Research On The Effect Of Recovery Of Weak Base Asp Flooding In Sazhong ClassⅡoil Layer

At persent, ASP flooding has been the dominant recovery technology in Daqing oilfield. ASP flooding include strong base ASP flooding and weak base ASP flooding. Weak base ASP flooding is gaining increasing attention because of the damage and scaling of formation. Therefore, the research of weak ASP flooding on recovery factor has a guiding significance for further development of oilfield.In this paper, based on the summary of classⅡoil layer characteristics, the influence of weak base ASP system on pore structure of classⅡoil layer is analyed; the influence factors of coil dimesion of weak base ASP system molecular、resistance coefficient and residual coefficient are stuied. The adaption of classⅡ oil layer permeability to weak base ASP system is gived. The migration and startup of weak base ASP system on residual oil and the influence factors of recovery are summaried.The results show that: the corrosion of weak base ASP system on the pore of classⅡ oil layer is not strong. But the corrosion will be stronger with alkali concentration increasing. Molecular weight and concentration of polymer in weak base ASP system will both have an effect on resistance coefficient and residual resistance coefficient. And the value of resistance coefficient and residual resistance coefficient will be lager with polymer molecular weight and concentration increasing. On the basis of injection ability judgement standard, the adaption of classⅡ oil layer permeability to weak base ASP system can be obtained. The residual oil will start up and move by the means of emulsification oil threadiness. Homogenizing alkali and surfactant will increase chemical flooding recovery. In the experiment of two parallel pore, chemical flooding recovery will be lager with injection slug viscosity decreasing.