塔里木盆地乌什凹陷石油地质特征

研究塔里木盆地乌什凹陷的石油地质特征对于准确掌握该区勘探目标层具有重要意义 .乌什凹陷是库车坳陷的一个次级负向构造单元 ,是在古生界基底之上发育起来 ,以前寒武系基底埋藏较深 ,中生界发育为特征的中—新生代沉积凹陷 .沉积环境以河流、湖泊相为主 ,乌什凹陷周边出露多套中生代、古生代的烃源岩 ,凹陷内部发育一系列近东西走向的逆冲断层 ,并在厚层泥岩之下的白垩系舒善河中获得工业气流 ,而古近系的厚层泥岩是一套好盖层 ,说明凹陷内部具有供烃条件并且油气聚集自成体系 .指出乌什凹陷的勘探目的层应立足于白垩系砂岩和古近系底砂岩 ,同时兼顾侏罗系砂岩

Petrogeologic feature of Wushi Sag in Talimu Basin

The study on the petrogeologic feature of Wushi Sag is of importance to accurately understanding the objective formation in this area. Wushi Sag is a secondary negative structural unit of Kuche Depression. It is a Mesozoic—Cenozoic sedimentary sag which develops on Palaeozoic base. Precambrian system floor is buried relatively deep, and Mesozoic develops well in the sag. The deposit is mainly composed of fluvial and lacustrine facies. Several sets of Mesozoic and Palaeozoic hydrocarbon sourse rock appear around the sag. A series of thrusts develop in the sag, and their strikes are near E—W. The thick mudstone of Paleogene is a set of good cap formation. A commercial gas flow is found in Cretaceous Shushan river under the thick mudstone. It shows that the sag has its own hydrocarbon supply and accumulation system. It is pointed that, the main objective formation of exploration in Wushi Sag are Cretaceous sandstone and Paleogene sandstone, at the same time, Jurassic sandstone must be given consideration.