Coupled Electro-hydrodynamic Transport in Geological Fractures - INSU - Institut national des sciences de l'Univers Access content directly
Conference Papers Year : 2018

Coupled Electro-hydrodynamic Transport in Geological Fractures

Yves Méheust
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Tanguy Le Borgne
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Abstract

Geological fractures constitute the basic structural units controlling the flow of fluids and the transport of solutes in subsurface crystalline rocks. Fracture wall roughness is responsible for flow channeling within the fracture plane, which impacts the fracture's transmissivitty [1], and can also impact the distribution of fluxes in-between fractures of the fracture networks [2]. The most prevalent way of computing the distribution of local fluxes in (and transmissivitty of) a rough fracture without resorting to a full 3D flow simulation, is to use the lubrication approximation, which leads to a simple linear equation for pressure: the Reynolds equation. However, the effect of the electrical properties of the solid walls on the transport properties of a fracture still remains an open question. Since dissolved minerals and salts are present in the fluids, Electrical Double Layers (EDLs) form at the fluid-solid interface [3]. Hence, the occurrence of externally-imposed or naturally-occurring gradients in electrical potential and/or ionic concentration leads to significant changes in the fluid flow and solute transport as compared to flows driven primarily by hydraulic head differences. We consider geological fractures with a realistic aperture field and explore the flow dynamics resulting from such coupled electro-hydrodynamic forcings. To this end we generalize the standard lubrication theory for flow to include a description of the coupled transport of fluid mass, solutes, and electrical current under application of fixed differences in hydraulic head (or pressure), electrical potential and concentration across the fracture. This generalized lubrication theory is solved using an iterative Finite Volume Method.

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Earth Sciences
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Dates and versions

insu-01927968 , version 1 (20-11-2018)

Identifiers

  • HAL Id : insu-01927968 , version 1

Cite

Yves Méheust, Uddipta Ghosh, Tanguy Le Borgne. Coupled Electro-hydrodynamic Transport in Geological Fractures. American Geophysical Union 2018, Fall Meeting, Dec 2018, Washington, United States. pp.H53A-03. ⟨insu-01927968⟩
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