Multiphase Mass and Heat Transport in Low Permeability Media

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The subsurface is rapidly becoming the focus of a global push to mitigate climate change, transition to a post-carbon society, safely store legacy energy wastes, and revitalize urban areas through brownfield remediation. These applications are governed by a single set of coupled physics - water and gas flow coupled with energy dynamics - often operating in low heterogenous permeability media, yet the implications of these coupled processes remain poorly understood. If nothing is done to better explore these processes, then all these applications may be well intentioned but unattainable. This proposed research program aims to address this knowledge gap with the help of experimental and modelling tasks that will examine the linkage between heat and multiphase flow in heterogenous low permeability domains. The program will examine these processes in both naturally occurring low permeability media and engineered soils (such as clay that is pressed into specific densities or processed into forms such as pellets, gapfills, or liners) as both types of soils are encountered in the various subsurface applications. The experiments will examine the effect of temperature on important soil parameters such as thermal conductivity and soil water characteristics. These results will be used in a newly developed model that links heat dynamics with gas and water movement in heterogeneous low permeability soils. The model will examine the effect of heterogeneity on water and gas movement as well as determine whether inter-pore gas and water dynamics have an impact on the overall mass transport in these types of domains. Lastly, the model and experiments will compare the performance of both naturally and engineered soils in heated subsurface domains. The long-term vision of this research program is to improve our understanding of the coupled mass and energy processes that occur in low permeability systems, leading to an improvement in remediation efficiencies at contaminated sites, minimize risks posed by gas movement in deep geological repositories, and improve the energy efficiency of geo-energy systems. These applications are particularly relevant given the current need to fight climate change and foster a cleaner environment. Funds requested for this research will support two doctoral students, one masters student, and eight undergraduate students.