Mechanical and hydraulic properties of carbonate rock: The critical role of porosity

Carbonate rocks are extensively used in civil infrastructure and play a critical role geoenergy geoengineering, either as hydrocarbon reservoirs or potential repositories for CO2 geological storage. genesis diagenetic overprint determine the properties of carbonate rocks. This study combines recent data gathered from Madison Limestone an extensive dataset compiled published sources to analyze hydraulic mechanical limestone Physical models analyses recognize inherently granular explain strong dependency physical on porosity. The asymptotically-correct power model terms (1-ϕ/ϕ∗)α is good approximation global trends unconfined stiffness E compressive strength UCS, cohesive intercept Mohr-Coulomb failure envelopes, brittle-to-ductile transition stress. analytical solution percolating structures. We adopted limiting porosity ϕ∗ = 0.5 all models, which was consistent with loosest packing monosize spheres. fitted has exponent (α 2) agreement percolation theory highlights sensitivity Data confirm porosity-independent ratio between strength, follows log-normal distribution mean (E/UCS) ≈ 300. high angle internal shear measured reflects delayed contact increased confinement, it not sensitive Permeability spans more than six orders magnitude. Grain size controls pore determines reference permeability k∗ at 0.5. For given grain fine coarse-grained dominant carbonates, very changes porosity, suggesting preferential network during compaction.