Frontier Observatory for Research in Geothermal Energy (FORGE) is a US government program supporting research into geothermal energy. [1] The FORGE site is near Milford, Utah, funded for up to $140 million. As of 2023, numerous test wells had been drilled, and flux measurements had been conducted, but energy production had not commenced. [2]
In February 2014, the Department of Energy (DOE) announced the intent to establish "a dedicated subsurface laboratory" [1] to investigate and develop enhanced geothermal systems. [3] In June 2018 DOE funded a location outside of Milford, Utah for up to $140 million. [4]
The site is located along the Colorado Plateau and Basin and Range Province transition zone. It is primarily composed of intrusive Oligocene through Miocene batholith emplaced into Precambrian metamorphic ( Gneiss) and Paleozoic sedimentary rocks. [5] [6] The site is west of the Mineral Mountains and about two km east of the north–south trending Opal Mond Fault (OMF), perpendicular to the east–west trending Negro Mag Fault (NMF). [5] [7] FORGE is dominated by a fault-fracture mesh system with OMF as one of its most active features. [6] [8] Fault structures vary from steeply dipping faults west of the Mineral Mountains to more gently steeping faults to the east. [6] [5]
The reservoir is located approximately between 1,525 and 2,896 meters (~5,000-10,000 ft) depth in which temperature ranges from 175 to 225 °C. [9] The rock is aged from 8 Ma to 25.4 Ma. [10] [11] [12] Roosevelt Hot Springs (RHS) to the east is a hydrothermal area with temperatures ranging from about 100°C at the surface to over 250 °C at a depth of roughly 4000 meters (13,123.4 ft). [8] These temperatures indicate the presence of cooling magma in the shallow crust. [8]
More than 80 shallow gradient wells (<500 m depth) and 20 deeps wells (>500 m depth) were drilled. [13] [14] Analyses from the shallow well data reported that the encountered granitic rocks were not producing fluids, but were hot. [13] A lack of fluid production indicated these rocks are impermeable and that the site is a classic example of a hot dry rock energy system. [9] The thermal grounds cover most of the northern Milford valley. [13] [14] The highest temperature wells (greater than 80 °C) are located east of the OMF above the RHS hydrothermal system. [14] Near-surface profiles (less than 80 m depth) of temperature gradient are similar in central, southern and western sectors at roughly 70 °C per km and do not exceed 270 °C, even at higher temperature wells to the west. [14]
The primary well descends vertically 6,000 feet (1.8 km), then continues 5,000 feet (1.5 kilometers) at a 65 degree angle. The well employed a diamond-tipped bit, cutting drilling costs by 20 percent. [2]
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: CS1 maint: multiple names: authors list (
link)
Frontier Observatory for Research in Geothermal Energy (FORGE) is a US government program supporting research into geothermal energy. [1] The FORGE site is near Milford, Utah, funded for up to $140 million. As of 2023, numerous test wells had been drilled, and flux measurements had been conducted, but energy production had not commenced. [2]
In February 2014, the Department of Energy (DOE) announced the intent to establish "a dedicated subsurface laboratory" [1] to investigate and develop enhanced geothermal systems. [3] In June 2018 DOE funded a location outside of Milford, Utah for up to $140 million. [4]
The site is located along the Colorado Plateau and Basin and Range Province transition zone. It is primarily composed of intrusive Oligocene through Miocene batholith emplaced into Precambrian metamorphic ( Gneiss) and Paleozoic sedimentary rocks. [5] [6] The site is west of the Mineral Mountains and about two km east of the north–south trending Opal Mond Fault (OMF), perpendicular to the east–west trending Negro Mag Fault (NMF). [5] [7] FORGE is dominated by a fault-fracture mesh system with OMF as one of its most active features. [6] [8] Fault structures vary from steeply dipping faults west of the Mineral Mountains to more gently steeping faults to the east. [6] [5]
The reservoir is located approximately between 1,525 and 2,896 meters (~5,000-10,000 ft) depth in which temperature ranges from 175 to 225 °C. [9] The rock is aged from 8 Ma to 25.4 Ma. [10] [11] [12] Roosevelt Hot Springs (RHS) to the east is a hydrothermal area with temperatures ranging from about 100°C at the surface to over 250 °C at a depth of roughly 4000 meters (13,123.4 ft). [8] These temperatures indicate the presence of cooling magma in the shallow crust. [8]
More than 80 shallow gradient wells (<500 m depth) and 20 deeps wells (>500 m depth) were drilled. [13] [14] Analyses from the shallow well data reported that the encountered granitic rocks were not producing fluids, but were hot. [13] A lack of fluid production indicated these rocks are impermeable and that the site is a classic example of a hot dry rock energy system. [9] The thermal grounds cover most of the northern Milford valley. [13] [14] The highest temperature wells (greater than 80 °C) are located east of the OMF above the RHS hydrothermal system. [14] Near-surface profiles (less than 80 m depth) of temperature gradient are similar in central, southern and western sectors at roughly 70 °C per km and do not exceed 270 °C, even at higher temperature wells to the west. [14]
The primary well descends vertically 6,000 feet (1.8 km), then continues 5,000 feet (1.5 kilometers) at a 65 degree angle. The well employed a diamond-tipped bit, cutting drilling costs by 20 percent. [2]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)