The oil recovery during the initial 2 PVs FW in core B31 was 45% of the OOIP. The same oil recovery (0.2% less) was observed in B35, while it was 44.1% in core B45 and 44.3% in core B47 (Figs. ). The pressure change across the cores was nearly the same with the pressure increasing from 0 psi to 5-6 psi. Similarly, the oil recovery was nearly the same in the first cycle of foam (0.5 PV SS + 0.5 PV CO2) in all four cores used in this section due to the identical properties of the Berea sandstone core plugs and the conditions applied in all experiments. The oil recovery for the first foam cycle was 6, 6.2, 6.3, 6.16% OOIP for cores B31, B35, B45, and B47, respectively (Figs. ). After 1 PV of foam was injected, 0.5 PV of SW was injected behind the foam, which provided an additional 3%