Volume 62

Experimental Study on Optimization of Polymer-Surfactant Binary Chemical Systems for Enhancing Waterflood Oil Recovery Jian LI , Yiqiang LI

Abstract

In the late stage of waterflood development in oilfields, a significant amount of residual oil remains trapped due to factors such as limited sweep volume, increased heterogeneity, and elevated water cut. The use of chemical agents to improve waterflooding can effectively mobilize residual oil and enhance oil recovery. This research optimized chemical systems for enhanced water flooding through microvisual core oil displacement experiments. The results showed that: under the water-wet film displacement mode, an emulsified polymer-surfactant binary system with 0.01% polymer and 0.3% sodium dodecylbenzene sulfonate achieved a recovery rate of 72.68%; under the water-wet cluster displacement mode, a low-interfacial tension polymer-surfactant binary system with 0.01% polymer and 0.3% oleic acid amidopropyl betaine solution achieved a recovery rate of 59.21%; under the oil-wet film displacement mode, a low-interfacial tension polymer-surfactant binary system with 0.01% polymer and 0.3% oleic acid amidopropyl betaine solution achieved a recovery rate of 79.23%; and under the oil-wet cluster displacement mode, a low-interfacial tension polymer-surfactant binary system with 0.01% polymer and 0.3% oleic acid amidopropyl betaine solution achieved a recovery rate of 70.06%. These results identified four displacement modes for improved waterflooding with optimized polymer-surfactant binary chemical systems, providing new insights into enhancing oil recovery in the late stages of waterflooding.

Keywords Enhanced Oil Recovery, Waterflooding Development, Improved Water Drive, Binary Chemical System, Core Flooding