PORE-SCALE SIMULATION OF COLLOID DISPERSION AND DEPOSITION IN POROUS MEDIA

In this work a multiphase system of fluid flow and particle transport and deposition in porous media is analyzed via pore-scale computational fluid dynamics simulations using finite-volume discretization. A number of different geometries were considered in order to explore a range of increasing complexity in the pore structure. First, a set of two-dimensional models was considered, some of which constituted by circular elements and others by realistic grains, in order to cover a wide range of medium porosity and grain diameters. On these models, steady-state simulations of particle deposition, employing the “perfect sink” boundary condition are then performed in an Eulerian framework. The gathered results are used to calculate the deposition efficiency due to Brownian diffusion and steric interception. The results are then compared to the theoretical results of Happel and co-workers, highlighting differences in the prediction of deposition efficiency with respect to the dependency on the relevant dimensionless numbers. Then, a preliminary simulation of fluid flow and transient particle transport (with no particle deposition) was performed on a fully three-dimensional geometry created “in-silico” by algorithmic reconstruction. A wide range of operating conditions was explored, obtaining the relative breakthrough curves and the impact of hydrodynamic dispersion, which was then compared with predictions from classic laws