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In-situ synchrotron characterization of fracture initiation and propagation in shales during indentation

DOI: 10.1016/ DOI Help

Authors: Lin Ma (The University of Manchester) , Anne-Laure Fauchille (Institut de Recherche en Génie Civil et Mécanique (GeM) - UMR CNRS 6183) , Michael R. Chandler (The University of Manchester) , Patrick Dowey (The University of Manchester) , Kevin G. Taylor (The University of Manchester) , Julian Mecklenburgh (The University of Manchester) , Peter D. Lee (University College London; Research Complex at Harwell)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Energy

State: Published (Approved)
Published: October 2020
Diamond Proposal Number(s): 15506

Abstract: The feasibility and advantages of synchrotron imaging have been demonstrated to effectively characterise fracture initiation and propagation in shales during indentation tests. These include 1) fast (minute-scale) and high-resolution (μm-scale) imaging of fracture initiation, 2) concurrent spatial and temporal information (4D) about fracture development, 3) quantification and modelling of shale deformation prior to fracture. Imaging experiments were performed on four shale samples with different laminations and compositions in different orientations, representative of three key variables in shale microstructure. Fracture initiation and propagation were successfully captured in 3D over time, and strain maps were generated using digital volume correlation (DVC). Subsequently, post-experimental fracture geometries were characterized at nano-scale using complementary SEM imaging. Characterisation results highlight the influence of microstructural and anisotropy variations on the mechanical properties of shales. The fractures tend to kink at the interface of two different textures at both macroscale and microscale due to deformation incompatibility. The average composition appears to provide the major control on hardness and fracture initiation load; while the material texture and the orientation of the indentation to bedding combine to control the fracture propagation direction and geometry. This improved understanding of fracture development in shales is potentially significant in the clean energy applications.

Journal Keywords: In-situ imaging; synchrotron quantification; fracture initiation; fracture propagation; 4D; shale

Subject Areas: Earth Science, Energy

Instruments: I13-2-Diamond Manchester Imaging

Added On: 02/11/2020 14:58

Discipline Tags:

Earth Sciences & Environment Energy Geology

Technical Tags:

Imaging Tomography