Water Sampling At Long Valley Caldera Geothermal Area (Sorey, Et Al., 1991)

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Exploration Activity: Water Sampling At Long Valley Caldera Geothermal Area (Sorey, Et Al., 1991)

Exploration Activity Details
Location Long Valley Caldera Geothermal Area
Exploration Technique Water Sampling
Activity Date 1985 - 1986

Usefulness useful
DOE-funding Unknown

Exploration Basis
Sorey et al. (1991) integrated information from previous scientific and private industry investigations with new data obtained from fluid sampling, test drilling, and geological and geophysical studies conducted between 1985-1988 into a comprehensive conceptual model of the present-day hydrothermal flow system at Long Valley caldera. Lithology and temperature gradient data from wells drilled prior to 1988 are summarized in detail in the compilation, which includes information from numerous wells described in previous studies, and data from many of the wells are available online through the U.S. Geological Survey (Farrar et al., 2010). Thermal conductivity, XRD, and isotopic analyses of core cuttings from several of the wells discussed have been completed in several studies, and seem to prove useful in most cases (Flexser, 1991; Goff et al., 1991; Smith and Suemnicht, 1991). Results from these studies are also summarized in Sorey et al. (1991). Relevant data from chemical and isotopic studies published during the same year are also considered in the review.
Single-phase liquid samples were collected at Casa Diablo in 1985 and 1986 from the production wellhead using a cooling coil to prevent flashing and from a mini-separator that allowed flashing of the fluid to liquid and gas under known conditions (Farrar et al., 1987, 1989). Samples were also collected from wells RDO-8 and 44-16, which were drilled in the west moat zone in 1986 (Sorey et al., 1991). Samples from RDO-8 were taken approximately five months after the well was completed and about one month after perforation of the well casing in October 1986. Waters were sampled from the well using both downhole equipment and a bailer. Water from 44-16 was sampled during airlifting of approximately 160,000 L of water from the wellbore following completion of the well. The authors note that some loss of steam and noncondensible gas occurred prior to sampling, and that the sampled contained relatively high levels of Na and SO4 due to drilling mud contamination.


Additional References