储层孔隙结构对油水两相相对渗透率影响微观模拟研究

油水相对渗透率曲线是表示两相渗流的重要信息,而储层微观孔隙结构特征是影响相对渗透率的重要因素.结合逾渗理论,采用截断威布尔分布作为孔喉分布函数,模拟初次油驱和二次水驱过程,建立了油水两相流的三维准静态孔隙网络模型.利用建立的孔隙网络模型,研究了水湿情况下储层微观孔隙结构参数如孔喉半径、孔喉比、配位数、形状因子等对油水相对渗透率的影响.结果表明:孔喉半径和孔喉比越大、配位数和形状因子越小,残余油饱和度越大,两相共流区越窄;配位数对非润湿相相对渗透率影响较大,而形状因子对润湿相相对渗透率影响较大.

Simulation study on the effect of the microscopic parameters of reservoir pore structure on oil-water relative permeability

oil-water relative permeability curve represents the important information of the two hase permeability,and the microscopic pore structure characteristics of reservoir are the important factor of influencing the relative permeability.Based on percolation theory,a quasi-static 3D pore network model is established,and it can be used to describe primary oil flooding and secondary water flooding and to calculate the relative permeability.The effects of pore-throat radius,pore-throat ratio,coordination number and shape factor on the relative permeability are investigated under water-wet condition by the model.The results show that would be larger as the greater the pore-throat radius and pore-throat ratio and the less the coordination number and the shape factor,the greater the residual oil saturation and the narrower the two-phase co-flow;the coordination number has greater influence on the relative permeability of non-wetting phase,but the shape factor has greater influence on the relative permeability of wetting phase.