Geothermal

Utah FORGE Drills First Deviated Deep Well

Utah FORGE has completed the first highly deviated, deep geothermal well to target depth and at planned trajectory, 60 days ahead of schedule.

Geothermal drill site
Credit: Eric Larson.

The US Department of Energy (DOE) -funded Utah Frontier Observatory for Research in Geothermal Energy (FORGE) has achieved another milestone with the successful completion of its first highly deviated deep well in hard, hot, crystalline granite. The well was completed 60 days ahead of schedule.

The upper part of the well was drilled vertically through approximately 4,700 ft of sediment before penetrating into high-strength, crystalline granite. The well was deviated at 65° from vertical after reaching a depth of 6,000 ft. This angle was maintained for the remainder of the well’s trajectory. The well ultimately reached a true vertical depth of 8,559 ft and a total measured depth of 10,987 ft. Preliminary measurements indicate that temperatures at the toe will exceed 442°F (228°C). Approximately 74 ft of core of the granitic and metamorphic rocks that will form the FORGE reservoir was also recovered.

“We are incredibly pleased with the success of the well,” said Joseph Moore, principal investigator of Utah FORGE. “It was drilled under complicated conditions and will serve as a prototype for similar wells around the world.”

With this well successfully completed, a series of tests can be run to facilitate the development of an enhanced geothermal system (EGS) resource. Some tests will help determine the stress conditions through short-term injection experiments, during which microseismicity will be carefully monitored. Others will enable interpretation of the orientation and distribution of existing and induced fractures in the granite, which will form pathways through which water will circulate and heat in the newly created EGS reservoir. In the future, a sister well will be drilled to form the basis of the EGS.

FORGE is an international field laboratory in Utah established for technology development and public education on geothermal energy in general and EGS development in particular. The facility is managed by a multidisciplinary team of engineers and scientists led by the University of Utah.