The effect of pulse frequency on the acoustic emission characteristics in coal bed hydraulic fracturing

J. Wu, S. H. Zhang, H. Cao, John M Kemeny

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

3 Scopus citations

Abstract

In order to fully understand the deformation and damage characteristics and to further reveal the evolutionary process of coal. In this article, experiments on acoustic emission characteristics of the Pulse Hydraulic Fracturing (PHF) process under different pulse frequencies, are carried out by the large-size true tri-axial hydraulic fracturing test system and the PAC AE instrument. The acoustic emission behavior evolution characteristics, the damage evolutionary rule, the AE location distribution and the dynamic feature of b-value are analyzed. The results show that the evolution of acoustic emission behavior stimulated by PHF in coal bed can be divided into four phases with time: gentle period, acceleration period, boosting period and steady period. The damage evolution process can be divided into three phases: initial damage period, damage development period and damage accelerating development period. Our results show that AE information can reasonably reflect the damage evolution character of coal. Besides, a lower frequency corresponded to a stronger AE energy release and a higher intensity of fracture extension inside the samples during the PHF process. Also in this case, a number of AE events were produced at early stage, where AE location distribution was more homogenous. For the b-value, during the whole PHF process, its variation was similar under different frequencies.

Original languageEnglish (US)
Title of host publication50th US Rock Mechanics / Geomechanics Symposium 2016
PublisherAmerican Rock Mechanics Association (ARMA)
Pages1496-1502
Number of pages7
Volume2
ISBN (Electronic)9781510828025
StatePublished - 2016
Event50th US Rock Mechanics / Geomechanics Symposium 2016 - Houston, United States
Duration: Jun 26 2016Jun 29 2016

Other

Other50th US Rock Mechanics / Geomechanics Symposium 2016
CountryUnited States
CityHouston
Period6/26/166/29/16

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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