@inproceedings{18407ce1439a428bab71ed5ad5982205,
title = "Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment",
abstract = "Experiment 2 of the EGS Collab project is aimed at testing stimulation by hydro-shearing of existing natural fractures, versus Experiment 1, which is focused on hydraulic fracturing a rock mass to enhance permeability. The main criterion for the testbed selection in Experiment 2 is the presence of an interconnected network of fractures, at least 10 meters in extent, and with orientations such that shear slip can be induced at injection pressures less than the minimum horizontal stress (Shmin). The feasibility analysis for this experiment requires a well-constrained stress state along with well-characterized fracture networks. The fracture systems at two candidate locations in the Sanford Underground Research Facility (SURF), the 4850 Level (number refers to depth below ground surface in feet) and the 4100 Level, have been characterized to different extents. The 4850 Level has a well-characterized Discrete Fracture Network (DFN) from borehole (drilled for an experimental test bed) and drift observations. In contrast, the 4100 level has a fracture network characterized only by observations from the drift wall, which provides little constraint on fracture extents. This paper will present assessments for the interpreted slip potential for the natural fractures at the two locations. Data uncertainties are addressed by performing a probabilistic analysis that takes into account the uncertainty in the stress state, uncertainty in the fracture properties, and preliminary borehole locations. There is strong evidence of shear stimulation of some natural fractures in Experiment 1 on the 4850 level. We use examples of natural fractures strongly linked to shear stimulation in Experiment 1 from multiple monitoring indicators to test the consistency of the stress model and guide the uncertainty interpretation. This analysis is intended to guide the site selection process for Experiment 2 by highlighting the fracture orientations that are likely to be shear-stimulated in a majority of modeled realizations.",
keywords = "EGS Collab, Shear Stimulation, Site Selection, Slip Potential",
author = "{The EGS Collab Team Multiple affiliations} and Ankush Singh and Mark Zoback and Ghanashyam Neupane and Dobson, {Patrick F.} and Kneafsey, {Timothy J.} and Martin Schoenball and Yves Guglielmi and Craig Ulrich and William Roggenthen and Nuri Uzunlar and Joseph Morris and Pengcheng Fu and Schwering, {Paul C.} and Knox, {Hunter A.} and Luke Frash and Doe, {Thomas W.} and Herb Wang and Kate Condon and Bud Johnston and J. Ajo-Franklin and T. Baumgartner and K. Beckers and D. Blankenship and A. Bonneville and L. Boyd and S. Brown and Brown, {S. T.} and Burghardt, {J. A.} and T. Chen and Y. Chen and K. Condon and Cook, {P. J.} and D. Crandall and T. Doe and Doughty, {C. A.} and D. Elsworth and J. Feldman and A. Foris and Z. Frone and P. Fu and K. Gao and A. Ghassemi and H. Gudmundsdottir and Y. Guglielmi and G. Guthrie and B. Haimson and A. Hawkins and J. Heise and M. Maceira and Y. Polsky",
note = "Publisher Copyright: {\textcopyright} 2019 Geothermal Resources Council. All rights reserved.; Geothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019 ; Conference date: 15-09-2019 Through 18-09-2019",
year = "2019",
month = jan,
day = "1",
language = "English",
series = "Transactions - Geothermal Resources Council",
publisher = "Geothermal Resources Council",
pages = "405--424",
booktitle = "Geothermal",
}
