This paper explores the feasibility of foam flooding for high-temperature and high-salinity reservoir in Tahe Oilfield to improve the oil recovery. The foaming agent was selected by means of Ross-Miles method with the evaluation indexes of foam comprehensive value, and its stability, surface/interfacial tension and foaming properties under high temperature and high pressure were evaluated. Its stratum adaptability and oil displacement efficiency were also evaluated. The results indicate that under the hightemperature and high-salinity conditions in Tahe Oilfield, the optimal foaming agent was amphoteric surfactant HTS-1, which had satisfactory stability and reduced the oil-water interfacial tension to 10^-1 mN/m. It has improved foaming and foam stability at high temperature and high pressure, and the higher the pressure, the better the foam stability. Single core experiment demonstrated that foam flooding has wide stratum adaptability, and the foam plugging performance will be improved with the increase of permeability and be reduced over a certain permeability. Oil displacement experiments show that foam can plug the high-permeability layer, leading to fluid diverting and higher oil displacement efficiency, and increase water flooding recovery by 17%.

Tahe Oilfield  /  high temperature and high salinity  /  high hardness  /  foaming agent  /  improved oil recovery