Observation of Buoyant Plumes in Countercurrent Displacement: Influence of Local Capillary Trapping in a Bench Scale Experiment

Abstract

A bench scale experiment is established to determine the extent of CO2 immobilization beneath small- scale capillary barriers, which can be expected in typical heterogeneous storage formations. The bench scale environment allows fluids analogous to CO2 and brine to migrate under gravity in a quasi-two dimensional domain packed with a range of sizes of beads/grains. A fluid pair is developed to mimic the phase densities and viscosities at pressure and temperature typical of storage aquifers. Domains are built with different types of heterogeneity that establish local capillary barriers, and hence possible local traps. Extent of trapping in a closed domain is qualitatively consistent with theoretical results and those from previous works. Persistence of local trapping after forced imbibition is also observed in line with theory.