Structure-Flow Correlations in Deformable Porous Media Probed by Magnetic Resonance Velocimetry

Abstract Although the influence of an applied stress across a deformable porous medium has been well studied theoretically and using numerical simulations, direct experimental studies of how applied stress influences both the microstructure of the pore space and the fluid flow through the porous medium remain challenging due to the optically opaque nature of porous media. Of particular interest has been the observation that the rate of permeability decrease reduces with increasing applied effective stress, and that this rate of permeability decrease is associated with a critical stress state at which substantial flow redistribution occurs. In this work, a randomly packed bed of monodisperse elastic spheres is used to study the effect of matrix deformation on fluid flow under conditions of confined uniaxial compression. Changes in the local hydrodynamics have been identified and are associated with structural changes such as pore expansion and closing, and generation of new pores. Evidence is reported for a change in the morphology of the pore space at the highest applied effective stress studied and that this is associated with a substantial redistribution of the flow. Highlights Pore structure deformation studied during uniaxial compression. MR velocimetry reveals redistribution of flow during compression. Direct evidence of redistribution of flow as applied effective stress increases.