UPDATE: Due to weather conditions and flight delays of the originally scheduled speaker, Jim Faulds will be filling in as speaker tonight at the NPGS meeting and will present about the Fallon FORGE site.
Topic: Geologic Setting of the Proposed Geothermal FORGE Site at Fallon, Western Nevada: Suitability for EGS Research and Development
Speakers: Jim Faulds, NBMG Director and State Geologist
Abstract: The Frontier Observatory for Research in Geothermal Energy (FORGE) offers a unique opportunity to develop the technologies, techniques, and knowledge needed to make enhanced geothermal systems (EGS) a commercially viable electricity generation option for the USA. The objective of this project is to establish and manage FORGE as a dedicated site, where the subsurface scientific and engineering community will be eligible to develop, test, and improve new technologies and techniques in an ideal EGS environment. This will allow the geothermal and other subsurface communities to gain a fundamental understanding of the key mechanisms controlling EGS success, in particular how to generate and sustain fracture networks in the spectrum of basement rock formations using different stimulation technologies and techniques. This critical knowledge will be used to design and test methodologies for developing large-scale, economically sustainable heat exchange systems, thereby paving the way for a rigorous and reproducible approach that will reduce industry development risk. Essential to this process is a comprehensive site characterization, monitoring instrumentation, and data collection effort that will capture a higher-fidelity picture of EGS creation and evolution processes than any prior demonstration. Finally, a dedicated FORGE allows for the highly integrated comparison of technologies and tools in a controlled and well-characterized environment, as well as the rapid dissemination of technical data to the research community, developers, and other interested parties.
The proposed Fallon FORGE site lies within and adjacent to the Naval Air Station Fallon (NASF) directly southeast of the town of Fallon, Nevada, within the large basin of the Carson Sink in west-central Nevada. The site is located on two parcels that include land owned by the NASF and leased and owned by Ormat Nevada, Inc. Late Miocene to Quaternary basin-fill sediments are 0.5 to >1 km thick and overlie Oligocene-Miocene volcanic and lesser sedimentary rocks. The volcanic section is 0.5 to 1.0 km thick and dominated by Miocene mafic lavas. The Neogene section rests nonconformably on heterogeneous Mesozoic basement, which consists of Triassic-Jurassic metamorphic rocks intruded by Cretaceous granitic plutons. The structural framework is dominated by a gently west-tilted half graben cut by moderately to steeply dipping N- to NNE-striking normal faults.
Fallon was selected for a potential FORGE site due to its extensional tectonic setting, abundance of available data, existing infrastructure, and documented temperatures, permeability, and lithologic composition of potential reservoirs that fall within the ranges specified by DOE for FORGE. Since the early 1970s, more than 45 wells have been drilled for geothermal exploration within the area. Four exploration wells within the FORGE site are available for use in the project. There is also an existing, ten-station micro-seismic earthquake (MEQ) array that has been collecting data since 2001. The well data indicate that a sizeable area (~4.5 km2) has adequate temperatures in crystalline basement but lacks sufficient permeability within the proposed FORGE site. There are two possible, competent target formations in Mesozoic basement for stimulation in the FORGE project area: 1) Jurassic felsic metavolcanic rocks/and or quartzite; and 2) Cretaceous granitic intrusions. These units make up at least 3 km3 in the project area and have target temperatures of ~175-215oC. The abundant well data and detailed geophysical surveys (e.g., gravity, MT, and seismic reflection) provide significant subsurface control for the site and will permit development of a detailed 3D model. The documented temperatures, low permeability, and basement lithologies, as well as abundant available data facilitate development of a site dedicated to testing and improving new EGS technologies and techniques, thus making Fallon an ideal candidate for FORGE.
Thursday January 7, 2016
Ramada Reno Hotel
1000 East 6th Street, Reno, NV 89512
Bar Sponsor: Krummrich Engineering
Cocktail Reception 6:30, Skyline Bar, 14th Floor
Dinner Served at 7:00 PM
NPGS Members $20, Non-Members $23, Students $10
Please RSVP for the Dinner Meeting by Tuesday, January 5 with the following link:
If you have RSVP’d, and find that you cannot attend, please notify NPGS as soon as you are able as NPGS will be charged for all no-shows. Thank you for your consideration.
Vicki D. Ehni
Ehni Enterprises, Inc.
P.O. Box 4228
Carson City, NV 89702-4228
(775) 883-1107, FAX (775) 883-7279