驱替体系的主要性质对驱油效率的影响

为了深入研究粘弹性、粘度和界面张力等性质对驱油效率的影响,采用系列驱替体系进行了大量的物理模拟实验。与前人研究方法不同,实验中将表面活性剂和碱的质量分数分别固定为0.3%和1.2%,通过调整烷基苯磺酸盐表面活性剂的组成配方,使三元复合体系具有不同的界面张力数量级,避免了化学剂质量分数变化引起的实验偏差。研究结果表明,在相同粘度下,三元复合体系的弹性小于聚合物溶液;与水驱相比,单独聚合物驱和表面活性剂—碱二元驱可分别提高采收率14.37%和7.05%;同时改变粘度和界面张力可提高采收率30.41%,证明两者的协同作用效果优于改变单因素时驱油效率的简单加和;粘度越高,降低界面张力对提高驱油效率的影响越大。因此,合理匹配粘度与界面张力之间的关系是提高驱油效率的有效途径。

Effect of main properties of flooding system on oil displacement efficiency

Experiments are implemented to analyze the effects of viscosity and interfacial tension and viscoelasticity of displacement system.The interfacial tensions of ASP solutions have different quantitative features under the same concentrations of surfactant and alkali.The displacement system can diminish the error caused by the change of chemical concentration.The result shows that the viscoelasticity of polymer is higher than that of ASP solution with same viscosity;it proves that the ASP solution enhances the displacement efficiency by reducing the interfacial tension.Single polymer or "surfactant and alkali" can enhance the efficiency within limited range.The concurrent function on increasing the viscosity and reducing the interfacial tension is better than simple mixture of these two single factors.The change of recovery ratio improves when the interfacial tension is below 10-1 mN/m especially.Interfacial tension affects the displacement efficiency more apparently than the viscosity.