Role of water-soluble polymer on foam-injection process for enhancing oil recovery

Abstract Role of polymer on foam transportation in porous media is still not entirely illustrated. In this study, we performed the foam injection process in cores and the parallel-layered micromodel, respectively. Combined with a series of static investigations, we found that adding polymer to foam could not only effectively generate a viscous force, but also create a protective enclosure around the bubble (i.e., viscoelastic film). This synergistic effect was supposed to increase the foam apparent viscosity, promote the foam strength in the low-quality regime, create the shear-thickening behavior, and restraint the defoaming effect of crude oil. The microflow experiments indicated that polymer-enhanced foam was capable of sharply increasing the sweep efficiency and EOR. Meanwhile, the presence of viscoelastic liquid films contributed to the microflow behaviors.