不整合纵向结构及其成藏作用物理模拟

不整合是地层中保留下来的地层缺失所呈现出的一种不协调的接触关系。在纵向上可划分为3层结构:不整合面之上岩石、风化粘土层及半风化岩石。它不仅是油气长距离侧向运移的重要通道,而且能形成地层不整合油气藏。模拟实验表明,油气沿不整合纵向结构运移受控于岩石物性、坡度,容易在风化粘土层薄弱环节突破,进行窜层运移;不整合面之上的地层超覆圈闭较不整合面之下的地层遮挡圈闭(潜山)更有利于油气成藏。 

Vertical structures of unconformity and its simulation experiment of hydrocarbon accumulation mechanism

The unconformity is an incoordinate connection kept in strata as a result of the depositional break. The vertical structures of unconformity can be divided into 3 layers: rocks above the unconformity interface, weathering clay and paleokarst zone. They not only are the pathways for oil and gas migration, but also provide accommodation for oil and gas accumulation. Simulation experiments show that the hydrocarbon migration along the vertical structures of unconformity is not only controlled by petrophysics and slope gradient, but also can breakthrough the weathering clay in the weak links to flow with communication between zones; Stratigraphic overlap hydrocarbon reservoirs on the surface of unconformity are more easily to form than stratigraphic screened hydrocarbon reservoirs under the surface of unconformity.