Effect of PH and Slug Ratio

The injection of water and gas alternatively offers better mobility control and hence improves the volumetric sweep efficiency. Although the WAG process is conceptually sound, its field incremental recovery is disappointing as it rarely exceeds 5 to 10% OOIP. Apart from operational problem, the WAG processes suffer from inherent challenges such as water blocking, gravity segregation, mobility control in high viscous oils. This study seeks to address these mentioned problems and propose a new combination method named as ASP alternating Gas. The unique feature of this method is, it uses alkaline, surfactant, and polymer as a chemical slug that is injected during the WAG process to improve the mobility ratio and decrease the interfacial tension (IFT). Essentially this process involves a combination of chemical flooding and immiscible carbon dioxide (CO2) injection these mechanisms are IFT reduction, reducing water blocking effect, mobility control, oil viscosity reduction due to CO2 dissolution and oil swelling. The experiment was conducted at laboratory conditions to determine the effect of pH and slug ratio on alternating ASP with Gas.