南堡凹陷的断裂构造与油气三次运移

油气沿断层三次运移是周期流动过程。在断层不活动期,大断层是封闭的,油气可以在高压生油层系内的断层圈闭中聚集成原生油气藏;但在断层活动期,大断层转化为开启,原生油气藏中的油气可以沿断层运移到浅层聚集成次生油气藏。由于是快速集中流动,这种三次运移没有明显的色层效应;但因为三次运移的油气主要是原生油气藏中顶部的轻质组分,所以原生油气藏与次生油气藏有明显的差异聚集现象。油气从原生油气藏中溢出的过程是连续的,但运移过程中被水流冲散,并随水流进入不同的储集层,导致次生油气藏纵向分布具有一定的随机性。

FRACTURE STRUCTURES AND HYDROCARBON THIRD MIGRATION IN NANPU DEPRESSION

Hydrocarbon third migratgion is a periodic flow process. When faults are in dormantstage,large faults are sealed and hydrocarbons could accumulate to the fault traps within abnormal high pressure source sets to form primary pools lwhen faults are active,large faultsare open,hydrocarbons in the primary pools would migrate upward along the large faults toform secondary hydrocarbon pools in shallow traps. As the third migration is quick and concentrated,it did not result in evident chromatographic effect but did result in obvious differentiae between the primary and secondary pools since most of the hydrocarbons overflowedfrom the primary pools are light components. The hydrocarbons overflowed continuouslyfrom the primary pools, and were flushed by water-flow, then entered different reservoirswith water-flow,thus resulting in random distribution of secondary pools vertically.