Pore-scale modelling of subsurface biomineralization for carbon mineral storage

This work is framed within the topic of microbially enhanced carbon mineralization: biological catalysts are utilized to alter reaction rates and enhance carbon mineralization in the context of CO2 storage in highly reactive minerals formations. We propose a micro -continuum Eulerian formulation of coupled flow and biogeochemical reactive transport at the pore -scale, in which the reactive transport model is fully coupled with a biomass -nutrient growth model treated with Monod's equation. In order to assess the role of biological catalysts in enhancing carbon mineralization, we then present simulations results and sensitivity studies of an application case of carbon mineralization in an idealized porous geometry with and without biomass growth at conditions relevant to CO2 storage in ultramafic rocks. Results clearly highlight the role of the biomass in enhancing the pH of the aqueous solution, a process called bioalkalinization, thereby leading in a highly non-linear way to enhanced calcite precipitation, resulting in an interesting potential methodology for CO2 immobilization.