An alternative interpretation of microseismic events during hydraulic fracturing

Arash Dahi Taleghani, Juan M. Lorenzo

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

It is common practice in industry to monitor hydraulic fracturing jobs by picking major, micro-earthquake events in seismograms whose source locations form a spatial pattern used for interpreting induced fractures. Surprisingly, controversy still surrounds the interpretation of these scattered, discrete events. Many authors conclude that hydraulic fractures are generated by shear failure events rather than tensile failures. This interpretation contradicts our common understanding of fracture mechanics, which describes the hydraulic fracture process as taking place predominantly in mode-I failure (pure tension). We propose that band-width limited instrumentation during seismic field recording may be partly to blame. Low-frequency (<5 Hz) tensile-source events which are expected to occur continuously between shear events are largely ignored. Herein, we try to compare the total energy of detected shear events with the total energy of expected low-frequency tensile events in the background in order to justify the main (tensile) mechanism of fracturing. Major, shear-mechanism events may not describe accurately the temporal and spatial pattern of induced fractures in the subsurface. Shear events may only represent the locations where hydraulic fractures intersect pre-existing discontinuities. Therefore, by only considering shear events, we may not be able to make a correct estimation of the orientation and extension of the hydraulic fractures. We suggest that only by recording silent (low frequency) events, we will truly be able to describe induced subsurface fracture geometries.

Original languageEnglish (US)
Title of host publicationSociety of Petroleum Engineers - SPE Hydraulic Fracturing Technology Conference 2011
Pages481-491
Number of pages11
StatePublished - Jun 27 2011
EventSPE Hydraulic Fracturing Technology Conference 2011 - The Woodlands, TX, United States
Duration: Jan 24 2011Jan 26 2011

Publication series

NameSociety of Petroleum Engineers - SPE Hydraulic Fracturing Technology Conference 2011

Other

OtherSPE Hydraulic Fracturing Technology Conference 2011
CountryUnited States
CityThe Woodlands, TX
Period1/24/111/26/11

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geotechnical Engineering and Engineering Geology

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  • Cite this

    Taleghani, A. D., & Lorenzo, J. M. (2011). An alternative interpretation of microseismic events during hydraulic fracturing. In Society of Petroleum Engineers - SPE Hydraulic Fracturing Technology Conference 2011 (pp. 481-491). (Society of Petroleum Engineers - SPE Hydraulic Fracturing Technology Conference 2011).