REV-Scale study of miscible density-driven convection in porous media

Abstract

Miscible density-driven convection in porous media has important implications for the long-term security of geological ${\text{CO}}_2$ sequestration. In this study, a REV-scale lattice Boltzmann equation method based on the generalized Navier–Stokes equations was used to simulate density-driven convection in porous media, Thus, the effects of the Rayleigh number, the Darcy number, the Schmidt number, and the porosity of porous media can be discussed separately. The results show that density-driven convection only occurs when the Rayleigh–Darcy–Schmidt number ${\text{Ra}}_{\text{D-S}}$ exceeds $10^2$. The larger the Ra, the more disordered the concentration field, the earlier the convective phenomenon begins, and the more significant the convective mixing; The larger the Da, the finer the generated fingers. These findings provide important insights for the development of geological sequestration technologies.