Shales: lessons learned from atomic-scale to strata-scale studies
Fine-grained sediments, mudrocks and shales have unique fabric and pore topology that reflect their mineral composition and formation history. Atomic-scale clay-clay electrical interactions coexist with the micron-scale mechanical interactions between silicate and carbonate grains, clay tactoids and organic matter; layering adds cm-scale vertical heterogeneity. The resulting strata define the performance of km-scale natural and engineering systems including oil and gas reservoirs and the long-term geological storage of CO2 and nuclear waste.
We conduct multi-scale studies to gain new insights into the behavior of fine-grained sediments, mudrocks and shales. Atomic-scale studies show the effect of isomorphic substitution and adsorbed water molecules on clay tactoid stiffness. Pore-scale analyses based on SEM images reveal spherical pores in organic matter and elongated/aligned pores bound by clay tactoids. Particle-scale simulations capture fabric evolution including tactoid alignment facilitated by organic matter deformation to accommodate the evolving mineral fabric, effectively giving rise to shale fissility. Layer-scale simulations help understand the brittle-to-ductile transition, and multi-strata studies elucidate the evolution of fracture networks during tectonism.
Fine-grained sediments, mudrocks and shales have unique fabric and pore topology that reflect their mineral composition and formation history. Atomic-scale clay-clay electrical interactions coexist with the micron-scale mechanical interactions between silicate and carbonate grains, clay tactoids and organic matter; layering adds cm-scale vertical heterogeneity. The resulting strata define the performance of km-scale natural and engineering systems including oil and gas reservoirs and the long-term geological storage of CO2 and nuclear waste.
We conduct multi-scale studies to gain new insights into the behavior of fine-grained sediments, mudrocks and shales. Atomic-scale studies show the effect of isomorphic substitution and adsorbed water molecules on clay tactoid stiffness. Pore-scale analyses based on SEM images reveal spherical pores in organic matter and elongated/aligned pores bound by clay tactoids. Particle-scale simulations capture fabric evolution including tactoid alignment facilitated by organic matter deformation to accommodate the evolving mineral fabric, effectively giving rise to shale fissility. Layer-scale simulations help understand the brittle-to-ductile transition, and multi-strata studies elucidate the evolution of fracture networks during tectonism.
