纳米颗粒协同阳-非离子Gemini表活剂润湿反转体系的构筑及其机理研究

Oil recoveries are enhanced by wettability alteration, which is an important technique to reduce the pressure and to increase the amount of liquid injection for the medium and low permeability reservoirs. The challenge and difficulty of this technology lie in the establishment of highly efficient wetting reversal system and the study of its mechanism for wettability alteration. For the above-mentioned key issues, a series of cationic-nonionic Gemini surfactant system with the controlled solid-liquid interfacial activity will be established by adjusting the structural parameters of the reaction substrate, which is based on the halogenation and quaternization reactions. Suitable nanoparticles and their concentrations will be optimized and the construction of the wetting reversal system of nanoparticle/cationic-nonionic Gemini surfactant will be achieved. For the ability of wettability alteration of oil-wet sandstone, differences between nanoparticles, cationic-nonionic Gemini surfactants and wetting reversal system will be investigated by spontaneous imbibition experiment and adsorption thermodynamics determination. From the molecular scale, quartz crystal microbalance, atomic force microscopy and molecular dynamics simulation will be used to study the interaction between the wetting reversal system and crude oil component, which is also verified by the above macroscopic and microscopic analysis methods. Thus, the mechanism of synergistic effect between nanoparticles and cationic-nonionic Gemini surfactants in the composite system will be further revealed, which can provide a certain theoretical basis for the development and application of highly efficient wetting reversing agent in oilfield.

润湿性改变是中低渗透油藏降压增注从而提高采收率的重要技术手段。目前，该技术面临的难题在于高效润湿反转体系的建立及其改变润湿性微观机理的研究。本项目针对上述难题，基于卤代化和季铵化反应，通过调节反应底物的结构参数，建立固-液界面活性可控的阳-非离子Gemini表面活性剂体系。优选合适的纳米颗粒，并进而实现对纳米颗粒/阳-非Gemini表面活性剂润湿反转复合体系的构筑。通过岩心自发渗吸实验、吸附热力学测定等，考察纳米颗粒、阳-非Gemini表面活性剂和润湿反转复合体系改变油湿性砂岩表面润湿性能力的差别。采用多种微观分析手段如石英晶体微天平、原子力显微镜及分子动力学模拟的方法，拟从分子尺度上获得复合体系与原油组分之间的相互作用原理，并与上述宏观分析手段相互验证，进一步揭示复合体系中纳米颗粒和阳-非Gemini表面活性剂协同改变润湿性的微观机理，为油田高效润湿反转剂的研发和应用提供一定的理论依据。

润湿性改变是中低渗透油藏降压增注从而提高采收率的重要技术手段。目前，该技术面临的难题在于高效润湿反转体系的建立及其改变润湿性微观机理的研究。本项目针对上述难题，基于卤代化和季铵化反应，通过调节反应底物的结构参数，建立了固-液界面活性可控的阳-非离子Gemini表面活性剂体系。项目制备了一种阳-非离子型Gemini表面活性剂（GABEO），相比其他几种体系来讲，经阳-非离子型Gemini表面活性剂GABEO处理的砂岩表面更加干净，沉积吸附的沥青质层更少一些，很显然在阳-非离子型Gemini表面活性剂GABEO中，阳、非离子两种基团相互起到了协同作用。优选合适的纳米颗粒，并进而实现对纳米颗粒/阳-非Gemini表面活性剂润湿反转复合体系的构筑。构筑了一种阳-非离子Gemini表面活性剂/纳米碳酸钙颗粒活性流体，并且活性流体中的纳米粒子促进了双子表面活性剂和原油的羧酸基形成离子对的过程。通过岩心自发渗吸实验等，考察了纳米颗粒、阳-非Gemini表面活性剂和润湿反转复合体系改变油湿性砂岩表面润湿性能力的差别。采用多种微观分析手段如石英晶体微天平和原子力显微镜，从分子尺度上获得了复合体系与原油组分之间的相互作用原理，并与上述宏观分析手段相互验证，进一步揭示了复合体系中纳米颗粒和阳-非Gemini表面活性剂协同改变润湿性的微观机理，为油田高效润湿反转剂的研发和应用提供一定的理论依据。