I Congreso de Postgrado fcfm: ingeniería, ciencias e innovación

80 Santiago, 10 al 12 de agosto, 2022 SCALING THE IRREVERSIBLE MIXING OF CARBON DIOXIDE IN BRINE-RICH PERMEABLE MEDIA Juvenal A. Letelier 1 *, Hugo N. Ulloa 2 , Julio Leyrer 1, Jaime H. Ortega3 1 Departamento de Ingenierí Civil, Universidad de Chile. Blanco Encalada 2022, Santiago, Chile. ²Department of Earth and Environmental Sciences, University of Pennsylvania, PA, USA. ³Departamento de Ingeniería Matemática, Universidad de Chile. Beauchef 851, Santiago, Chile. *Email: juvenal.letelier@uchile.cl ABSTRACT The supercritical CO2 injection and dissolution into deep brine aquifers allow its sequestration within geological formations. After its injection, CO2 is placed over the denser brine in an apparent gravitational stable distribution. However, mixing CO2 and brine leads to a cabbeling-like process, i.e., the resulting mixture is even denser than the pure brine. Here, we investigate the f luid dynamics of CO2 sequestration in underground brines at a laboratory scale utilising the Hele-Shaw model [1]. At this scale, the CO2 -brinemixture densitymeets a non-linear misciblemodel ( w ), with w the CO2 mass fraction. We performed direct numerical simulations to quantify the irreversible mixing of CO2 in brines, recovering experimental results in porous media [2,3]. More remarkably, for the Hele-Shaw model, we found that the mean scalar dissipation rate, scalar , depends on the Rayleigh number, , a novel result not predicted by previous works. The results show that the dissolved CO2 mass f lux, characterised by the Sherwood number, ℎ , satisfies the scaling law ℎ ∼ scalar within the time window between the onset of convection and the arrival of the first megaplume at the Hele-Shaw cell bottom. This work sheds light on the f luid dynamics, the irreversible mixing and trapping of CO2 into geological reservoirs. ACKNOWLEDGMENT This research was partially supported by the supercomputing infrastructure of the National Laboratory High Performance Computing NLHPC (ECM-02). REFERENCES [1] J. A. Letelier, N. Mujica, J. H. Ortega, J. Fluid Mech. 864 , 746-767 (2019) [2] J. A. Neufeld, M. A. Hesse, A. Riaz, M. A. Hallworth, H. A. Tchelepi, H. E. Huppert, Geophys. Res. Lett. 37 , 22 (2010) [3] R. Guo, H. Sun, Q. Zhao, Z. Li, Y. Liu, C. Chen, Geophys. Res. Lett. 48 , 23 (2021) F Í S I CA Y A S T ROF Í S I CA 05