Effects of Nanoparticles on Gas Production, Viscosity Reduction, and Foam Formation during Nanofluid Alternating Gas Injection in Low and High Permeable Carbonate Reservoirs

Application of enhanced recovery methods to decrease residual oil saturation is the main challenge in some carbonate reservoirs which are low-permeable and mixed-wet to oil-wet. To enhance the performance of the water alternating gas (WAG) injection method the wettability of rock should be changed and mobility of the injected gas should be controlled through adding nanoparticles (NWAG) to the aqueous phase. Core-flooding experiments dynamic foam generation and viscosity measurement were performed to investigate the effect of nanoparticles on gas production viscosity reduction and possibility of foam formation in the NWAG process. The results indicated that the gas production was decreased and the viscosity of produced oil was lower in the NWAG process. CO₂dissolved in the oil and led to oil swelling and oil viscosity reduction. Oil recovery was higher in the samples with lower permeability due to the formation of foam in the porous media. Foam formation increased viscosity and controlled mobility which led to better sweep efficiency.