Prediction of water configuration in wet unsaturated porous media

A numerical model for predicting the air-water interfacial area of fluid in wet unsaturated particulate media is utilized to predict the pore-scale configuration of the fluid in the porous matrix. The model is based on simulating annealing and random swapping of air and water elements in the system to achieve a global energy minimum. Predictions of water configuration are consistent with descriptions found in the literature. Explanations for phenomena observed for surfactant-induced capillary pressure gradient-driven flow of fluid in porous media are suggested and supported by model predictions of fluid configuration. The shape of the experimental air-water interfacial area versus water content curve is explained in terms of hydraulic conductivity and its inhibiting role in achieving thermodynamic equilibrium.