亲水多孔介质残余油滴的微观运移机理

Microscopic displacement mechanism of oil droplet remaining in hydrophilic porous media

为分析高含水期剩余油微观分布特征,以毛细束渗流模型为基础,建立油滴状残余油微观渗流模型,推导毛细管中油、水微观运动方程,进而导出基于微观渗流模型条件下油、水相对渗透率表达式;分析毛细管半径、驱替压力梯度、油滴与水滴的长度比、油滴半径和原油黏度对油、水相对渗透率的影响.结果表明:随着毛细管半径增大,相对渗透率曲线向右平移;随着驱替压力梯度增大,油、水两相相对渗透率增加;随着油滴与水滴长度比的减小,水相相对渗透率曲线陡峭上升;随着油滴半径减小,油相相对渗透率提高;原油黏度越大,油相相对渗透率下降越快.该结果为分析高含水期残余油渗流机理及提高采收率提供指导.

According to the distribution feature of residual oil in high water cut stage,combined with the capillary flow model,microscopic seepage model of residual oil droplet is established.By means of improving the capillary model,the microscopic migration equation of oil and water in capillary tube is deduced.Meanwhile,the influence of the capillary radius,driving pressure gradient,the radio of the length of the oil droplets and water droplets,the oil droplet radius and fluid viscosity on the relative permeability curve are analyzed.The results show:with the increase of the capillaries radius,the whole relative permeability curve shifts to the right;with the increase of the driving pressure gradient,the permeability of the oil phase increases;with the decrease of size of the oil droplets,the permeability of the oil phase increases;the water relative permeability curve translates to the up right when the viscosity of oil increases.The formula deduced and the results provide theoretical guidance to the study of microscopic displacement mechanism of oil film and further improve oil recovery at high water cut period.