Experimental Study on the Migration and Adsorption of Gel Profile Control Agent in Medium-Permeability Sandstone in the Sabei Block of Daqing Oilfield

After a long period of alkali-surfactant-polymer (ASP) flooding, an ASP system channeling was observed in the medium-permeability sandstone reservoir in the Sabei block of Daqing Oilfield, resulting in a decreased recovery. Therefore, it is necessary to improve the effect of ASP flooding with gel profile control agent. In order to further determine the influence of gel profile control agent on the field development effect under ASP flooding and identify its contribution to ultimate recovery, the dynamics of adsorption and residence of the gel profile control agent during its migration in formation were studied. In this study, the concentration of produced liquid components, the viscosity of the system, and the micromorphology of the displacing fluid and quartz sand were tested at each sampling point during the injection of ungelled polymer gel with a sand-filled pipe model (seven sampling points) with a length of 250 cm. The changes in the adsorption volume, adsorption rate, and shear viscosity of the profile control agent on the rock during the migration and those of the micromorphology on the surface of the displacing fluid and quartz sand during adsorption were studied. The results show that during the injection of profile control agents, the cumulative adsorption volume of polymer increases exponentially with the increase of the injection volume, while the dynamic adsorption rate decreases linearly with the increase of the injection volume. In addition, the decrease of dynamic viscosity of profile control agents is caused by viscosity shear and adsorption and residence. This study clarifies the dynamics of adsorption and residence of gel profile control agent in the process of dynamic migration, which is instructive to optimize the system and reasonable selection of implementation technologies, implementation plan, and profile control on field site.