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This content will become publicly available on November 5, 2018

Title: CT scanning and flow measurements of shale fractures after multiple shearing events

A shearing apparatus was used in conjunction with a Hassler-style core holder to incrementally shear fractured shale cores while maintaining various confining pressures. Computed tomography scans were performed after each shearing event, and were used to obtain information on evolving fracture geometry. Fracture transmissivity was measured after each shearing event to understand the hydrodynamic response to the evolving fracture structure. The digital fracture volumes were used to perform laminar single phase flow simulations (local cubic law with a tapered plate correction model) to qualitatively examine small scale flow path variations within the altered fractures. Fractures were found to generally increase in aperture after several shear slip events, with corresponding transmissivity increases. Lower confining pressure resulted in a fracture more prone to episodic mechanical failure and sudden changes in transmissivity. Conversely, higher confining pressures resulted in a system where, after an initial setting of the fracture surfaces, changes to the fracture geometry and transmissivity occurred gradually. Flow paths within the fractures are largely controlled by the location and evolution of zero aperture locations. Lastly, a reduction in the number of primary flow pathways through the fracture, and an increase in their width, was observed during all shearing tests.
Authors:
 [1] ;  [1] ;  [1] ;  [2]
  1. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
  2. National Energy Technology Lab. (NETL), Morgantown, WV (United States); The MITRE Corp., McLean, VA (United States)
Publication Date:
Report Number(s):
NETL-PUB-20420
Journal ID: ISSN 1365-1609; PII: S136516091630449X
Type:
Accepted Manuscript
Journal Name:
International Journal of Rock Mechanics and Mining Sciences
Additional Journal Information:
Journal Volume: 100; Journal Issue: C; Journal ID: ISSN 1365-1609
Publisher:
Elsevier
Research Org:
National Energy Technology Lab. (NETL), Morgantown, WV (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
04 OIL SHALES AND TAR SANDS; 25 ENERGY STORAGE; 58 GEOSCIENCES; computed tomography; local cubic law; fractured seals; fracture transmissivity
OSTI Identifier:
1409310