Public Abstract

DE-SC0018357: Nonequilibrium Physics of Multiphase Flow in Porous Media: Wettability and Disorder

Award Status: Inactive

Institution: Massachusetts Institute of Technology, Cambridge, MA
UEI: E2NYLCDML6V1
PM: Rustad, James

Most Recent Award Date: 07/29/2020
Number of Support Periods: 3
PI: Juanes, Ruben

Current Budget Period: 08/01/2019 - 07/31/2021
Current Project Period: 08/01/2017 - 07/31/2021

Public Abstract

Carbon capture and geologic storage, dissociation of methane hydrates in permafrost, enhanced oil recovery, and water dropout in low-temperature fuel cells, all have something in common: two or more fluids flow simultaneously through a porous medium; and the displacement of one fluid by another is often unstable (either due to gravity or viscous forces). Yet, our ability to model multiphase flow in porous media has remained a challenge. The traditional equations are unable to predict, explain, or even reproduce, the formation of the complex patterns observed in experiments. It has been known for decades that wetting---the affinity of the solid to one of the fluids---can have a strong impact on the flow. However, and despite recent advances in our ability to accurately measure wettability under reservoir conditions, and to engineer wettability in the subsurface, the complex physics of wetting continues to challenge our microscopic and macroscopic descriptions. Objectives. The overarching goal of the project is to develop new physical understanding of the role of wettability and disorder in multiphase flow through permeable media, and to develop new mathematical and computational models at the pore scale and at the continuum scale. The proposed research addresses the following key scientific questions: 1. Emergence of nonequilibrium capillary pressure. (1) How does the contact line evolve in a confined geometry like a capillary tube or a Hele-Shaw cell under different wetting conditions in viscously unstable displacements? (2) Can one predict, and model, the transition from a moving contact line to the deposition of a thin film? (3) How is the pressure difference across the moving interface related to the Laplace pressure under static conditions? 2. Impact of wetting and disorder on multiphase flow in porous media. (1) How can one characterize the wetting transition from pore invasion to corner flow? (2) What is the role of roughness and geometry in this wetting transition? (3) What are the statistical properties of invasion (pinning, avalanches) as a function of wetting properties, capillary number, viscosity contrast, and disorder? Description. Building on our recent DOE Early Career Award (Grant Number DE-SC0003907), we propose a new approach---phase-field modeling---to advance our fundamental understanding and predictive capabilities of multiphase porous media flow. The basic tenet, with origins in the mathematical description of solidification processes, is that the system is far from equilibrium, and the energy of the system is a function of the inhomogeneous distribution of fluid phases. The research agenda is organized around a set of hypotheses on hitherto unexplained behavior of multiphase flow. We propose an integrated research plan organized in three main tasks: (1) Immiscible fluid displacements in a capillary tube; (2) Impact of wetting and disorder on multiphase flow in a patterned Hele-Shaw cell; (3) Impact of wetting on multiphase flow in 3D porous media. Each task includes two subtasks---visual laboratory experiments, and computational phase-field modeling. We start the research program with flow in a capillary tube and a Hele-Shaw cell they are of interest in their own right---especially for microfluidic applications---and they isolate cleanly some interesting aspects of immiscible flow (such as wetting behavior) and the passage from the microscale to the macroscale involves less empiricism than in a random porous medium. Impact. Finding a parsimonious theory of multiphase flow through porous media is an open scientific problem. If successful, this proposal will provide new understanding of the pore-scale physics and a continuum mathematical framework that predicts the stability--instability of fluid displacement at large scales. This would be a landmark result in soft-matter physics, leading to advances in subsurface energy, environment and technology applications in which the evolution of fluid-fluid interfaces and the development of hydrodynamic instabilities at the pore scale is essential to predict macroscale phenomena.

Carbon capture and geologic storage, dissociation of methane hydrates in permafrost, enhanced oil recovery, and water dropout in low-temperature fuel cells, all have something in common: two or more fluids flow simultaneously through a porous medium; and the displacement of one fluid by another is often unstable (either due to gravity or viscous forces). Yet, our ability to model multiphase flow in porous media has remained a challenge. The traditional equations are unable to predict, explain, or even reproduce, the formation of the complex patterns observed in experiments.
It has been known for decades that wetting---the affinity of the solid to one of the fluids---can have a strong impact on the flow. However, and despite recent advances in our ability to accurately measure wettability under reservoir conditions, and to engineer wettability in the subsurface, the complex physics of wetting continues to challenge our microscopic and macroscopic descriptions.

Objectives.
The overarching goal of the project is to develop new physical understanding of the role of wettability and disorder in multiphase flow through permeable media, and to develop new mathematical and computational models at the pore scale and at the continuum scale. The proposed research addresses the following key scientific questions:
1. Emergence of nonequilibrium capillary pressure. (1) How does the contact line evolve in a confined geometry like a capillary tube or a Hele-Shaw cell under different wetting conditions in viscously unstable displacements? (2) Can one predict, and model, the transition from a moving contact line to the deposition of a thin film? (3) How is the pressure difference across the moving interface related to the Laplace pressure under static conditions?
2. Impact of wetting and disorder on multiphase flow in porous media. (1) How can one characterize the wetting transition from pore invasion to corner flow? (2) What is the role of roughness and geometry in this wetting transition? (3) What are the statistical properties of invasion (pinning, avalanches) as a function of wetting properties, capillary number, viscosity contrast, and disorder?

Description.
Building on our recent DOE Early Career Award (Grant Number DE-SC0003907), we propose a new approach---phase-field modeling---to advance our fundamental understanding and predictive capabilities of multiphase porous media flow. The basic tenet, with origins in the mathematical description of solidification processes, is that the system is far from equilibrium, and the energy of the system is a function of the inhomogeneous distribution of fluid phases.
The research agenda is organized around a set of hypotheses on hitherto unexplained behavior of multiphase flow. We propose an integrated research plan organized in three main tasks: (1) Immiscible fluid displacements in a capillary tube; (2) Impact of wetting and disorder on multiphase flow in a patterned Hele-Shaw cell; (3) Impact of wetting on multiphase flow in 3D porous media. Each task includes two subtasks---visual laboratory experiments, and computational phase-field modeling. We start the research program with flow in a capillary tube and a Hele-Shaw cell they are of interest in their own right---especially for microfluidic applications---and they isolate cleanly some interesting aspects of immiscible flow (such as wetting behavior) and the passage from the microscale to the macroscale involves less empiricism than in a random porous medium.

Impact.
Finding a parsimonious theory of multiphase flow through porous media is an open scientific problem. If successful, this proposal will provide new understanding of the pore-scale physics and a continuum mathematical framework that predicts the stability--instability of fluid displacement at large scales. This would be a landmark result in soft-matter physics, leading to advances in subsurface energy, environment and technology applications in which the evolution of fluid-fluid interfaces and the development of hydrodynamic instabilities at the pore scale is essential to predict macroscale phenomena.