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

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.