三元复合驱的驱油特征研究

大量室内研究和矿场试验结果表明,在高效的表活剂条件下,三元复合驱是一种非常有效的三次采 油方法,具有良好的应用前景。文中应用数值模拟技术并结合室内研究,给出了三元复合体系不同界面张 力和粘度比条件下,在非均质油层中的驱油特征。分析结果表明,三元复合驱与聚合物驱相比,对油层非 均质性有更大的适用范围;对于非均质油层的三元复合驱,采用增加体系的粘度和降低体系的界面张力的 方式都能获得较好的提高采收率效果,但高粘度是获得好的提高采收率的关键;采取分层注入的方式,或 者在三元复合驱后对高渗透层进行封堵,能更有效地采出中、低渗透层的剩余油,进一步提高采收率。本 项研究对认识三元复合驱的驱油机理和编制调整矿场试验方案提供了重要依据。

A study on features of oil displacement of alkali-surfactant-polymer flooding

Laboratory study and field experiments show that al- kali - surfactant - polymer flooding is a very effective tertiary oil recovery method in conditions of highly effective surfactants. This paper presents the features of oil displacement of alkali - surfactant - polymer flooding system in heterogeneous oil layers at different interfacial tensions (IFT) and viscosity ratios by using numerical simulation technologies and in combination with laboratory studies. Analysis shows that alkali - surfactant - polymer flooding has larger range of application in heterogeneous oil layers compared with that of polymer flooding. As to alkali -surfactant - polymer flooding in heterogeneous oil layers, both increase of viscosity of alkali - surfactant - polymer system and lower of interfacial tension can effectively enhance oil recovery, while high viscosity is critical to enhance oil recovery. The remaining oil in reservoirs with medium to low permeability can be effectively recovered by using layered injection method or by plugging highly permeable layers after alkali - surfactant - polymer flooding, thus recovery factor can be improved further. The study provides an important basis for understanding oil displacement principles of alkali - surfactant - polymer flooding and establishing field testing program.