松辽盆地南部两井地区扶余油层油藏成藏机制及主控因素

摘要

在深入解剖两井地区断裂和储层分布规律的基础上，通过油藏解剖和油藏成藏条件空间配置关系，对两井地区扶余油层油运聚成藏机制和主控因素进行了研究。油源区内油藏运聚成藏模式为：长岭凹陷青一段源岩生成的油在超压作用下通过T2油源断裂向下“倒灌”运移进入扶余油层后，再在浮力作用下沿断裂、砂体向高断块圈闭进行短距离的运聚成藏。源内油成藏主要受控于：T2油源断裂控制着油运聚的部位；距离T2油源断裂的远近控制着产能的大小。油源区外油运聚成藏模式为：长岭凹陷扶余油层中的油首先经油源断裂向下“倒灌”运移至扶余油层，再在浮力作用下沿被断裂沟通的砂体侧向运移至邻凹斜坡断层-岩性圈闭中聚集成藏。源区外扶余油层油成藏主要受控于：位于两井古鼻状构造轴部及两翼的圈闭更易成藏；断裂展布方向控制着油气的富集。源岩、断裂和砂体的合理匹配是扶余油层成藏的关键因素。综合上述研究可以得到油源区内T2油源断裂附近和油源区外古鼻状构造两翼运移路径附近北西向断裂、砂体均发育区应为油勘探的有利目标。%Based on the deeply study of faults and reservoir distribution, through reservoir anatomy and space configuration of reser-voir forming conditions, this paper studies oil accumulation mechanism and its main controlling factors of Fuyu layer in Liangjing area. In oil source area of Qing-1 formation, Changling sag, reservoir migration and accumulation mode is that the oil generated from source rock migrates downward into Fuyu layers through the passageway of the T2 oil source faults under overpressure, and then under the effect of buoyancy, the oil migrates short distance along the faults, accumulating in the high block traps. In oil source area, reservoir forming mechanism is controlled by two factors, one is that T2 oil source faults controls the place of oil accu-mulation;the other one is that the distance to T2 oil source faults controls deliverability. Outside oil source area of Fuyu layer, Chan-gling sag, reservoir migration and accumulation mode is that the oil migrates downward into Fuyu layers through the passageway of oil source faults, and then laterally migrates along sand bodies connected by faults under the effect of buoyancy, accumulating in concave slope faults, namely lithologic traps. Outside oil source, reservoir forming mechanism is controlled by two factors, one is that the traps located in axis and two wings of ancient nose structure accumulate more easily, the other one is that the direction dis-tributions of faults control hydrocarbon enrichment. The reasonable match of mother rock, faults and sand body is the key to oil ac-cumulation. The researches show that the region near T2 oil source faults in oil source area, and northwest trending faults and sand body development zone near migration path of two ancient nose structure wings outside oil source area should be favorable targets for oil exploration.