Micromechanics Digital Rock: Parameterization of Consolidation Level using a Grain Contact Model

Abstract

The mechanical behaviour of sedimentary rocks is conditioned by the interactions at the grain-grain contacts. We present a micromechanics digital rock workflow based on a cohesive contact model and introduce a general parameterization that can capture two extreme contact behaviours: free grains and fixed grains, as well as any intermediate degree of grain consolidation. With this parametric cohesive contact model, we can simulate a wide range of sedimentary rocks, from unconsolidated to well-consolidated rocks. We present a benchmark study on several samples and compare with laboratory-measured elastic moduli to calibrate its degree of consolidation. Simulations that do not include the grain contact modelling, tend to overestimate the elastic moduli, which manifests the significance of this contribution to capture well the grain contact behaviour. To demonstrate the impact of properly capturing the degree of consolidation on the rock strength and failure pattern, we present results for numerical uniaxial compression testing. This workflow provides physics-based solution to complex grain contact behaviour, which complements laboratory core analysis, and can be useful to reveal underlying grain-scale processes governing rock mechanical behaviour.