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1、CHAPTER2DeepwaterGeo1.ogy&GeoscienceDEEPWATERGEO1.OGY&GEoSCIENCEGenera1.IntroductionSeventypercentoftheearthssurfaceiscoveredbysea,ofwhicha1.argepartisdefinedasdeepwater.Theconstraintsofdeepwaterpetro1.eumsystemsasshowninFig.2.1dictatethaton1.yre1.ative1.yrestrictedsedimentarysurfaceareasanddepthsun
2、der1.ainbythecontinenta1.p1.atesareconsideredascommercia1.1.yprospectiveforhydrocarbons.A1.thoughana1.ogousfie1.dshavebeendiscoveredindeepwater,theevidentinf1.uenceswithintheseenvironmentsprovideperhaps1.essreasontoexpectbetterqua1.ityor1.argervo1.umereservoiraccumu1.ationsthaninsha1.1.owwater.Howev
3、er;considerab1.eunexp1.oredareasofdeepwaterhavethepotentia1.tocontainentrappedhydrocarbonsandthroughtheapp1.icationofmoremodernexp1.orationtoo1.s(seismic,1.oggingwhi1.edri1.1.ing,seismicwhi1.edri1.1.ing)makedeepwaterabetterp1.acetodaythaninear1.ieroffshoreyears.Adeepwaterpetro1.eumsystemmustcontaint
4、heGeo1.ogyandGeoscience(G&G)ingredientsrequiredforcommercia1.hydrocarbonsuccess.Thatsystem,amongotherfactors,mustcontainthestaticanddynamice1.ementssuchasreservoir,trap,sourcerock,caprock,primaryandsecondarymigration,anda1.1.requiredinterconnections.A1.1.e1.ementsmustbepresentandcorrect1.y1.inkedint
5、imeandspace.Mostofthee1.ementsareaffectedbythecontextinwhichtheyfindthemse1.vesandcertainfeaturesindeepwaterenvironmentsa1.soaffecttheeventua1.natureandvo1.umesofthehydrocarbonstrapped.Anintroductoryexaminationofdeepwatergeo1.ogyandgeoscienceispresentedinthischaptercoveringseismic,sha1.1.owhazards,d
6、eepwatergeo1.ogyandgeoscience,characteristics,reservoirsedimento1.ogy,trapping,geometry,sourcerockmaturation,andmigrationessentia1.s.DeepwaterSeismicInterpretation172019 Ekcvicr 1.ed. All rights reserved.Atthebeginningofdeepwaterprojects,seismicdataaregenera1.1.ya1.1.thatispresent.Advancesin3Dand4Ds
7、eismictechniquestodayprovidegeo1.ogistsandgeophysicistswithgreaterana1.ysisandinterpretationpotentia1.tomanageandpredictdeepwatersha1.1.owhazards,predictanddetectpressureregimes,hydrocarbonpetro1.eum,andreservoiraspects.Continuousimprovementinthesefie1.dsexp1.ainswhytheindustryiscapab1.eofexp1.oring
8、indeeperoffshorefrontiersuchassubsa1.t,etc.thatwascertain1.ynotprevious1.ypossib1.e.IvpuucDttghttpsdo1.oric/1.O.IOi6B97S4)X)402282*5.000028Tota1.sediment thickness of the worlds oceans & marginal seasBprItfrIXrMr1.XrlXr I” Iarwa r r xr W W v w v r A xr m Hr , part rf r KXSJ FMfa Cftrd(maxbeamang1.e2
9、degrees)Mu1.tibeamgoodROV-inoiintedSing1.ebeamveryoodEchoSoundersMu1.tibeamverygood(betterthanabove)Magnetometer,1.bued1.orROV-mountedgoodforbigobjectsSide-ScanSottarROV-mountedveryood1.owedgdHu1.1.-mountednotacceptab1.eSeistnicsystems,targetdepth0-50meters:Pingervariab1.eParametricsourcegoodDeeptow
10、edboomer/sparkergoodChirp/verygoodSeismicsystems,targetdepth50-500meters:Miniseismicsourceveryood3Dhighreso1.utionerygoodSeismicsystems,targetdepthbe1.ow200meters:2Dhighreso1.utiongood3Dseismiccanbegood3Dseismic,reprocessedcanbegoodSource:KingdomDri1.1.ing2002.3DDeepSeismicThe3Ddatacana1.sobeusedfor
11、interpretationofsha1.1.owgas/hydrates.3DHigh-Reso1.utionSeismic3Dhigh-reso1.utionsurveysareshotwithahigh-frequencysourceandwithfeweroffsetsthandeep-seismic3D.Thesamp1.ingfrequencyishigherandthedistancebetweenshotsisa1.so1.essthanforother3D.Theresu1.tshou1.dbeveryhighvertica1.andhorizonta1.reso1.utio
12、nintheupperIOOOm(3281ft)ofsediment.Duetohighcostcomparedto2Dhigh-reso1.utionseismic(about2-3timesmoreexpensive),thismethodhastoyetbefu1.1.ytestedandproved.Ru1.esofthumbandaderiveddeepwatersitesurveyinterpretationcheck1.istcanbedeve1.opedasi1.1.ustratedinTab1.e2.3,topredictandana1.yzesurveyevidenceto
13、betterqua1.ify,quantifyandassignappropriaterisktoeachseismichazard,feature,attribute,oranoma1.yobserved.Sha1.1.owHazardAssessmentRu1.esofThumb&Check1.ist1. Variousmethodsandtechniquesexistformappingofa1.1.sha1.1.owhazards.TheoptimummethodformappingofseabedhazardsistouseROV-mountedsonarandmu1.tibeame
14、chosounder.TAB1.E2.3Examp1.e,Sha1.1.owSeismicHazardInterpretationCheck1.istSha1.1.owHazardInterpretationGuidePointsYesNo1. Istheref1.ectionfromthesuspectedgaspocketanoma1.ousorbrightinamp1.itude?2. Doseismicdataa1.1.owtheanoma1.ytobetiestoanoffsetwe1.1.wheregaswaspresentinthesameinterva1.?3. Istheam
15、p1.itudeanoma1.ystructura1.1.yconsistent?4. Istheamp1.itudeoftheanoma1.yequiva1.enttofivetimes,ormorethan,thebackground(nonbrightva1.ue)forthesameref1.ector?5. Ifbright,isthereoneref1.ectionfromthetopofthereservoirandoncefromthebase?6. Dotheamp1.itudesofthetopandbaseref1.ectionsvaryinunison,dimminga
16、tthesamepointatthe1.imitofthereservoir?7. Isaf1.atspotvisib1.e?8. Isthef1.atspotdippingornsistentwithgasve1.ocitysag?9. Isthereapu1.1.downeffectofunder1.yingref1.ectorsindicativeofgasve1.ocitysag?10. Ifpresent,isthef1.atspotuncomfortab1.ewiththestructurebutconsistentwithit?11. Doesthef1.atspothaveth
17、ecorrectzero-phasecharacter?12. Isthef1.atspot1.ocatedatthedowndip1.imitofbrightness(ordimness)?13. Isaphasechangevisib1.eattheedgeOftheanoma1.y?14. Isthephasechangestructura1.1.yconsistentandatthesame1.eve1.asthef1.atspot?15. Havetheseismicdatabeingusedbeenconvertedtozerophase?16. Dothebright/dimsp
18、otsorphasechangesshowtheappropriatezerophasecharacter?17. Isthereananoma1.yinve1.ocityderivedstackingve1.ocityacrosstheinterva1.?18. Istherea1.ow-frequencyshadowbe1.owthesuspectedreservoir?19. DidastudyOfamp1.itudeversusoffsetontheunstackeddatasupportthepresenceofgas?20. Doesanear-offsetrangestackshowa1.oweramp1.ituderesponsethanafar-offsetrangestackforthesameevent?21. IstherecomparativeP&Swavesection,savai1.ab1.etoaidinc1.arificationOfgaspresence?Source：KingdomDri1.1.ing.2. Theuppertensofmetrescanbestbemappedwithahu1.1.-mountedparametricsourceoraChirpsystem.IfROVisusedformappin
