Poromechanical Properties of a Sandstone Under Different Stress States

Comparison of advanced discretization techniques for image-based modelling of heterogeneous porous rocks

“…They are equal to 10 MPa and 37°respectively. Those values are also consistent with the ones reported by Hu [23]. A uniaxial compressive strength σ c of 60 MPa is therefore considered.…”

“…First, a purely isotropic triaxial compression. The considered sample being isotropic (because of its limited size, unlike the overall material [23]), this matches an almost isotropic triaxial macroscopic strain state.…”

“…The second strategy is based on the projection of such an implicit geometry on an unstructured tetrahedral mesh, with an incompatible kinematic enrichment defined at the element level to account for the heterogeneity of phases. The comparison will here be performed through mechanical simulation on a subset of the CT-scanned image of a sandstone [23].…”

“…Indeed, it must accurately reflect the complexity of the geometry at hand, be able to identify the different phases of the material, and make the results usable in the subsequent processes. The sample used in this paper to illustrate the comparison between the two selected discretization methods is a subset of the CT scan of a dry Vosges sandstone obtained by X-ray tomography as part of Cong Hu's PhD thesis [23]. The scan resolution is 5 microns per voxel for a geometry size of 100x100x100 voxels (see Figure 1).…”

“…The subset of the CT scan considered shows a isotropic behaviour, leading to a triaxial isotropic compression. Note that the base material is not fully isotropic [23], and the isotropy of the considered sample is caused by its limited size (lack of representativity).…”