Numerical Investigation of Multi-layer CO2 Injection in Deep Saline Aquifers with Improperly Abandoned Wells

Single-layer and multi-layer CO2 injection scenarios in idealized three-aquifer-two-aquitard systems have been numerically investigated. The investigation also assesses the impact of an improperly abandoned leaky well in the vicinity of the injection zone for both injection strategies. It is found that the maximum pressure buildups in multi-layer CO2 injection cases are significantly less than that predicted in the corresponding single-layer CO2 injection cases. Additionally, focused CO2 leakage rates in multi-layer injection cases are found to be highly dependent on the thickness of the separating aquitard, which influences the mutual interference of the active-injection aquifers.