Interfacial properties of petroleum sulfonate for oil displacement in separation process

Abstract

In order to provide valuable information for the separation process of petroleum sulfonate and the mixing rule of petroleum sulfonate components, the methods of water extraction and column chromatography were used to separate non-sulfonated oil and petroleum sulfonate components, respectively. The effects of oil separation rate, source of crude oil, and composition of petroleum sulfonate on oil–water interfacial tension (IFT) were investigated. The results showed that the oil–water IFT of petroleum sulfonate products for oil displacement was affected by many factors. The presence of a small amount of non-sulfonated oil in petroleum sulfonate had positive synergistic interaction on the reduction of IFT. Reasonable mixture of petroleum sulfonate components with different polarities could avoid chromatographic separation and improve the interfacial activity of products. When the oil separation rate was 70%, the IFT between oil and water was the lowest, which served as a reference for the separation of non-sulfonated oil. Under the same oil displacement conditions, crude oil from different blocks had a greater impact on oil–water IFT. The ultra-low IFT appeared when intermediate petroleum sulfonate and water-soluble petroleum sulfonate were compounded with 3:1.