Distribution of injected CO2 in a stratified saline reservoir accounting for coupled wellbore‐reservoir flow

Abstract Geological storage in sedimentary basins is considered a viable technology in mitigating atmospheric CO 2 emissions. Alternating high and low permeability strata are common in these basins. The distribution of injected CO 2 among such layers affects e.g. CO 2 storage efficiency, capacity and plume footprint. A numerical study on the distribution of injected CO 2 into a multi‐layered reservoir, accounting for coupled wellbore‐reservoir flow, was carried out using the T2Well/ECO2N code. A site‐specific case as well as a more general case were considered. Properties and processes governing the distribution of sequestrated CO 2 were identified and the potential to operationally modify the distribution was investigated. The distribution of CO 2 was seen to differ from that of injected water, i.e. it was not proportional to the transmissivity of the layers. The results indicate that caution should be taken when performing numerical simulations of CO 2 injection into layered formations. Ignoring coupled wellbore‐reservoir flow and instead adopting a simple boundary condition at the injection well, such as an inflow rate proportional to the transmissivity of each layer, may result in significant underestimation of the proportion of CO 2 ending up in the shallower layers, as not all relevant processes are accounted for. This discrepancy has been thoroughly investigated and quantified for several CO 2 sequestration scenarios.