吐鲁番坳陷温吉桑油气聚集带成藏机理研究

STUDY ON THE POOLING MECHANISM OF THE WENJISANG HYDROCARBON ACCUMULATION ZONE IN TURPAN DEPRESSION

温吉桑油气聚集带是吐鲁番坳陷的主要油气聚集带之一。该区油气分布是同一套烃源岩两期生烃、成藏的结果。中燕山运动时期 ,丘东凹陷的生油岩进入生油门限 ,以生成轻质油为主 ,通过断层向位于生油凹陷中的温吉桑构造带供源。此时丘东背斜尚未形成 ,油气由北向南方向运移 ,轻质油在运移过程中以氧化作用占主导地位。喜山运动时期 ,丘东凹陷和温吉桑构造带进一步深埋 ,烃源岩以生成凝析气为主 ,同时由于挤压作用形成了丘东背斜。油气沿由北向南方向运移 ,凝析气运移过程中以地层层析作用为主。同期形成的丘东背斜只捕获了该时期生成的凝析气 ,形成纯的凝析气田。米登背斜由于聚集了中燕山运动时期形成的轻质油 。

The Wenjisang hydrocarbon accumulation zone is one of the main accumulation zones in Turpan Depression.Hydrocarbon was resulted from two periods of hydrocarbon generation and expulsion of the same set of source rocks in the area.During the Middle Yanshanian movement phase,the source rocks in Qiudong sag entered threshold of hydrocarbon generation,and dominately generated light oil.It was migrated to Wenjisang structural zone within the sag along fault.At this time Qiudong anticline was not formed and oil was migrated from north to south with oxidizing as a main change during migration.During the Himalayan movement phase Qiudong sag and Wenjisang structural zone were deeply buried and source rocks mainly generated condensate gas.At the same time,Qiudong anticline was formed as a result of regional compression.The condensate gas was migrated from north to south with bed absorbing process.Due to only condensate gas was captured,a pure condensate gas field was formed in Qiudong anticline.But Miden anticline only accumulated condensate gas in the deep part as it had captured light oil generated during Yanshanian period.