رضا آذین

There are many studies which focus on the CO2 injection into underground formations to fulfill enhanced oil recovery and/or sequestration purposes. Diffusion of CO2 in these reservoirs is modeled with Fick’s second law. In this work, numerical model of Fickian transport with equilibrium and non-equilibrium boundary condition is compared with non-Fickian one for experimental diffusivity data. The experimental procedure is based on the pressure-decay method illustrated in the literature. Based on the results, non-Fickian equation with equilibrium boundary condition (EBC) shows a better match compared to Fickian equation with (EBC) for CO2/heavy oil. It is found that the Fickian model with non-equilibrium boundary condition (NEBC) shows the best match for CO2/heavy oil. For CH4/heavy oil system, type of the equation and boundary condition has no effect on the results and both Fickian and non-Fickian equations indicates the same results.