A 3-D network model is used to simulate the impairment of porous medium permeability during the flow of water with suspended particles.

Digitized 2-D images of the porous systems are obtained by petrographic image analysis of rock thin sections. Geostatistical procedures are applied to construct 3-D virtual realizations of the medium. The pore body and throat sizes distributions of the virtual medium and its connectivity, expressed by the average coordination number, are determined. Alternatively, these characteristics are obtained by using capillary driven porosimetry data and empirical correlations. A regular cubic network of sites (pore bodies) and bonds (pore throats) that reproduces these characteristics is structured.

Network absolute permeability can be calculated by solving a system of linear mass balance equations for the sites, along with equations of hydraulic conductivity for the bonds. Realistic permeability estimates are obtained.

Motion and contingent capture of injected particles inside the medium are simulated. Both physicochemical interception and size exclusion mechanisms of particle retention are modeled, the former with the aid of two empirical parameters. Particle capture modifies the flow in the network, that is recurrently calculated, resulting in permeability decline as more particles are retained.

Network simulated data and their comparison with those obtained in laboratory tests are reported. Besides particle to pore throat size ratio, concentration and flow velocity, other important factors governing the permeability impairment are: 1. medium coordination number and 2. shape of pore throats.

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