The Hydro‐Mechanical Properties of Fracture Intersections: Pressure‐Dependant Permeability and Effective Stress Law

Abstract Fluid flow through the brittle crust is primarily controlled by capability of fracture networks to provide pathways for fluid transport. The dominant permeability orientation within fractured rock masses has been consistently correlated with development intersections; an observation also made at meso‐regional scale. Despite importance attributed intersections in promoting flow, magnitude their enhancement not yet quantified. Here, we characterize hydro‐mechanical properties samples Seljadalur Basalt generating two orthogonal, tensile fractures produced separate loadings using a Brazilian test apparatus, and measuring as function hydrostatic pressure. We observe that intersecting are significantly more permeable less compliant than independent macro‐fractures. formulate model intersection pressure adding contributions plus tube‐like cavity effective elastic compressibility determined its geometry. Permeability measurements during cyclic loading allowed determination stress coefficient ( α p e = c − αp ) permeability. trend lower values respect , which suggests channels controlling have higher aspect ratio (are tubular) relative fractures. Our results suggest play critical role maintaining depth, significant implications quantification upscaling toward reservoir‐scale simulations.