TY - GEN
T1 - Effect of Injection Rate on Micro-seismicity Due to the Hydraulic Fracturing of Granite
AU - Grewal, Inderdeep
AU - Li, Bing Q.
AU - Gonçalves da Silva, Bruno
N1 - Publisher Copyright:
© Springer Nature Singapore Pte Ltd. 2018.
PY - 2018
Y1 - 2018
N2 - Enhanced Geothermal Systems (EGS) utilize the heat of the earth to produce electricity or to heat buildings. In EGS, a crystalline rock, usually granite, is hydraulically-fractured to produce a network of fractures through which the water is circulated. While several pilot projects have proven that this technology can be successful, the strong seismicity caused during the hydraulic fracturing stage is limiting its widespread use. Therefore, the causes of this micro-seismicity need to be better understood. This research evaluated the effect of the rate of water injected in granite specimens on the magnitude and number of micro-seismic events produced during recently-conducted hydraulic fracturing tests. In these tests, granite specimens subjected to two different vertical loads (0 and 5 MPa) were hydraulically-fractured while visual and micro-seismic monitoring was performed. The objectives of this paper were to examine the relationship between the number and amplitudes of the first P-wave arrivals of micro-seismic hits, and the rates of water injected used in the tests. It was found that in pressure increments closer to failure, more AE (Acoustic Emission) hits occur after the highest injection rates. This delayed seismic response may be due to the release of stresses accumulated during the high injection-rate stages of the tests.
AB - Enhanced Geothermal Systems (EGS) utilize the heat of the earth to produce electricity or to heat buildings. In EGS, a crystalline rock, usually granite, is hydraulically-fractured to produce a network of fractures through which the water is circulated. While several pilot projects have proven that this technology can be successful, the strong seismicity caused during the hydraulic fracturing stage is limiting its widespread use. Therefore, the causes of this micro-seismicity need to be better understood. This research evaluated the effect of the rate of water injected in granite specimens on the magnitude and number of micro-seismic events produced during recently-conducted hydraulic fracturing tests. In these tests, granite specimens subjected to two different vertical loads (0 and 5 MPa) were hydraulically-fractured while visual and micro-seismic monitoring was performed. The objectives of this paper were to examine the relationship between the number and amplitudes of the first P-wave arrivals of micro-seismic hits, and the rates of water injected used in the tests. It was found that in pressure increments closer to failure, more AE (Acoustic Emission) hits occur after the highest injection rates. This delayed seismic response may be due to the release of stresses accumulated during the high injection-rate stages of the tests.
KW - Granite
KW - Hydraulic fracturing
KW - Injection rate
KW - Micro-seismic events
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U2 - 10.1007/978-981-13-0113-1_16
DO - 10.1007/978-981-13-0113-1_16
M3 - Conference contribution
AN - SCOPUS:85197862548
SN - 9789811301124
T3 - Proceedings of GeoShanghai 2018 International Conference: Rock Mechanics and Rock Engineering
SP - 137
EP - 144
BT - Proceedings of GeoShanghai 2018 International Conference
A2 - Zhang, Lianyang
A2 - Goncalves da Silva, Bruno
A2 - Zhao, Cheng
PB - Springer
T2 - 4th GeoShanghai International Conference - Rock Mechanics and Rock Engineering, GSIC 2018
Y2 - 27 May 2018 through 30 May 2018
ER -