The Utah Frontier Observatory for Research in Geothermal Energy (Utah FORGE) has begun an extended circulation test at a site 10 miles northeast of Milford in Utah.
The work is expected to last upwards of four months.Utah FORGE is the world’s only full-scale field laboratory for de-risking and testing the tools and technologies necessary to advance Enhanced Geothermal Systems (EGS).
“This extended circulation will allow us to study heretofore unknown variables required to ensure long term EGS production remains commercially viable,” said Dr Kristie McLin, Principal Investigator of Utah FORGE.
“Although major advancements have been achieved in the past few years, there is still a great deal we do not know about thermal breakthrough and water loss over time.”
The work includes an initial injection of five barrels per minute (bpm), stepped up to 7.5 bpm, finally a ramp-up to 10 bpm over approximately 48 hours to ensure system stability.
This closed-loop system of cooler, non-potable water pumped into the injection well (16A) and brought back to the surface through the production well (16B) at a rate of 10 bpm, will continue for roughly 90 days, and possibly up to 120 days, a statement from Utah FORGE read.
This will allow time to evaluate reservoir performance under continuous flow, as well as vet water treatment dosages to prevent scaling and corrosion.
This latest circulation builds on the project’s earlier findings, the statement noted.
In April 2024, the production and injection wells were stimulated by perforating the steel casing in the wells and pumping water into them under pressure — this process created the fracture network that formed the reservoir.
The stimulation was followed in August 2024 by a commercial scale circulation, a 30-day test in which water was injected at a consistent rate of 420 gallons per minute.
Nearly 90% of the produced fluid was recovered and the temperature remained at approximately 370°F.
According to Utah FORGE, the results provided positive initial indications of the long-term behaviour of the reservoir and the amount of heat that can be extracted.
“The positive results achieved by the project over the past few years have been very beneficial to the industry,” said McLin.
“However, there is still so much we do not know. This extended circulation will provide answers to the pressing questions about thermal decline and water loss, allowing geothermal companies to continue growing and to flourish.”