Multiphase flow towards coupled solid-liquid interactions in 2D heterogeneous porous micromodels: a fluorescent microscopy and micro-PIV measurement at pore scale*

Multiphase flow in porous media is relevant to a range of applications in the energy and environmental sectors. Recently, the interest has been renewed by geological storage of CO$_{2}$ within saline aquifers. Central to this goal is predicting the fidelity of candidate sites pre-injection of CO$_{2}$ and its post-injection migration. Moreover, local pressure buildup may cause micro-seismic events, which could prove disastrous, and possibly compromise seal integrity. Evidence shows that the large-scale events are coupled with pore-scale phenomena, necessitating the understanding of pore-scale stress, strain, and flow processes and their representation in large-scale modeling. To this end, the pore-scale flow of water and supercritical CO$_{2}$ is investigated under reservoir-relevant conditions over a range of wettability conditions in 2D heterogeneous micromodels that reflect the complexity of real sandstone. High-speed fluorescent microscopy, complemented by a fast differential pressure transmitter, allows for simultaneous measurement of the flow field within and the instantaneous pressure drop across the micromodels. A flexible micromodel is also designed, to be used in conjunction with the micro-PIV technique, enabling the quantification of coupled solid-liquid interactions.