准噶尔盆地原油地球化学特征与油源讨论

准噶尔盆地原油物性和生物标志化合物组合特征综合研究表明,玛北、夏盐、玛东等玛湖凹陷斜坡区的原油以二叠系风城组为主要油源,其地化特征可与西北缘原油对比;该类原油中特高含量的三环萜烷和较高的C₂₉甾烷αββ/（αββ+ααα）异构化比值主要受长距离运移作用的影响。石西油田、石南油田及陆南地区的原油以盆1井西凹陷的二叠系乌尔禾组为主要油源;马桥凸起和莫北凸起的原油以盆1井西凹陷的乌尔禾组为主要油源,同时有侏罗系的贡献;盆地东部五彩湾油田为石炭系自生自储的原油,北三台油田的源岩为二叠系芦草沟组。从西北缘、玛北油田、陆南构造西段到东段源岩的沉积环境逐渐偏向氧化,呈现渐变过渡的特征。

Geochemistry of Crude Oil and Oil-Source Analysis of Junggar Basin

Geochemical analysis of physical property andbiomarker compositions of crude oils from Junggarbasin show that oils produced from Mabei, Xiayanand Madong oil fields distributed along the Muhu slo-pe are mainly derived from Permian Fengcheng Fm..The unusually high content of tricyclic terpanes andhigh C_(29) sterane isomerisation ratios of these oils aremainly attributed to long distance of migration. Thecompositions of these oils are similar to that of oilslocated along northwestern margin of the basin. Crudeoils from Shinan, Shixi and Lunan oil fields aremainly from Permian Uerhe Fm. distributed in west ofPen-1 sag. Oils from Maqiao and Mobei uplift are alsomainly derived from Permian Uerhe Fm. of west ofPen-1 sag and with some contribution of Jurassicsource rock. In the east part of the basin, oils producedfrom Wucaiwan and Beisantai oil field are derivedfrom organic-rich beds within Carboniferous andPermian Lucaogou Fm. respectively. The geochemis-try of the oils indicates that sedimentary environmentof source rocks in the basin changes from strong re-ductive conditions to slightly oxidative conditionsgradually from northwestern margin of the basin, Ma-bei oil field, west pat of Lunan structure to east partof Lunan structure.