柴达木盆地西南部凹陷特征及生烃潜力分析

13个区块的三维大连片资料显示柴达木盆地西南部(简称“柴西南”)现今存在红狮、扎哈泉、阿拉尔和切克里克等4个主要凹陷(或次级凹陷)。通过对凹陷构造演化和生烃潜力分析，认为红狮凹陷、扎哈泉凹陷和切克里克东凹陷为早期持续沉降凹陷，发育古近系-新近系厚度较大的优质烃源岩，生烃潜力大。同时，结合油源对比和油气分布指出，柴西南具有大凹陷局部生烃中心，油气“环凹近源”聚集的特征，预算红狮和扎哈泉-切克里克2个生烃中心资源量为8.86×108t，临近生烃中心长期持续发育的七个泉-砂西、跃进、乌南、昆北等古鼻状凸起及外围斜坡带，不但有红狮凹陷和扎哈泉-切克里克凹陷2个生烃中心为其提供充足的油源，而且继承性发育多个三角洲沉积体系前缘相带、滨浅湖滩坝优质储砂体，源储配置好，是岩性、岩性-构造油气藏勘探的有利区带。

Characteristics of Depression and Their Hydrocarbon Generation Potency in Southwestern Qaidam Basin

According to 3D seismic data in southwestern Qaidam basin,it can be find that there are 4 secondary depression:Hongshi,Zhahaquan,Alaer and Qiekelike.Through research on structure evolution and hydrocarbon generation of the depression,we get a viewpoint that Hongshi,Zhahaquan and eastern Qiekelike depression are early sustained sedimentation,the source rocks in Tertiary System have a characteristics of multi-bed,great thickness and superior quality,and Zhahaquan and eastern Qikelike is an entire hydrocarbon generation depression in early time.Combined with oil source comparison and oil-gas,it can be indicated that there are two hydrocarbon generation center in Hongshi and Zhahaquan-Qiekelike with a figure of partly generating hydrocarbon in big depression and oil-gas accumulate near-source and around the depression.While,the two source center contain 8.86 hundred million tons oil and gas.Provided hydrocarbon by the two oil source center,Qigequan-Shaxi,Yuejin,Wunan,and Kunbei,which develop several delta frontal zones and beach bar sand zone,become a favorable area for lithologic hydrocarbon reservoir.