Li Guoqiao, Zhou Zhaohui, Fan Jian, Zhang Fan, Zhao Jinyi, Zhang Zhiqiu, Ding Wei, Zhang Lu, Zhang Lei
College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318, China.
No. 2 Oil Production Plant, Daqing Oilfield Corp., Ltd., Daqing 163414, China.
Materials (Basel). 2024 Sep 11;17(18):4457. doi: 10.3390/ma17184457.
Alkali-surfactant-polymer (ASP) flooding is one of the most effective and promising ways to enhance oil recovery (EOR). The synergistic effect between alkali, surfactant, and polymer can respectively promote emulsification performance, reduce interfacial tension, and improve bulk phase viscosity, thus effectively improving flooding efficiency. However, the displacement mechanism of ASP flooding and the contribution of different components to the oil displacement effect still need further discussion. In this study, five groups of chemical slugs were injected into the fracture model after water flooding to characterize the displacement effect of weak alkali, surfactant, polymer, and their binary/ternary combinations on residual oil. Additionally, the dominant mechanism of the ASP flooding system to improve the recovery was studied. The results showed that EOR can be improved through interfacial reaction, low oil/water interfacial tension (IFT), and increased viscosity. In particular, the synergistic effect of ASP includes sweep and oil washing. As for sweep, the swept volume is expanded by the interfacial reaction between the alkali and the acidic components in Daqing crude oil, and the polymer increases the viscosity of the system. As for oil washing, the surfactant generated by the alkali cooperates with surfactants to reduce the IFT to an ultra-low level, which promotes the formation and migration of oil-in-water emulsions and increases the efficiency of oil washing. Overall, ASP can not only activate discontinuous oil ganglia in the pores within the water flooding range, but also emulsify, decompose, and migrate the continuous residual oil in the expanded range outside the water flooding. The EOR of ASP is 38.0% higher than that of water flooding. Therefore, the ASP system is a new ternary composite flooding technology with low cost, technical feasibility, and broad application prospects.
碱-表面活性剂-聚合物（ASP）驱油是提高采收率（EOR）最有效且最具前景的方法之一。碱、表面活性剂和聚合物之间的协同效应可分别促进乳化性能、降低界面张力并提高体相粘度，从而有效提高驱油效率。然而，ASP驱油的驱替机理以及不同组分对驱油效果的贡献仍需进一步探讨。在本研究中，在水驱后向裂缝模型中注入五组化学段塞，以表征弱碱、表面活性剂、聚合物及其二元/三元组合对残余油的驱替效果。此外，还研究了ASP驱油体系提高采收率的主导机理。结果表明，可通过界面反应、降低油水界面张力（IFT）和增加粘度来提高采收率。特别是，ASP的协同效应包括波及和洗油。对于波及，碱与大庆原油中的酸性组分之间的界面反应扩大了波及体积，聚合物增加了体系的粘度。对于洗油，碱生成的表面活性剂与表面活性剂协同作用，将IFT降低至超低水平，促进了水包油乳液的形成和迁移，提高了洗油效率。总体而言，ASP不仅可以激活水驱范围内孔隙中的不连续油团，还可以乳化、分解和迁移水驱范围外扩大区域内的连续残余油。ASP的采收率比水驱高38.0%。因此，ASP体系是一种低成本、技术可行且应用前景广阔的新型三元复合驱油技术。
