Chapter 3 - Deepwater Pressure Management.docx

CHAPTER3DeepwaterPressureManagementPressureManagementThePressureManagementofdeepwaterwe1.1.smaynotappeartobethatmuchdifferentfromanyotheroffshorewe1.1.,butmakingsuchanassumptioncontributestoamu1.titudeofdri1.1.ingandwe1.1.operationa1.prob1.ems.Certainc1.assesofdeepwaterwe1.1.saspresentedthroughoutthisguidehavepressureregimecomp1.exitiesanddifficu1.tiesinac1.assoftheirown.Thatdemandsfargreaterwe1.1.p1.anning,construction,dri1.1.ing,andde1.iveryrequirementsuti1.izingamu1.tidiscip1.inaryapproach.Deepwater'smostdisastrous,consequentia1.,1.osscontro1.dri1.1.ingevent,i1.1.ustratedinFig.3.1,resu1.tedfromsevera1.pressuremanagement1.osscontro1.eventfai1.ures.Theconsequentia1.impactresu1.tedinarigexp1.osionand1.ossofthevesse1.totheseabed,11fata1.ities,17furtherinjuries,uncontro1.1.ed1.ossofwe1.1.contro1.with>5mi1.1.ionbarre1.sofcrudeoi1.re1.easedintotheGu1.fofMexicointhemonthsthatfo1.1.owed.Thedisasterdevastatedtheregion'seconomyandcontinuestothreatenthehea1.thofresidentsandtheenvironment.Thisoneeventa1.oneservestoremindpersonsusingthisguidetothePressureManagementassurancedemandedindeepwaterprojectsasisab1.ydemonstratedthroughtheevidenttensofhundredsofcomp1.ex,cha1.1.enging,anddifficu1.tdeepwaterwe1.1.sasi1.1.ustratedinFig.3.3thathavebeensafe1.yeffective1.yandefficient1.ydri1.1.ed.PressureManagementStudiesandObjectivesREVIEWOFPRESSUREDRI1.1.INGANDGEO1.OGICA1.ANA1.OGUESChapter2high1.ightedhowseismic-basedexp1.orationadvancementscontributetotheidentificationofnewpotentia1.deepwaterhydrocarbonbasinsandprovidestrongevidenceforactivepetro1.eumsystems.2Dand3Dseismicinterpretationandattributeunderstandingindicatesthepresenceoftrappinggeometryandf1.uidtype,drivingagreaterneedtounderstanddeepwaterpressureregimes.Interdiscip1.inaryteamsIeamhowtoassessthesedataanduseexistingexperiencesfromsimi1.arana1.oguewe1.1.stofurtherderiskbasininterpretationwherenowe1.1.dataorpressurecontro1.exists.Suchawe1.1.may,insomecases,be1.ocatedmanyhundredsofkmsaway.Manybasinstudiesforse1.ectionofana1.oguesevo1.vearoundbasin-sca1.etectonostratigraphicstudiesoftentoderiskthebasin.Intermsofgeo1.ogica1.pressureforthesebasins,furtherworkisrequiredtoderisktheoperatingpressure1.imits.Forexamp1.e,sand-sha1.egeometries,reservoirp1.umbing,topofcementwithinsha1.es,therma1.evo1.ution,andsedimentationrate).Ivpuuc<Dttghttpsd0iar1.l 016B97S4)X)4 02282500003, X69»2019 Ekcvicr 1.ed. All rights reserved.FIG.3.1DeepwatcrhorizononfirebeforesinkingtothebottomoftheGu1.fofMexicobasin.Fromhttps:/en.wikiPediaQrgwikiDeqnUatejHorizoxexp1.osion#/”Iedia/FikQeepwaterJiOriZonJ）於horeiHning_unit/m_fire_2010.jpg.Fordeepwaterenvironments,g1.oba1.1.ythesebasinssharecharacteristicsthatcanhe1.pde-riskthepressureenvironment;suchcharacteristicsinc1.udemorec1.aystone/sha1.e/iso1.atedsandfacies,thinneroverburden,missingorerodedsequences,moreor1.essfracturing/fau1.t-ing.Examp1.esofporeandfracturepressuresarethenpredictedtoassistintheunderstandingofthe1.ike1.ypressureregimes,andguidethedri1.1.ingoperating1.imits,environmentsandconditionsexpected.DEEPWATERSTUDIESOnceaprojectisapproved,apressureandwe1.1.borestabi1.itystudyworkwou1.dbeconsideredandscoped,particu1.ar1.yfornewareas.Theworkscopeidentifiedthenresourced,tasked,andschedu1.edtoprovideacomprehensiveregiona1.pressureana1.ysisofa1.1.representativewe1.1.data,withtheresu1.tantoutputusedtopredictpressuretoassuresafewe1.1.1.ocation,designand1.aterdetectpressuretoassurethatdri1.1.ingmeetsdesiredgoa1.s,objectivesandwe1.1.va1.ue-addedrea1.ization.Studiescanfurtherprovideadefinitiveana1.ysisofthepressuresintheregiontoenab1.eanunderstandingofpressuredistribution,operatinghazards,andrisks.STUDYOBJECTIVESRepresentativestudyobjectiveswou1.dbeto:1. Identifyre1.evantoffsetorana1.oguewe1.1.s.2. Gatherre1.evantpressuredatainc1.udingmeasuredformationpressures,kickpressures1.eak-offdata,mudweight,measuredannu1.arpressures,dri1.1.ingpressureindicators,ve1.ocity,andresistivity1.ogs.3. Understandthepressureregimeandcausesofoverpressuregeneration.4. E>erisktrapmechanisms,sea1.fai1.ure,andidentifypositivereservoircharacteristics.5. Determineandeva1.uatekeycomponentsrequiredforsafewe1.1.p1.anning:reservoirpressure,c1.ay/sha1.epressure,overburden,fracture,andco1.1.apsepressuremode1.s.6. Providearobustdeterministicpressureandoverpressureprofi1.ewe1.1.-tiein(basedonseismic1.inesprovided)forthepurposesofseismicve1.ocityca1.ibration.7. Understandtheovera1.1.pressuremagnitudesanddistributionsconsideredtorepresentthedeep-waterenvironmentstobedri1.1.ed.8. Useoffsetwe1.1.datatoca1.ibrate1.itho1.ogyusedintheporosity-permeabi1.ity-effectivestressre1.ationships,tobui1.dorrun1D-3Dbasinmode1.s.Comparebasinmode1.withthepressuremeasurementsandgeo1.ogica1.1.ydrivenbasinmode1.toproduceamost1.ike1.ypressureprofi1.e.9. Capturereasonab1.euncertaintiesingeo1.ogica1.understandingandpressureprofi1.es,andcommunicatethere1.evantrisks.DATABASE,ANA1.OGUEREVIEWSStudyinterpretationswou1.dbeweighted,ranked,andriskedbasedontheirqua1.ityandre1.evancehe1.pingana1.ysttocapturetheuncertaintiesinthedataandderivedmode1.s.Thesedatacanbegroupedintotwomainareas:directandindirectmeasurements.DirectMeasurementPorepressurefromwe1.1.boreformationtestsisviewedasthemostre1.iab1.emethodtoacquirepressuremeasurementsfromana1.oguewe1.1.szprovidingdatathatareassessedandinterpretedeffective1.y,particu1.ar1.yifpermeab1.eformationinterva1.sweretested.1.ostcircu1.ationandkick1.osseventsprovidere1.iab1.eandaccuratedirectpressuremanagementmeasurementwe1.1.contro1.datawithinana1.oguedatasetsreviewed.IndirectMeasurementIndirectporepressuremeasurementsareobtainedfromavarietyofsources,inc1.uding:1. Mudweighthistory2. Gasmonitoringatthewe1.1.3. Dri1.1.ingparameterana1.ysis(e.g.,deexponent)4. Interpretationofporositytrendsfromwire1.ineor1.WD/MWDdataPrimaryandsecondarypressurepredictionanddetectionindicators,before,during,andafterdri1.1.ingoperationsaresummarizedinFig.3.2,Tab1.es3.1and3.2.Inconc1.usion,manymethodsareusedtodetectabnorma1.1.ypressuredzoneswhi1.edri1.1.ing.Itisimportanttonotethesecanvaryineffectivenessandshou1.dbec1.assifiedonthebasisofre1.iabi1.ityasshowninTab1.e3.1.1.itho1.ogyviewedasthekeydeterminanttocorrectinterpretationthanmustbe1.inkedtoeachparameterindependent1.y.Pressuremanagementindeepwaterisnoteasyorstraightforward,becauseofa1.1.petrophysica1.,engineering,scientific,andreservoirinterpretationsdemanded.Deposition,conditions,andenvironmentsarea1.sooftenverycomp1.exinnature/characteristicsandthereforefraughtwithhazards,risksanduncertainties.Bringinga1.1.specia1.istski1.1.s,know1.edge,andexperiencetogetherthroughoutaprojectshou1.dnotbeunderestimatedtode1.ivertheessentia1.pressuremanagementoutcomesrequired.Pressureor formation test too1.s and methods Formation interval tester Drill string test Kick or lost circulation events Gas Measurementand/or1.oggingwhi1.edri1.1.ing Wire1.inetoo1.s,seismicve1.ocities Mudweight Equiva1.entdepthmethods 'D'exponent;modifiedmethodsoup一MUooFIG.3.2Hierarchyofpressuredataviaconfidenceranking.Note:rankingwou1.dvaryandishigh1.ydependentondataqua1.ity,"Equiva1.entdepth“inthiscasereferstore1.ativemparisonofdata.Source:KingdomDri1.1.itig2018.DetectionParameterRe1.iableModerate1.yreliableRea1.Time MethodsDrilling rate e.g., drilling break.Flow measure (increase/decrease)Losses and/or gainsMeasurement vrhile drilling "MWD" (Neutron density)MWD (Gamma ray/Resistivity)Notre1.iablePumppressureDe1.ayed(Lag Time) MethodsGas MensuremetitDrilled (background gas)Connection gasReservoir gasGas: compositionTrip GasShale density, shale factor.Abundance, size shape of cuttingsMud temperatureTAB1.E3.1Whi1.eDri1.1.ingPrimaryPressureIndicatorsSource:KingdomDri1.1.ing.PressureRegimeEssentia1.sPressureregimestobemanagedandcontro1.1.edindeepwaterarePore,Fracture,andOverburdenco1.1.apsepressureprofi1.es.Regimesareoftenverydifferenttooffshoresha1.1.owwaterwe1.1.s,whichdrivesgreaterdemandsinwe1.1.p1.anning,design,andoperatingstandards.Examp1.e:Fig.3.3providesagenera1.izedreviewastothevarianceofdeepwaterpressureregimesanddri1.1.ingoperatingwindowsthatexist.Someregimesaredifficu1.ttopressuremanagewithgreatercomp1.exitiesintermsofwe1.1.design,engineering,andoperationa1.requirements:morecasingstrings,contingencies,revisedcasingsettingdepths,differentstringsizeDEEPWATERPRESSUREMANAGEMENTTAB1.E3.2SummaryofPressureManagement!DetectionMethods73SourceofDataParametersTimeofRecordingGeo1.ogica1.Regiona1.geo1.ogyOffsetdatastudiesandana1.ysisPorepressureandwe1.1.borestabi1.itystudiesPriortospuddingwe1.1.Geophysica1.Formationve1.ocity(Seismic,3D,high-reso1.ution,etc.),Gravity,Magnetics,&E1.ectrica1.prospectingmethodsDri1.1.ingparametersDri1.1.ingrate,1.itho1.og)；WOB/RPM,torque,drag,pressureeffects(swab/surge,EMW,ECD)zdexponent,sigma1.og,norma1.izeddata,MWD,APWD,Peop1.e&equipment.Duringdri1.1.ing(rea1.time)De1.ayedbytimerequiredforsamp1.ereturns.Dri1.1.ingMudGasContent,Mudweightsin/out,w1.osses&kicks,“Temperature,Ch1.orinevariation,Dri1.1.pipe&annu1.arpressures,Pitvo1.umes,F1.owrate,Ho1.eFi1.1.upDri1.1.ingCuttings1.itho1.ogy,Sha1.ecuttings,vo1.ume,shapesize,density;sha1.efactor.Cuttingsgas.E1.ectrica1.resistivity.Nove1.geochemica1.,andothergeomechanica1.techniquesWe1.1.1.oggingE1.ectrica1.survey;ResistivityConductivitySha1.eformationfactor,Sa1.inityvariationsInterva1.transittime,Bu1.kdensityHydrogenindex,Therma1.neutronNuc1.earmagnetic,ResonanceDownho1.egravitydataAfterdri1.1.ingDirectpressuremeasuringdevicesDri1.1.stemtestWire1.ineformationtestCheckshots,VSPWhenwe1.1.formationsaretestedormp1.etedSource:KingdomDri1.1.big.andse1.ection,enhancedpressurescrutiny,morewe1.1.contro1.,andgreaterknow1.edgeunderstandingandski1.1.setstoassuresafeand1.ossfreedri1.1.ingofwe1.1.s.Thedeepwaterpressureregimesi1.1.ustratedinFig.3.3canbedividedintotwocategories:1. Conventiona1.:DeepTransitiona1.,Norma1.,andConstantpressuregradienttop1.an,design,construct,engineer,dri1.1.,manage,andcontro1.rangingupto2. Comp1.ex:PressureRegression,ContinuousNarroWMargin,andRicochetpressuresthatcanbemorehazardprone,extreme,cha1.1.enging,timeconsuming,andcost1.y.Note:Thepressureprofi1.esinFig.3.3provideacompositerangeofdeepwaterwe1.1.sthatexisttodaytoi1.1.ustrateandrepresentthescopeofwe1.1.design,engineering,andoperationa1.aspectstobeeva1.uatedinthecontextOfdeepwaterwithinthisguide.Norma1.PorePressureNorma1.porepressurevariesfrom8.33ppgpoundsperga1.1.on(998kgm3)infreshWateUto8.66ppg(1038kgm3)inseawater,andupto10.0ppg(1198kgm3)inhigh1.ysa1.tsaturatedwaterenvironments.PRIMARYCAUSEOFNORMA1.PRESSURENorma1.hydrostaticpressurespredominant1.yresu1.twhenf1.uidescapesataratere1.ativeto1.oading,suchthat:1. Porositywi1.1.decreaseinequi1.ibriumwiththeincreasing1.oad2. Theentire1.oadissupportedbyframeworkgrains3. Noneofthe1.oadissupportedbytheporef1.uidsothattheporef1.uidpressureremainsnorma1.(hydrostaticpressure).Abnorma1.andSubnorma1.PorePressureDeepwaterpressureprofi1.esarenorma1.1.ypressuredfromtheseabedtoavertica1.depthwhereanabnorma1.orsubnorma1.pressuremechanismwou1.dexistasi1.1.ustratedinFig.3.4.Pressurechangeresu1.tsandvariesduetodepositiona1.setting,environment,mechanica1.,andchemica1.processesthatexist.t,AbnonnaV'and,tsubnonnaV,aregreateror1.essthanthenorma1.pressureenvironmentandconditionthatexist.PressureFIG.3.4Norma1.andabnorma1.pressure.Source:KingdomDri1.1.ing2018.Inthesesituations,pressure-re1.ateddri1.1.ingoperatingmarginsarereducedasi1.1.ustratedinFig.3.4.WHATIS"ABNORMA1."PRESSURE?Abnorma1.pressureisderivedwhenwaterispresentastheporef1.uidinaformationorreservoirinterva1.Whenthepressuregradientisgreaterthanthehydrostaticgradient,thepressuredifferenceatthisspecifieddepthbetweenthef1.uidpressurea1.ongthisgradient(PP)andthehydrostaticpressure(PhydrO)istheamountofoverpressure(P)present.AsrepresentedinEq.(3.1).DEFINITIONOFOVERPRESSUREP=PP-Kydm(3.1)Maximumf1.uidpressureischaracteristica1.1.ycontro1.1.edbythefracturestrengthoftheweakestexposedformationtowhichthewe1.1.boref1.uidsareexposed.FracturePressuresandGradientsFracturegradientsresu1.tduetotheeffectivechangeinoverburdenandpore-pressureprofi1.esandinsitustressesdrivenbysedimentation,tectonichistory;1.itho1.ogy,operatingenvironments,andsubsurfacedeve1.opmentconditionswithineachbasin.Afractureindri1.1.ingtermsisnotedbyfirstinstanceoff1.uidbeingtakenintowe1.1.boreformationthathasbeenorisbeingdri1.1.ed.Thefracturepressureisthepressurethatfracturesformations,whentheminimumcompressivestressandtensi1.estrengthareexceededbytheporef1.uidpressure.Inpractica1.terms,thefracturepressureistheupper1.imitofpressurethatthewe1.1.boreformationcanwithstandfromtheexertedmudco1.umnandassociatedcumu1.ativewe1.1.boreoperatingpressureeffects.We1.1.IntegrityTestsOnceeachintermediateorproductionwe1.1.boresectionisdri1.1.ed,cased,andcementedwithstee1.tubu1.arpipetoprovidetherequiredwe1.1.andbarrierintegritydemandedtosafe1.yprotectthewe1.1.fromfai1.ingduringitsintended1.ifecyc1.e.Thep1.anning,design,andengineeringofeachwe1.1.boresectionisdecidedthroughdeterminingandeva1.uatinganoptima1.safesettingdepthrange(howsha1.1.oworhowdeepcanthisbeset)tomeeta1.1.we1.1.objectivesandtofurtherenab1.esafe,1.oss-freedri1.1.ingofthenextwe1.1.boresection.Dri1.1.ingengineerssha1.1.haveapreferencetosetcasinginfine-grained(1.owpermeabi1.ity)1.itho1.ogy,suchasc1.aystone/sha1.esandcertaintypesofcha1.ks,and/oraboveoracross(toiso1.ate)troub1.ezoneswithpotentia1.abnorma1.orsubnorma1.pressure,instabi1.ity;orassociatedpressureprob1.ems.Whendri1.1.ingthroughknownabnorma1.interva1.sortransitionzones,boththeengineeredandoperationa1.p1.ansandfactorsexperiencedduringoperationssetthedri1.1.ing1.imitsasfarasispractica1.beforesettingcasing.Thekeyadvantageifab1.etosetcasingdeeperinabnorma1.1.yorhigh-pressuretransitionregimeprovidesthemostprobab1.esetoffconditionstoachieveahigherfracturegradienttoenab1.edri1.1.ingthenextsectiontoitsrequireddepthorpotentia1.1.ydeeper,whichcanreduceoperatingrisksandrequirementstorunadditiona1.casingstrings,etc.somewhat.Ateachcasingsettingdepth,we1.1.integrityofthecement/formationaroundthebase(shoe)canbeconfirmedbydri1.1.ing3-5m(10-16ft)ofnewformationandthenconductingawe1.1.(orformation)integritytestpriortodri1.1.ingahead.We1.1.,1.imited,Intake,Formation,1.eak-Off,orExtended1.eak-Offintegritytests(FIT,1.OT,X-1.OT).Note:Anextended1.eak-offtestasi1.1.ustratedinFig.3.5SerVeStoprovidewe1.1.integritymethodsofchoicetoconsiderconducting.Examp1.e:A1.eak-offtestprovidestheFIG.3.5ExtendedIeakP仟testschematichigh1.ightinga1.1.thepotentia1.stagesOfthistest.Source:IkonScience,Pressuresandoverpressureinthesubsurfacecourse2015.maximumstaticmudweightthatcanbeusedbeforemud1.ossresu1.tsduetohydrau1.icfracturingoftheweakestformationexposedinthewe1.1.boreatthetimeofthetest.Forexp1.orationandappr