Size-Exclusion Colloidal Transport in Porous Media-Stochastic Modeling and Experimental Study

Suspension, colloidal, and emulsion flow in rocks with particle size-exclusion may have a strong effect on the reservoir and on the well behavior during fines migration and production, drilling-fluid invasion into oil- or gas-bearing formations, or injection of seawater or produced water. The stochastic microscale equations for size-exclusion colloidal transport in porous media (PM) are derived. The proposed model includes the following new features: It accounts for the accessible flux in the expression for capture rate, it accounts for the increase of inlet concentration caused by the injected particles entering only the accessible area, and it accounts for the dilution of effluent accessible flux in the overall flux of the produced suspension. Two sets of laboratory tests on short-term injection of mono-sized suspensions have been carried out in engineered PM. The treatment of the laboratory data for short-term continuous-suspension injection shows good agreement with the modeling results. The proposed model shows a better fit to the experimental data than the previous population-balance model for suspension transport in PM, which validates the proposed modified model.