油气沿断裂向下幕式运移的机理

Mechanism of Episode Petroleum Migration Along Faults Down

通过分析松辽盆地北部扶扬油层断裂活动与油气运聚成藏特征,认为扶扬油层油气藏的形成不能简单地用"断裂超压倒灌机理模式"来解释,青山口组烃源岩排出的成熟油气能够沿断裂向下长距离倒灌运移的主要原因是超压的间歇释放,即泄压区断裂不断活动而形成的泄压区流体流失和压力降低,是导致憋压区流体长距离沿断裂向下倒灌至泄压区的根本原因和动力机制";超压间歇释放断裂幕式倒灌成藏机理模式"不仅解释了断裂在上覆超压下运载油气向下运移的机理,而且为油气沿断裂向下长距离"倒灌"运移提供了理论依据,同时也为在超压发育区下伏地层及其深层油气勘探提供了思路。

The analysis of fault activity and hydrocarbon migration and accumulation in Fuyang reservoir in northern Sungliao basin suggests that this reservoir could not he explained simply by overpressure allowing hydroearhon to migrate down ahmg faults rather than by the model of intermittent overpressure releasing along fauhs and episodic eounterflow/accumulation, which is the main reason of mature hydrocarbon from Qinshankou source rock migrating down along faults for a long distance. Such a model can not only explain that it is the fault that carried the till and gas migrating down in condition of overpressure, but also provides theoretic basis for petroleum long-distance counterflow migrating down along fauhs. Also, it is pointed out thai the underlying strata and the deep strata with overpressure in this area are favoarable for petroleum exploration.