Study On The Performance Of Binary Compound Oil Displacement In North-Three-West Area

After polymer flooding,there is still a large number of remaining oil in the formation, how to fully produced the potential of remaining oil is the current problem needed to solve. Although ASP flooding can be significantly enhanced oil recovery after polymer flooding, the use of alkali not only reduces the viscosity of the polymer, also causes a series of issues such as the formation of clay migration, dispersion, permeability decreasing, oil reservoir and the bottom of well scale, decreasing of produce well fluid production capacity, the shortened of pump inspection period and difficulty of produced water demulsification and dehydration. For binary complex flooding characteristics on North Third West, emulsification properties and interface properties of binary composite system are researched, the adsorption characteristics binary composite system in the Daqing oil sands are studied under the conditions of changing the wettability of oil sands and adsorption times, the effects of polymer concentration, surfactant concentration and slug size on enhanced oil recovery are also discussed.The results showed that: the addition of surfactant increased the stability of the viscosity of the binary system, with reduction of the oil-water ratio and the increasing polymer concentration, the viscosity and stability of emulsion which is composed of compound system and crude oil increases; at higher polymer concentrations, the non-ionic surfactant has good surface activity, the interfacial tension can be reduced to 10-2mN/m and can't be reduced to 10-3mN/m when the concentration of surfactant is varied form 0.05% to 0.3%,the polymer solution before and after shear has an effect on the time of interface equilibrium value, the interface stability of compound system is stable,within90 days to maintain the 10-3mN/m; the adsorption isotherm of surfactant on the Daqing oil sands is the type of"S", the maximum adsorption is 2.43mg/g and the adsorption isotherm of polymer on the Daqing oil sands is the type of"S", the maximum adsorption is 0.888mg/g in binary system, the static adsorption capacity of oil displacement agent in the oil sands which is soaked by the water and polymer are different, the adsorption of surfactant and polymer in the oil sands soaked by water adsorption is minimum, the adsorption of surfactant in oil sands that is not soaked is maximum, the adsorption of polymer in oil sands that is soaked by polymer solution is maximum; the laboratory flooding experiments showed that binary compound system can greatly enhance oil recovery in the homogeneity core.