The EGS Collab hydroshear experiment at the Sanford underground research facility - Siting criteria and evaluation of candidate sites

EGS Collab Team

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

3 Scopus citations

Abstract

The objective of the EGS Collab project is to establish a suite of intermediate-scale (~10-20 m) field test beds coupled with stimulation and interwell flow tests to provide a basis to better understand fracture stimulation methods, resulting fracture geometries, and processes that control heat transfer between rock and stimulated fractures. Experiment 1 of the project is being conducted at a depth of ~1.5 km in the Sanford Underground Research Facility (SURF) on the 4850 Level (ft. below the ground surface). The stimulation method planned for Experiment 2 of this project is hydroshearing of an existing natural fracture. In siting this experiment, there are several key geologic criteria that need to be met. These include: 1) the fracture should be least 10 m in length so that it could be intersected by two boreholes that are spaced that far apart; 2) it should be optimally oriented relevant to the stress field so that it is critically stressed; 3) the site should have appropriate stress conditions (not too shallow a depth); 4) the fracture should have sufficient permeability to allow for prestimulation flow testing, but not too high a permeability that would preclude permeability enhancement via shear stimulation; 5) the fracture should not intersect other features (permeable fractures, boreholes, adjacent drifts) that could serve as major leak-off zones; 6) the site should not be complicated by geology (a single lithology would be preferred). In addition, there are logistical criteria that will also influence site selection, including: 1) site availability/access, 2) logistical support, e.g., power, internet, water, operating rail system; 3) drift size and orientation compatible with drilling and site operations; 4) appropriate ground support. There are only two deep levels at SURF that can be accessed by the Yates Shaft: the 4100 and the 4850, so we limited our search to these two levels. Currently, three candidate sites are being evaluated: the existing Experiment 1 site and its surroundings on the West Drift on the 4850 level, and two locations on the 4100 level. This paper will evaluate advantages, disadvantages, and risks associated with these three options at SURF.

Original languageEnglish (US)
Title of host publicationGeothermal's Role in Today's Energy Market - Geothermal Resources Council 2018 Annual Meeting, GRC 2018
PublisherGeothermal Resources Council
Pages708-723
Number of pages16
ISBN (Electronic)0934412235
StatePublished - 2018
EventGeothermal Resources Council 2018 Annual Meeting: Geothermal's Role in Today's Energy Market, GRC 2018 - Reno, United States
Duration: Oct 14 2018Oct 17 2018

Publication series

NameTransactions - Geothermal Resources Council
Volume42
ISSN (Print)0193-5933

Conference

ConferenceGeothermal Resources Council 2018 Annual Meeting: Geothermal's Role in Today's Energy Market, GRC 2018
CountryUnited States
CityReno
Period10/14/1810/17/18

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Geophysics

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    EGS Collab Team (2018). The EGS Collab hydroshear experiment at the Sanford underground research facility - Siting criteria and evaluation of candidate sites. In Geothermal's Role in Today's Energy Market - Geothermal Resources Council 2018 Annual Meeting, GRC 2018 (pp. 708-723). (Transactions - Geothermal Resources Council; Vol. 42). Geothermal Resources Council.