毛管数对濮城沙一下油藏渗流规律的影响研究  

Influence of capillary number on the percolation law in Shayixia reservoir of Pucheng oilfield.

作　　者：吴济畅[1] 王强[2] 

机构地区：[1]中原石油勘探局 [2]西南石油学院

出　　处：《油气采收率技术》1999年第1期50-56,共7页

摘　　要：理论分析表明：毛管数Ｎｃ的值越大，储层孔隙中的油滴越易移动；注水压力梯度ΔＰ／Ｌ越大，油水界面张力σ越小，润湿角越接近９０°，储层孔隙中的油滴越易流动。取濮城沙一下油藏的岩心进行了５０次实验，表明：Ｎｃ增至１０－２时，驱油效率ＥＤ达８０％，剩余油饱和度Ｓｏｒ下降至５％；随着Ｎｃ的增大，油、水相渗透率均增大（但油相渗透率的增幅大于水相渗透率），产油率ｆｏ增加，产水率ｆｗ减小；当驱替相的粘度μｗ和速度Ｖｗ一定时，σ减小，则剩余油饱和度Ｓｏｒ减小，当σ降到１０－３ｍＮ／ｍ时，Ｓｏｒ低于７％。研究认为，增大毛管数，降低界面张力，尽可能将油藏改造为弱水湿性，这是提高驱油效率和降低剩余油饱和度的有效手段。濮城沙一下油藏采出程度已达４８．７１％，采收率５０．８％，研究结果将为该油藏进一步开采剩余油、提高最终采收率提供依据。It is shown by theoretical analysis that the more the capillary number and the larger the injecting pressure gradient and the smaller the oil water interfacial tension and the more the wetting angle near to 90°, the easier the oil droplets in reservoir pore move. 50 times core experiments of Shayixia reservoir show that when capillary number increases to 10 -2 , the oil dispalacment efficiency will reach 80% and the remaining oil saturation will reduce to 5%. With the increasing of capillary number, the permeability of both oil and water will increase(the increasing degree of oil is greater than that of water). As the oil production rate increasing, the water cut will reduce. While the viscosity and velocity of displacing phase are constant and the interfacial tension decreases, the remaining oil saturation will reduce. As the interfacial tension reduced to 10 -3 mN/m , the remaining oil saturation will be below 7%. It is thought that increasing capillary number, reducing interfacial tension and converting the reservoir to weak water wetting as possible are the efficient measures of improving oil displacement efficiency and reducing remaining oil saturation. Now the produced degree and oil recovery in Shayixia reservoir of Pucheng oilfield have reached 48.71% and 50.8% respectively, the above results would provide efficient basis for further developing of this reservoir.

关 键 词：毛细管作用 岩心分析 油藏 渗流规律 低渗透油田 

分 类 号：TE311[石油与天然气工程—油气田开发工程] TE348