Fallon Frontier Observatory for Research in Geothermal Energy (FORGE): Phase 2a,b

Project PI: Doug Blankenship – Sandia National Laboratories.

GBCGE project personnel: Dr. James Faulds; Nicholas Hinz; Dr. Bridget Ayling; Elijah Mlawsky

Project collaborators: Navy Geothermal Program Office; United States Geological Survey; LBNL; Innovate Geothermal Inc.; Ormat Nevada Inc.; Hi-Q Geophysical; GeothermEx, Itasca.

Project duration: Phase 2a,b: 18 months, October 2016 to December 2018.

Funding agency: U.S. Department of Energy Geothermal Technologies Office

Total federal funding: Phase 2a,b: $9,500,000

Funding to UNR (sub-award): ~$675,000

Project goals and activities:

This project aimed to demonstrate site viability to host the eventual FORGE field research laboratory, where the scientific and engineering communities can conduct research and test technologies to make Engineered Geothermal Systems (EGS) commercially viable. In Phase 1, the Fallon FORGE site was selected as a potential candidate for experiments related to developing deep, engineered geothermal reservoirs. Phase 1 activities included substantial compilation and review of the existing geological, geochemical, geophysical, environmental, logistical, and hydrological data from the Fallon site to determine the suitability of the site to host FORGE. The site was demonstrated to meet the criteria required to progress to Phase 2, including: (1) reservoir temperatures between 175 – 225 °C, (2) target reservoir depth between 1.5 – 4 km, (3) low permeability rocks (< 10-16 m²), (4) crystalline basement lithology, (5) favorable stress regime, and (6) no hydrothermal system present (Faulds et al., 2015; Siler et al., 2016). The Fallon FORGE project advanced to Phase 2, in which environmental permitting was completed and additional geoscientific data was collected to further characterize the site and reduce the geological uncertainty. A major activity of Phase 2 was drilling a deep observation well (well 21-31 to 2,460 m) to further characterize the Mesozoic basement characteristics.

Map showing well locations at Fallon FORGE.
Map illustrating wells drilled at the Fallon FORGE site, including the location of the well 21-31 that was drilled during Phase 2b of the project (February – March 2018).
Photo of a geothermal drill rig
Drilling of Fallon FORGE well 21-31 commences in February 2018. The well reaching total depth in late March, at 2481 meters below surface. Photo credit: Bridget Ayling.
Photo of people visiting a drill rig at the Fallon FORGE site
GBCGE staff and students enjoy a site visit during the drilling of Fallon FORGE well 21-31 in February 2018. From L to R; Kurt Kraal, Elijah Mlawsky, and Jason Craig. Photo credit: Bridget Ayling.

Project outputs and conference publications (listed chronologically):

Faulds, J.E., Blankenship, D., Hinz, N., Sabin, A., Nordquist, J., Hickman, S., Glen, J., Kennedy, M., Siler, D.L., Robertson-Tait, A., Williams, C., Drakos, P., Calvin, W., (2015), Geologic Setting of the Proposed Fallon Forge Site, Nevada: Suitability for EGS Research and Development. Geothermal Resources Council Transactions, Vol. 39. https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1032163

Hinz, N.H., Faulds, J.E., Siler, D.L., Tobin, B., Blake, K., Tiedeman, A., Sabin, A., Blankenship, D., Kennedy, M., Rhodes, G., Nordquist, J., Hickman, S., Glen, J., Williams, C., Robertson-Tait, A., Calvin, W.,  (2016), Stratigraphic and Structural Framework of the Proposed Fallon FORGE Site, Nevada. Proceedings of the 41st Workshop on Geothermal Reservoir Engineering, Stanford University. SGP-TR-211.  https://www.geothermal-energy.org/cpdb/record_detail.php?id=26439

Siler, D.L., Faulds, J. E., Blankenship, D., Hinz, N. H., Sabin, A., Nordquist, J., Hickman, S.,  Glen, J., Kennedy, M., Robertson-Tait, A, Williams, C., Drakos, P., Calvin, W., (2016), The geologic framework of the Fallon FORGE site: Geothermal Resource Council Transactions, v. 40, p.573-584.  https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1032373 

Hinz, N.H., Faulds, J.E., Glen, J., Siler, D>L., Queen, J., Witter, J.B., Tiedeman, A., Blake, K., Blankenship, D.,  (2017), Fallon Forge: Analog Geologic Studies, Reanalysis of 2D Seismic Profiles, and New Potential Fields Geophysics Studies. Geothermal Resources Council Transactions. https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1033724

Majer et al., (2017), Seismicity near the Fallon FORGE Site and Development of an Induced Seismicity Mitigation Plan. Geothermal Resources Council Transactions, Vol. 41. https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1033726 

Blankenship et al., (2017), Proposed Fallon FORGE Site: Phase 2 Update. Proceedings of the 42nd Workshop on Geothermal Reservoir Engineering, Stanford University. https://www.geothermal-energy.org/cpdb/record_detail.php?id=27866

Sonnenthal, E., Pettitt, W., Smith, T., Riahi, A., Siler, D., Kennedy, M., Majer, E., Dobson, P., Ayling, B. F., Damjanac, B., Blankenship, D. (2018). Continuum Thermal-Hydrological-Mechanical Modeling of the Fallon FORGE Site. Geothermal Resources Council Transactions, Vol.42. https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1033933

Robertson-Tait, A., Camacho-Lopez, T., Sullivan, P., Villavert, M., Tang, J., Blankenship, D., Kennedy, M., Majer, E., Nordquist, J., Akerley, J., Ayling, B. F., Faulds, J. E., Roque-Rivera, R., (2018), Communications and Outreach for Public Acceptance of Complex Technical Projects: Experience from the Fallon FORGE Project. Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford University, February 12-14th, 2018, SGP-TR-213. https://www.geothermal-energy.org/cpdb/record_detail.php?id=28278

Siler, D., Hinz, N. H., Faulds, J. E., Ayling, B. F., Blake, K., Tiedeman, A., Sabin, A., Blankenship, D., Kennedy, M., Rhodes, G., Glen, J., Phelps, G.A, Fortuna, M., Queen, J., Witter, J. B., (2018), The Geologic and Structural Framework of the Fallon FORGE Site. Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford University, February 12-14th, 2018, SGP-TR-213. https://www.geothermal-energy.org/cpdb/record_detail.php?id=28293

Faulds, J.E., Hinz, N.H., Siler, D.L., Glen, J.M., Fortuna, M.A., Queen, J.H., Blake, K., and Fallon FORGE team, (2018), Update on the stratigraphic and structural framework of the proposed Fallon FORGE site, Nevada: Geothermal Resources Council Transactions, v. 42, p. 1026-1046.

Ayling, B., and Blankenship, D., (2018). Phase 2 update for the Fallon FORGE site, Nevada, USA. Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford University, February 12-14th, 2018. SGP-TR-213.  https://www.geothermal-energy.org/cpdb/record_detail.php?id=28153

Kraal, K., and Ayling, B.F., (2019). Hyperspectral Characterization of Fallon FORGE Well 21-31: New Data and Technology Applications. Proceedings of the 44th Workshop on Geothermal Reservoir Engineering, Stanford University, February 11-13th, 2019. SGP-TR-214. https://www.geothermal-energy.org/cpdb/record_detail.php?id=29032 

Kraal, K.O., Ayling, B.F., Blake, K., Hackett, L., Perdana, T.S.P., (2021). Linkages between hydrothermal alteration, natural fractures, and permeability: Integration of borehole data for reservoir characterization at the Fallon FORGE EGS site, Nevada, USA. Geothermics, Vol. 89. https://doi.org/10.1016/j.geothermics.2020.101946

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