Effect of Diagenesis on Geomechanical Properties of Organic‐Rich Calcareous Shale: A Multiscale Investigation

This study investigates the nano to core-scale geomechanical properties of a maturity series organic-rich, calcareous shales buried 100°C–180°C, with focus on: (a) mechanical organic matter; (b) elastic response and anisotropy shale composite at micro core scale; (c) creep response. Atomic force microscopy was used target kerogen nanoscale resolution, it found that stiffness increased thermal from 5.8 GPa in an immature sample 11.3 mature sample. Nanoindentation testing matrix showed diagenesis is key factor determining bulk elasticity, increasingly intense carbonate cementation higher maturities contributing stiffer A multiscale model formulated upscale solid clay minerals microcracked scale, good predictions comparison indentation triaxial results. negative correlation between modulus clay/kerogen content, greater displacement observed nanoindentation tests clay- kerogen-rich compared samples maturity.