Multiphase Flow in Porous Media: I. Macroscopic Observations and Modeling

Abstract

ABSTRACT Tracer displacements were run during steady-state, two-phase flow, where tracers were added to both the wetting and nonwetting phases. Such experiments were conducted in the primary drainage, imbibition, and secondary drainage cycles over a wide range of fractional flows. The effluent tracer profiles from these experiments were fit with a four-parameter, capacitance-dispersion model, which divides each phase into three fractions: flowing, dendritic, and isolated. Mixing in the flowing fraction is described by a dispersion coefficient, and communication between the flowing and dendritic fraction is represented by a single mass transfer coefficient. This model is shown to adequately fit tracer effluent data over a wide range of conditions. In some areas the model is nonunique--thus, more than one solution fits the experimental data equally well. Additional experiments were conducted to differentiate mechanisms in these regions. The effects of core wettability were investigated and shown to be important. The results of all of these experiments were used to formulate a mechanistic picture of steady, two-phase flow in strongly wetted porous media.