Research on Basic Properties of Alkali-Surfactant-Polymer Flooding Produced Water and Influence of Oil-Displacing Agent on Settlement

The basic properties of alkali‒surfactant‒polymer (ASP) flooding produced water and effect of oil displacing agent on the stability of flooding produced water were obtained, through measuring and analysing water quality, oil content-settling time relationship and oil displacing agent-oil droplet size relationship of Zhong-106, Zhong-312, Zhong-417, Nan 4-8 and Bei 2-7 flooding produced water from Daqing Oilfield. The addition of ternary oil displacement agent to ASP flooding produced water greatly increases the difficulty of oil-water separation, and higher the concentration, worse the separation effect after standing. The effects of alkali, surfactant, and polymer on oil-water stability in simulated ASP flooding produced water were studied respectively. The ASP flooding produced water after 48 hours of settling formed a trace amount of nano-oil droplets, also accompanied by the accumulation and separation of a part of the oil droplets.