大庆油田三元复合驱油体系相行为研究

PHASE BEHAVIOUR OF ASP SYSTEM IN DAQING OILFIELD

通过表面活性剂浓度、含盐量、碱、醇等对相态影响研究发现 ,低浓度三元复合体系在合适的pH值和含盐量下 ,与模拟油或原油都可以形成三相。而且与模拟油形成的表面活性剂富集中间相的表面活性剂浓度非常高。这样的三元体系与原油可以形成超低界面张力和中间乳化相。但这种中间混合层不透明 ,为乳白色 ,可以稳定很长时间。通过分析发现中间混合层粒径大部分在 10 0nm以内。粒度分析和冷冻蚀刻透射电镜技术表明 ,中间混合层为胶束、微乳液、乳状液等表面活性剂聚集体共存的结构 ,其中微乳液结构占主要地位。

This paper studies the effect of concentration, salt content, alkali and alcohol of surfactant on phase state and draws a conclusion, i.e., low concentrated ASP flooding system can form 3 phases both with simulated oil and crude oil in the condition of proper pH value and salt content. The surfactant concentration of the surfactant enrichment medium phase formed with simulated oil is higher. Such ASP system can form super low interfacial tension with crude oil and medium emulsified phase. Therefore, this medium mixed phase layer is not transparent but white. It can be stable for a long time. Analysis shows that the grain size of the medium mixed layer is usually within 100nm. Grain size analysis and refrigeration etcher transmission electron microscope technique show that the medium mixed layer is a structure in which the surfactant like micella, microemulsion, emulsion exist simultaneously and microemulsion occupies the main position. This knowledge has a theoretical and practical significance for the understanding of the displacement mechanism of ASP flooding.