Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment

The EGS Collab Team Multiple affiliations

Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment

The EGS Collab Team Multiple affiliations

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

9 Scopus citations

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 (S_hmin). 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.

Original language	English
Title of host publication	Geothermal
Subtitle of host publication	Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019
Publisher	Geothermal Resources Council
Pages	405-424
Number of pages	20
ISBN (Electronic)	0934412243, 9781713806141
State	Published - Jan 1 2019
Event	Geothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019 - Palm Springs, United States Duration: Sep 15 2019 → Sep 18 2019

Publication series

Name	Transactions - Geothermal Resources Council
Volume	43
ISSN (Print)	0193-5933

Conference

Conference	Geothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019
Country/Territory	United States
City	Palm Springs
Period	09/15/19 → 09/18/19

Funding

This material was based upon work supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Office of Technology Development, Geothermal Technologies Program, under Award Number DE-AC02-05CH11231 with LBNL and other subcontracts. The United States Government retains, and the publisher by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The research supporting this work took place in whole or in part at the Sanford Underground Research Facility in Lead, South Dakota. The assistance of the Sanford Underground Research Facility and its personnel in providing physical access and general logistical and technical support is gratefully acknowledged; we thank Kathy Hart and Jaret Heise for providing geologic maps of the Homestake Mine. The hydrostructural model was created using Golder's FracMan software. The earth model output of the fractures was generated using Leapfrog Software. This material was based upon work supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Office of Technology Development, Geothermal Technologies Program, under Award Number DE-AC02-05CH11231 with LBNL and other subcontracts. The United States Government retains, and the publisher by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The research supporting this work took place in whole or in part at the Sanford Underground Research Facility in Lead, South Dakota. The assistance of the Sanford Underground Research Facility and its personnel in providing physical access and general logistical and technical support is gratefully acknowledged; we thank Kathy Hart and Jaret Heise for providing geologic maps of the Homestake Mine. The hydrostructural model was created using Golder’s FracMan software. The earth model output of the fractures was generated using Leapfrog Software. Copyright © Seequent Limited. Leapfrog and all other Seequent Limited product or service names are registered trademarks or trademarks of Seequent Limited.

Keywords

EGS Collab
Shear Stimulation
Site Selection
Slip Potential

Cite this

The EGS Collab Team Multiple affiliations (2019). Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment. In Geothermal: Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019 (pp. 405-424). (Transactions - Geothermal Resources Council; Vol. 43). Geothermal Resources Council.

The EGS Collab Team Multiple affiliations. / Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment. Geothermal: Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019. Geothermal Resources Council, 2019. pp. 405-424 (Transactions - Geothermal Resources Council).

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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",

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The EGS Collab Team Multiple affiliations 2019, Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment. in Geothermal: Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019. Transactions - Geothermal Resources Council, vol. 43, Geothermal Resources Council, pp. 405-424, Geothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019, Palm Springs, United States, 09/15/19.

Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment. / The EGS Collab Team Multiple affiliations.
Geothermal: Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019. Geothermal Resources Council, 2019. p. 405-424 (Transactions - Geothermal Resources Council; Vol. 43).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - The EGS Collab Team Multiple affiliations

AU - Singh, Ankush

AU - Zoback, Mark

AU - Neupane, Ghanashyam

AU - Dobson, Patrick F.

AU - Kneafsey, Timothy J.

AU - Schoenball, Martin

AU - Guglielmi, Yves

AU - Ulrich, Craig

AU - Roggenthen, William

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AU - Johnston, Bud

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AU - Baumgartner, T.

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AU - Brown, S. T.

AU - Burghardt, J. A.

AU - Chen, T.

AU - Chen, Y.

AU - Condon, K.

AU - Cook, P. J.

AU - Crandall, D.

AU - Doe, T.

AU - Doughty, C. A.

AU - Elsworth, D.

AU - Feldman, J.

AU - Foris, A.

AU - Frone, Z.

AU - Fu, P.

AU - Gao, K.

AU - Ghassemi, A.

AU - Gudmundsdottir, H.

AU - Guglielmi, Y.

AU - Guthrie, G.

AU - Haimson, B.

AU - Hawkins, A.

AU - Heise, J.

AU - Maceira, M.

AU - Polsky, Y.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - 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.

AB - 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.

KW - EGS Collab

KW - Shear Stimulation

KW - Site Selection

KW - Slip Potential

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M3 - Conference contribution

AN - SCOPUS:85096149776

T3 - Transactions - Geothermal Resources Council

SP - 405

EP - 424

BT - Geothermal

PB - Geothermal Resources Council

T2 - Geothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019

Y2 - 15 September 2019 through 18 September 2019

ER -

The EGS Collab Team Multiple affiliations. Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment. In Geothermal: Green Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019. Geothermal Resources Council. 2019. p. 405-424. (Transactions - Geothermal Resources Council).

Slip tendency analysis of fracture networks to determine suitability of candidate testbeds for the EGS collab hydroshear experiment

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