LAUSR

Foam flooding is an important method to enhance oil recovery after water flooding. In this paper, a novel low interfacial tension (LIFT) nitrogen foam was successfully prepared by an amphoteric surfactant and sodium formate. It has good foaming ability and can reduce interfacial tension to a low interfacial tension level (10–1 mN/m order of magnitude) in high-temperature (90 °C) and high-salinity (183 g/L salinity) reservoirs. The influence of surfactant concentration, organic bases concentration, and aging on the performances of the LIFT foam system has been systematically studied through the modified Ross-Miles experiment. Furthermore, the foam displacement in flat-panel sand model and etched-glass micromodels were conducted to investigate the foam displacement mechanisms for enhanced oil recovery. The results of flat-panel sand model experiment showed that the LIFT foam could block high permeability channels and divert following injection fluid to adjacent low permeability areas efficiently. Meanwhile,...