Wells 16A&16B Stimulation

Frontier Observatory for Research in Geothermal Energy

Utah FORGE Successfully Completes Stimulation and Circulation Tests – Establishing Effective Communication

-  Enhanced connectivity between two wells achieved
-  No induced seismicity greater than magnitude 1.9
-  Culmination of extensive collaboration between geoscientists and
engineers
-  Foundational step to realizing the promise of EGS technologies

The Utah Frontier Observatory for Research in Geothermal Energy (FORGE) at the University of Utah has successfully stimulated wells 16A(78)-32 (injection) and 16B(78)-32 (production). A 9-hour circulation test that followed stimulation proved fluid flow and energy transfer from an Enhanced Geothermal Systems (EGS) reservoir in hot dry granite – a major breakthrough for the industry.

“These stimulations and the short-term circulation test are the culmination of more than two years of planning and in-depth data analysis,” stated Professor John McLennan who oversaw the activities. “Enfranchising the knowledge gained from previous activities, and with advice from a diverse team of specialists from industry and academia, the Utah FORGE team was able to achieve outstanding results. Importantly, the maximum induced seismicity was magnitude 1.9, falling well short of the threshold of felt seismicity.”

In 2020, the injection well was drilled to a true vertical depth of 8,559 feet and a measured depth of 10,897 feet. Two years later, this well was hydraulically fractured in three intervals towards the toe. State-of-the-art seismic monitoring mapped these fracture networks. The production well was subsequently drilled in 2023. The two wells are parallel with lateral sections at 65 degrees to the vertical and spaced apart vertically by 300 feet. Immediately following the drilling of 16B(78)-32, a brief circulation test revealed some connectivity between the two wells.

Beginning on April 3, 2024, commercial-scale stimulation was conducted on both wells to develop interwell connectivity. Over two weeks, well 16A(78)-32 was hydraulically fractured in eight different stages. The three intervals previously stimulated were re-fractured and seven new intervals were perforated and hydraulically fractured. Four stages of the production well were then injected. Overall, 118,000 barrels (4,956,000 gallons) of water were used for the experiment. This non-potable injected water was produced from a shallow well on the Utah FORGE site.

To locate fractures intersecting well 16B(78)-32, fiber optic cables were monitored during the stimulation of its sister well, 16A(78)-32. The recorded fiber optic signatures highlighted intervals of fracture intersection or proximity. These intervals were selected and perforated for subsequent stimulation. Stimulating both wells ensured connectivity.

“We are thrilled to see these remarkable achievements at FORGE, and the promise this geothermal breakthrough holds for our clean energy future,” said Jeff Marootian, Principal Deputy Assistant Secretary for Energy Efficiency and Renewable Energy. “The ability to tap more of the Earth’s natural heat through enhanced geothermal systems will expand access to affordable, secure, and resilient clean energy for everyone.”

Following the stimulation, a short circulation test was conducted. Water was injected into well 16A(78)-32 for nine hours at rates up to 15 barrels-per-minute (630 gallons-per-minute). The injection led to corresponding production from well 16B(78)-32 of up to 8 bpm (344 gpm). Significantly, this is an efficiency rate of around 70% recovery. This reconfirms that conductivity between the wells was established. The temperatures of the outflow water also continually increased to approximately 139° C (282° F). Microseismic events, fiber optics data, and spinner logging showed that multiple independent flow paths had been created. During the stimulation use of proppant, custom frac plugs, multiple clusters per stage, and different treating fluids were evaluated.

The short circulation test capped this phase of experimentation. Hot water was produced and the testing confirmed the potential of EGS energy production. These exciting results and the rich sets of data are being analyzed to plan additional fieldwork, including a 30-day circulation test scheduled for July 2024. All of the data collected are publicly available on the Geothermal Data Repository (GDR).

“We are excited to have had such great success during our most recent stimulation and circulation testing,” said Professor Joseph Moore, Managing Principal Investigator of the Utah FORGE project. “Each test brings us closer to realizing the full potential of Enhanced Geothermal Systems and the important role it will play in world’s energy portfolio.”

The work undertaken by Utah FORGE shares a goal of de-risking the tools and technologies needed to make commercial-scale EGS affordable and accessible anywhere in the world.

Please see below for data:

Well 16A(78)-32 &16B(78)-32 Stimulation Production Logging Tests These are the Halliburton production logging tests (PLT) run during the nine hour circulation test performed (injecting into well 16A(78)-32 and producing out of well 16B(78)-32) after fracturing both of those wells -- performed in April 2024.
Wells 16A(78)-32 and 16B(78)-32 Stimulation Pressure and Circulation Data This dataset consists of all of the pressure pumping data for 16A frac stages and 16B frac stages and the 9-hour circulation test following the fracing after all of the frac plugs were drilled out. They are all Excel files and there is a ReadMe file for each of the uploads to detail what data is available. This also included the Pason data that is referred to in the ReadMe files. The stimulation was done in April 2024.
Well 16B(78)-32 Fiber Optic Distributed Temperature Sensing Data This dataset includes Neubrex Energy Services fiber optic distributed temperature sensing data from well 16B(78)-32 during stimulation and circulation, including interaction with well 16A(78)-32, during April and May 2024. This also includes a PowerPoint presentation with graphics.
2024 Stimulations Microseismic Event Catalog from Seismic Surface Network This is a link to the microseismic catalog of the 2024 stimulations at Utah FORGE is based on the surface monitoring network consisting of 5 permanent seismic stations deployed by the University of Utah Seismograph Stations and a temporary deployment of 144 nodal geophones. The catalog and its compilation are described in: Niemz et al. (2024). Mapping Fracture Zones with Nodal Geophone Patches: Insights from Induced Microseismicity during the 2024 Stimulations at Utah FORGE. Submitted to Seismological Research Letters. The local coordinate system is relative to well 16A(78)-32 (lat=38.50402147, lon=-112.8963897, elev=1650m NAD 83). The magnitudes in this catalog were calibrated based on the local magnitude provided by the University of Utah Seismograph Stations. They are not authoritative.
2024 Neubrex Fiber Optic Monitoring During Stimulation of Well 16B(78)-32 These reports feature pressure/temperature and strain monitoring fracture driven interactions (FDI) for well 16B(78)-32 during the stimulation in 2024.
2024 Wells 16A/16B(78)-32 Stimulation Daily Reports This zip file contains the daily reports for the spring 2024 wells 16A/16B(78)-32. These reports cover a period from March 29th to April 28th, 2024. They discuss the activity on the rig each day.
Well 16A(78)-32 Injection, Production, Flow Rate, Gamma, Temperature and Pressure Logs These files include injection, production, flow rate, gamma, temperature and pressure survey results from well 16A(78)-32 injection testing in August 2024. This includes two reports.
Neubrex Energy Services Fiber Optics Reports This zip file contains two reports discussing the use of fiber optics during well 16B(78)-32 stimulation and circulation tests in the summer of 2024. This was to collect data on strain change rate and temperature changes including temperature changes on the fiber-optic cable.
Wells 16A(78)-32 and 16B(78)-32 Circulation Test Daily Reports from August 2024 These are the daily reports created during and around the August 2024 circulation test done on wells 16A(78)-32 and 16B(78)-32 at the Utah FORGE site. Information about the rig activity during this period includes details on rig up, depths, pumping, water temperature, safety, and cleanout. The reports span all rig activities from July 29th, 2024 through September 5th, 2024.
Wells 16A(78)-32 and 16B(78)-32 Extended Circulation Test Data from August/September 2024 This zipped file includes: 1. Manual Temperature and Pressure Data.xlsx: 2. Field Calibration of Flow Meters.xlsx: 3. Extended Circulation Test Data 08082024 to 09052024 (30 sec increment).xlsx: RAW, UNCORRECTED digital data. 4. Extended Circulation Test Report-Final.docx: This document describes the extended circulation test and shows how the Pason data can be corrected for calibrations that were done in the field. A plot of efficiency (ratio of mass flow rates) is provided.
Utah FORGE: Neubrex Circulation Test Results and Fiber Optics Technical Report - April, 2024 This report examines the fiber optic measurements made on the 16B well after both wells were hydraulically stimulated and shortly thereafter a 9 hour cross well circulation test was run between the two slant wells, 16A and 16B. The report reviews distributed fiber optic signal processing and analysis results using Rayleigh Frequency Shift - Distributed Strain Sensing and Distributed Strain Sensing (DTS) data. The data are integrated with pumping and discharge rate data from the two wells. All data are depth registered to Measured Depth (MD) Relative to Kelly Bushing (RKB).
Neubrex Well 16B(78)-32 DAS Data - April, 2024 This dataset comprises Distributed Acoustic Sensing (DAS) data collected from the Utah FORGE monitoring well 16B(78)-32 (the producer well) during hydraulic fracture stimulation operations conducted in April 2024. The data were acquired continuously over the stimulation period at a temporal sampling rate of 10,000 Hz (10 kS/s) and a spatial resolution of approximately 3.35 feet (1.02109 meters). The measurements were captured using a Neubrex NBX-S4100 Time Gated Digital DAS interrogator unit connected to a single-mode fiber optic cable, which was permanently installed within the casing string. All recorded channels correspond to downhole segments of the fiber optic cable, from a measured depth (MD) of 5,369.35 feet to 10,352.11 feet. The DAS data reflect raw acoustic energy generated by physical processes within and surrounding the well during stimulation activities at wells 16A(78)-32 and 16B(78)-32. These data have potential applications in analyzing cross-well strain, far-field strain rates (including microseismic activity), induced seismicity, and seismic imaging. Metadata embedded in the attributes of the HDF5 files include detailed information on the measured depths of the channels, interrogation parameters, and other acquisition details. The dataset also includes a recording of a seminar held on September 19, 2024, where Neubrex's Chief Operating Officer presented insights into the data collection, analysis, and preliminary findings. The raw data files, stored in HDF5 format, are organized chronologically according to the recording intervals from April 9 to April 24, 2024, with each file corresponding to a 12-second recording interval.
Neubrex Well 16A(78)-32 Stimulation Crosswell RFS Fiber Optic Monitoring Report - April, 2024 Neubrex Well 16A(78)-32 Stimulation Crosswell RFS Fiber Optic Monitoring Report - April, 2024
Post Hydraulic Fracturing Circulation Testing Fiber Optics Report - August, 2024 This report documents the post hydraulic fracturing extended circulation test between wells 16A and 16B during August 2024. In 16B, fiber optic measurements of RFS DSS and DTS were primarily used to detect and map thermal inflow anomalies, as detected by thermally driven strain changes and thermal changes from DTS. The report provides a first pass integration of SLB Production Logging Tool (PLT) results with fiber optic results to look for correlations between the two different types of data. The report also takes a close look at the Fiber Optic derived cross well strain signatures created during the 16A frac, as detected at 16B producer well and correlates those Fracture Driven Interactions with the Circulation Flow Test results.
Neubrex Hydraulic Fracturing DAS Based Fluid Injection Efficiency and Plug Analysis Report Report reviews results acquired by Neubrex using Distributed Acoustic Sensing of the 16B(78)-32 Hydraulic Fracturing operations, Stages 1-4. The DAS data acquisition, processing and analysis focuses on acoustic noise signatures during each stage and analyzes the acoustic noise produced at each perforation cluster. Pumping curve data are integrated with fiber optic DAS results. The acoustic data and the pumping curve data are integrated to generate relative Injection Allocation percentages for each cluster of each stage. Plug holding efficacy is also analyzed using the DAS Acoustic energy band data.
Well 16A(78)-32 Perforation Images and Raw Data This archive contains raw data of visual and acoustic mapping of perforations in Utah FORGE well 16A(78)-32 acquired during the August 2024 circulation program. The dataset includes downhole images captured by EV, a downhole visual analytics company, providing visual records of each perforation. Images are organized in two folders: one set with perforation visualization overlays and one without. An included Excel spreadsheet provides the organized raw data.
Neubrex Fiber Optic Crosswell Cumulative Strain Change Data during 16A Frac at 16B This is Rayleigh Frequency Shift Distributed Strain Sensing Cumulative Strain Change data. It was acquired during the 16A well Frac Stimulation period in April 2024 and was monitored using fiber optics in the 16B well. It was acquired using Neubrex SR7000 RFS DSS Distributed Strain sensing instruments. It is in the format of HDF5 files (.h5 extension). The spatial sampling on the full wellbore profiles is 0.20 centimeters. The data is the far field strain change response from a baseline profile made down the 16B well on April 3, 2024, so each strain value represents the strain change at each depth relative to the baseline reference profile.
Neubrex Fiber Optic Crosswell Strain Change Rate Data during 16A Frac at 16B Digital data of cross well fiber optic RFS DSS strain rate data from the 16A frac period, stages 3R through 10 as detected and recorded on the 16B monitor well fiber optics data in hdf5 format.
Neubrex Well 16A(78)-32 and Hydraulic Fracturing Stage 8 Crosswell Strain FDI and Microseismic Presentation - April, 2024 This is a pair of PowerPoint presentation by Neubrex Energy Services (US), LLC describing their work in April 2024 on crosswell strain fracture driven interactions (FDI) and micro seismic events during hydraulic fracturing in stage 8 of well 16A(78)-32. Well 16B(78)-32 was the monitoring well.
Wells 16A(78)-32/16B(78)-32 Stimulation Program Report -- May 2024 This is the end of job report for the stimulation program run on wells 16A(78)-32 and 16B(78)-32 done during May 2024.
QuantumPro Tracer Test Results for Well 16A(78)-32 and 16B(78)-32 This dataset includes the data, a report, and a PowerPoint presentation for tracer tests done during the 2024 stimulation and circulation tests, where tracers were injected into 16A(78)-32 and recovered in 16B(78)-32.
RESMAN Energy Technology Wells 16A(78)-32 and 16B(78)-32 Tracer Test Results This dataset, compiled by RESMAN Energy Technology, contains the tracer test results from stimulation and circulation experiments conducted on Utah FORGE wells 16A(78)-32 and 16B(78)-32. The files include data collected from flowback, short- and extended-duration circulation tests, and reinjection sampling, spanning tests in April, August, and September 2024. Advanced time-series tracer analysis provides a detailed understanding of fracture flow paths, production contributions, and circulation efficiency. Tracer responses offer key insights into fluid movement between wells, helping refine strategies for optimizing reservoir performance. Given the proprietary nature of some tracer methodologies, users should refer to the accompanying interpretation report for further insights into experimental procedures and data contextualization.
EGS Reservoir Produced Fluids Geochemistry 2022-2024 The spreadsheet contains geochemical analyses of produced fluids obtained from wells 16A(78)-32,16B(78)-32 and 58-32 from stimulation, flowback and circulation tests, 2022-2024. Contextual information is covered in the accompanying report by Simmons et al (2025), which was presented at the Stanford Geothermal Workshop, February 10-12, 2025.
Neubrex 16B(78)-32 RFS DSS Strain Change Rate vs Depth Data (frac hit log) This dataset contains cumulative strain change rate vs depth data in tabulated form, along with an explanation of how the fiber optic strain frac log was produced. The data set comes from a nine stage stimulation of injection well 16A(78)-32 in April 2024, with data acquired from a fiber optic cable in the anulus of production well 16B(78)-32, approximately 300 ft away.
Well 16B(78)-32 DTS, RFS DSS Strain, and Absolute Strain Circulation Test Fiber Optic Data - August 2024 This dataset contains processed fiber optic measurements collected during the extended cross-well circulation test at the Utah FORGE site in August 2024. The data was acquired from the 16B(78)-32 well using distributed fiber optic sensing (DFOS) technology, including distributed temperature sensing (DTS) on multimode fiber and distributed strain sensing (DSS) measurements on single-mode fiber. The dataset includes Brillouin absolute strain, Rayleigh frequency shift (RFS) DSS strain change, RFS DSS strain change rate, and temperature (DTS) data, all stored in HDF5 format. Time coordinates are provided in UTC, and depth measurements are given in measured depth relative to the rotary kelly bushing (MD RKB) in feet. The spatial sampling on the RFS DSS strain data and the Brillouin Absolute Total Strain data is 20 cm and the spatial sampling on the DTS data is 1m. The dataset is accompanied by a report from Neubrex, which provides further documentation.
Seismic DAS and Geophone Borehole Data Processing and 3D Imaging of Vp/Vs Ratio in the 2024 Stimulated Reservoir This dataset includes a final report and a 3D velocity model derived from seismic DAS and geophone borehole data collected during the April 2024 stimulation of the reservoir at Utah FORGE. The report details the processing of over 50,000 P- and S-wave travel times used in a tomographic inversion to estimate the Vp/Vs ratio, revealing anomalies adjacent to wells 16A and 16B that may be associated with injected fracturing fluids. Additionally, Wadati analysis of more than 27,000 pairs of differential P- and S-wave travel times supports this interpretation with a high Vp/Vs estimate of 1.86, averaged over the dimensions of the earthquake cluster. The accompanying data file provides a 3D model of P- and S-wave velocities and Vp/Vs ratios, structured with spatial coordinates and velocity values.
Triggered DAS and Continuous Downhole Geophone Data from April 2024 Stimulations This dataset contains distributed acoustic sensing (DAS) and downhole geophone data collected during the April 2024 stimulation experiments at the Utah FORGE site. DAS data were acquired from well 16B(78)-32 by Neubrex and processed by GeoEnergie Suisse (GES), covering the period from April 1 to April 19, 2024. The DAS data are stored in a non-standard SEGY format due to trace lengths exceeding compatibility limits in standard tools such as ObsPy. To facilitate use, a custom Python module is included for reading the data into ObsPy streams. The DAS files are sampled at 4000 Hz with 12-second traces (48,000 samples per trace), and timestamp information includes millisecond and microsecond precision via custom header fields. The dataset also includes continuous downhole geophone data, available in both raw and curated forms, with some data gaps. These data were recorded from March 28 to April 17, 2024, using instruments deployed in three wells: 58-32, 78B-32, and 56-32. The curated geophone data include detailed metadata, local receiver coordinates, and documentation on outages and instrument changes. Sampling rates vary by well and tool: GES tools in wells 56-32 and 78B-32 recorded at 4000 Hz, while SLB instrumentation in well 58-32 used a 2000 Hz sampling rate. Note that the data from 58-32 were not synchronized with the other wells, and usage is only recommended after extensive quality control.
Well 16B(78)-32 Cuttings X-ray Diffraction Data X-ray diffraction (XRD) results of cuttings samples collected during the drilling of Utah FORGE well 16B(78)-32. This is a spreadsheet of XRD data from 77 cuttings samples taken from 3,120 to 10,977 feet measured depth (measured from the Kelly Bushing 31 ft above ground level). Sample spacing is largely 100 ft. Mineral abundance results are given in weight percent of the sample, with results rounded to the nearest whole number. Fields marked with tr (trace) indicate that mineral is present, but that its abundance calculated from the Rietveld refinement was less than one weight percent; that it was observed in the clay-sized fraction, but not the bulk; and/or that it was observed in low abundance during petrographic analyses.
Report on Geodetic Observations of Fracture Development During April 2024 Stimulations 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.
EGS Reservoir Produced Fluids Trace Elements 2024 This spreadsheet contains the geochemical analyses of set of analyzed trace elements in produced fluids obtained from wells 16A(78)-32, 16B(78)-32, and 58-32 during a circulation test (August-September) in 2024.
Low Frequency Distributed Acoustic Sensing Data from 16A/16B Stimulation - April, 2024 This dataset contains processed low-frequency Distributed Acoustic Sensing (LF-DAS) data collected between April 2 and April 12, 2024, during the Utah FORGE stimulation sequence involving wells 16A and 16B. The DAS measurements were acquired using a Silixa Carina interrogator unit on the FOGMORE distributed fiber optic sensing (DFOS) cable installed in well 16B. Installation details for the cable can be found at the report link below. Due to pre-existing damage to the cable, the signal-to-noise ratio is slightly lower than expected. The data has been processed with a 0.5 Hz low-pass filter and a median filter in time, and values are expressed in units of nanostrain per second. All timestamps are in UTC. Data are provided in CSV format, with each file corresponding to a specific time segment. The repository also includes a channel map and a metadata catalog to support interpretation. Please see the included README for detailed dataset information. This dataset was produced under the FOGMORE R&D project (Fiber Optic MOnitoring for Reservoir Evolution), Utah FORGE R&D Project 3-2417, and was assembled by researchers from Rice University, Lawrence Berkeley National Laboratory, and partners, with documentation finalized in July 2025.

Overview Geology Water Chemistry/Ground Water Geophysics Earth/Fracture Modelling

Seismicity GIS Data/Maps R&D Projects Wells 16A&16B Stimulation Reports

Well 58-32 Well 78-32 Well 78B-32 Well 68-32 Well 56-32 Well 16A(78)-32 Well 16B(78)-32 Wells General

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