Geological storage of CO2 in subsurface saline aquifers is a promising way to reduce CO2 emissions. During this process, CO2 first dissolves into pure brine, forming an acidic and denser mixture that falls down under the gravity and reacts with the rock [1, 2]. From the fundamental science point of view, the above process is indeed flow and reactive transport processes in porous media.
Pore-scale studies on the density-driven flows with heterogeneous chemical reactions are con- ducted numerically in the present work based on the lattice Boltzmann method . The main objective is to investigate the effect of chemical reactions on the interfacial instabilities. Rayleigh-Taylor instability caused by the density contrast between the incoming and displaced fluids is observed in the simulations of pure density-driven flows (without chemical reactions) for both two- and three-dimensional porous media, which agrees well with the previous experimental and theoretical studies . In addition, density-driven flows with heterogeneous chemical reactions are further simulated. The results indicate that heterogeneous chemical reactions at the fluid-solid interface can suppress the gravitational instability. Considering that the chemical reactions can consume the CO2 in the incoming fluids, which reduces the density of the incoming fluids, Rayleigh-Taylor instability caused by the density ratio will be suppressed by the reactions. The overall instability in this system depends on the competition between the density contrast and the chemical reaction rate at the fluid-solid interface.
 L. T. Ritchie, and D. Pritchard. Natural convection and the evolution of a reactive porous medium. Journal of Fluid Mechanics, 673: 286-317 (2011).
 S. S. S Cardoso, and J. T. H. Andres. Geochemistry of silicate-rich rocks can curtail spreading of carbon dioxide in subsurface aquifers. Nature Communications, 5: 5743 (2014).
 X. H. Meng, and Z. L. Guo. Multiple-relaxation-time lattice Boltzmann model for incompress- ible miscible flow with large viscosity ratio and high P ́eclet number. Physical Review E, 92: 043305 (2015).
 J. Fernandez, P. Kurowski, P. Petitjeans and E. Meiburg. Density-driven unstable flows of miscible fluids in a Hele-Shaw cell. Journal of Fluid Mechanics, 451: 239-260 (2002).
|Acceptance of Terms and Conditions||Click here to agree|