Physical Simulation of Water Alternation Gas Technology at the Heavy Oil Carbonate Reservoir Conditions

Laboratory simulation results of water alternative gas (WAG) processes under the heavy oil carbonate (viscosity equals to 316 cP) and terrigenous (viscosity equals to 439 cP) reservoir conditions are reported. Dependences of reservoir fluid viscosity, density, gas-oil ratio and reservoir volume factor on pumped gas-to-liquid ratio and the dynamics of major oil displacement characteristics (including displacement efficiency, residual oil saturation, displacement pressure gradient, gas and water breakthrough rates etc.) were received. Researches were conducted close to the geological and physical reservoir characteristics, using linear physical models of oilfields composed from native core samples and recombined oil samples; produced water and recombined samples of associated gas were taken as displacement agents. Summary - After the dissolving of pumped gas in reservoir oil viscosity of reservoir fluid reduces more than four times, oil density reduces as well, volume factor and gas-oil ratio increases; - Displacement efficiencies for Bashkir and Bobrikov deposits while water alternative gas were estimated as 65.4% and 73.3% respectively, 33% and 21.1% up as compared to traditional water injection; WAG has additional environmental and associated gas utilization benefits.