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U.S. Department of Energy
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DCIF (Directional Cooling-Induced Fracturing) Westerly Granite AE Borehole Damage Effect Test (Task 3-0)

Dataset ·
DOI:https://doi.org/10.15121/1842336· OSTI ID:1842336
 [1]
  1. Lawrence Berkeley National Laboratory

Directional Cooling-Induced Fracturing (DCIF) experiments were conducted on three rectangular Westerly granite blocks (width=depth=4.0", height=2.0") which were preheated to 200, 400, and 600 degree C to induce damage (microcracks) with varying degrees. Liquid nitrogen was poured in a small, 1"-diameter copper cup attached to the top of the sample, and the resulting acoustic emissions (AEs) and temperature changes on the surface of the sample were monitored. The experiments were conducted under one selected biaxial stress (5.8MPa). The obtained AEs were used to determine the microcracking source locations and amplitude, and the associated moment tensors. The onset time of the AEs was correlated with the cooling temperature, which was used to show that the temperature at the onset of microcracking is not affected significantly by the preexisting damage, compared to the impact of the stress in the sample. Included in this submission are the animations of the AE locations and graphics displaying the measured temperature-AE activity changes for samples with different degrees of microcrack damage.

Research Organization:
DOE Geothermal Data Repository; Lawrence Berkeley National Laboratory
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Program (EE-4G)
Contributing Organization:
Lawrence Berkeley National Laboratory
DOE Contract Number:
EE0009033
OSTI ID:
1842336
Report Number(s):
1362
Availability:
GDRHelp@ee.doe.gov
Country of Publication:
United States
Language:
English