Homogenization of Dissolution and Enhanced Precipitation Induced by Bubbles in Multiphase Flow Systems

Multiphase flow is ubiquitous in subsurface energy applications and natural processes, such as oil recovery, CO2 sequestration, and water flow in soils. Despite its importance, we still lack a thorough understanding of the coupling of multiphase flow and reaction of transported fluids with the confining media, including rock dissolution and mineral precipitation. Through the use of geomaterial microfluidic flow experiments and high-performance computer simulations, we identify key pore-scale mechanisms that control this coupling. We compare the reactivity of fractured limestone with CO2-saturated brine (single phase) and a mixture of supercritical (sc) CO2 and CO2-saturated brine (multiphase). We find that the presence of scCO(2) bubbles significantly changes both the flow dynamics and the resulting reaction patterns from a single-phase system, spatially homogenizing the rock dissolution. In addition, bubbles redirect oversaturated fluid into low-velocity regions, thereby enhancing carbonate precipitation occurs.