基于孔隙网络模型的微观水驱油驱替特征变化规律研究

Law of Characteristic Variations of Microscopic Water Displacement Based on Pore Network Model

结合逾渗理论,采用截断威布尔分布作为孔喉特征分布函数,模拟储层岩心的初次油驱过程和二次水驱过程,建立了油水两相三维准静态孔隙网络模型;通过模型计算与试验结果的对比,验证了孔隙网络模型的有效性。利用建立的孔隙网络模型,研究了岩心在水湿情况下,储层微观孔隙结构参数如孔喉比、配位数、形状因子等对水驱油驱替特征的影响。研究结果表明,储层岩心的孔喉比越小、配位数和形状因子越大,残余油饱和度越小,水驱油的驱替效果越好;形状因子的变化对驱油效率影响较大。

Based on percolation theory, truncated Weibull distribution is used as the pore throat distribution function, a two phase and 3 dimensional quasi-static network model is established to simulate the primary oil displacement and secondary water flooding of reservoir cores. The validity of the model is verified by comparison of calculation with experimental result. A pore network model is established. The effects of pore structural parameters, such as pore throat ratio, coordination number, shape factors on water displacement characteristics are studied. The result shows that the less the pore throat ratio is , the more the coordination number and shape factors are, the less the residual oil saturation is , the better effect of waterflooding will be, less influence is caused on oil displacement by shape factors.