The EGS Collab project: Status and Accomplishments

EGS Collab Team

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

1 Scopus citations


The EGS Collab project, supported by the US Department of Energy, is addressing challenges in implementing enhanced geothermal systems (EGS). This includes improving understanding of the 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 project is performing intensively monitored rock stimulation and flow tests at the 10-m scale in an underground research laboratory. Data and observations from the field test are compared to simulations to understand processes and to build confidence in numerical modeling of the processes. In Experiment 1, we examined hydraulic fracturing an underground test bed at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, at a depth of approximately 1.5 km. We drilled eight sub-horizontal boreholes in a well-characterized phyllite. Six of the boreholes were instrumented with many sensor types to allow careful monitoring of stimulation events and flow tests, and the other two boreholes were used for water injection and production. We performed a number of stimulations and flow tests in the testbed. Our monitoring systems allowed detailed observations and collection of numerous data sets of processes occurring during stimulation and during dynamic flow tests. Long-term ambient temperature and chilled water flow tests were performed in addition to many tracer tests to examine system behavior. Data were rapidly analyzed, allowing adaptive control of the tests. Numerical simulation was used to answer key experimental design questions, to forecast fracture propagation trajectories and extents, and to analyze and evaluate results. Many simulations were performed in near-real-time in conjunction with the field experiments, with more detailed process study simulations performed on a longer timeframe. Experiment 2 will examine hydraulic shearing in a test bed being built at the SURF at a depth of about 1.25 km in amphibolite under a different set of stress and fracture conditions than Experiment 1. Five sets of fracture orientations were considered in design, and three orientations seem to be consistently observed.

Original languageEnglish (US)
Title of host publicationUsing the Earth to Save the Earth - 2021 Geothermal Rising Conference, GRC 2021
PublisherGeothermal Resources Council
Number of pages16
ISBN (Electronic)0934412278
StatePublished - 2021
Event2021 Geothermal Rising Conference: Using the Earth to Save the Earth, GRC 2021 - San Diego, United States
Duration: Oct 3 2021Oct 6 2021

Publication series

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


Conference2021 Geothermal Rising Conference: Using the Earth to Save the Earth, GRC 2021
Country/TerritoryUnited States
CitySan Diego

All Science Journal Classification (ASJC) codes

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


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