松辽盆地北部岩性油藏形成机制及主控因素

Formation mechanism and main controlling factors for lithologic reservoirs in northern Songliao basin

在研究松辽盆地北部岩性油藏类型及特征的基础上 ,提出岩性油藏形成的 3种机制 :在毛细管力作用下油气进入位于烃源岩内部的岩性圈闭 ;在超压和浮力作用下油气沿断层向上进入位于烃源岩之上的岩性圈闭 ;在超压作用下油气沿断层向下倒灌进入位于烃源岩之下的岩性圈闭。三角洲前缘相带及古河道是松辽盆地北部岩性圈闭形成的主要场所 ,断层是烃源岩外岩性圈闭油气运聚的唯一通道 ,位于烃源区内是岩性油藏形成的关键。

Based on studying the types and characteristics of lithologic oil reservoirs in northern Songliao basin, this paper puts forward three formation mechanisms for lithologic oil reservoirs: oil or gas from source rock migrating into lithologic traps in sourcerock and forming oil or gas reservoirs under the action of capillary pressure; oil or gas from source rock migrating into lithologic traps over source rock and forming oil and gas reservoirs under the action of abnormal pore fluid pressure and buoyancy, and oil or gas from source rock migrating into lithologic traps under source rock and forming oil or gas reservoirs under the action of abnormal pore fluid pressure. Delta and ancient river are the main places where the lithologic oil and gas reservoirs were formed in northern Songliao basin. Fault is the sole passage for oil or gas to migrate into the lithologic traps over or under source rock. The key that oil or gas accumulates in lithologic trap would be in the source rock.