鄂尔多斯盆地天环坳陷迁移演化与坳陷西翼油气成藏

鄂尔多斯盆地是我国陆上最重要的含油气盆地之一,本文以鄂尔多斯盆地西缘为研究对象,以地震反射资料为基础,主要采用地震剖面"层拉平"与"平衡剖面恢复"等技术手段,对天环坳陷形成与迁移演化历史进行了动态分析。研究结果表明:1)天环坳陷最早形成于晚侏罗世,后期由于受燕山晚期及喜马拉雅山期构造运动影响,坳陷核部逐渐向东迁移至现今位置,前后累计迁移距离约30 km;2)当坳陷核部向东迁移至有效烃源岩范围附近时,原先已形成的油气藏发生重新调整,油气向坳陷西翼高部位运移、聚集,从而形成了次生构造油气藏。

Migration history of the Tianhuan depression of the Ordos Basin and it's effects on the hydrocarbon accumulation in the west part of the depression

The Ordos Basin is one of the most important hydrocarbon prolific basins in China. Based on seismic data and horizon flatterning as well as seismic balance section technique,dynamic analysis regarding the formation and the history of the migration and evolution of the Tianhuan depression was conducted. Two main results were obtained: 1)The Tianhuan depression was primarily formed during the Late Jurassic and later it's axis migrated about 30 km eastward to current position due to the impact of the late Yanshan and Xishan tectonic movements; 2)When the axis of the depression moved near to the effective source rock area,the previous pool readjusted and the hydrocarbon migrated to and accumulated at the higher position of the west part of the Tianhuan depression and consequently secondary structural reservoirs were formed.