Geomechanical evaluation of natural shear fractures in the EGS Collab experiment 1 test bed

L. P. Frash, N. J. Welch, J. W. Carey, J. Ajo-Franklin, S. J. Bauer, T. Baumgartner, K. Beckers, D. Blankenship, A. Bonneville, L. Boyd, S. T. Brown, J. A. Burghardt, T. Chen, Y. Chen, K. Condon, P. J. Cook, P. F. Dobson, T. Doe, C. A. Doughty, D. ElsworthJ. Feldman, A. Foris, Z. Frone, P. Fu, K. Gao, A. Ghassemi, H. Gudmundsdottir, Y. Guglielmi, G. Guthrie, B. Haimson, A. Hawkins, J. Heise, C. G. Herrick, M. Horn, R. N. Horne, J. Horner, M. Hu, H. Huang, L. Huang, K. Im, M. Ingraham, T. C. Johnson, B. Johnston, S. Karra, K. Kim, D. K. King, T. Kneafsey, H. Knox, J. Knox, D. Kumar, K. Kutun, M. Lee, K. Li, R. Lopez, M. Maceira, N. Makedonska, C. Marone, E. Mattson, M. W. McClure, J. McLennan, T. McLing, R. J. Mellors, E. Metcalfe, J. Miskimins, J. P. Morris, S. Nakagawa, G. Neupane, G. Newman, A. Nieto, C. M. Oldenburg, W. Pan, R. Pawar, P. Petrov, B. Pietzyk, R. Podgorney, Y. Polsky, S. Porse, S. Richard, B. Q. Roberts, M. Robertson, W. Roggenthen, J. Rutqvist, D. Rynders, H. Santos-Villalobos, M. Schoenball, P. Schwering, V. Sesetty, A. Singh, M. M. Smith, H. Sone, C. E. Strickland, J. Su, C. Ulrich, N. Uzunlar, A. Vachaparampil, C. A. Valladao, W. Vandermeer, G. Vandine, D. Vardiman, V. R. Vermeul, J. L. Wagoner, H. F. Wang, J. Weers, J. White, M. D. White, P. Winterfeld, T. Wood, H. Wu, Y. S. Wu, Y. Wu, Y. Zhang, Y. Q. Zhang, J. Zhou, Q. Zhou, M. D. Zoback

Research output: Contribution to conferencePaperpeer-review

8 Scopus citations


Natural fractures can have a significant influence on hydraulic stimulation. One must estimate the peak and residual geomechanical strengths, hydraulic conductivity, and in-situ stress state for the exiting natural fractures in a site in order to identify those natural fractures that are prone to hydraulic opening and/or shear. We apply a triaxial direct-shear method to measure these fracture properties in the Poorman’s schist for the EGS Collab project’s Experiment 1 test bed at the Sanford Underground Research Facility. In addition, we measure rock matrix density, matrix permeability, and acoustic velocity anisotropy. Using this data, we identify that south-east striking foliation-parallel fractures in this test bed are vulnerable to shear stimulation and can be hydrosheared at in-situ stress conditions. However, natural infilled fractures which are relatively easy to locate and are ubiquitous at the site were found to be too strong and high-friction for hydroshearing, with exception for those parallel to the foliation of the rock.

Original languageEnglish (US)
StatePublished - Jan 1 2019
Event53rd U.S. Rock Mechanics/Geomechanics Symposium - Brooklyn, United States
Duration: Jun 23 2019Jun 26 2019


Conference53rd U.S. Rock Mechanics/Geomechanics Symposium
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics

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