Application potential of in situ emulsion flooding in the high-temperature and high-salinity reservoir

Abstract

In this research, an emulsifier formulation named SC-18 for W/O system was screened out and evaluated for feasible application of in-situ emulsion flooding in high-temperature and high-salinity reservoir. Results showed that SC-18 could reduce interfacial tension to 10–2 order of magnitude and change rock wettability from oil-wet to water-wet, which was beneficial to decrease residual oil saturation and improve displacement efficiency. Meanwhile, rheological testing showed that emulsion produced by SC-18 exhibited good temperature tolerance and mechanical stability, which favored mobility control and sweep efficiency enhancement under harsh conditions. In addition, good viscoelasticity of produced emulsions could also improve sweep efficiency by strengthening plugging and diverting effects of emulsion droplets, namely enhancing “Jiamin effects.” By means of natural core flooding and visualized plate model, it was proved that in-situ emulsion flooding with SC-18 could improve both displacement efficiency and sweep efficiency for high-temperature and high-salinity reservoir.

Graphical Abstract

Keywords:

• Application potential
• high temperature and high salinity
• in-situ emulsion flooding
• rheological properties
• visualized plate model

Acknowledgments

The authors gratefully acknowledge the support received from the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University.