Modeling of Multiphase Flow in Porous Medium Systems

Amber Sallerson Jackson, University of North Carolina

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The study of multiphase flow in porous media is applicable to a wide range of physical interactions in nature as well as industry. Driven by important human interests such as sustainable management of water resources and optimal exploration of oil reservoirs, the need for reliable tools to predict the response of systems under different flow scenarios is apparent. Experimentation can be expensive and difficult, and thus implementation of numerical mathematical models to develop reliable tools for simulation is an essential part of understanding these systems.

Multiphase flow in porous medium systems occurs when the pore space is filled with at least two distinct immiscible liquid or gas phases. Multiphase systems require that the dynamics of not only solid-fluid interactions, but also fluid-fluid interactions be resolved. Traditional models, however, suffer from numerous deficiencies in describing these dynamics, and as a result have motivated tremendous efforts to investigate the complex processes governing these systems over the past two decades. Nonetheless, much work remains to be done.

The overall goal of this work is to improve macroscale models of multiphase flow in porous media for two-fluid-phase flow by addressing deficiencies of traditional models such as inadequate description of system physics and ill-defined parameters. A model must establish a clear connection between pore-scale physics and larger scale behavior; obey the second law of thermodynamics; and include only well-defined variables and measurable parameters. To support these efforts, the thermodynamically constrained averaging theory (TCAT) approach is utilized in developing consistent, well-defined, and flexible macroscale models. These models require closure relations formulated in terms of macroscale variables that retain connection to the microscale physics, in order to produce solvable macroscale models. Pore-scale simulations using Lattice Boltzmann models are exercised to confirm and enforce consistency between scales for development of such closure relationships.

Abstract Author(s): Amber B. Sallerson, William G. Gray, James E. McClure, and Cass T. Miller