Exploratory Well At Long Valley Caldera Geothermal Area (Suemnicht, 1987)

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Exploration Activity: Exploratory Well At Long Valley Caldera Geothermal Area (Suemnicht, 1987)

Exploration Activity Details
Location Long Valley Caldera Geothermal Area
Exploration Technique Exploratory Well
Activity Date 1985 - 1985

Usefulness useful
DOE-funding Unknown

 
Exploration Basis
After several temperature-gradient holes were drilled in 1982 to the west of the resurgent dome and a geothermal lease acquisition in the western caldera by Union Oil Company (a.k.a Unocal Geothermal Division) in 1983, two test wells were drilled in the west moat that encountered reservoir temperatures > 200°C. These wells included the Research Drilling Office #8 (RDO-8) core hole drilled to 715 m depth at Shady Rest in June 1986 as a part of the DOE Continental Scientific Drilling Program (Urban et al., 1987a,b; Wollenberg et al., 1987), and the 44-16 well rotary drilled by Union Oil Company to 1,800 m depth in 1985 (Suemenicht, 1987; Suemenicht and Varga, 1988).
 
Notes
Well 44-16 encountered two temperature reversals, the first occurring at the base of the Bishop Tuff after temperatures of 218°C were reached at 1.1 km depth, and the second occurring within Tertiary Dacites and Andesites below the Bishop Tuff after temperatures of 192°C were reached at approximately 1.5 km depth (Suemnicht, 1987) A bottom hole temperature of 181°C encountered in 44-16 represents the hottest temperature measured in metamorphic basement within the caldera at the time.


Additional References