Exploratory Well At Long Valley Caldera Geothermal Area (Suemnicht, 1987)
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|
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).
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.
- Gene A. Suemnicht (1987) Results of Deep Drilling in the Western Moat of Long Valley, California
- Gene A. Suemnicht, Robert J. Varga (1988) Basement Structure and Implications for Hydrothermal Circulation Patterns in the Western Moat of Long Valley Caldera, California
- Michael L. Sorey, Gene A. Suemnicht, Neil C. Sturchio, Gregg A. Nordquist (December 1991) New Evidence On The Hydrothermal System In Long Valley Caldera, California, From Wells, Fluid Sampling, Electrical Geophysics, And Age Determinations Of Hot-Spring Deposits