西藏羌塘盆地羌D2井原油类型及其勘探意义

羌D2 井是目前羌塘盆地首口钻遇侏罗系布曲组含油层的地质井。通过对白云岩油层岩心样品系统采样和分析，发现钻井原油有两种类型。根据生物分子标志化合物中类异戊二烯烃、甾烷、萜烷系列进行的油源对比研究，初步认为羌塘盆地不同类型的两类原油可能有不同的来源，产自于不同环境的烃源岩之中。第一类原油来源于开阔海环境，生油母质以低等水生物为主，与侏罗系下统曲色组、中统布曲组烃源岩具有亲缘性；第二类原油来自于具有大量淡水注入的海湾河口环境，生油母质中高等植物标志显示明显，烃类可能来自侏罗系中统雀莫错组或夏里组烃源岩。该研究结果对确定羌塘盆地生油层系、圈定生烃洼陷具有指导意义。

Crude oil types of the Well Qiang D-2 in Qiangtang Basin,Tibet and its exploration significance

The Qiang D-2 well is the first geological well which penetrates an oil-bearing horizon of the Jurassic Buqu Formation in the Qiangtang Basin. By systematic sampling and analyzing core samples from the dolomite oil-bearing horizon, two types of crude oils in the well can be classified. The oil-source correlation based on biomarker distributions of isoprenoid alkanes, steranes and terpanes indicated that these two types of crude oils are probably derived from source rocks deposited in different environments. The first type is an oil derived from an open marine environment dominated by lower aquatic organisms and its source rock shows a close affiliation with the Lower Jurassic Quse Formation and the Middle Jurassic Buqu Formation; while the second type is an oil derived from an estuarine environment with significant freshwater influence and terrestrial higher plant input and its source rock may be related with the Middle Jurassic Quemocuo Formation or Xiali Formation. The results of this study are of importance in the source kitchen identification and resource potential assessment of the Qiangtang Basin.