Reconnaissance-hydrocarbon-geology-of-the-Anadyrsk

AUTHORSWilliamHarbert
DepartmentofGeologyandPlanetaryScience,UniversityofPittsburgh,200SRCC,Pittsburgh,Pennsylvania,15260;[e-mail]iversity(1987).HehastraveledextensivelyinRussiaduring11visitsbeginningin1985.HeispresentlythechairmanoftheDepartmentofGeologyandPlanetaryScienceattheUniversityofPittsburgh.SergeiSokolov
GeologicalInstitute,RussianAcademyofSciences,PyzhevskyLane7,Moscow109017,RussiaSergeiDmitrievichSokolovearnedhisCandidateofGeologicalandMineralogicalSciences(1975)andDoctorofScienceinGeotectonics(1989)degreesattheGeologicalInstituteoftheRussianAcademyofSciences.HeispresentlythedirectoroftheLaboratoryofOceansandPeri-OceanicZonesattheGeologicalInstituteoftheRussianAcademyofSciences,Moscow,studyingaccretionarytectonics,terraneanalysis,andpaleotectonicreconstructions.AlexanderHeiphetz
AlexHeiphetzGroup,StateCollege,Pennsylvania,16803AlexanderHeiphetzearnedhisB.S.andM.Sc.degreesingeologyfromMoscowUniversity(1985).HeworkedinRussianacademicinstitutionsstudyinggeologyandpaleomagnetismofKamchatka,KoryakHighlands,andKomandorskiyIslands.AfterearninghisPh.D.ingeophysicsfromtheUniversityofPittsburghin1995,HeiphetzworkedforGeoMechanics.Since1997,Heiphetzhasrunhisownconsultingandsoftwarecompany.ReconnaissancehydrocarbongeologyoftheAnadyrsky,Khatyrsky,andPenzhinskayaGubaCenozoicsedimentarybasins,northernKamchatkaPeninsula,RussiaWilliamHarbert,SergeiSokolov,andAlexanderHeiphetzABSTRACTInnortheasternRussia,reconnaissanceanalysisoftheAnadyrskyandKhatyrskysedimentarybasinsindicatesthatoilandgasfieldswereformedwherestrataofpotentialreservoirqualityarepresent,andfaultsorzonesofhighpermeabilityconnectthesourcerockstozoneswhereimpermeablestrataoverliereservoirformations.UpperCenozoicrocks,whichhavebeensubjectedtoPaleocenetoQuaternarytectonicreactivation,thedegreeofwhichgenerallyincreasessouthwardwithinindividualbasins,containknownoilandgasdepositsinthesebasins.TheformationofthesebasinsistheresultofextensionandriftingalongthenorthwesternedgeoftheKamchatkaPeninsula,specificallyinthePenzhinskayaGubaregion.INTRODUCTIONTheAnadyrskyandKhatyrskysedimentarybasinsofnortheasternRussiaareamongthelesswell-describedoilbasinsoftheformerSovietUnion(Anonymous,1985,1997;Persitsetal.,1997).ThefirstoilandgasdepositsintheAnadyrskyandKhatyrskysedimentarybasinswerediscoveredduringtheearly1980s.Thesediscoverieshavestimulateddetailedstudyoftheirstructureandgenesistolocalizeotherprospectiveproductiveregions.Inthisarticle,wepresentadescriptionoftheAnadyrskyandKhatyrskysedimentaryGEOLOGICNOTECopyright#2003.TheAmericanAssociationofPetroleumGeologists.Allrightsreserved.ManuscriptreceivedOctober2,2000;provisionalacceptanceSeptember21,2001;revisedmanuscriptreceivedApril8,2002;finalacceptanceSeptember3,2002.DOI:10.1306/09030201082AAPGBulletin,v.87,no.2(February2003),pp.183–195183184GeologicNotebasinsandathirdpotentialregionofoilandgasexploration,thelargerPenzhinskayaGubabasin.EachofthesebasinsislocatedalongamarginoftheKamchatkaPeninsulaofnortheasternRussia.AmodelisproposedtoexplaintheformationandevolutionofthesebasinsrelatedtotheopeningofagulfalongthenorthwesternmarginoftheKamchatkaPeninsula.REGIONALGEOLOGYInnortheasternRussia,theAnadyrskyandKhatyrskybasinsformedaboveabasementconsistingofMesozoicsandstone,siltstone,andshale,althoughPaleozoicandearlyMesozoicmetamorphicandig-neousrocksarepresentinvaryingproportionsinthebasementofbothbasins(McLean,1979).SeveralthrustfaultsinthebasementoftheAnadyrskybasinbringtogetherUpperJurassictoLowerCretaceousthrustsheetsofbasaltandjasper;tuffaceous,terrige-nousrocksandjasper;andanUpperJurassictoMaastrichtiansedimentarycomplexupto5kmthick.MicrofossilagesfromdrillsamplessuggestthatthebasinstartedtofillduringtheDanianinthesouthernpartsofthebasinsandduringtheEoceneinthenorthernpartsofthebasins.Thesestrataconsistofinterbeddedcontinentalorveryshallow-watermarinesandstone,conglomerate,shale,andcoalstrata.Inbothbasins,theregionofoilandgasformationislocatedinthesouthernpartsofthebasins,wherePaleogenedepositsreachtheirmaximumthicknessandtheseformationsaremostdeformedandthermallyaltered.Compressiveconditionsprevailedthroughoutthisregionduringthesubductionofoceanicplatesinthepaleo-PacificbasinbeneaththeKoryaksuperterrane,whichdefinedtheedgeoftheEurasiancon-tinent.Previouslypublishedpaleomagneticdataconstrainthetim-ingofcollisionoftheOlyutorskiyterranetothispartofthecontinenttoapproximatelymiddleEocene(Zonenshainetal.,1990).AnadyrskyBasinTheAnadyrskysedimentarybasin(Figure1)isthemostthoroughlystudiedbasininthewesternBeringSearegion.LocatedintheLowerAnadyrRiverlowland,intheAlkatvaamskyterrane,thebasinex-tendsoffshoreintotheGulfofAnadyr(Figure1).TuroniantoMaas-trichtiansandstone,siltstone,andmudstone,whicharegenerallyfoldedinisoclinalandoverturnedfoldsbutexhibitnoneorfewpost-epigeneticchanges,overlapthecomplexthruststructure.Thesedi-mentaryrocksoftheAnadyrskybasinoverlayacomplexoftec