| ASP flooding appear many problems, especially alkali lead to bad effect, so we must effort study on no alkali system. Surfactant/polymer flooding become a new flooding means, which can furthest exert viscoelasticity of polymer, decrease effect of emulsion and make a clean sweep of encrustation of stratum and mineshaft due to being alkali.In this paper several dozen kinds of surfactants were screened for the polymer/surfactant (PS) system. The non-ionic surfactant SNS-1 carbonxylate SNS-1 are chosen and researched in detail. The effects of surfactant concentration, polymer concentration, salinity, temperature on interfacial tension were studied. Adsorption of surfactants on the Daqing oil sand and oil displacement efficiency of two PS systems are also studied.The results show: 1.The interface tension of SNS-1 system can reach 10-2mN/m. The concentration of polymer influences the time to reach the balance value. But the effect is not obvious when the concentration of polymer is smaller than 1000 mg/L. When the temperature is varied from 45℃to 50℃, the interfacial tension reduces with the increasing of temperature.2.The adsorption value of SNS-1 is 1.0 mg/g oil sand. 3.After PS flooding the rock water wettability is strengthen. The degree of wettability increases with the increasing of polymer or surfactant concentration.4. Emulsion of PS system and oil is instability, emulsion contain about 30% water at change type spot of emulsion 5.The recovery of SNS-lsystem is near to ASP system when the cost of chemistry is equal. When the concentration of polymer is 1500 mg/L, the recovery of PS flooding is higher than ASP flooding.6. Optimize duality preflush PS slug can preventing ASP emulsification.7.The mechanism of PS flooding is summarized out. Besides reducing interfacial tension to increase the displacemnt efficiency and polymer increase the sweep efficiency coefficient, the elasticity of polymer also can increase the displacement efficiency.
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