existingoperatingpersonnelestablishbase datapoints. Thesetests the facilitywoulduse oilfield-typeinstru-indicatedonlyn.sgligiblemountsofoxygen mentationand proceduresinsteadof plant-in the fieldproductionfacilitiesand in typeinstrumentation.the sourcewaterproductionstream. Someunusualfeatureswere incorporatedintothe5. Oil-waterseparationtes~. Settlingtime stationdesign. Figure3 showsa schematicof thetestswere conductedto determinethe required inletwatersettlingtanke. As discussedearlier,ratentiontime for adequateoil-watersep- thesetankswere designedfor 12 hoursretentiontimearationof fieldproducadsaltwater. In additionto normalinlet,outletand drainconnec-tions,each tankis internallyequippedwith a conica6. Injectivitytestina. Existingwellscom- bottomsand trap,8 feetin diameterand 19 feethighpletedin theFriosandwere utilizadfor Theseeandtrapeare pipedso thatheaviersuspendedinjectionteeting. rhesetestsinvolved solidswill fellout of the waterstreamwithintheeethe injectionof producadsaltwaterinto devices andcanbe periodicallydumpedto theplant-isting completionintervals.Fressure- emergencypit. A uniquefeaturewas incorporatedinratedata fromthesetestswereused to eachof thesetanksto insureuniformmovementofdetermineInjectioncharacteristicfor the waterthroughthe tanks. Aa shownon the leftsiderespectivesandstringerefromwhichrequired of Figure3, each tankcontainsa dischargepipingsurfaceinjectionpressureewere determined. eystemdesignedto eliminatethe channelingof proces


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---- . . . .. . . . . . 3PE 688U B. L. IllnInu.J. awater fromthe tankinletto the pointof dlecharge. dureswereused for controland progressevaluationThe dischargesystemis simplisticin nature,ccn- procedures.sistingof 12 inchpipe tiedto the tankoutletandlaidon thebottomof the tank. Thispipe thentakee OPERATIONSa suctionfrom16 differentpoints. This diechargesystemenablesa reasonablyuniformverticalmovement Duringthe firetthreeyearsof operations,of theprocesewaterthrougheachtank,therabyeli- severalunexpectedprobleaneavebeen encountered.minatingthepossibilityof channelingreducing Duringtheearlystagesof operationwhileinjectingretentiontimein the tank. wateretraightfromthe sourcewells,somecorrosionproblemsbecameevidentin the plantarea. h in-A eecondunusualfeatureof thiswaterflood teneecorrosionmonitoringprogramwae initiatedstationis itehighdegreeof automation.The design consistingof water eamples,corrosioncouponsinincorporatedtheuae of etandardoil fieldautomation strategiclocationsand calipersurveysin bothhardwaretiedto the existingproductionautomation sourceand injectionwells. The presenceof oxygensyetemto providecontinuousmonitoringof critical was diagnosedas themain culprit. However,theopera?ioneparameters.More then 50 individualalarm wateranalyeesindicatedthatoxygenwas not intro-pointewere includedin thewaterfloodplantarea. ducedin the surfaceequipment.NativeoxygeninTheeealarmsincludehighand low levelstatueof the the sourcewaterwas discountedas a potentialeourcesettlingand eurgetanke,individualtankgas blanket sincecalipersurveysof thesourcewaterwell tubingpressures,high end lowpressureof transferand in- indicatedno significantcorrosion. It becamejectionpumps,flowto the emerge. lcy pit,statueof apparentthatthe corrosionwas caueedby oxygenoperationof eachinjectionpump,abnormalfuelgas introducedduringhydrostatictestingof the dis-pressure,endhighliquidlevelson theemergencypit. tributioneye t im. A significantperiodof timeThis eystemaffordssurveillanceof thisplantduring was requiredto removethesecontaminenesfromtheunattendedperiodsthroughalarmdisplayat nearby system;however,therewere no apparenteconomicExxon facilities.Supervisorypersonneldirectly alternativeto avoidthisproblem.responsiblefor the waterfloodoperationsare noti-fiedof criticalalarmsas theyoccurand they Laterin 1975 afterstart-upof theplant,directany remedtalactionrequired. abnormalcorroeionrateswerenotedin theproducedwater eystsin.SubsequentteetingindicatedsulfateAutomationof fieldmeasurementswere also reduc%ngbacteriawere beingintroducedintotheincludedon thedesign. Liquidmeasurementis accom- plantby theproducedwater. Periodicbatchtypeplishedby theuseof turbineand orificemeterend bactericidetreatment correctedthisproblemanddevicee. Plantinletvolumesfromaachseparatesourc(!thesetreatmentshave beenoptimizedto 100 ppm forand plantdischargevolumesto the variouscomponents eighthoureon a weeklybasic. Ae a resultof theof the injectionsyetemare accumulatedand proceesed corrosionproblem,some injectionwell pluggingby the automationeystem. Injectionratesand tubing problms were experiencedin 1975and 1976,especiallpreseuresof the individualinjectionwelleare read in the tighterinjectionzonee. Selectiveacidizingmanuallyand thenenteredintothe automationsystem. techniques,usinga perforationwash tool,haveFromthesedataand the plantdischargeratee,the proveneffectivein the removalof thesepluggingcomputercalculatesand storesthe injectionvolumes ageutsfromthewellboree.intoeachwell. Thesedataare thenavailableon arealtimebarisfor reservoirengineersto monitor Optimizationof surveillanceactivitiesis ainjection performanceof eachsandmemberbeing cent.nuingroceesin a facilityof thiesize.flooded. All accumulateddataare Initiallyheld in Cur:ently,hissurveillanceprogramconeistsof theshort-termstorageforeasyaccessibilityy local foilowingactivitlee:Exxonoperatingand engineeringpersonneland thenare automaticallyddedto permanentcomputerrecords. 1. Computerizedpreventivemaintenanceprogramsin whichmonthlyschedulesarepreparedAfterdevelopingthe basicdesignconcepts, indicatingthe requiredmaintenancechecke,contractswerelet for thedetaildesignand conetruc and calibrationsof variousplantequipmenttion. A uniqueappllcattonof existingtechnology forthemonth. Suchoperationsincludeallowedthe initiationof waterinjection9 months checkeof varioustanklevelandpressurepriorto completionoz thewaterfloodstation. Upon alarmsend the calibrationof individualcompletionof the distributionsystem,injectionwas filterflowratecontrollers.initiatedin September1974by producingtwo sourcewellsdirectlyto a groupof injectionwells, 2. Corrosioncouponehavebeen installedinby-paseingtheprocessplantwhichwaa stillunder strategiclocationein the facility.Theseconstruction.Submergiblepumpswereused to produce coupor.are retrievedon a regularbasiswaterat sufficientwellheadpressureto moveapprox- forevaluation.imetely32,000BW/D throughthe distributionsyetemand allowedthe in~ectionof waterat pressuresof 3. Periodicwaterqualitysurveysaremade300- 400pslg. in whichcheckeof suspendedsolids,oxy-gen,oil content,and bacterialcounta reConstructionon thewaterfloodetationwas corn- madeat variouslocationsin thesyetem.pl.etedin earlyklay1975. Within10 daysof inttial Systematicanalysisof theeedsta canplantstart-up.theinjectionrate throughthe plant indicatepooroperationof specificitemswas 57,000barrelsof waterper day. The completed of equipment,the earlydetectionof whichstattonis shownin Figure4. The waterfloodstation may preventcostlyequtpmentbreakdownwas completedapproximately3 monthsafterapproval and/orinjectionwell damage. Dailymini-for construction.Throughoutthe vartouadesignand pore filtertestsare takenaa a visualconstructionphases,crititialath enalyeisproca- checkof waterqualityat variouapoints


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i WEBSTERFIELDUNITW,

4*In theIystem.Plotsof veeklyinjectionwellrateandpressuretests-are-maintained.hesedata,whencom~iledwith otherpertinentdataeuchas plantupsets,wellservicejobs,etc.,providea valuabletoolin theover-all surveillanceof the entiresystemsperformance.

I CONCLUSIONSThispaperhas outlinedkhe concepteusedinthe designof a majorEaotonCompany,U.S.A.,water-floodfacility. Someunusualdesignconceptswereq

ERFLOODFACILITIES SPE6880utilizedto maximizewaterqualityand to providebetteroperationalcontrolthroughuse of automationequipment. In the firstthreeyearsof ulantoner-ation,no problemshaveoccurredto rest~ictth~-operationand throughputbelowtargetrates.ACKNOWLEDGEMENT

The authorwishedto expressappreciationtoE~on Company,U.S.A.,forpermiseioito prepareand publishthispaper. Specialacknowledgementie givento Mr. W. J. Frank,annuitantof ExxonCompany,U.S.A.,forhis adviceand counselin thedesignstagesof thisproject.

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FACILIDADES DE AGUA DE INYECCIÓN EN LA UNIDAD DEL CAMPO WEBSTER