碳酸盐岩缝洞型油藏剩余油类型及影响因素

缝洞型碳酸盐岩油藏具有储集空间特殊、连接方式复杂、流体流动规律复杂等的特点,这些特点导致水驱开发后剩余油特征差异很大。文中通过可视化物理模拟实验,模拟了不同缝洞组合模式的油藏底水驱替开发过程。研究结果表明,缝洞型油藏剩余油分为：连通性差的孔洞剩余油、绕流油、阁楼油和油膜。与其他缝洞连通较差的孔洞几乎可以认为是封闭孔洞,因其无法进行油水置换从而形成剩余油;流体沿最低流动阻力方向流动导致重力效应降低,故在溶洞与裂缝出口处形成绕流油;沟通溶洞的裂缝在溶洞的低部位,故注入水无法达到顶端与油发生置换而形成阁楼油;受岩石表面润湿性、原油黏度以及温度的影响,在溶洞和裂缝表面易形成油膜。

Remaining oil types and influence factors for fractured-vuggy carbonate reservoir

Fractured-vuggy carbonate reservoir has the characteristics of special storage space,complex connection mode and fluid flow law,which lead to big differences in characteristics of remaining oil after waterflooding.By visual physical simulation experiments,two different models have been established and the process of waterflooding has been simulated in this paper.The results show that the types of remaining oil,including remaining oil trapped in the closed fractures and caves,by-pass oil,attic oil and oil film have been determined.Remaining oil is trapped in the closed caves due to bad connectivity with other fractures and caves.Because the minimum resistance is the fluid flow direction,the by-pass oils are easy to form under the link between the fractures and caves.The attic oils are trapped in the top of caves where the flooded water can not arrive in.On the wall of fractures and caves,the oil films form,which are affected by wettability,oil viscosity and temperature.