Investigation into the effect of polymer microspheres (PMs) on oil-water relative permeability and oil-in-water emulsion stability for enhanced oil recovery

Abstract

A new gel particle named pore-scale polymer microspheres (PMs) has been considered as an effective chemical enhanced oil recovery (EOR) agent used for conformance control. But how to achieve deep profile control of PMs remains some problems. This work aimed at investigating the effect of PMs on oil-water relative permeability and oil-in-water emulsion stability. The results indicated that as PMs diameter matched well with pore-throats size, the PMs could exhibit a superior dynamic migration and plugging performance in the core; in this scenario, in the course of PMs flooding and subsequent water flooding, water phase permeability fluctuated obviously, and oil phase permeability increased and then decreased. Additionally, it was observed that the PMs could reduce the negative influence of elevated mobility ratio caused by the increment in oil viscosity to promote oil seepage. The zeta potential results indicated that the PMs facilitated enhancing oil-in-water emulsion stability, predominantly as a result of the increase of electrostatic repulsion between oil droplets, and deceleration of floating and convergence of oil droplets.