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1、EVALUATIONOFTECHNICALDRILLINGOPERATION-CASESTUDYININDONESIAFinalExaminationReportBy:ALRisAlfharisiNIM.12211014GUSTiArdiansahNIM.12211039AstiDamayantiNIM12211063SubmittedasthefinalexaminationofDrillingEngineeringLectureDepartmentofPetroleumEngineeringFacultyofMiningandPetroleumEngineeringInstitutTekn
2、ologiBandungDEPARTMENTOFPETROLEUMENGINEERINGFACULTYOFMININGANDPETROLEUMENGINEERINGInstitutteknologibandung2014VALIDATIONSHEETEVALUATIONOFTECHNICALDRILLINGOPERATION-CASESTUDYININDONESIAFinalExaminationReportBy:ALRisAlfharisiNIM.12211014GUSTiArdiansahNIM.12211039AstiDamayantiNIM12211063Submittedasthef
3、inalexaminationofDrillingEngineeringLectureDepartmentofPetroleumEngineeringFacultyofMiningandPetroleumEngineeringInstitutTeknoIogiBandungApproval,Date:Supervisor,Dr.Ing.BOnarTUaHaIOmoanMarbUnN1P.197512222009121002EVALUATIONOFTECHNICALDRILLINGOPERATION-CASESTUDYININDONESIAA.Alfahrisi*,G.Ardiansah*,A.
4、Damayanti*,InstitutTeknologiBandungCopyright2014zInstitutTeknologiBandungThisreportwaspreparedtofulfilldrillingengineeringlecturefinalexaminationattheDepartmentofPetroleumEngineering,InstitutTeknologiBandung.ThisreportwaswrittenusingstandardSPEPublicationStylein2013.AbstractWellplanningisanessential
5、partindrillingengineeringbecauseitwillbethebackboneofeveryotherprocessthatwearegoingtodowiththeoilfieldthatwearedealingwith.Processsuchasreservoirsimulation,productionengineering,orevensurfacefacilitiesoperationwillbeaffectedbythewellplanningprocess.Wellplanningprocessareconstitutedbyseveralstepswhi
6、chstartfromdeterminingtheporepresureandfracturepressureinordertodeterminethecasingdesign.Casingdesignisthenimportanttodeterminethecasingsettingdepth,andalsotocreatethemostefficientcosttobepaidforthecasingoperation.Afterthecasingdesignisfinished,thewellplanningprocesswillgotothenextstepwhichismuddesi
7、gnprocess.Themuddesignistheheartofdrillingengineeringbecauseitsthemaincomponenttomaintainboreholestabilitytopreventblowoutfromhappening.Becauseofthat,muddesignisconsideredtobeveryimportant.Otherthanmuddesign,anotherdesignthatwehavetodoisthecasingdesigninordertoprovidestrongmixtureofcementthatcanhold
8、thecasingweight.Nexttothatisbitchoosingbytakingintoaccounttheboreholesize,formationcharacteristic,andalsotheeconomiccost.Incasingdesignprocess,weneedtotakeintoaccountburst,collapse,andtensionloadofthecasingtodeterminethesizeofthecasingandalsocasingsettingdepth.Thisisveryimportanttoensurethecasingcan
9、withstandtheloadthatwillbehandledduringthewelllifetimeperiod.Afterthat,weneedtoproceedwiththedrillstringdesigninordertodesignthetypeofdrillpipetobeusedandthesize.Thisisimportanttomakethedrillingprocessmoreefficientbecausethewrongselectionofdrillpipemaycreateeconomiclossthat,sveryimportanttothecompan
10、y.Thecasinganddrillstringdesignareverynecessarytocalculatethemaximumloadtobeheldbytherigthatwecanuseindeterminingtherightypeandsizebecauserigrentingisoneofthemajorbudgetportionineverydrillingoperation.Allthedesignprocessthataredescribedabovearethenintendedtoavoidthenon-productivetimeofdrillingoperat
11、iontocreatemoreefficientdrillingprocess.Additionalanalysisisthenrequiredtodeterminewhetherweneeddirectionalorhorizontaldrillingoperationbasedongeologicalconsiderationsandeconomicreasonstorecovermoreoilandgas.BackgroundWellTM-19isaverticalwellwithtotaldepthof3610feet.Thedrillingactivityisintendedtoev
12、aluatethehydrocarbonappearanceonsandstoneformation.Thewellwasdrilledon7thAugust2009andreached3610feeton18,hAugust2009byusing2PDCdrillingbits(bothofthemaresecond-hand).Thecompanystartedtheoperationfrom572feet(hole12tttrajectory)until3610feet(TD).The12xtrajectorystartedfrom572feetuntil1874feetbyusingm
13、udof8.8-9.2ppgdensity.Onthistrajectorythereadingofbackgroundgasisontheintervalof10-30unitswithmaximumgasof411unitson1724feet.Bygettingin49jointsofK-55,36ppfR3BTCcylinder95/8withoatshoeseton1870feet.The8%”holetrajectorystartedfrom1874feetdeepuntil3610fetbyusingmudweightof9.2-9.4ppg.Onthistrajectory,t
14、hebackgroundgasisaround5-15unitswithmaximumgasof172unitson2065feet.TherecordingdataElectricLoggingisdonebySchlumbergerwhichisPEX-BHC-AIT-GR;GR-RFT;CST-GR.Gettingin97jointsK-55,23ppf,R-3,BTCCylinderof7,withfloatshoeseton3610feet.Thisstudyisintendedtoanalyzewhehterthemeasurethathavebeendonebythecompan
15、yisefficientenoughtothedrillingprocessandgiveabetterrecommendationthatwillfinallyleadtoeffectivenessofthedrillingoperation.Inordertodothat,thisstudywillbeusingtheoreticalapproachandcalculationthatwillhopefullyhelpthecompanytoevaluatetheinefficientmeasuresintheTM19WellProjectandputabettermeassurebase
16、donouranalysisontheirnextproject.Theevaluationalanalysiswillincludeonthefollowingmeasures:porepressure,fracturegradient,casingsettingdepth,holegeometryselection,mudplan,cementplan,bitprogram,casingdesign,drillstringdesing,rigsizingandselection,fieldperformance,anddirectionaldrilling.TheoreticalBackg
17、roundAliteraturereviewwasperformedtogainknowledgeofdifferentporepressureandfracturegradientpredictionmethodsandeconomicaldesigninanefforttofindthebeststrategyforthisareaPorePressure.Formationpressure(porepressure)isanimportantfactorthataffectsthedrillingoperation,duetoimproperevaluationmayleadtodril
18、lingproblemssuchaslostcirculation,blowout,stuckpipeandholestability.Foroptimizationofthedrillingprocess,sowhendeterminingfonationpressureshouldwefocusondeterminingtheareaswherethereareformationsthathaveanoverpressure,itrequiressomemethodstodetectandpredictwherethepressurewillbeencounteredover.Basica
19、llyitisaidedbytheseismicdata,butitisnotveryaccurateprecisionandaccuratebecausethedataobtainedisdatathatisrough.Therefore,weneedtomakeobservationsofcertainparametersrecordedduringdrillingunderwaythatwillhelpinpreventingtheoccurrenceofwildbursts(blow-out)asaresultofthedetectionarea/zoneoverpressure.Dr
20、illingparametersthatneedtobeconsideredinclude:drillingpenetrationrate(rateofpenetration/ROP),rotationalspeed(RPM)andloadonthechisel(WOB),inwhichtherelationshipofthethreeparametersshowninthefollowingformula.where:d=drillingexponentR=rateofpenetration(ROP),ft/hrsN=rotarySpeed(RPM)W=weightofbit(WOB),lb
21、sB=bitdiameter/bit(inchi)Thevaluefromaboveequationstillneedstobecorrectedagainagainstthenormalgradientandthedensityofthemud,sothat:d-=dfc)2)where:dcorr=d-exponentIerkoreksipmn=muddensityonnormalformation(normalgradient),lbgalPmC=circulationmuddensity,lbgalInIndonesia,especiallyinSumateraandthesurrou
22、ndingsareahavenormalvalueofthegradientaround1.06SG(8.8ppg).Inthesewellsestimateformationpressureorporepressurebasedon:backgorundgas,gasconnection,temperatureout,theinteretationoflithology,observationwellsandd-exponenl.Valueofporepressurecanbeobtainedfromthedatad-exponentoftheresultdcorrplotagainstga
23、sconnection.Ifthereisaconnectiontoagasdrillingcontinuouslymudweightindicatesthatweuseisapproximatelyequaltotheporepressureoftheformation,meanporepressureoftheformationisequivalenttotheweightofthemudthatweuse.Atthetimeofthegasdrillingtakesplacedoesnotlookgreat,becausecoveredbyECD(EffectiveCirculating
24、Density)ofmudwhosemagnitudedependsonthepropertiesofthemud.ECDvalueitselfisaffectedbythedensityofthemudusedandthepressurelossintheannulusalongthecircuitasafunctionofdepth,canbecalculatedbythefollowingequation:ECD= MW +6p0.052*D3)where:ECD=EffectiveCirculatingdensity,lbgalMW=muddensity,lbgal6p=totalpr
25、essurelossesinannulus,psiD=depth,ftFracturePressure.Pressurefracturing(fracturegradient)isthehydrostaticpressureoftheformationofthemaximumthatcanbedetainedwithoutduecausefracturingincaseoffracturefearedtobetheinclusionofaninfluxofgasthatcancausekick.Inaddition,byknowingthefracturingpressuregradienti
26、sveryusefulwhenresearchingthebasicstrengthcasing(casing),whereaswhenthefracturingpressuregradientisnotknownitwillfinditdifficulttocloakingwellcementingandcasingormounting.Thevalueofthefracturingpressureisaffectedbyoverburdenpressure,formationpressureandrockstrengthconditions.Thecalculationofthegradi
27、entestimationoffracturingwellsusingthecalculationmethodofMatthewsandKelly.ThiscalculationisbasedonthevalueofKi(matrixstresscoefficient)derivedfromtheresultsLeakOffTest.Fracturinggradientcalculationformulais:4)F=P/D+KiDwhere:F:fracturegradient,psi/ftP:formationporepressure,psi:matrixstressatpointofin
28、terest,psiD:depthatpointofinterest,TVD,ftKi:matrixstresscoefficient,dimensionlessCasingDesignDepth.Casingsettingdepthisdeterminedbasedondownholeconditionsuchasporepressure,fracturepressure,andpressurewindow.Fromthepressurewindowwehaveconstructedwecananalyzetheintervalofourcasingused.Afterdetermining
29、casingsizeanddepthforeverycasingstring,anddesigndrillingoperation,loadtowardsthecasingcanbecalculated.Weightandgradeofcasingthatissuitabletocounteraloadcanbecalculated.1. CollapseLoadCasingwillreceivemaximumloadiftheexternalradialforceismorethaninternalradialforce.Maximumcollapseloadoncasingcanbecal
30、culatedbyassuminginnercasingisinemptycondisiton.Collapseloadoneverypointalong5)thecasingcanbecalculatedwith:PColIaPSe=externalinternal2. BurstLoadCasingalsowillgainaburstloadiftheinternalradialloadisbiggerthanexternalradialload.Burstloadalongcasing,canbecalculatedwith:6)PCollaPSeinternalPeXternal3.
31、AxialLoadAxialLoadoncasingcanbeintheformoftensileloadandcompressiveload,dependsontheoperation.Axialloadoncasingcanhaveaveryvarietyvalue.Axialloadwillappliedonsomeoperationsandhavetocalculatedandsumtodeterminetotalaxialloadtowardthecasing.HoleGeometrySelection.Bitandcasingsizeselectioncanmeanthediffe
32、rencebetweenawellthatmustbeabandonedbeforecompletionandawellthatmustbeabandonedbeforecompletionandawellthatisaneconomicandengineeringsuccess.Impropersizeselectioncanresultinholessosmallthatwellmustbeabandonedduetodrillingorcompletionproblems.Thedrillingengineer(andwellplanner)isresponsiblefordesigni
33、ngtheholegeometrytoavoidtheseproblems.However,asuccesfulwellisnotnecessarilyaneconomicsuccess.Forexample,awelldesignthatallowsforsatisfactory,trouble-freedrillingandcompletionmaybeaneconomicfailurebecausethedrillingcostsaregreaterthanbeexpectedreturninvestment.Holegeometryselectionisacriticalpartoft
34、heengineeringplanthatcanmakethedifferencebetweeneconomicandengineeringfailureorsuccess.RigSizingandSelection.Rigisoneofthemostimportantcomponenttodrillawell,andthefirstcomponentthatweneedtopreparebeforedrilling.UsuallyRigDesignisrelatedtoitsmaximumloadtoruninacasingoradrillstring.7)casing的”casing(ft
35、)x3.281Where:WIOtaI=Totalweightofcasing(Ibs)WCaSing=Weightofcasing(lbft)hcasing=Casingdepth(ft)MaxRigLoad=wtal(n+2)8)Where:WtOtai=Totalweightofcasing(Ibs)n=Numberofcoileddrillinglineinthecrownblock(Assume:n=l()MudPlan.Ingeotechnicalengineering,drillingfluidisusedtoaidthedrillingofboreholesintotheear
36、th.Drillingmudisoneofthemostimportantelementondrillingoperation.Drillingfluidhasmanyfunctionswhichneedtobeoptimizedtoovercomeholeproblem.Failureofthedrillingfluidtomeetitsdesignfunctionscanproveextremelycostlyintermsofmaterialsandtime,andcanalsojeopardisethesuccessfulcompletionofthewellandmayevenres
37、ultinmajorproblemssuchasstuckpipe,kicksorblowouts.Sotypeplanning,additiveandvolumeofdrillingfluidisimportanttomakethedrillingoperationsucceed.Oftenusedwhiledrillingoilandnaturalgaswellsandonexplorationdrillingrigs,drillingfluidsarealsousedformuchsimplerboreholes,suchaswaterwells.Liquiddrillingfluidi
38、softencalleddrillingmud.Thethreemaincategoriesofdrillingfluidsarewater-basedmuds(whichcanbedispersedandnon-dispersed),nonaqueousmuds,usuallycalledoil-basedmud,andgaseousdrillingfluid,inwhichawiderangeofgasescanbeused.Themainfunctionsofdrillinguidsincludeprovidinghydrostaticpressuretopreventformation
39、fluidsfromenteringintothewellbore,keepingthedrillbitcoolandcleanduringdrilling,carryingoutdrillcuttings,andsuspendingthedrillcuttingswhiledrillingispausedandwhenthedrillingassemblyisbroughtinandoutofthehole.Thedrillingfluidusedforaparticularjobisselectedtoavoidformationdamageandtolimitcorrosion.Hp=0
40、.052xMw(ppg)xD=Psi8)where:Hp=Hydrostaticpressurefromthemud,psi.Mw=Muddensity,ppg/pcfD=Depth,ft.Therearemanydrillingfluidadditiveswhichareusedtodevelopthekeypropertiesofthemud.Thevarietyoffluidadditivesreeclthecomplexityofmudsystemscurrentlyinuse.Thecomplexityisalsoincreasingdailyasmoredifficultandch
41、allengingdrillingconditionsareencountered.Weshalllimitourselvestothemostcommontypesofadditivesusedinwater-basedandoilbasedmuds.Theseare:1. WeightingMaterialWeightingmaterialsordensifersaresolidsmaterialwhichwhensuspendedordissolvedinwaterwillincreasethemudweight.Mostweightingmaterialsareinsolubleand
42、requireViscosiferstoenablethemtobesuspendedinafluid.Exampleofweightingmaterialsare:barite,hematite,magnetite,etc.2. ViscosifiersTheabilityofdrillingmudtosuspenddrillcuttingsandweightingmaterialsdependsentirelyonitsviscosity.ExampleofViscosifiersare:bentonite,CMC,PAC,XanthanGum3. StarchesStarchisanat
43、uralpolymerusedindrillingmudsprimarilytoreducefiltratelossandtoprovideviscosity.CementPlan.Inordertoplancementwemustdeterminetopofcement(TOC)isthepointwherethecementbegantobepumpedorcementtopspot.Incementingoperationsweknowthetermsqueezecementingisaconditioninwhichthehydraulicpressureisusedtopushthe
44、cementpassesthroughtheholeinthecasingandintotheannulus.Inanycementingoperation,decisivestepbysubtractingtheTOCissqueezecementinginten,alswith50fttoobtaintheTOCvalue.Inthiscase,becausethecasingisinstalledat571ft,thentheselectedTOCat521ft.Topofcementcanbedeterminedby2ways: SurveiTemperaturThisinvolves
45、runningathermometerinsidethecasingjustafterthecementjob.Thethermometerrespondstotheheatgeneratedbythecementhydration,andsocanbeusedtodetectthetopofthecementcolumnintheannulus.Figure-1.DeterminingTopofCementbyusingtemperaturelog(Source:Heriolt-WattUniversity,DrillingEngineering) RadioactiveSurveyRadi
46、oactivetracerscanbeaddedtothecementslurrybeforeitispumped(Carnoliteiscommonlyused).Aloggingtoolisthenrunwhenthecementjobiscomplete.Thistooldetectsthetopofthecementintheannulus,byidentifyingwheretheradioactivitydecreasestothebackgroundnaturalradioactivityoftheformation.Figure-2.DeterminingTopofCement
47、byusingRadioactivelog(Source:Heriott-WaitUniversity,DrillingEngineering)Incementingoperationsrecognizedtwotypesofcementnamelyleadandtailcementcement.Bothtypesofcementhavedifferencesintermsofdensityandalsothepenyemenannya.Headcementisthecementthatwasfirstpumpedatthelopofthedrillholeastemperatureandlo
48、werpressuresothatthequalityofcementevenworsethanthetailcement.Whilethetailcementiscementwhichislocatedinthedeeperpartsothatithasbetterqualitybecausetheyhavetowithstandtemperaturesandhigherpressures.Figure-3.LeadcementandTopcementSource:http:WWWFigure-3.PartitionofCementingProgramSource:Source:http:WWWdrillinformulascon/What-areleadand-tail-cement/accessedon10,hMay2014BitProgram.ADrillbit,isadeviceattachedtotheendofthedrillstringthatbreaksapart,cut
