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1、CHAPTER9DeepwaterWe1.1.DesignWE1.1.DES1.GNESSENTIA1.SIntroductionThischapterout1.inesdeepwatercasingand1.inerdesignforexp1.oration,appraisa1.,anddeve1.opmentwe1.1.s.1.oads,strengthca1.cu1.ations,andkeydesignmethodaspectsareout1.ined,fromconceptthroughtobasecasedesigns.Note:Computersoftwareprograms,t
2、henverifyorigina1.hand-madedesignca1.cu1.ations.DeepwaterWe1.1.DesignGenera1.Threeresponsibi1.itiesaretobemetwhenconductingcasingortubu1.ardesign:1. Assuredwe1.1.andbarrierintegrityisfu1.1.ycomp1.ianttoindustrystandardsandoperatingneedsthroughde1.iveringbasisofdesignsthataccountforMaximum1.oadConcep
3、tstobeapp1.iedforeachwe1.1.,soperating1.ifecyc1.e.2. Designcasingandtubu1.arstringssothatmaximum1.ife-of-we1.1.operatingva1.ueresu1.ts.3. Providec1.earandevidentbasisofdesigndocumentsforoperationa1.personne1.susetoassure1.ifeofdesignoperatingenve1.opessha1.1.notbeexceeded.Variancewithindeepwaterwe1.
4、1.designsexistsasi1.1.ustratedinFigs.9.1z9.2andTab1.e9.1.We1.1.designstandards,1.oads,andbestpracticeoperatingandengineeringrequirements,functions,anddefinitionsfordri1.1.ingandproductionstringsandtubu1.arsusedarecoveredinthissection.Deepwaterstandardc1.earancecasingdesignsrangefrom1.owtomediumriske
5、dnorma1.1.ypressuredregimes.Fewercasingsarerequiredtode1.iverthesewe1.1.stotota1.depthobjectives.Standardwe1.1.boresizesandcasingconnections(Fig.9.2)aremorereadi1.yaccommodatedwith1.itt1.ewe1.1.boreen1.argementneeds.321Tboptimizespecificwe1.1.designcases,highergradecasing,e.g.z13%to14(346.1-355.6mm)
6、casingtoaccommodatecasingsor1.iners(Fig.9.2)ztoopenwindowsofuti1.izationopportunityforadaptiveexpandab1.etubu1.arand1.inertechno1.ogy.Thisthenpermits1.esssubsequentcasingsandtripsastheu1.timateprize.IvpuucDttghttpsd0iar1.1.0i6B97S4)X)4022825.00009X)FIG.9.1Wor1.dwidedeepwaterwe1.1.designconfiguration
7、s.Source:RidgeEngineering2017.FIG.9.2Norma1.-c1.earancedeepwatercasing/1.inerwe1.1.designexamp1.es.Source:Kingdomdri1.1.ingtraining2018.WE1.1.DESIGNESSENTIA1.S323TAB1.E9.1DeepwaterCasingTypesSizesC1.earancesandDescriptionCasingDescriptionNomina1.&TightC1.earanceCasingOD(in)Structura1.conductorand/or
8、surface1.argeODcasing;jettedinordri1.1.edandcemented36,3042,36Additiona1.casingrunbe1.owstructura1.casing,i.e.,forsha1.1.owf1.owrisks26”26,28,SurfaceCasinginc1.udingHPWHH:firstcasingstringattachedtosubseaBOPs20w22vSurface1.iner1.argediameterpiperunasa1.inerandhungoffinacasingprofi1.ewithinthesurface
9、casing.Oftenreferredtoas“surfaceextensionsn/a18,16”Intermediatecasing1.ongcasingstring12ndrift,sizesrange13vto14vwithcasinghangerinthesubseawe1.1.headhousing13w13%Intermediate1.iner1.inerhungbe1.owintermediatecasing/1.inern/a13z1.1.,TiebackstringCasingrunfromtopof1.inertothesubseawe1.1.headhousing,i
10、.e.,forincreasedpressurecapacityand/orcasingwearconsiderationsn/a13moptiona1.ProdcasingFu1.1.stringofproductioncasingfrombe1.owtheobjectiveinterva1.withcasinghangerinthesubseawe1.1.headhousing9n/aProd1.inerProductioncasingrunfrombe1.owtheobjectivesectionandhungintheintermediatecasingorintermediate1.
11、inern/a9/ProdtiebackCasingfromtopoftheproduction1.inertothesubseawe1.1.headhousingn/a10tf9NotezTab1.eprovidesexamp1.eson1.y.We1.1.shavevariationsinnumberofcasingstringsandsizes.Namingconventionsa1.sovary.Heavy-wa1.1.surfacecasingdesignsareusedincertaincases.13x9v,andothercasingsareoftenrunas1.iners.
12、We1.1.DesignProb1.emsandComp1.exitiesDeepwaterwe1.1.prob1.emdesignareastorecognize,identify;andconsiderare:1. Extendedwaterandtota1.depthsdemandgreaterpressures,mudweights,vo1.umes,andcapacitiestomeetwe1.1.designneeds.2. Abnorma1.andsubnorma1.pressureregimescreatereducedoperatingmarginstoexist.3. In
13、creasedburstpressuresatthewe1.1.headandshoecanresu1.t.4. Equipmentratingand1.imitationsbothaboveandbe1.owthemud1.inemustbefu1.1.yassessed.5. Subsurface-specificgeo1.og/hazards/risks,e.g.,sha1.1.owf1.owhazards,insituhydrates,unstab1.ezones,pressuretransitioninterva1.s,sa1.t,andregressionzonesa1.1.tob
14、eassessed.6. Metocean(heavecompensation)effectsnotab1.yasoperatingconditionsandenvironmentsdeterioratemustbefu1.1.yaddressed.7. Extendedoperationa1.durationswherecasingwearandheatcheckingcanthenresu1.tduetoextendeddri1.1.piperotationandside1.oadsmustbeaccountedfor.8. Therma1.f1.uidexpansion,trappeda
15、nnu1.arpressurebui1.dupAPB,andwe1.1.headgrowth1.oads.9. Greaterwe1.1.headandhanger1.oadcapacitiesandreducedannu1.arc1.earancesthatcanresu1.t.10. SubseaBOP1.imitations,e.g.zshear1.imitationsinregardstohigh-strengthtubu1.ars,annu1.are1.ementssea1.ingon1.argeouterdiameter(OD)casing,andpotentia1.forcasi
16、ngco1.1.apse.11. PresenceofH2S,CO2,acce1.eratedcorrosionduetoco1.derseabedtemperatures.12. Sa1.t,we1.1.boreinc1.inationhorizonta1.andextendedreach1.engthsthatthenfurtherchaengeandimpactsdesignandsafeoperatingwindowthatexist.Tbaddresspotentia1.designprob1.emissuesthatoftencombinedtoincreasecomp1.exit
17、yandcha1.1.engedesign,avarietyofadaptive,innovative,andtechno1.ogica1.constructshaveemergedtode1.iversaferdesigns.Forexamp1.e:1. Morecasingstringsso1.utionsrequiredtode1.iverwe1.1.objectiveattota1.targetdepths.2. Nonstandardcasingsizestoassurebest-fitso1.utionsresu1.t.3. We1.1.boreen1.argementoftenn
18、ecessarytoenab1.eandde1.iversaferoperatingmargins.4. Useoff1.ushjointcasingconnectionsandspecia1.izedcentra1.izationrequiredtode1.iverabettertechnica1.so1.utionwithoutcompromisingoperatingintegrity.5. Somedesignsprefera13wcasingindeepwatervs.standard9%casingsettingdepthtoreduceannu1.arcircu1.atingfr
19、ictionpressurestosafeoperating1.eve1.s.6. 1.inersrunversusfu1.1.casingstringstothewe1.1.headtode1.iversimi1.aroperatingbenefits.7. 1.ongerheavier1.andingstrings,requiredduetoresu1.tinghighercasing1.oads,andsubsequentincreasedaxia1.1.oadsandhydrau1.icdri1.1.stringrequirementthatthenexist.8. Subseawe1
20、.1.headsare1.imitedtoacertainnumberofstrings.Therefore,adaptiveinnovativeandnewwe1.1.headso1.utionshadtoevo1.vetoaccommodateaddedstringsrequired.DeepwaterWe1.1.Design:Guide1.inesDeepwaterdesignbest-practiceguide1.inestoconsiderare:1. Designssha1.1.beinaccordancewithexistingoperatingstandardspractice
21、s,ru1.esandregu1.ations.2. Standarddesignsmaynotwork.Theprincip1.egoa1.remainingistoassurethateachdesignmeetsawe1.1.,sintendedsafe,effective,andefficientuse.3. Initia1.we1.1.smustaccountformaximumconcept1.oads,notab1.y:burstpressure,basedonfu1.1.gasgradientfromwe1.1.headtoatthecasingor1.inershoe.4.
22、Deepwaterwe1.1.designrequiresintimateknow1.edgeandexperienceofpressureandsubsurfacewe1.1.boremechanica1.stressregimesandwe1.1.operatingconditions.Unti1.moreaccuratedataexist:(a)Pressureestimationispredictivebasedontheriskanduncertaintyofseismicprofi1.esdata,fromrangesestab1.ishedfromsimi1.arwe1.1.s.
23、(b) We1.1.saremoreconservative1.ydesignedunti1.provendataexistforpressureregimes,H2S,CO2,we1.1.geo1.ogica1.,andoperatingfactors.(c) Pressureandwe1.1.borestabi1.itymode1.sarederivedandusedtoaidmorepreciseinformationtoenab1.eimproveddesignmanagementneedsandde1.ivery.Furtherdeepwatercasingdesignaspects
24、tobeviewedare:1. We1.1.-engineeredandcost-effectivedesignscanresu1.tdespitehigherrisksanduncertainties,notab1.eifhigh-qua1.ityinputdataaremet.2. Theabi1.itytomeeta1.1.designobjectivesandsafe1.yreducethenumberofcasingstringscanhaveasubstantia1.impactonwe1.1.-1.ifecosts,againrecommendingastrongcasefor
25、higherqua1.itydataacquisitiontoaidbetterinterpretationtode1.ivermoreoptima1.designs.3. Preciseandaccuratese1.ectionofcasingshoedepthsisparamounttodrivethenumberofcasingstrings,designintegrity;andoperating1.ifecyc1.esuccess.(a) canaddmorecasingstrings,1.argerdiameterwe1.1.bores,increasedvo1.umes,weig
26、hts,capacitiesandassociatedrigzsystemsandoperatingrequirementsthatresu1.t.(b) Risk-baseddesignsthat1.acksufficientcontingenciescanontheotherhandbefarworse,e.g.zasexhibitedbymu1.tip1.ewe1.1.sthatfai1.edtoreachtargetdepths.4. Strikingtherighttechnica1.,innovative,andadaptiveso1.utionsba1.ancebyassurin
27、gcompetentpersonsareassignedistobeviewedasva1.uedadded,e.g.zuseofc1.oseto1.erancetechno1.ogica1.,expandab1.etubu1.ars,1.iners,andinnovativeadaptivedesigns.PressureManagementandDesignPressuremanagementisacentra1.drivingdesignissuedrivenbytheweakestwe1.1.boreexposuresinconjunctionwithoperatinghazardsp
28、redictedanddetectedasdri1.1.ed.Designstandards,ru1.es,regu1.ations,orbestpracticesmaynotworkthatwe1.1.insomecaseswheregreaterdesignski1.1.sandsensitivityana1.ysisarerequiredtobeconductedtoassurea1.1.risk,safety;andoperatingfactorsresu1.tinafitforpurposedesign.Whenreducedoperatingmarginsexist,farmore
29、preciseengineeringisdemandedwherepersonne1.assignedmustagainidentifyandeva1.uatethespecific1.imitswhentostopoperating,runandsetcasingistheon1.ysafeoption.Keypressure-re1.atede1.ementsare:1. Aswaterdepthsincrease,theeffectoftheseawaterhydrostaticgradientco1.umnadds1.esstooverburdenthantheformationpre
30、ssure.Ifhigherporepressuresexist,additiona1.casingstringsare1.ike1.yrequired.2. Fracturegradientsvarygreat1.ydependingon1.itho1.ogyandporepressuresthatexist.3. Operatingpressurewindowscanbedrivenbyregu1.ations/standards,bywe1.1.hydrau1.ics,temperature,mud,cementandoperatingpressureeffects.AHtobecare
31、fu1.1.yconsideredandaccountedfor.Specificpressuremanagementandwe1.1.designaspectstobeconsideredare:POREPRESSURE1. Initia1.we1.1.designsaredeterminedandderivedfromseismicinterpretations.Note:Thesethenfurtherrefineddirect1.yfromwe1.sdri1.1.ingdata,e.g.,resistivityandsonicp1.ots,RFTpressures,we1.1.kick
32、s,DST,anddri1.1.ingparameterresu1.ts.2. Forseismic-derivedporepressure,matrixstresstechniquesinconjunctionwithinterva1.ve1.ocitydataobtainedduringdri1.1.inghavebeensuccessfu1.1.yused.3. Ve1.ocitydatafromseismicshotpointscanbeinterpretedtopredictinitia1.poreandfracturepressurevs.depthtrend.4. Stackin
33、gve1.ocitiesareconsidered1.esssuccessfu1.inestimatingformationpressures.5. At1.east,800-1200mofnorma1.1.ypressuredc1.asticformationsisestimatedtoberequiredtoestab1.ishnorma1.trends.6. Formationpressuressha1.1.varydependingonthegeo1.ogica1.distancefromthemainpressuredepositiona1.centers.Thistobeaccou
34、ntedforineachwe1.1.zsdesignstage.FRACTUREGRADIENTANDOVERBURDEN1. Fractureandtemperaturegradientsdataareestimatedinsomedegreeviaseismicdata.(a) Upactiontrendsexist,temperatureisestimatedviainterva1.ve1.ocitytrends.(b) Temperatureprofi1.eswi1.1.changeinabnorma1.orsubnorma1.pressurezonesandasafunctiono
35、fdistancefrommaindepositiona1.centers.(c) Be1.owthetopoftheoverpressure,temperaturegradientsmayincreaseduetoincreasedf1.uidcontentwithintheundercompactedsediments.2. 1.eak-offtestsoractua1.formationpressurescanberefinedtoofferpredictivees6mates.3. Overburdenpressurescanbeestimatedreasonab1.yifpressu
36、recurvesareaccessib1.efromsimi1.arsha1.1.owerbasinsthatmayexist.Note:Thismethodassumessimi1.arformationdensities.Actua1.densitiesarethenusedaswe1.1.saredri1.1.ed.4. Stressratioscanbeusedtoestimateusingexistingcorre1.ationsastheyareprimari1.yafunctionoftheoverburdenstress.5. Usingporepressureestimati
37、onsviageophysica1.methods,fracturepressurecanbeca1.cu1.atedusingoverburdenpressureandstressratioestimations.Thistechniquecanbeconsideredifva1.iddatacanbeextrapo1.atedfromsimi1.arsha1.1.owaterareas.ConcepttoBasisOfDesignProcessOut1.ineAfitforpurposedeepwaterwe1.1.-designcanbede1.iveredbyconductingaco
38、ncepttobasisofdesignscopereview,designana1.ysisandse1.ectionrecommendationprocessasi1.1.ustratedinFig.9.3.Oncetheevidentwe1.1.dataisgatheredandassemb1.edintheassessprojectphase.Afirstphaseright-scopingpassorfai1.exerciseisconductedasi1.1.ustratedinFig.9.3andTab1.e9.2.Theoutputandoutcomebeingtode1.iv
39、errecommendedwe1.1.designstofurtherprocessandeva1.uate.ThefirstpassstageasrepresentedinTab1.es9.2and9.3out1.inestheinitia1.rightscopingprocesstode1.iveraseriesofconceptdesignsasshowninFig.9.4.Optionsareonebyonereviewedviaamorerefinedprocessuti1.izinga1.1.projectdiscip1.inestoscrutinize,determine,and
40、eva1.uatethata1.1.evidentandre1.evantdesignaspects,goa1.s,va1.ues,anddriversaremet.Thefina1.outputfromtherefinedstageassuresthatthebest-fitdesignsresu1.tbasedonva1.ue,safety,risk,andtechnica1.rating.Inthecaseasi1.1.ustrated,Recommenededdesign1We1.1.designFIG.93Concepttobasisofdesignprocess.Source:Ri
41、dgeEngineering2017,reconstructedKingdomDri1.1.ingtraining2018.TAB1.E9.2ConceptDesignDriversandVa1.ueRankingExercisePriorityDriver&Va1.ueIssueExp1.anationZRationa1.eWeighting1,2,3etc. Safewe1.1.operation Dataacquisition We1.1.assurance/integrity Techno1.ogyapp1.ication Timecostqua1.ity Standards,comp
42、1.ianceEachdriverandva1.uetobeexp1.ainedwithrationa1.eevident1.yprovidedWeightingtobeassignedtoeachkeydriverthreeoptionsresu1.tedinadditiontoacomparativeconventiona1.designasshownFig.9.4andTab1.e9.4.Thesefina1.designoptionsthenundergothefina1.detai1.edp1.anning,design,we1.1.engineering,andoperationa
43、1.assessmenttose1.ectabasecaseandcontingentdesign(s)throughassuringa1.1.invo1.veddotherightthingsfora1.1.therightdesignreasons.Note:Aconventiona1.designisinc1.udedinFig.9.4toserveasacomparisonstandardtomeasure,assess,andeva1.uatebasecaseandcontingentdesignsthatevo1.veagainst.Thefirstpassfina1.scoped
44、esign(s)se1.ectedinFigs.9.4and9.5(Fig.9.6)arethenworkedandstrengthenedtode1.iverabasecaseoptionasshowninFig.9.7Successfu1.de1.iveryofthefina1.designisdependentonsevera1.evidencebasedfactors,e.g.:-Issite-specificsurveydataavai1.ab1.etorefinethewe1.1.sstructura1.constructioninsta1.1.ation,anddesign.-H
45、ighfront-end-1.oadingandengineeringexpertise.1.Conventiona1.2.Conventiona1.Designw/3.DeepSet4.CAN5.Conventiona1.+6.,Deep7.CAN8.S1.imHo1.eDesignNoSurface9.S1.imHo1.eDesignNoIntmMainIssueSubissueZRequirementDesign1.inerConductorDuctorExpandab1.eCasing161.inerS1.enderCasingCasingTAB1.E93RightScopingSum
46、maryOutcomeFromAssessmentandEva1.uationWorkConductedSafewe1.1.operationDifferentwe1.1.5designscarrydifferentsafetyexposure.Thechosendesignshou1.dkeepthesafetyexposure(inc1.HSE,we1.1.contro1.,andwe1.1.integrity)as1.owasreasonab1.ypossib1.e78866755DataacquisitionTheconceptsaffectthe8riskofachievingdat
47、aacquisitiondifferent1.y.Theso1.utionshou1.dminimizeriskof1.osinganyreservoirinformation,andshou1.dmaximizethede1.iveryofdataacquisitionwe1.1.objectives88896888Adaptivetechno1.ogyandRobustnessThewe1.1.designshou1.d8a1.1.owforcontingencies.Conceptsthatminimizenumberoffirsts,newtechno1.ogydeve1.opment
48、and,edgeOfteehnO1.ogy”areconsideredbeneficia1.,asisthedoabi1.ityor“easeofapp1.ication”oftheconcept.However,thedesignshou1.dbecheckedagainstvariousdeepwaterdesignsusedwor1.dwideandtechno1.ogyareconsideredrobustifthishasbeensuccessfu1.1.yusedonsimi1.arwe1.1.s1041065755=DEEPWATERP1.ANN1.NGDES1.GNANDENG1.NEERING=DEEPWATERP1.