Gemini表面活性剂对原油-水界面性质的影响

Crude oil-water interface is complex of its components, relating to oil-displacement efficiency of bi-component combination/ASP flooding, the stability of air foam flooding, the change in wettability of crude oil-rock interface, the effectiveness in emulsifing crude oil and breaking of emulsion, which is of important theoretical and practical significance in enhancing oil recovery. As a new generation of surfactants, Gemini surfactant has decisive impact on the property of crude oil-water interface, but there is still lack of systematic research in this area. According to different reservoir and composition of crude oil, static and dynamic interfacial tension and interfacial dilational rheology are introduced to investigate three serious of Gemini surfactants such as ①sulfonate surfactants (anionic type), ②CnN2NCn (nonionic type) and ③Di-CnPh (nonionic type, gemini surfactants with heterocyclic group), which are now commonly used in oil recovery. Gemini surfactants are studied on the influence on properties of crude oil-water interface in the aspect of the nature of the charge, molecular structure (heterocyclic structure, alkyl chain length) and environmental factors (pH, temperature, electrolyte concentration), which could reveal the ability of gemini surfactant to stabilize the oil-water interface and membrane rupture mechanism from the molecular level, build gemini surfactant molecular model for efficient emulsification and demulsification according to a similar compatible principle, form quantitative oil displacement by molecular design theory, lay a foundation for the description of the process of flooding on macro, prediction and optimization of oil recovery.

原油-水界面是一类成分复杂，且关乎二元/三元复合驱的驱油效率、空气泡沫驱的稳定性、原油-岩石表面润湿性的转变以及原油分散系统高效乳化和破乳的核心问题，其性质研究对提高石油采收率具有重要的理论和现实指导意义。Gemini表面活性剂作为新一代驱油剂，对于改变原油-水界面性质具有决定性影响，但目前尚缺乏此方面的系统研究。本课题将针对不同油藏和组成的原油，系统分析油田上常用的三类gemini表面活性剂：①磺酸盐型(阴离子型)；②CnN2NCn(非离子型)和③Di-CnPh(含杂环亲水头基)在电荷性质、分子结构和环境影响因素等方面对原油-水界面性质的影响，从分子水平揭示gemini分子对于原油-水界面膜的稳定和破裂机制，根据相似相容原理构建高效乳化和破乳的驱油用gemini分子模型，形成定量化驱油用分子设计理论，宏观上为驱油过程的描述、预测和优化采油奠定基础。

结合不同油藏原油在物化性质和化学成分方面的差异，系统分析了油田上常用的三类gemini表面活性剂：磺酸盐型、非离子型和含杂环亲水头基型在电荷性质、分子结构和环境因素等方面对原油-水界面膜、流变性质和聚集形貌的影响，从微观角度研究了gemini表面活性剂分子对于原油-水界面膜的稳定和破裂机制，建立了gemini表面活性剂的结构-性质关系，为新型gemini表面活性剂的开发提供了理论指导，且宏观上为驱油过程的描述、预测和优化采油奠定了基础。