关键词: 纳米乳液, 甜菜碱, 界面张力, 降压增注

Abstract:

To solve the problems of high injection pressure and low injection efficiency during the process of water flooding, three nanoemulsion systems（S-S12, S-S16, and S-C16）for pressure reduction and injection stimulation were developed. Their stability, particle size morphology, interfacial tension, wetting ability, stripping ability, and performance of reducing pressure and increasing injection were evaluated. Laboratory evaluation results showed that all the three nanoemulsion systems had good stability, nano-sized droplets（all less than 350 nm）, and low oil-water interfacial tension. Among them, the interfacial tension between 0.1% S-S16 nanoemulsion and crude oil reached an ultra-low level, which changed the wettability of the core surface from lipophilic to weakly hydrophilic. It was also the best one for stripping crude oil, leading to a 48% reduction in carbon content. In addition, the injection of S-S16 nanoemulsion system after water flooding in natural cores could lead to a 78.70% reduction in the replacement pressure, which achieved efficient performance in pressure reduction and injection stimulation.

Key words: nanoemulsion, betaine, interfacial tension, pressure reduction and injection stimulation