Linear elastic properties of granular rocks derived from Xray-CT images

The elastic response of clastics rocks and grain packs is controlled to a large extend by the arrangements of grains and the strength of the contacts between them. For well-cemented rocks like Fontainebleau sandstone, the elastic moduli of the grains and the contact moduli can be taken as the one of quartz with good agreement to experimental data. In general, and in particular for less well cemented granular rocks, this is not the case, the contact moduli typically being weaker than the surrounding grains. In this study, we utilize microtomographic images and grain-partitioning techniques to assign grain moduli, and employ effective medium theories based on a relation between Xray-CT density and porosity to assign contact moduli between grains. We numerical derive the macroscopic effective elastic moduli of several reservoir rocks, and study their sensitivity to variations of contact moduli between grains in a parametric study.