  In this work we present a non-standard model for microbial enhanced oil
recovery including the oil-water interfacial area. Including the interfacial
area in the model, we eliminate the hysteresis in the capillary pressure
relationship. One of the characteristics that a surfactant should have, it is
biological production at the oil-water interface. Therefore, we consider the
production rate of surfactants not only as a function of the nutrient
concentration, but also the interfacial area. To solve the model equations, we
use an efficient and robust linearization scheme that considers a linear
approximation of the capillary pressure gradient. A comprehensive, 1D
implementation based on two-point flux approximation of the model is achieved.
We consider different parameterizations for the interfacial tension and
residual oil saturation reduction. Illustrative numerical simulations are
presented, where we study the spatial distribution and evolution in time of the
average pressure, water saturation, interfacial area, capillary pressure,
residual oil saturation and bacterial, nutrient and surfactant concentrations.
Inclusion of the interfacial area in the model leads to different predictions
of oil recovery. The model can also be used to design new experiments
contributing to a better understanding and optimization of MEOR.
