查干凹陷原油地球化学特征与油源对比

213OIL&GASGEOLOGY20009:02539985(2000)030249-03林卫东(,730020):查干凹陷是一个中新生代断陷盆地,其原油属低密度低粘度低硫中蜡轻质油,具饱和烃含量高(占原油的80~90)C27甾烷丰富等特点该凹陷发育下白垩统巴音戈壁组二段和苏红图组一段两套烃源岩甾烷(20R)C27/C29比值,类异戊二烯烷烃Pr/Ph,Pr/nC17比值及碳同位素曲线特征均显示原油与巴音戈壁组二段的白云质泥岩具有较好的亲缘关系,而与苏红图组一段深灰色泥岩亲缘关系不明显因此,查干凹陷的原油主要来自下白垩统巴音戈壁组二段的白云质泥岩:原油;烃源岩;地球化学特征;油源对比;查干凹陷:林卫东,男,31岁,工程师,石油地质:TE122:A,NESW,60km,32km,2000km2(K1b)(K1s1,K1s2),11,1,,(K2w),(1),(1)1,;2081~084g/cm3,925~93,0020~0037,263~1Fig.1CrosssectionofChaganSag:1999110911Table1.OrganicmatterabundanceofdarkmudrockinChacan1Well/m/!A∀///mg#g-148140(5)00191(3)78∃10-4(3)059(3)40085(19)00545(19)558∃10-4(12)127(19)381055(21)00835(8)655∃10-4(8)104(21)155093(13)00601(5)484∃10-4(5)109(12)2685061(7)00185(4)182∃10-4(3)037(7)*606mPa#s,65~120%,2(1)80~90,(2)nC17,nC20/144~156(3)1C27,C27/C29070,C28/C290601C27/C29C28/C29039069,C271,111,/153,/C30488,1,/C31527,(4)OEP112~122,C29S/(S+R)/!C2904045,:11C31S/(S+R)068058,Ts/Tm145085331311甾烷,15,14,17(20R)C27,C28C29,(20R)C27/C29(20R)C28/C29(20R)C27/C29(20R)C28/C29039~07504~07,01~0601~03,050~06503~07,04~0703~07,06~0903~07(2),(2)2Fig.2Relativeratioofsteranebothincrudeoilandtypicalsourcerocks1-K1s1;2-K1b2;3-1K1b;4-1;5-1;6-K1b2;7-K1b2;8-1;9-1K1s1312类异戊二烯烷烃Pr/PhPr/nC17079~094083~134,Pr/nC17,Pr/nC1704,Pr/nC17,(2,3)2Table2.Comparisonofsteraneandisoprenoidalkanebetweencrudeoil,oilsandandpossiblesourcerocks(20R)C27/C29039~07501~0605~06504~0706~09(20R)C28/C2904~0701~0303~0703~0703~07Pr/Ph079~09407~2507~1407~141~15Pr/nC17083~13405~105~205~20~05250213Pr/PhPr/nC17Fig.3RelationshipbetweenPr/PnandPr/nC17inbothcrudeoilandsourcerocks32,11∀13C,(4)4Fig.4Curvesofisotapictypesincrudeoilandsourcerocks4,,,GEOCHEMICALCHARACTERISTICSOFCRUDEOILANDCORRELATIONOFOILSOURCEINCHAGANSAGLinWeidong(NorthwestInstituteofGeology,CNPS,Lanzhou)Abstract:ChaganSagisaMesoCenozoicfaultdepression.Thecrudeoilinitisoflowdensity,lowviscosity,lowsulfurcontent,midparaffinandlightweightoilcharacterizedbyhighsaturatedhydrocarboncontents(80~90)andrichC27sterane.ThesecondmemberofBayingebiFormation(K1b2)andthefirstmemberofSuhongtuFormation(K1s1)oftheLowerCretaceousarepotentialsourcerocksofthesag.Theratioof(20R)C27/C29and(20R)C28/C29ofcrudeoilandtheextractfromoilbearingsandis0.39~0.75and0.4~0.7respectively.TheratioofPr/PhandPr/nC17is0.79~0.94and0.83~1.34.ThecarbonisotopiccharacteristiccurveofcrudeoilismoresimilartodolomiticmudstoneofK1b2anddiffersfromthedarkgreymudstoneofK1s1.SyntheticalcorrelationshowsthatthecrudeoilismainlyderivedfromthesecondmemberofBayingebiFormation(K1b2)dolomiticmudstane.Keywords:crudeoil;sourcerock;geochemicalcharacteristics;oilsourcecorrelation;chagansag2513: