DISSOLUTION OF CARBON DIOXIDE IN DEEP AQUIFERS

Abstract

As the emergency of cutting back CO2 emissions intensifies within an overwhelming climate change context, one engineering solution that could significantly contributes is the underground trapping of carbon dioxide emitted from plants into deep aquifers. It would constitute an enhanced recovery scheme as it would naturally refill Earth fossil fuel reserves. In this report, simulations on different reservoirs modeled by Rayleigh numbers of 100, 250, 1000 and 2500 have been conducted and solved on COMSOL. The main purpose is to analyze how the dissolution of carbon dioxide into pure brine evolves through particular fluid mechanisms occurring at studied Ra. Those results on dissolution are used to build up some general parametrizations to make viable predictions on any potential reservoir storage capacity without any prior expensive simulations. Obtained results are first compared to literature references. Differences shed light on the significant influence of the choice of solver settings on simulation results. Those data are afterwards approximated into different law powers, which make dissolution regimes easier to spot. Post-processing highlights a dependence of the onset time of convection τ_c in Ra^(−2) and a proportional relation between the maximum of the dissolution flux J_max and the Rayleigh number Ra.