Abstract: Based on oriented percolation,this article is focused on construction of stochastic network model,which can truly characterize the features of pore structure and wettability of sand. With this kind of model,the microcosmic composition and distribution of residual oil is then simulated theoretically. And the effects of wettability on the micro-distribution of residual oil are also simulated and discussed with the help of the network model. The results of simulating with the model are quite consistent with the results of microcosmic experiment. It has been found with network simulation that within residual oil the microcosmic composition and distribution of oil blobs with various sizes have some statistic character. That means generally the single and double blobs are in majority but only a few large size blobs in residual oil. However, the amount of the large size blobs could be the major part in residual oil, especially with a low oil recovery. It is also proved that stochastic network simulation is quite fast and less restricted by conditions,and that the way can reveal a visible picture about the changeable processes of micro-displacement and the micro-distribution of residual oil. Therefore,stochastic network simulation could be a flexible and convenient method used for research of the microcosmic features of residual oil.

Key words: residual oil, distribution, microcosmic, network model, stochastic simulation

摘要： 应用定向渗流理论建立了能表征岩石微观孔隙结构特征及润湿性特征的随机网络模型,从理论上模拟讨论了剩余油的微观组成特征及润湿性对微观剩余油分布的影响,得到了与微观实验一致的模拟结果。模拟结果表明,在剩余油中,不同大小的微观剩余油液滴的组成和分布具有一定的统计特征和规律性,单、双液滴的频数组成较高,大尺寸液滴数目较少;但是,驱替效率较低时,数量微小的大尺寸液滴在剩余油总量中的比例不可忽视,甚至可能是剩余油的主要部分。结果证实,随机网络模拟速度快、所受条件限制少,并能直观地再现动态的微观驱替过程及剩余油的微观分布状况,为微观剩余油提供了一种方便、灵活的研究手段。

关键词: 剩余油, 分布, 微观, 网络模型, 随机模拟