Experimental Study on Gas Reservoir Pore Pressure Changes During Natural Gas Recovery and CO2 Storage in Porous Medium

Abstract

Much research has been conducted to determine the impact of gas injection settings on residual natural gas recovery and CO2 sequestration. However, little research has been conducted on how reservoir pore pressure varies during natural gas displacement by CO2 flooding. Using a core flooding experiment, this article examined the effects of gas injections on reservoir pore pressure and compression ratio. A core flooding experiment was done at 30-40 °C and 1500 psig to investigate the effect of gas injections on reservoir pore pressure and compression ratio. The CO2 injection rate and N2 booster volume were adjusted to 0.2-1.2 ml/min and 8-36 cm3, respectively. Because of the turbulence effect, high mean interstitial velocity raises the molecular kinetic energy of the gas species, which subsequently influences the molecular agitation of the gas species and so alleviates reservoir pressure and gas compression. The typical CO2 injection experiments revealed substantial compression and pore pressure rises as the injection rate increased. The trial with N2 as a booster resulted in a steady increase, which explains their low dispersion coefficient value. As a result, there is less gas mixing and compression compared with typical CO2 flooding.