Performance and optimization of biological and chemical composite flooding system for enhanced oil recovery

Abstract

Biological and chemical compound flooding systems have excellent performance and broad application prospects in enhanced oil recovery. In this study, the most efficient and environmentally friendly type of bio-chemical compound alkaline-surfactant-polymer (ASP) flooding system, namely the ASP-PST85, is constructed with Na2CO3, petroleum sulfonate (NPS), biosurfactant surfactin, polyacrylamide, and Tween-85. The interfacial activity, dilution stability, adsorption stability, aging stability, temperature stability, and emulsification property of the ASP-PST85 system are evaluated. The results show that the range of interfacial tension of 10−4 mN/m between the ASP-PST85 system and crude oil is significantly expanded compared to that of the original ASP system, which is referred to as the ASP-PS system. Simultaneously, the emulsion and adsorption stability are also significantly improved. The microfluidic measurement results show that the ASP-PST85 system reaches the saturated adsorption of surfactant at the oil-water interface faster than the ASP-PS system, probably due to its higher emulsion stability. This study provides a reference for the construction of high-performance and bio-chemical compound flooding systems, providing a theoretical and methodological basis to obtain basic data of rapid adsorption kinetics at the oil-water interface.