TY - JOUR
T1 - The Role of Mineral Composition on the Frictional and Stability Properties of Powdered Reservoir Rocks
AU - Zhang, Fengshou
AU - An, Mengke
AU - Zhang, Lianyang
AU - Fang, Yi
AU - Elsworth, Derek
N1 - Funding Information:
This research is supported by the National Natural Science Foundation of China under grants 41672268 and 41772286, and the U.S. Department of Energy (DOE) under Grant DE-FE0023354. The useful discussions with Chris Marone and Changrong He are also greatly appreciated. We thank the two reviewers for their insightful comments and instructive suggestions to improve the manuscript. The data for this paper are in the tables and the supporting information.
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/2
Y1 - 2019/2
N2 - The growing hazard of induced seismicity driven by the boom in unconventional resources exploitation is strongly linked to fault activation. We perform laboratory measurements on simulated fault gouges comprising powdered reservoir rocks from major oil and gas production sites in China, to probe the control of mineral composition on fault friction and stability responses during reservoir stimulation. Double direct shear experiments were conducted on gouges with phyllosilicate content ranging from 0 to 30 wt.% and grain sizes <150 μm, at constant normal stresses of 10–40 MPa and conditions of room temperature and water saturation. The velocity step and slide-hold-slide sequences were employed to evaluate frictional stability and static healing, respectively. Results indicate that the mineralogy of the gouges exhibit a strong control on the frictional strength, stability, and healing. Phyllosilicate-rich samples show lower frictional strength μ and higher values of (a − b), promoting stable sliding. For the gouges studied, the frictional strength decreases monotonically with increasing phyllosilicate content, and a transition from velocity weakening to velocity strengthening behavior is evident at 15 wt.% phyllosilicates. Intermediate healing rates are common in gouges with higher content of phyllosilicates, with high healing rates predominantly in phyllosilicate-poor gouges. As an indispensable component in reservoir rocks, the carbonates are shown to affect both the frictional stability and healing response. These findings can have important implications for understanding the effects of mineralogy on fault behavior and induced seismic potential in geoengineering activities, particularly in reservoirs in China.
AB - The growing hazard of induced seismicity driven by the boom in unconventional resources exploitation is strongly linked to fault activation. We perform laboratory measurements on simulated fault gouges comprising powdered reservoir rocks from major oil and gas production sites in China, to probe the control of mineral composition on fault friction and stability responses during reservoir stimulation. Double direct shear experiments were conducted on gouges with phyllosilicate content ranging from 0 to 30 wt.% and grain sizes <150 μm, at constant normal stresses of 10–40 MPa and conditions of room temperature and water saturation. The velocity step and slide-hold-slide sequences were employed to evaluate frictional stability and static healing, respectively. Results indicate that the mineralogy of the gouges exhibit a strong control on the frictional strength, stability, and healing. Phyllosilicate-rich samples show lower frictional strength μ and higher values of (a − b), promoting stable sliding. For the gouges studied, the frictional strength decreases monotonically with increasing phyllosilicate content, and a transition from velocity weakening to velocity strengthening behavior is evident at 15 wt.% phyllosilicates. Intermediate healing rates are common in gouges with higher content of phyllosilicates, with high healing rates predominantly in phyllosilicate-poor gouges. As an indispensable component in reservoir rocks, the carbonates are shown to affect both the frictional stability and healing response. These findings can have important implications for understanding the effects of mineralogy on fault behavior and induced seismic potential in geoengineering activities, particularly in reservoirs in China.
KW - fault gouge
KW - frictional stability
KW - healing
KW - mineral composition
KW - reservoir rocks
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U2 - 10.1029/2018JB016174
DO - 10.1029/2018JB016174
M3 - Article
AN - SCOPUS:85062353988
SN - 2169-9313
VL - 124
SP - 1480
EP - 1497
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
IS - 2
ER -