Abstract: The alkali-surfactant-polymer (ASP) flooding is becoming the dominant recovery technology in Daqing oilfield. In order to recommend the feasible type of ASP flooding, the ASP flooding with weak base is compared with the ASP flooding with strong base. The results show that the oil recovery by the weak-base ASP flooding process is over 20% higher than water flooding process, which is comparable with that by the strong-base ASP flooding one. Both of ASP flooding processes have the same emulsion viscosity of over 100 mPa·s, but the emulsification of weak-base one is a little better than that of strong-base one. In addition, the former has the advantage of the latter in the injection-production capacity and recovery rate. In particular, the scaling tendency of the former is weaker than that of the latter, with little effect on production wells. Therefore, the ASP flooding with weak base should be selected as a candidate for the process in expanding application.

Key words: Daqing oilfield, ASP, alkali, recovery rate, emulsification, scaling