大型挤压构造事件对油气成藏的影响

传统石油成因理论认为有机质成熟度主要受温度、时间与压力等因素的控制。依据松辽盆地勘探实践经验认为热演化程度受温度控制明显,只要温度高,烃源岩可在短时间内大量生烃。构造运动不仅可以产生大量的热,使烃源岩生烃、排烃过程具有突发性,而且挤压作用可以促进烃源岩的排烃作用、运移作用。另外,构造运动又可以形成一系列的圈闭,从而使油气从生成到聚集的过程可以在短时间内完成。因此,在挤压构造发育的区域,即使烃源岩埋藏较浅,也具有一定的排烃能力,形成工业性油气聚集。基于这一认识,应该改变烃源岩埋藏浅就不能排烃的这一常规理念,把盆地边部构造变形较强的区域也纳入勘探视野。 

Influence of large-scale tectonic compression events on the hydrocarbon accumulation

According to traditional hydrocarbon genesis theory,it is accepted that organic maturity is affected by temperature,time and pressure.After summarizing exploration practices,it reveals that thermal maturity of organic matter is mainly controlled by temperature.So long as the temperature is high enough,substantial hydrocarbon can be generated from source rock.Tectonic movements do not only produce great amount of heat,but also make hydrocarbon generation and expulsion abruptly.Compressive process promote the hydrocarbon generation and migration.In addition,tectonic movements can form a set of traps,which shorten the time from generation to accumulation.Therefore,in areas where tectonic compression are well developed,though shallow buried source rock,they also have the capacity for hydrocarbon expulsion,and can form economic oil reservoirs.Based on these findings,the traditional theory that shallow source rock can not expulse oil should be broke,and regions of marginal basin with intense structural deformation should be taken into the exploratory frontier.