单一微孔隙中油水相对渗透率特性研究

Study on Relative Permeabilities of Oil and Water in Single Micropore

孔隙渗流是多孔介质渗流的微观基础。本文对孔隙中的两相流应用分相模型,结合达西渗流定律,提出了适用于油水两相的相对渗透率模型,得到相对渗透率与孔隙度无关、相对渗透率只是微孔隙中相态分布的几何尺度以及流体饱和度的函数等结论。设计了微流动实验装置,以去离子水和白油的乳化液为两相流体,在不同含油率下研究了微孔隙中油水两相的渗流特性,并与相应条件下的模型计算结果进行对比。结果表明,对于低渗透尺度等级的微孔隙,实验与计算结果吻合较好,对于高渗透尺度等级的微孔隙,实验与计算结果存在偏差。在某些条件下,油与水的相对渗透率之和存在大于1的情形。

Percolation in pores is the microcosmic foundation of flow in porous media.Based on the separated model of two-phase flow in pores and Darcy’s law,a new model of relative permeability is put forward for oil-water two-phase flow.The new model indicates that the relative permeability is independent of porosity.The relative permeability is a function of the geometric scale of phase distribution and the fluid saturation in micropores.A microflow experimental device is designed,in which the emulsion of deionized water and white oil is used to study the percolation characteristics of oil-water two-phase mixture under different oil content in micropores.The experimental data are compared with the results of model calculation under corresponding conditions.It is found that the experimental data are in good agreement with the calculated results for the micropores of low permeability scale,and different from the calculated results for the micropores with high permeability scale.In addition,the sum of relative permeabilities of oil and water is greater than 1 under some conditions.