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Current Activities at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE)
Joseph MOORE, John MCLENNAN, Kevin ENGLAND, Kristine PANKOW, Clay JONES, Stuart SIMMONS, Aleta FINNILA, Robert PODGORNEY, Benjamin BARKER
[Energy & Geoscience Institute, USA]
The Utah Frontier Observatory for Research in Geothermal Energy (FORGE) is a field-scale laboratory dedicated to developing and testing technologies for the commercialization of Enhanced Geothermal Systems (EGS). The project is funded by the US Department of Energy. Since 2016, nine wells deeper than 300 m depth have been drilled, with the deepest reaching 2896 m and a temperature of 241°C. Seven of the wells are vertical. These wells are utilized for microseismic monitoring and tool testing. The remaining two wells, 16A(78)-32, the injection well, and 16B(78)-32, the production well, were drilled parallel to each other and 90 m apart vertically. Both wells were deviated 65° from vertical, and oriented approximately in the direction of the minimum horizontal stress. The wells encountered temperatures near 220°C in the low permeability Tertiary granitoid and Precambrian metamorphic rocks of the reservoir. In 2025, the production and injection wells were cleaned out, and a fiber optic cable was removed from the production well. As part of Texas Tech University and California State University-Long Beach R&D programs, coiled tubing containing fiber optic cables was successfully deployed to a depth of about 3078 m in 16B(78)-32 to monitor seismicity, temperature and strain. Two new 305 m boreholes were drilled for seismic monitoring. Construction of a piping system for circulation testing between the production and injection wells is planned for late 2025. The primary objectives of the testing are to quantify the rate of temperature decline and the extent of water loss at an injection rate of 10 bpm. A refined Discrete Fracture Network (DFN) model was constructed based on seismic, strain and geologic data to facilitate the thermal modeling. Numerical simulations suggest temperature declines can occur within several months. The circulation testing will be monitored using the fibers in the coiled tubing, downhole geophones and surface nodal arrays. Silica proppant that settled in the open hole section of the injection well were examined for evidence of water-rock interactions. The proppant displayed evidence of dissolution. Infillings between the proppant grains consist of clay minerals, calcite, anhydrite and halite. Samples of the fluids were collected and are being analyzed for their liquid and gas compositions. All Utah FORGE data are available to the public at no charge through the Geothermal Data Repository or the wiki pages on the Utah FORGE website at utahforge.com.
Topic: FORGE