Study On Properties Of Produced Liquid From ASP Flooding And Optimal Design Of Oil-water Separator

The ASP (Alkali/Surfactant/Polymer) flooding is a potential flooding technology after water flooding and polymer flooding processes. It can greatly enhance oil recovery by increasing the swept efficiency and displacing efficiency and has long been proved important and effective by in situ experiments. But produced liquid from ASP flooding has high water content at present and it is more difficult to treat because of the emulsification of residual chemical.In this paper, the properties of produced liquid from ASP flooding are studied systematically and then separator is optimized in order to realize the oil-water separation. The research indicates that:(1) The viscosity of oil phase and water phase decrease with increasing temperature and they decrease with increasing the shear rate, but shear rate has little effect on viscosity above certain temperature.(2) The shear stress of the water phase and oil phase increase with increasing the shear rate and they reduce with increasing the temperature.(3) Interfacial rheology of produced liquid is effected by alkali,surfactant and polymer. With all the three chemicals in the liquid, interfacial rheology increases and interfacial tension decreases with increasing the content of chemicals.(4) Interfacial rheology is one of the ways to measure the demulsifiers.Based on systematical study on properties of ASP produced liquid, novel coalescent packing is developed. Internal parts of oil-water separator and operation conditions are optimized with the in situ experiments. Results show that separation efficiency depends decreasingly on packing length, packing type, inlet part and steady-flow plate. Oil concentration in discharged water reduces to 800mg.L-1 and water content in oil is below 15%, which is up to the separation standard of ASP produced liquid.Analysis of oil droplets distribution shows that most of the oil droplets distribute during 1μm to 10μm in the water phase and average diameter is about 6μm.The separator can remove the oil droplet whose diameter is bigger than 36μm. Compared to the previous separators, this new separator fits the ASP produced liquid better.