CMX Lunch Seminar
I study the motions of fluids underground and how they shape our natural and engineered environments. In pursuit of such knowledge, I pay special attention to the roles of fluid mechanical instability, phase transitions, chemical reactions and fluid-solid interactions. My approach is often mathematical and computational and my primary tools are phase-field modeling and high-resolution numerical simulations. However, my work benefits tremendously from collaborations with experimentalists and field-going scientists. My work is applied to a wide range of geoscience problems, including gas hydrate systems, geologic carbon sequestration, hydrology and volcanic systems.
In this talk, I will discuss the modeling of complex multiphase flow in porous media using phase-field methods. I will start with the modeling of viscous fingering between two fluids of partial miscibilityâ€" a scenario that is rarely addressed. Through a careful design of the thermodynamic free energy of a binary mixture, we develop a phase-field model of fluid-fluid displacements in a Hele-Shaw cell for the general case in which the two fluids have limited (but nonzero) solubility into one another.
Then I will address the modeling of methane clathrate (gas hydrate) in multiphase environments using phase-field methods. Motivated by field and laboratory observations, I will describe how the spontaneous formation of a solid hydrate crust on a moving gas-liquid interface gives rise to a new type of flow instability we term crustal fingering. I will further show that this solid-modulated gas percolation mechanism is crucial to our understanding of methane venting in the world's oceans.
Finally, I will discuss challenges on modeling fluid-solid coupling due to phase change in porous media, and opportunities to address new questions at the interface of engineering and geosciences.