PhD defense Nathan Bernard

Abstract

Carbon capture and storage has been proposed as one of the solutions to the current ecological crisis. This technology relies on the injection of CO2 in underground geological reservoirs, like saline aquifers or depleted oil and gas reservoirs, to mitigate the greenhouse effect. But until now, residual trapping, one of the mechanisms trapping CO2 underground, is still not well understood. This creates uncertainty about the amount of carbon that can be trapped in these geological formations. This work aims to study the residual trapping to better predict how it impacts the storage of CO2. To achieve this, we used both experimental and numerical approaches to study two-phase flow in porous media. We introduced the pore-doublet model as a way to simplify the description of porous media. Using this pore-doublet model, we showed that inertia, often neglected in porous media, can alter the movement of the front during drainage. We also observed that Bretherton’s films that appear during two-phase flow can impact the stability of the invasion in a pore-doublet. Finally, we proposed a protocol to experimentally study how the wettability of the porous matrix is altered in the presence of both brine and CO2 in the geological formations. We believe that this work helps to further our understanding of the subsurface’s two-phase flow.