Title:

The Utah Frontier Observatory for Research in Geothermal Energy (FORGE): an International Laboratory for Enhanced Geothermal System Technology Development

Authors:

Joseph MOORE, John McLENNAN, Rick ALLIS, Kristine PANKOW, Stuart SIMMONS, Robert PODGORNEY, Philip WANNAMAKER, William RICKARD

Key Words:

enhanced geothermal systems, FORGE, reservoir, stimulation, induced fractures

Conference:

Stanford Geothermal Workshop

Year:

2019

Session:

Enhanced Geothermal Systems

Language:

English

Paper Number:

Moore

File Size:

2717 KB

View File:

Abstract:

In 2018, the US Department of Energy selected a location near Milford Utah as the site for its Frontier Observatory for Research in Geothermal Energy (FORGE). In contrast to previous EGS projects designed to generate electricity, the primary objective of the FORGE laboratory is to provide a controlled environment where technologies for characterizing, creating and sustaining EGS reservoirs can be developed and tested. The site lies within Utah’s Renewable Energy Corridor, close to the Roosevelt Hot Springs geothermal field, a windfarm and a solar field. Extensive geoscientific and environmental investigations conducted since the 1970s in support of these renewable energy projects demonstrate seismic hazards and the risk of induced seismicity are low, there are no endangered flora or fauna, and the local groundwater is not potable. Well 58-32 was drilled in 2017 to a measured depth of 2297 m on the FORGE site to characterize the reservoir rocks and thermal regime. Additional supporting data was provided by new geologic mapping and 3-D seismic reflection, gravity, hydrologic and soil gas surveys. The well penetrated 1323 m of Tertiary plutonic rocks dominated by granite and quartz monzonite below 968 m alluvial deposits. The thermal regime is conductive and the well encountered a bottom hole temperature of 197oC. More than 2000 natural fractures were identified, but measured permeabilities are low, less than 30 microdarcies. Induced fractures indicate the maximum horizontal stress trends NNE-SSW, consistent with geologic and well observations from the surrounding area. Microhydraulic and Diagnostic Fracture Injection Tests (DFIT) were conducted in the open hole section of the well from 2248 m to TD. A wellhead pressure of ~27.6 MPa (4000 psig) and an injection rate of 22 l/s (8.7 bpm) were reached during the DFIT. Stress gradients based on analysis of the tests are 14.0 kPa/m (0.62 psi/ft) for SHmin and 17.4 kPa/m (0.77 psi/ft) for SHmax. A gradient of 25.6 kPa/m was calculated for SV. Despite the low stimulation pressures and injection rates, enhancement of the induced fractures is clearly apparent when pre- and post-injection Formation Microscanner Image (FMI) logs are compared. These changes demonstrate the suitability of the FORGE reservoir rocks for EGS development. Three stimulations will be conducted in well 52-38 in 2019; one in the open hole section of the well below 2248 m and two in the cased portion of the well below 1981 m, where temperatures exceed 175oC. The stimulations will evaluate the behavior of fractures with different orientations at injection rates higher than those achieved during the 2017 stimulations and provide a test of the seismic monitoring system. Drilling of the injection and production well pair and creation of an EGS reservoir is scheduled to begin in late 2019.


ec2-3-219-233-54.compute-1.amazonaws.com, you have accessed 0 records today.

Press the Back button in your browser, or search again.

Copyright 2019, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.


Attend the nwxt Stanford Geothermal Workshop, click here for details.

Accessed by: ec2-3-219-233-54.compute-1.amazonaws.com (3.219.233.54)
Accessed: Friday 29th of March 2024 04:42:10 AM