考虑介质微观非均质特征的乳状液渗流模型

A MODEL FOR THE FLOW OF EMULSION IN POROUS MEDIA WITH MICRO-HETEROGENEITIES

油水乳化渗流是三元复合驱和热力采油过程中常见的现象,地层介质的微观孔隙结构特征对乳状液流动有着重要影响.现有描述乳状液渗流的理论模型都属于确定性方法,只能反映出介质孔隙结构的体积平均效果.当介质内部微观非均质性相比其尺寸不能被忽略时,采用确定性方法描述会与实验结果存在偏差.基于连续时间随机游走理论建立了描述乳状液渗流的随机理论模型.该模型引入反映液滴微观运动特征的跃迁时间和跃迁位移两个概率分布函数来反映多孔介质微观非均质特征.研究结果表明该模型能很好地刻画实验曲线中出现的与介质尺度相关的拖尾现象,可作为更一般的过滤模型.

The flow of crude oil-water emulsion in porous media is common phenomena in the process of alkali-surfactant-polymer （ASP） flooding and thermal oil recovery. Microscopic structural characteristics of porous media show crucial effects on the flow of emulsion. Existing theoretical models on the flow of emulsion in porous media are deterministic approaches to describe macroscopic volume-averaged performance of porous media with microscopic structures. There are inherent deviations between deterministic descriptions and experimental results when smaller-scale heterogeneities can not be omitted with the comparison of the size of porous media. In this paper, a stochastic method on the flow of emulsion in porous media is developed based on continuous time random walk （CTRW） formalism. The probability distribution functions of transition time and displacement of dispersed-phase droplets give description of microscopic heterogeneities of porous media. The results show that present model can effectively describe the scale-dependent long-tailed phenomena of experimental results and be used as general filtration model.