Events

Dr. Ruben Juanes, Associate Professor at MIT, will give a talk entitled "Nonequilibrium physics of multiphase flow in porous media" as part of the Claude R. Hocott Lectureship series.

Abstract:

The displacement of one fluid by another in a porous medium can give rise to a rich variety of hydrodynamic instabilities. Beyond their scientific value as fascinating models of pattern formation, unstable porous-media flows are essential to understanding many natural and man-made processes, including water infiltration in soil, enhanced oil recovery from hydrocarbon reservoirs, and CO2 sequestration in deep saline aquifers. Despite its importance, the ability to model multiphase flow at the macroscale has remained a challenge. Traditional mathematical models are unable to predict, or explain, the hydrodynamic instabilities—viscous, gravitational and mechanical instabilities—that ensue during immiscible displacements in porous media.

I will present a phase-field formulation to model multiphase porous media flow, which recognizes explicitly that fluid-fluid displacements are out of thermodynamic equilibrium. Phase-field modeling is based on the tenet that the continuum balance equations must account for the presence of fluid-fluid interfaces. Mathematically, this is captured by a nonlocal free energy, which naturally leads to governing equations with higher-order terms.

I will apply this framework to several examples, including the flow of two phases (like air and water) in a capillary tube, thin-film flows with partial wetting, and gravity-driven fingering during infiltration in dry soil. These applications illustrate the potential of the phase-field modeling as a predictive tool in the deployment of energy systems (oil and gas recovery, CO2 sequestration, mixing in microfluidic devices), which depend critically on the formation and control of fluid-fluid instabilities.