Zhu Xiuyu, Zhang Qun, Cheng Changkun, Han Lu, Lin Hai, Zhang Fan, Fan Jian, Zhang Lei, Zhou Zhaohui, Zhang Lu
Oil & Gas Technology Research Institute, PetroChina Qinghai Oilfield Company, Dunhuang 736202, China.
State Key Laboratory of Enhanced Oil & Gas Recovery, PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China.
Molecules. 2025 Mar 3;30(5):1145. doi: 10.3390/molecules30051145.
As an efficient and economical method to enhance oil recovery (EOR), it is very important to explore the applicability of chemical flooding under harsh reservoir conditions, such as high temperature and high salinity. We designed microscopic visualization oil displacement experiments to comprehensively evaluate the oil displacement performance of the zwitterionic surfactant betaine (BSB), a temperature- and salinity-resistant hydrophobically modified polymer (BHR), and surfactant-polymer (SP) binary systems. Based on macroscopic properties and microscopic oil displacement effects, we confirmed that the BSB/BHR binary solution has the potential to synergistically improve oil displacement efficiency and quantified the reduction in residual oil and oil displacement efficiency within the swept range. The experimental results show that after water flooding, a large amount of residual oil remains in the porous media in the form of clusters, porous structures, and columnar formations. After water flooding, only slight emulsification occurred after the injection of BSB solution, and the residual oil could not be activated. The injection of polymer after water flooding can expand the swept range to a certain extent. However, the distribution of residual oil in the swept range is similar to that of water flooding, and the oil washing efficiency is low. The SP binary flooding process can expand sweep coverage and effectively decompose large oil clusters simultaneously. This enhances the oil washing efficiency within the swept area and can significantly improve oil recovery. Finally, we obtained the microscopic oil displacement mechanism of BSB/BHR binary system to synergistically increase the swept volume and effectively activate the residual oil after water flooding. It is the result of the combined action of low interfacial tension (IFT) and suitable bulk viscosity. These findings provide critical insights for optimizing chemical flooding strategies in high-temperature and high-salinity reservoirs, significantly advancing EOR applications in harsh environments.
作为一种提高采收率（EOR）的高效且经济的方法，探索化学驱在高温、高盐等恶劣油藏条件下的适用性非常重要。我们设计了微观可视化驱油实验，以全面评估两性离子表面活性剂甜菜碱（BSB）、耐温耐盐疏水改性聚合物（BHR）以及表面活性剂 - 聚合物（SP）二元体系的驱油性能。基于宏观性质和微观驱油效果，我们证实了BSB/BHR二元溶液具有协同提高驱油效率的潜力，并量化了波及范围内残余油的减少量和驱油效率。实验结果表明，水驱后，大量残余油以团簇、孔隙结构和柱状形态残留在多孔介质中。水驱后注入BSB溶液仅发生轻微乳化，残余油未被激活。水驱后注入聚合物可在一定程度上扩大波及范围。然而，波及范围内残余油的分布与水驱相似，洗油效率较低。SP二元驱过程可扩大波及范围并有效分解大油团簇。这提高了波及区域内的洗油效率，能显著提高采收率。最后，我们得到了BSB/BHR二元体系协同增加波及体积并有效激活水驱后残余油的微观驱油机理。这是低界面张力（IFT）和合适的本体粘度共同作用的结果。这些发现为优化高温高盐油藏的化学驱策略提供了关键见解，显著推动了恶劣环境下的EOR应用。
