滨里海盆地东缘构造演化及油气成藏模式分析

滨里海盆地是中亚地区油气资源最为丰富的沉积盆地之一。本文以油气地质理论为指导,对盆地东缘的构造演化以及其油气成藏组合进行分析,认为乌拉尔造山运动对盆地东缘的构造演化造成了深刻影响。盆地东缘盐上层系的生烃条件较差,主要油气来源应为盐下层系。石炭系碳酸盐岩KT-I层和KT-II层是盆地东缘发育的良好储层。下二叠统盐层为区域性盖层,特别是对盐下油气藏起到了良好的区域封盖效果,盐相关构造圈闭类型发育。不整合面、断层和孔、洞、缝等组成复合的油气输导体系。盆地东缘的油气成藏模式主要为盐下层系的"自生自储型"和"下生上储型"以及盐上层系的"下生上储型"。

Tectonic evolution and hydrocarbon accumulation model in eastern Precaspian Basin

The Precaspian Basin has proved to be one of profilic sedimentary basins in Central Asia. A preliminary study is made in the present paper for the tectonic evolution,source-reservoir-seal associations and migration of hydrocarbons on the eastern margin of the Precaspian Basin. Uralian orogeny is believed to have exerted an important effect on the eastern margin of the Basin. Generally speaking,the suprasalt strata are poor in hydrocarbon accumulation. Instead,the hydrocarbons mainly originated from the subsalt strata. The Carboniferous carbonate rocks KT-I and KT-II beds are interpreted to be the excellent reservoir rocks in the study area. The Lower Permian salt beds appear as the regional cap rocks,and contribute a lot to the local sealing of subsalt hydrocarbons. The salt-associated structural traps are well developed,and the unconformities,faults,pore spaces and fissures constitute a compound oil-gas carrier system. The models for the hydrocarbon accumulation include the ＂selfgeneration and self-accumulation＂type for the subsalt strata,and＂lower-generation and upper-accumulation＂type for the suprasalt strata.