Potential application of dispersed particle gel strengthened alkali as a novel combination flooding system for enhanced oil recovery

Abstract

A novel dispersed particle gel strengthened alkali (DPGSA) combination flooding system was proposed for enhanced oil recovery in high water cut mature oilfields. When crude oil and the alkali in the DPGSA combined flooding system interact, petroleum soap is produced, causing a lowering of the interfacial tension (IFT). It can reverse the oil-wetted rock surface to a water-wetted rock surface. The dispersed particle gel (DPG) has viscosity, and the particles are less affected by alkali, temperature, and aging time. Additionally, DPG can strengthen the mobility control ability through single particle expansion and micro coalescence of multiple particles at a specific temperature. Compared with the alkali and polymer/alkali (PA) flooding system, the DPGSA combination flooding system has better viscosity retention and mobility control ability. Based on the sand-pack flow experiment, the DPGSA combination flooding system has good injectability and profile improvement ability. The dispersed particle gels plug the macropore throats through adsorption and bridging. Through the synergistic effect of reducing IFT and increasing swept volume, the DPGSA combination flooding system also shows excellent performance in EOR. The DPGSA combination flooding system is better than the alkali and polymer/alkali (PA) combination flooding system. It can be used as a new alternative to enhance oil recovery in high water cut and highly heterogeneous mature oilfields.