基于胶束结构特性的驱油用表面活性剂分子设计

Surfactants play an important role in enhanced oil recovery. The development of surfactant molecules for different oil reservoirs is an urgent problem to be solved. Surfactants exhibit complex meso-scale structures (aggregations) during the process of self-assembly. Within the aggregations, the hydrophilic and lipophilic groups of surfactants expose to water and oil respectively to decrease the interfacial tension. A deep understanding and control of the meso-scale structure is the key to design the molecular structure of surfactants. Focusing on the meso-scale structures at material and interface level, this proposal attempts to establish a meso-scale model to characterize the relation between the molecular structure of surfactants and meso-scale structure, and then to determine the effiency for enhanced oil recovery. The target is achieved via analysis the dominant mechanisms and their compromise in the determination of stability condition of the studied system, and then comparisons between the results from parallel computations and experiments. The proposed meso-scale model is then integrated with Lattice Boltzmann model to systematically study the effects of meso-scale structures on the hydrodynamics of oil reservoirs, and therefore guide the molecular design of surfactants for enhanced oil recovery.

表面活性剂驱油对提高油田采收率具有重要意义，适用不同油藏条件的表面活性剂的开发是一个亟待解决的技术难题。表面活性剂分子在自组织过程中呈复杂的介尺度结构（表面活性剂聚团），且聚团中表面活性剂分子的疏水端朝向油、亲水端朝向水以降低界面张力。认识并调控这种结构是指导驱油用表面活性剂分子设计的关键。本项目针对材料及表界面层次的介尺度结构，通过分析表面活性剂体系内在的控制机制间的协调来确定体系的稳定性条件，明确表面活性剂分子结构同聚团结构和理化性质间的关系；然后通过大规模并行计算和相关实验测试，建立并验证胶束的介尺度模型；进而将介尺度模型与格子玻尔兹曼模型计算耦合，对表面活性剂–油–水–固体系进行三维动态模拟，探索介尺度结构与驱油能力二者之间的关系,以指导驱油用表面活性剂的分子设计。

本项目通过实验和模拟的紧密结合，通过调控油-水-表面活性剂体系中的介尺度结构，回答了油藏强化开采中采用何种表面活性剂能实现较大幅度提高原油采收率的问题。实验研制新型高性能阴非离子表面活性剂和阴阳离子表面活性剂协同增效体系，为分子模拟提供基础数据参考，验证模型的准确性。同时通过分子模拟来研究不同组分间的相互作用机制，给出介尺度结构形成的控制机制，对其性能进行预测。并将乳液体系表界面介尺度结构的动力学模型耦合至反应器介尺度结构的流体力学计算中，准确预测了油-水-表面活性剂体系在流场中的动态结构。本工作共发表论文11篇，（SCI收录5篇），并促成了项目团队同知名石油公司及化工公司的国际合作。