Enhanced Oil Recovery: Potentialities of the WAG injection (Water Alternating Gas)

Abstract

The increase in the recovery factor in an oil reservoir is an essential goal in the oil industry and in this sense, complementary and alternative methodologies have been developed, for example, the alternating injection of water and gas (WAG), which has been used ever as a more advanced method of recovering oil. This method combines the best gas displacement and swept the water efficiencies. Recent discoveries of oil reserves in the Pre-Salt layer, with a significant amount of gas whose CO 2 content is in the range 8-12%, the use of CO 2 gas in WAG injection (WAG-CO 2) has emerged as an opportunity for Brazil. Besides the good prospect of increased oil recovery factor of these reservoirs, this process is in line with mitigation actions by greenhouse emissions CO 2. This article is a compilation of WAG application projects in the literature, as well as issue related to Brazilian initiatives that focuses on numerical simulations using reservoir models, since the carbonate rocks common to the pre-salt reservoirs are reactive the injected fluids.