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Locating microearthquakes induced by hydraulic fracturing in crystalline rock
Author(s) -
House Leigh
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i009p00919
Subject(s) - microseism , geology , hydraulic fracturing , induced seismicity , borehole , microearthquake , fracture (geology) , seismology , fracturing fluid , wellbore , petrology , geotechnical engineering , petroleum engineering
Microearthquakes induced by hydraulic fracturing in crystalline rock at a depth of 3.5 km were located with a precision of better than 30 m to obtain information about the geometry and dimensions of the fracture system produced. The induced microseismicity was monitored by a network of five borehole seismic stations; a total of about 800 induced events were reliably located from arrival times. Event locations show a tabular distribution that strikes 350° and dips 65° east, subparallel to the injection well. The injection was intended to produce a fracture system that would hydraulically connect two subparallel wells. A lack of fluid communication between them is consistent with a lack of induced microearthquakes near the target wellbore. The 150 m thickness of the zone of seismicity far exceeds the relative locational uncertainties. The injected fluid appears to have stimulated a zone of rock, rather than simply a single fracture. The distribution of microseismic events presumably envelops the zone of fluid paths created by the fracture experiment.