The Influence of Heterogeneity and Confining Pressure on the Hydromechanics of a Sandstone Using Neutron and X-Ray Imaging

Abstract This study utilizes advanced 3D imaging techniques, combining X-ray and neutron tomography, to investigate the hydromechanical evolution of Idaho Gray sandstone during coupled triaxial permeability tests. The analysis involved correlating mechanical and hydraulic bulk measurements, porosity fields, strain fields derived from Digital Volume Correlation analysis and fluid speed fields derived from time series of neutron tomograms. This experimental approach provides an improved understanding of the relationship between the volume of active pores and bulk hydraulic conductivity on our samples. In particular, the results reveal that the confining pressure and rock porosity heterogeneity play crucial roles in global and local mechanisms, strain field evolution and fluid flow dynamics.