# Numerical simulations on compression behaviors of the laminated shale based on the digital image technology and the discrete element method

## TL;DR

This paper uses digital imaging and simulations to study how the microstructure of shale affects its mechanical behavior under compression.

## Contribution

A novel approach combining CT imaging and discrete element simulations to analyze the anisotropic mechanical behavior of laminated shale.

## Key findings

- Microscopic parameters and layering angle significantly influence macroscopic mechanical properties of shale.
- Initial microstructures and cracks in numerical samples affect failure modes and strength of laminated shale.
- Confining pressure impacts the mechanical behavior of layered shale as revealed by numerical simulations.

## Abstract

As an unconventional reservoir sedimentary rock, shale contains a series of layers and various microstructures that lead to complex mechanical properties, such as the anisotropy of stiffness and strength. This study is directed towards the anisotropy caused by the microstructures of the shale, employing the 2D particle flow code (PFC2D) to explore stiffness, strength, failure mode, and micro-crack evolution. More realistic microstructures and the calibration of microscopic parameters of the shale are reasonably considered through the computed tomography (CT) images and mineral analysis. The corresponding numerical simulation results are fully compared with the experimental results. In what follows, the sensitivity analysis is conducted on the key microscopic parameters and microstructure characteristics in numerical samples with laminated characteristics. The results show that the influence of microscopic parameters of the parallel bonding model on macroscopic parameters is related to the layering angle and the face type, and the microstructures and initial cracks of numerical samples can considerably affect the macroscopic mechanical behaviors of the laminated samples. Next, the effect of confining pressure on the mechanical properties of layered shale is also discussed based on the numerical results. These findings highlight the potential of this approach for applications in micro-scaled models and calibration of microscopic parameters to probe mechanical behaviors of the laminated rock.