Multiscale approach to micro-poro-mechanical modelling of unsaturated shales

Abstract

The paper outlines the multiscale mathematical formulation of clay-rich shales as a swelling capillary porous medium with a resolution as fine as the nanoscale. The starting point is the description of the physicochemical interactions between elementary crystalline units–the so-called clay sheets or platelets. By way of homogenization, the clay platelet physics is upscaled to represent a system of randomly dispersed shale particles at the microscale with the void spaces partially saturated with a liquid, i.e. water. The end result is the constitutive description of clay shales enriched with microstructural details down to the clay platelet level that can readily describe swelling or shrinkage in terms of physicochemical loading.