In the process of the tertiary recovery of oil and gas resources, it is necessary to use external fluids to displace the crude oil in the reservoir. Whether the crude oil on the surface of the rock can be effectively displaced and the wettability of the rock can be changed to avoid re-adsorption by the crude oil is directly related to the level of oil recovery. Therefore, it is critical to study the cleaning and wettability reversal of reservoir rock surface. Because microemulsions have outstanding performance in changing the wettability of rocks and solubilizing crude oil, this paper uses cetyl trimethyl ammonium bromide (CTAB) as a surfactant and n-butanol as a co-surfactant to prepare microemulsions. The performance of microemulsions with different microstructures on the cleaning and wettability changes of crude oil on the rock surface were studied. The results show that the water-in-oil (W/O) microemulsion has good cleaning efficiency, and the oil removal rate on the sandstone core surface can reach 79.65%. In terms of changing the wettability of the rock surface, W/O, bi-continuous phase (B.C.) and oil-in-water (O/W) microemulsions can change the core surface from lipophilic to hydrophilic. And the effects of the B.C. and O/W microemulsions are more obvious. The microemulsion system that was prepared based on cationic surfactants has a good application prospect in changing the wettability of the reservoir and cleaning the adsorbed crude oil.

中文翻译：

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通过表面活性剂稳定的微乳液逆转储层岩石表面的润湿性

在油气资源三次采油过程中，需要利用外部流体驱替储层中的原油。能否有效驱替岩石表面的原油，改变岩石的润湿性，避免被原油重新吸附，直接关系到采收率的高低。因此，研究储集岩表面的清洁和润湿性反转至关重要。由于微乳液在改变岩石润湿性和增溶原油方面具有突出的性能，本文采用十六烷基三甲基溴化铵（CTAB）作为表面活性剂，-丁醇作为辅助表面活性剂制备微乳液。研究了不同微观结构的微乳液对岩石表面原油的清洁和润湿性变化的影响。结果表明，油包水（W/O）微乳液具有良好的清洗效率，砂岩岩心表面除油率可达79.65%。在改变岩石表面的润湿性方面，W/O、双连续相（BC）和水包油（O/W）微乳液可以将岩心表面从亲油性改变为亲水性。并且BC和O/W微乳液的效果更加明显。基于阳离子表面活性剂制备的微乳液体系在改变油藏润湿性和净化吸附原油方面具有良好的应用前景。