Descripción del proyecto
Atmospheric CO2 contributes to 2/3 of the Earth’s global warming by greenhouse effect. Storing CO2 in deep geological formations is the main mitigation measure currently available. ExpeCO2SolTrap addresses solubility trapping (ST), a trapping mechanism of CO2 in dissolved form within the resident brine of the subsurface porous medium, which allows storing CO2 perennially by gravity. ST has been studied extensively in the last 10 years. But numerical studies cannot account for the pore scale heterogeneity of the flow, while most experiments cannot provide a full measurement of the system’ evolution (in particular its dissolution flux). Recent ground-breaking experiments by the host group and secondmend group of ExpeCO2SolTrap have shown that the growth of the instability is orders of magnitude faster than that predicted by a Darcy scale numerical simulation of the experimental process, due to coupling beween the gravitatitional instability and the heterogeneity of pore scale flow. This effect has been hitherto ignored in the literature. Furthermore, the impact of Darcy scale heterogeneity has hardly been studied, in particular not experimentally. ExpeCO2SolTrap proposes to (i) extend the experiments developed in the host group and secondment group to allow for pore scale measurement of fluid velocities three-dimensional (3D) granular porous media, in order to fully understand the aforementioned coupling, and (ii) to study the impact of Darcy scale (e.g., permeability/porosity) heterogeneity of the medium experimentally in granular porous media as well as in 3D-printed porous media of controlled heterogeneity. Two experiments, both relying on refractive index matching of the flowing liquid to the solid phase, but using respectively analogue fluids and dissolved CO2, will be used in parallel. Pore scale concentration fields will be measured by laser-induced fluorescence and scanning by laser sheets, while fluid velocities will be measured by stereo-PIV.