鄂尔多斯盆地长91湖相优质烃源岩成藏意义

为了查明鄂尔多斯盆地长91湖相黑色泥页岩烃源岩的成藏意义,运用测井-有机地球化学综合识别方法圈定其分布范围,通过地球化学参数的对比,厘定油-源关系,评价其生排烃规模和有利成藏区带.志丹地区南部是长91优质烃源层的主要发育区带.长91优质烃源层不仅生烃能力强,而且排烃能力也较强.以志丹地区长91烃源岩具有异常高的C30-重排藿烷、异常低的C30藿烷这一显著特征为主要依据,结合其他地球化学参数进行的油源对比表明,志丹南部地区的长8-长9储集层原油与长91烃源岩具有密切的亲缘关系,而其他地区长91储集层原油与长91烃源岩的可对比性差.长91烃源岩是重要的区带性油源岩,在志丹南部地区延长组长8-长9储集层成藏中起着重要的作用.图10表2参13

Hydrocarbon accumulation significance of Chang91 high-quality lacustrine source rocks of Yanchang Formation, Ordos Basin

The comprehensive identification by logging and organic geochemistry reveals that the Chang91 high-quality source rock of black lacustrine mud shale mainly develops in the south of Zhidan region. The source rock has both strong hydrocarbon-generating capability and strong hydrocarbon-expulsion power. According to the characteristics of high C30-rearranged Hopane and extremely low C30 Hopane of the Chang91 source rock, in combination with other geochemical parameters in oil-source correlation, Chang8-Chang9 reservoir oil has a close relationship with Chang91 source rock in the south of Zhidan region and there is a poor correlation between Chang91 reservoir oil and Chang91 source rock in other areas. Chang91 source bed is important zonal oil source rock and it plays an important role in the formation of the Chang8-Chang9 reservoir in the Yanchang Formation, south of Zhidan region.