Modeling of multi-phase flow in porous media including phase interfaces
"We present a new numerical model for macro-scale two-phase flow in porous media which is based on an existing physically consistent and general theory of multi-phase flow. This
model is able to capture physical phenomena that cannot be described by standard two-phase flow models.
The standard approach for modeling the flow of two fluid phases in a porous medium consists of a continuity equation for each phase, an extended form of Darcy's law as well as constitutive relationships for relative permeability and capillary pressure.
However, it has been shown that this approach is deficient with respect to physics.
The alternative is to use an extended model which is founded on thermodynamic principles and is physically consistent. We present results of a numerical modelling study based on
this extended model. In addition to the standard equations, the model uses a balance equation for specific interfacial area and a constitutive relationship for specific
interfacial area as function of capillary pressure and saturation.
We show that the extended model can capture additional physical processes compared to the standard model, such as hysteresis. New features of the extended model, such as a physically motivated description of mass transfer between phases are discussed."