This is the final topical report for the Phase 2B Utah FORGE project, which is located near Roosevelt Hot Springs, Utah. This PDF format report details results associated with the conceptual geologic model, deep well 58-32, rock geomechanics, reservoir temperatures, seismic surveys, seismic monitoring, certainty, and NEPA. The report also provides an overview of all of the deliverables which were used to produce the results and full appendices.

This archive contains a report on the Mineral Mountains West fault system as part of phase 2C and the evidence for the northern terminus of this structure. Geologic field mapping, reprocessing of 3D seismic reflection data, and soil gas surveys contributed to this effort.

This report presents geodetic observations from the April 2024 stimulations at the Utah FORGE site, as part of LBNL FORGE Project 3-2535. It focuses on Distributed Strain Sensing (DSS) data from an optical fiber in well 16B, capturing localized strain linked to fracture propagation during several stimulation stages. DSS signals correlate well with injection timing and pressure, particularly during early stages like 3R. Microseismic data show spatial alignment with strain observations, supporting interpretations of fracture development. In contrast, InSAR analysis using Sentinel-1 data from 2019-2025 reveals no clear surface deformation.

Plugging of fracture porosity from mineral precipitation due to injecting cold water into a a geothermal reservoir can impact the overall permeability of the fracture network in the reservoir. This can have serious ramifications on the efficiency of the geothermal resource. Geochemical modeling can be useful in providing a first-hand evaluation of potential of mineral precipitation along the different reaction paths. We developed geochemical models for injecting four different relevant water compositions in the FORGE Utah geothermal reservoir through well 58-32. Results and discussions related to this work are presented in this technical report.

Plugging of fracture porosity from mineral precipitation due to injecting cold water into a a geothermal reservoir can impact the overall permeability of the fracture network in the reservoir. This can have serious ramifications on the efficiency of the geothermal resource. Geochemical modeling can be useful in providing a first-hand evaluation of potential of mineral precipitation along the different reaction paths. We developed geochemical models for injecting four different relevant water compositions in the FORGE Utah geothermal reservoir through well 58-32. Results and discussions related to this work are presented in this technical report.

This is a presentation on the Experimental Determination and Modeling-Informed Analysis of Thermo-poromechanical Response of Fractured Rock for Application to Utah FORGE project by the University of Oklahoma, presented by Dr. Ahmad Ghassemi, McCasland Chair Prof. The project objective is to improve understanding and control of coupled thermo-poromechanical (or thermo-hydro-mechanical- TPM) processes in reservoir development, and to study any role in interpretations of the fracture closure. This presentation was featured in the Utah FORGE R&D Annual Workshop on September 8, 2023. The workshop provided a valuable opportunity to explore the progress made in each of the 17 Research and Development projects funded under Solicitation 2020-1 which aim to enhance our understanding of the crucial factors influencing the development of Enhanced Geothermal Systems (EGS) reservoirs and resources.

This is a presentation on the Experimental Determination and Modeling-Informed Analysis of Thermo-poromechanical Response of Fractured Rock for Application to Utah FORGE project by the University of Oklahoma, presented by Dr. Ahmad Ghassemi, McCasland Chair Prof. The project objective is to improve understanding and control of coupled thermo-poromechanical (or thermo-hydro-mechanical- TPM) processes in reservoir development, and to study any role in interpretations of the fracture closure. This presentation was featured in the Utah FORGE R&D Annual Workshop on September 8, 2023. The workshop provided a valuable opportunity to explore the progress made in each of the 17 Research and Development projects funded under Solicitation 2020-1 which aim to enhance our understanding of the crucial factors influencing the development of Enhanced Geothermal Systems (EGS) reservoirs and resources.

Report on possible geodetic signature of the 3 stimulations in April 2022 as well as a comparison with existing InSAR data gathered over the site before, during, and after the stimulation. In geothermal production it is important to understand the existing stress field and the changes in the stress associated with field development. The stress field is a controlling factor in the development and properties of natural and stimulated fractures. Furthermore, changes in the stress field can lead to associated seismicity and the potential for felt earthquakes. It is difficult to estimate stresses directly and they are typically inferred from well tests and observed strain. In this task our goal is to incorporate observed strain data into the fully integrated models of the stimulations at the FORGE site. FORGE project 3-2535 is planning on using a casing source EM method for detecting and imaging a deep localized stimulated fracture zone at the Utah FORGE site. Details on other stages of the project are included in the linked GDR submissions below.

This is a compilation of logs and data from Well 82-33 in the Roosevelt Hot Springs area in Utah. This well is also in the Utah FORGE study area. The file is in a compressed .zip format and there is a data inventory table (Excel spreadsheet) in the root folder that is a guide to the data that is accessible in subfolders.

This dataset contains a map, showing the Utah FORGE seismic stations, and seismic velocity model data. There are 61 1-D velocity models which are in a compressed TAR file. A paper is referenced at the end of this description which discusses the use of these data in 3D modelling. The paper summary follows: We expand the application of spatial autocorrelation (SPAC) from typical 1-D Vs profiles to quasi-3-D imaging via Bayesian Monte Carlo inversion (BMCI) using a dense nodal array (49 nodes) located at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE) site. Combinations of 4 and 9 geophones in subarrays provide for 36 and 25 1-D Vs profiles, respectively. Profiles with error bars are determined by calculating coherency functions that fit observations in a frequency range of 0.2-5 Hz. Thus, a high-resolution quasi-3-D Vs model from the surface to 2.0 km depth is derived and shows that surface-parallel sedimentary strata deepen to the west, consistent with a 3-D seismic reflection survey. Moreover, the resulting Vs profile is consistent with a Vs profile derived from distributed acoustic sensing (DAS) data located in a borehole at the FORGE site. The quasi-3-D velocity model shows that the base of the basin dips ~22 degrees to the west and topography on the basement interface coincident with the Mag Lee Wash suggests that the bedrock interface is an unconformity. Reference: Zhang, H. and K. L. Pankow (2021). High-resolution Bayesian spatial auto-correlation (SPAC) pseudo-3D Vs model of Utah FORGE site with a dense geophone array, Geophys. Res. Int, https://doi.org/10.1093/gji/ggab049