Sequestration of CO 2 and other associated waste gases in natural gas reservoirs is an option to mitigate greenhouse gases and enhanced gas recovery. This paper examines strategies to maximize enhanced gas recovery in a natural gas reservoir via subsurface storage of potential associated waste gases such as CO 2 and H 2 S. Numerical simulations are performed with a compositional reservoir simulator 'Tempest' using experimental data initially produced by Clean Gas Technology Australia (CGTA) at

more »

... urtin University in 2009. The simulation results shows that additional gas is recovered by gas-gas displacement after injecting CO 2 and acid gas (CO 2 -H 2 S) in two separate scenarios. Importantly, when pure CO 2 is injected, CO 2 breakthrough at the production well occurred faster than the breakthrough under mixed CO 2 -H 2 S injection.