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Micromechanical characterisation of overburden shales in the Horn River Basin through nanoindentation

Lookup NU author(s): Dr Tom CharltonORCiD, Dr Mohamed Rouainia



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2023 Institute of Physics Publishing. All rights reserved.The paper presents a micromechanical characterisation of Fort Simpson shale, which overlies unconventional gas-producing lithologies in the Horn River Basin, NW Canada. The Fort Simpson formation is clay-rich and microseismic data recorded during hydraulic fracturing events in the underlying reservoir has shown the formation acts as a barrier to fracture development, with a notably anisotropic seismic response. Samples were prepared from core fragments and the composition and texture of the shale was characterised using X-ray diffraction, mercury injection porosimetry and scanning electron microscopy (SEM). Nanoindentation testing was used to obtain the mechanical response of the shale microstructure, at grain-scale. The indentation was conducted on a grid pattern and samples were oriented both parallel and perpendicular to the bedding plane to assess the inherent mechanical anisotropy. Chemical analysis of the grids was also undertaken through SEM/EDS (energy dispersive X-ray spectroscopy) and the coupled chemo-mechanical data was used to characterise the material phases of the shale through a statistical clustering procedure. The results show that Fort Simpson shale broadly consists of a soft clay phase, with strongly anisotropic elastic stiffness, and stiffer but effectively isotropic grains of quartz and feldspar. A simple upscaling scheme was also applied to link the grain-scale elastic stiffness to the field-scale microseismic data.

Publication metadata

Author(s): Charlton TS, Rouainia M, Aplin AC, Fisher QJ, Bowen L

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Eurock 2022 Rock and Fracture Mechanics in Rock Engineering and Mining

Year of Conference: 2022

Pages: 012087

Online publication date: 10/01/2023

Acceptance date: 02/04/2022

Date deposited: 07/02/2023

ISSN: 1755-1307

Publisher: Institute of Physics


DOI: 10.1088/1755-1315/1124/1/012087

Series Title: IOP Conference Series: Earth and Environmental Science