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Investigating the Onset of Strain Localization Within Anisotropic Shale Using Digital Volume Correlation of Time-Resolved X-Ray Microtomography Images

McBeck, Jessica; Kobchenko, Maya; Hall, Stephen A. LU ; Tudisco, Erika LU ; Cordonnier, Benoit; Meakin, Paul and Renard, François (2018) In Journal of Geophysical Research: Solid Earth 123(9). p.7509-7528
Abstract

Digital volume correlation analysis of time-resolved X-ray microtomography scans acquired during in situ triaxial compression of Green River shale cores provided time series of 3-D incremental strain fields that elucidated evolving deformation processes by quantifying microscopic strain localization. With these data, we investigated the impact of mechanical anisotropy on microscopic strain localization culminating in macroscopic shear failure. We conducted triaxial compression experiments with the maximum compressive stress, σ1, aligned perpendicular and parallel to lamination planes in order to investigate end-member stress states that arise within sedimentary basins. When the preexisting laminations were perpendicular to... (More)

Digital volume correlation analysis of time-resolved X-ray microtomography scans acquired during in situ triaxial compression of Green River shale cores provided time series of 3-D incremental strain fields that elucidated evolving deformation processes by quantifying microscopic strain localization. With these data, we investigated the impact of mechanical anisotropy on microscopic strain localization culminating in macroscopic shear failure. We conducted triaxial compression experiments with the maximum compressive stress, σ1, aligned perpendicular and parallel to lamination planes in order to investigate end-member stress states that arise within sedimentary basins. When the preexisting laminations were perpendicular to σ1, a lamination-parallel region with high axial compaction developed within the macroscopically linear deformation phase of the experiment and then thickened with increasing applied differential stress. Scanning electron microscopy images indicate that this axial compaction occurred within a lower density lamination and that more axial compaction occurred within the center of the core than near its sides. Boundary element method simulations suggest that this compacting volume promoted shear fracture development within the upper portion of the shale. When the laminations were parallel to σ1, lamination-parallel dilation bands formed, thickened, and intensified in dilation. Population densities of the distributions of incremental shear strain, radial dilation, and axial contraction calculated by digital volume correlation analysis enabled quantification of the evolving overall impact of, and interplay between, these various deformation modes.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
digital volume correlation, fracturing, rock deformation, shale, strain localization, X-ray microtomography
in
Journal of Geophysical Research: Solid Earth
volume
123
issue
9
pages
7509 - 7528
external identifiers
  • scopus:85053445413
ISSN
2169-9313
DOI
10.1029/2018JB015676
language
English
LU publication?
yes
id
e9ed21d5-3460-406a-8c8b-f2c3f57a76d8
date added to LUP
2018-10-24 12:12:27
date last changed
2019-03-17 05:09:56
@article{e9ed21d5-3460-406a-8c8b-f2c3f57a76d8,
  abstract     = {<p>Digital volume correlation analysis of time-resolved X-ray microtomography scans acquired during in situ triaxial compression of Green River shale cores provided time series of 3-D incremental strain fields that elucidated evolving deformation processes by quantifying microscopic strain localization. With these data, we investigated the impact of mechanical anisotropy on microscopic strain localization culminating in macroscopic shear failure. We conducted triaxial compression experiments with the maximum compressive stress, σ<sub>1</sub>, aligned perpendicular and parallel to lamination planes in order to investigate end-member stress states that arise within sedimentary basins. When the preexisting laminations were perpendicular to σ<sub>1</sub>, a lamination-parallel region with high axial compaction developed within the macroscopically linear deformation phase of the experiment and then thickened with increasing applied differential stress. Scanning electron microscopy images indicate that this axial compaction occurred within a lower density lamination and that more axial compaction occurred within the center of the core than near its sides. Boundary element method simulations suggest that this compacting volume promoted shear fracture development within the upper portion of the shale. When the laminations were parallel to σ<sub>1</sub>, lamination-parallel dilation bands formed, thickened, and intensified in dilation. Population densities of the distributions of incremental shear strain, radial dilation, and axial contraction calculated by digital volume correlation analysis enabled quantification of the evolving overall impact of, and interplay between, these various deformation modes.</p>},
  author       = {McBeck, Jessica and Kobchenko, Maya and Hall, Stephen A. and Tudisco, Erika and Cordonnier, Benoit and Meakin, Paul and Renard, François},
  issn         = {2169-9313},
  keyword      = {digital volume correlation,fracturing,rock deformation,shale,strain localization,X-ray microtomography},
  language     = {eng},
  month        = {08},
  number       = {9},
  pages        = {7509--7528},
  series       = {Journal of Geophysical Research: Solid Earth},
  title        = {Investigating the Onset of Strain Localization Within Anisotropic Shale Using Digital Volume Correlation of Time-Resolved X-Ray Microtomography Images},
  url          = {http://dx.doi.org/10.1029/2018JB015676},
  volume       = {123},
  year         = {2018},
}