Modeling of capillary pressure and phase entrapment in porous media with account for wettability change

The development of efficient IOR technologies relies on understanding and accurate modeling of multiphase flow mechanisms encountered on various scales, from pore-scale to Darcy scale and further to geo-facies and reservoir scale. Such an integrated multi -scale modeling of water-alternating-gas injection has proved to be successful for a North-sea reservoir. In this project we are addressing the problem of pore-scale modeling. Generally, there exists an understanding that wettability alteration is contr olled by the disjoining pressure, but to the best of our knowledge, there have not been done any attempts to take into account an explicit form of the disjoining pressure into a pore scale modeling tool with a realistic representation of pore space. The d isjoining pressure is the pressure in a thin film separating a non wetting phase and the rock. How the disjoining pressure behaves as a function of film thickness, chemical properties of the oil, water and rock is crucial in order to understand wettabilit y alteration. We will develop a novel model, which explicitly takes into account the disjoining pressure in combination with a realistic representation of the porous medium obtained by imaging techniques like CT, and Cryo-SEM. The developed modeling techn ology will then be tested by comparison with experimental measurements on macro-scale (capillary pressure measurements) and micro-images taken by Cryo-SEM.