Simultaneous Determinations of Effective Porosity and Dispersion Coefficient from Core Flooding Experiments, Considering Chemical Reactions

The objective of this work is to develop and apply a numerical workflow for the simultaneous determinations of the effective porosity and the dispersion coefficient from core flood taking chemical reactions into account. This approach consists of modeling the species transport at the core scale coupled with the chemical reactions, as involved in alkali flooding core experiments. Then, the one-dimensional model is compared with experimental breakthrough curves of tracer and pH, and the optimization process based on a genetic algorithm permits to identify the optimal parameter combination of effective porosity and dispersion coefficient. This approach is validated for an artificial case, then investigated on two distinct experimental configurations of core flooding. The proposed workflow, which involves an additional experimental measurement for pH, provides both an estimate of the kinetic porosity that is lower than the measured porosity, as well as an estimate of the dispersion coefficient that is significantly different from the usual single signal approach. The tests performed in this work do not take the interactions of the fluid with the rock into account.