Reservoir-Simulation Model with Surfactant Flooding Including Salinity and Thermal Effect, Using Laboratory Experiments
Résumé
Surfactant injection is a process used by oil companies to improve the oil‐recovery factor. Surfactant modifies the interfacial tension (IFT) and to a lesser extent the mobility‐reduction factor. Both the salinity and the temperature will affect the efficiency of the surfactant. As a result, a series of laboratory experiments are commonly conducted to evaluate dependency. However, these experiments are expensive and time consuming. In this paper, we present numerical simulations coupled to a model that allows taking into account the modification of the IFT and the mobility‐reduction factor caused by both the salinity and temperature variations during surfactant injection.
In this work, we propose a coupled numerical model using five equations: two transport equations of water and oil phases modelized by Darcy's law, two transport equations for the surfactant and the salinity (the surfactant and the salinity are transported only in the water phase), and one energy‐conservation equation to take into account the thermal effect on surfactant flooding. The system of equations includes the salinity and temperature effects on the surfactant adsorption and thermal degradation, as well as the IFT. Thus, this model allows improving the analysis of thermal corefloods or reservoir operations resulting from the surfactant injection.
On the basis of corefloods, we use the coupled model to reproduce laboratory experiments. We analyze the interaction phenomena between the surfactant, salinity, and temperature. Then, we demonstrate a competition between two phenomena: the thermal effect on the viscosity of water and the effect of surfactant on the mobility of water. This study highlights the efficiency of numerical simulations for the analysis and choice of the surfactant applied to the given reservoir and well conditions.