THE INFLUENCE OF MINERALOGY AND FAILURE-MODE ON FRACTURE GEOMETRY

The connectivity, permeability, and strength of mechanical discontinuities, such as micro-cracks, factures, joints, and faults, are easily perturbed by many geodynamical process and anthropogenic activities that disturb the Earth’s subsurface. The key link among fracture properties is the deformed fracture topology that results from the contact of two rough surfaces under stress. A key question is what affects fracture geometry during formation under tensile and shear failure conditions.

In this presentation, we examine the role of depositional layers and mineral fabric orientation on tensile and mixed-mode crack formation and geometry using geo-architected samples created through additive manufacturing. The relative orientation between the layering and mineral fabric creates an orthorhombic material and determines whether corrugated surfaces are generated, suppressed, or enhanced during fracturing. The generation of corrugated surface roughness leads to anisotropic fracture flow paths. The corrugations are observed to rotate with increases in the shear stress contributions to failure. These results suggest that careful examination of in-layer mineral fabric is important during the design of subsurface strategies to maximize production or inhibit flow.