The EGS Collab project: Outcomes and lessons learned from hydraulic fracture stimulations in crystalline rock at 1.25 and 1.5 km depth

Journal Article · 22 November 2024 · Geothermics

DOI: https://doi.org/10.1016/j.geothermics.2024.103178 · OSTI ID:2481285

Kneafsey, Tim  ^[1]; Dobson, Pat  ^[1]; Blankenship, Doug ^[2]; Schwering, Paul  ^[2]; White, Mark  ^[3]; Morris, Joseph P.  ^[4]; Huang, Lianjie  ^[5]; Johnson, Tim ^[6]; Burghardt, Jeff  ^[6]; Mattson, Earl  ^[7]; Neupane, Ghanashyam  ^[8]; Strickland, Chris ^[6]; Knox, Hunter  ^[6]; Vermuel, Vince ^[6]; Ajo-Franklin, Jonathan ^[9]; Fu, Pengcheng ^[4]; Roggenthen, William ^[10]; Doe, Tom ^[11]; Schoenball, Martin  ^[12]; Hopp, Chet ^[1] ; Tribaldos, Verónica Rodríguez  ^[13]; Ingraham, Mathew ^[2]; Guglielmi, Yves ^[1]; Ulrich, Craig ^[1]; Wood, Todd ^[1]; Frash, Luke ^[5]; Pyatina, Tatiana ^[14]; Vandine, George ^[15]; Smith, Megan  ^[4]; Horne, Roland ^[16]; McClure, Mark  ^[17]; Singh, Ankush  ^[18]; Weers, Jon  ^[19]; Robertson, Michelle ^[1]

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1. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
3. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pacific Northwest Modeling, LLC, Kennewick, WA (United States)
4. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
5. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
6. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
7. Idaho National Laboratory (INL), Idaho Falls, ID (United States); Mattson Hydrology, Victor, ID (United States)
8. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
9. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Rice Univ., Houston, TX (United States)
10. South Dakota School of Mines and Technology, Rapid City, SD (United States)
11. TDoeGeo, Bellevue, WA (United States)
12. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); National Cooperative for the Disposal of Radioactive Waste (Nagra), Wettingen (Switzerland)
13. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Helmholtz-Zentrum Potsdam (HZP), (Germany). German Research Centre for GeoSciences
14. Brookhaven National Laboratory (BNL), Upton, NY (United States)
15. Sanford Underground Research Facility, Lead, SD (United States)
16. Stanford Univ., CA (United States)
17. ResFrac Corporation, Palo Alto, CA (United States)
18. Stanford Univ., CA (United States); ResFrac Corporation, Palo Alto, CA (United States)
19. National Renewable Energy Laboratory (NREL), Golden, CO (United States)

With the goal of better understanding stimulation in crystalline rock for improving enhanced geothermal systems (EGS), the EGS Collab Project performed a series of stimulations and flow tests at 1.25 and 1.5 km depths. The tests were performed in two well-instrumented testbeds in the Sanford Underground Research Facility in Lead, South Dakota, United States. The testbed for Experiment 1 at 1.5 km depth contained two open wells for injection and production and six instrumented monitoring wells surrounding the targeted stimulation zone. Four multi-step stimulation tests targeting hydraulic fracturing and nearly year-long ambient temperature and chilled water flow tests were performed in Experiment 1. The testbed for Experiments 2 and 3 was at 1.25 km depth and contained five open wells in an outwardly fanning five-spot pattern and two fans of well-instrumented monitoring wells surrounding the targeted stimulation zone. Experiment 2 targeted shear stimulation, and Experiment 3 targeted low-flow, high-flow, and oscillating pressure stimulation strategies. Hydraulic fracturing was successful in Experiments 1 and 3 in generating a connected system wherein injected water could be collected. However, the resulting flow was distributed dynamically, and not entirely collected at the anticipated production well. Thermal breakthrough was not observed in the production well, but that could have been masked by the Joule-Thomson effect. Shear stimulation in Experiment 2 did not occur - despite attempting to pressurize the fractures most likely to shear - because of the inability to inject water into a mostly-healed fracture, and the low shear-to-normal stress ratio. The EGS Collab experiments are described to provide a background for lessons learned on topics including induced seismicity, the correlation between seismicity and permeability, distributed and dynamic flow systems, thermoelastic and pressure effects, shear stimulation, local geology, thermal breakthrough, monitoring stimulation, grouting boreholes, modeling, and system management.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: US Department of Energy; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Office; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23), Climate and Environmental Sciences Division (SC-23.1 )
• Contributing Organization: EGS Collab Team
• Grant/Contract Number: 89233218CNA000001; AC02-05CH11231; AC05-76RL01830; AC07-05ID14517; AC36-08GO28308; AC52-07NA27344; NA0003525
• OSTI ID: 2481285
• Report Number(s): LA-UR--24-27407; LLNL--JRNL-2002362; NREL/JA--6A20-92437; PNNL-SA--201843; MainAdminId:75497; UUID:96db144b-3e35-4715-abda-b25d4c7bc63b; MainId:94218
• Journal Information: Geothermics, Journal Name: Geothermics Vol. 126; ISSN 0375-6505
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English