The effect of vug distribution on particle straining in permeable media

Most studies of particulate transport have been performed in porous and permeable media of uniform pore size, such as sandstones and sandpacks. Carbonates often contain large openings, called vugs, which can affect the flow and transport properties (particle straining) of the porous medium. Here we perform straining experiments on artificial vuggy media with two different vug distributions. Changes in porosity, permeability, vug size, and particle effluent volume are monitored using pressure measurements and computed tomography (CT) scanning. We find that vugs that are parallel to the flow direction behave independently, with retention profiles similar to single vugs of the same volume (Khan et al., 2019). For vugs in series, different retention profiles are observed in each vug and injected particles penetrate deeper in the series vug configuration. We perform flow simulations for both configurations and find the experimentally observed particle deposition is consistent with changes in the flow streamlines. In particular, retention is enhanced where streamlines converge, which in turns alters the vug size and straining potential of the porous medium over time.