Development of borehole tangential deformation gage and its application for determining the stress in rock

A. Igarashi, T. Ito, K. Sekine, Kazuo Hayashi

Research output: Contribution to conferencePaperpeer-review

2 Citations (Scopus)

Abstract

We developed a new reusable gage designed upon a concept completely different to that of the conventional ones. The gage allows us to measure the tangential deformation of borehole wall. We tested the gage by a laboratory experiment and examined how it could measure accurately borehole deformation caused by packer inflation. The rock specimen had two drilled borehole of 76 mm in diameter with hydraulically-induced axial fractures. The results show that the deformation measured by the gage located near by the fracture mouth increased linearly with the packer pressure initially and it deviated from the initial trend afterwards. The deviation from linearity of the deformation-packer pressure curve was associated with the fracture opening. Then we confirmed that the packer pressure at the beginning of deviation was close to the reopening pressure Pr estimated by the Kirsch equation, i.e. Pr = 3Sh - SH, where SH and Sh (S H ≥ Sh) are the biaxial compressive loads externally applied to the specimen as the direction of Sh being normal to the fractures. This indicates that we can estimate the magnitude of SH from the detected reopening pressure and the Kirsch equation on condition that the magnitude of Sh is estimated using other approaches.

Original languageEnglish
Publication statusPublished - 2008 Dec 1
Event42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 2008 - San Francisco, CA, United States
Duration: 2008 Jun 292008 Jul 2

Other

Other42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 2008
CountryUnited States
CitySan Francisco, CA
Period08/6/2908/7/2

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Fingerprint Dive into the research topics of 'Development of borehole tangential deformation gage and its application for determining the stress in rock'. Together they form a unique fingerprint.

Cite this