Field Experiments and Model Validation: The EGS Collab Project

The EGS Collab Team

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

1 Scopus citations


Implementing enhanced geothermal systems (EGS) will require improvements in understanding stimulation of crystalline rock to create appropriate flow pathways, and the ability to effectively simulate both the stimulation and the flow and transport processes in the resulting fracture network. The US Department of Energy (DOE) is addressing these and other challenges at multiple scales. The EGS Collab project, addressed here, is performing tests and modeling at the 10 m scale. The FORGE project is performing tests at the full reservoir scale. The EGS Collab team created an underground testbed at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, at a depth of approximately 1.5 km to examine hydraulic fracturing (Experiment 1). We are currently building a second testbed at SURF at a depth of about 1.25 km aimed at investigating shear stimulation (Experiment 2). In Experiment 1, we drilled eight boreholes in a well-characterized phyllite and installed geophysical sensors in six of them to create a well-instrumented testbed to allow careful monitoring of stimulation events and flow tests. Numerical simulation was used to answer key experimental design questions, to forecast fracture propagation trajectories and extents, and to analyze and evaluate results both in near-real-time and in detailed process studies. Stimulations performed in this testbed allowed quantification of processes occurring during stimulation and the examination of dynamic flow occurrences. Long-term ambient temperature and chilled water flow tests were performed in addition to many tracer tests to examine system behavior. Our second testbed, targeted at shear stimulation, is currently being built at the SURF Facility at a depth of about 1.25 km in amphibolite under a different set of stress and fracture conditions than Experiment 1.

Original languageEnglish (US)
Title of host publication55th U.S. Rock Mechanics / Geomechanics Symposium 2021
PublisherAmerican Rock Mechanics Association (ARMA)
ISBN (Electronic)9781713839125
StatePublished - 2021
Event55th U.S. Rock Mechanics / Geomechanics Symposium 2021 - Houston, Virtual, United States
Duration: Jun 18 2021Jun 25 2021

Publication series

Name55th U.S. Rock Mechanics / Geomechanics Symposium 2021


Conference55th U.S. Rock Mechanics / Geomechanics Symposium 2021
Country/TerritoryUnited States
CityHouston, Virtual

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics


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