反五点井网水驱剩余油分布定量研究

Quantitatively Study on the Residual Oil Distribution after Water Flooding in the Inverted Five Spot Well Patterns

为了研究高含水期剩余油分布及提高采收率方法,利用微观可视化装置实验模拟反五点井网水驱油开发过程,定性分析水驱后剩余油的状态及分布,提出微观渗流实验定量分析剩余油的方法,定量分析剩余油饱和度和水驱采收率。结果表明,低速水驱时剩余油以柱状、簇状、孤岛状及分散的油滴为主,高速水驱后剩余油以柱状、簇状为主,增加流速主要将簇状、孤岛状及分散的油滴驱出。驱替速度为0.05m L/min时水驱采收率为63.39%,驱替速度为0.2m L/min时水驱采收率为75.68%,高速水驱的驱油效率大大提高,高含水期可通过高速生产来提高驱油效率。反五点井网中,距主流线越远的部位剩余油饱和度越高,生产井附近剩余油饱和度比注水井附近低。

In order to study the distribution of residual oil in high water cut period and the method of enhancing oil recovery,the micro visualization device has been used to simulate the development process of inverted five point well pattern.The state and distribution of residual oil after water flooding were analyzed qualitatively,and the quantitative method for analyzing residual oil was obtained by microscopic seepage experiment,which used for the analysis of the saturation of residual oil and recovery of water flooding.Results showed that the residual oil was dominated in the shapes of column,cluster and island and dispersed droplets when flooding at low speed,but when the flooding was at high speed,the residual oil would be mainly in the shape of column and cluster,the increased flow rate can drive the clustered,isolated and dispersed oil droplets out.When the flooding rates are 0.05 m L / min and 0.2m L / min,the recovery rates are 63.39% and 75.68% respectively,so,the high flow rate flooding can raise the efficiency,which should be adopted at high water cut stage.In the inverted five spot well patterns,the farther the point from the mainastream line,the higher the residual oil saturation is,and the residual oil saturation near the production well is lower than that of the water injection wells.