Computerized X-ray Microtomography Observations and Fluid Flow Measurements of the Effect of Effective Stress on Fractured Low Permeability Porous Media

This work shows the observed changes in sample permeability and fracture geometry that occur within a fractured piece of low permeability shale with different effective stress gradients applied to the plug sample. These observations were made using an in-situ micro-CT fluid flow imaging apparatus with a carbon fibre Hassler-type core holder. Changes within the preferential fluid flow path under different stress regimes as well as physical changes to the fracture geometry are reported. Lattice-Boltzmann single phase permeability flow simulations were performed on the extracted flow paths and compared to experiment permeability measurements. Experimental flow measurements showed significant changes in the permeability of the fractured system with varying stress states. Imaged fracture apertures were also used in simple parallel plate flow calculations, and compared to results from fluid flow simulations on segmented sample void space and experimental fluid flow measurements.