Physical results of research drilling in thermal areas of Yellowstone National Park, Wyoming

Abstract

ABSTRAGr analysis of our data indicates that four of our drill holes affected nearby springs, generally converting them temporarily into geysers.Our conclusions from Yellowstone indicate that physical relations in many commercially explored geothermal reservoirs are not as uniform as routine postdrilling measurements have indicated.' I used as the circulating fluid. Storage tanks of 1,000-gal capacity at each drill site provided a reserve water supply in the event the pump failed. Drilling mud was not

05/00715 Simulation of water-rock interaction in the Yellowstone geothermal system using TOUGHREACT

“…The stratigraphy consists of three main units: volcaniclastic sandstone (down to a depth of 55.2 m), perlitic rhyolitic lava (55.2-62.6 m), and pumiceous ash-flow tuff (62.6-153.4 m). White et al (1975) also report the results of downhole temperature and pressure surveys. Temperatures increase with depth down to a depth of ~55 m, where near-isothermal conditions (160-170°C) persist down to the total depth of 153.4 m.…”

“…A general description of the stratigraphy is given by White et al (1975). The stratigraphy consists of three main units: volcaniclastic sandstone (down to a depth of 55.2 m), perlitic rhyolitic lava (55.2-62.6 m), and pumiceous ash-flow tuff (62.6-153.4 m).…”

“…Yellowstone has been the site of extensive studies of hydrothermal alteration, including the examination of samples from 13 core holes drilled by the U.S. Geological Survey (White et al, 1975). The Y-8 core, consisting of three distinct geologic units (volcaniclastic sediments, perlitic rhyolitic lava, and nonwelded pumiceous ash-flow tuff), was selected for this modeling study.…”

Behavior of nuclear waste elements during hydrothermal alteration of glassy rhyolite in an active geothermal system: Yellowstone National Park, Wyoming

“…Y7 is in an area having no surficial thermal activity, whereas Y8 is within a cluster of discharging pools and geysers. The petrography and mineralogy of the Y7 and Y8 drill core samples have been characterized in detail by Keith et al [2]; drilling techniques and physical measurements in the drill holes are discussed by White et al [3].…”

“…In Y7, the Biscuit Basin Flow consists predominantly of rhyolite flow breccia from -52.7 m to the bottom of th« hole at -73.8 m. In Y8, the same flow breccia occurs from -55.2 m to -62.8 m, and is underlain by pumiceous tuff that extends to the bottom of the hole at -153.4 m. The flow breccia and pumiceous tuff are interpreted to have formed from the same magma, but through different modes of eruption, on the basis of close similarities in their bulk composition and plagioclase characteristics [2]. Bottom-hole temperatures within the Biscuit Basin Flow during drilling, considered representative of pre-drilling conditions [3], ranged from about 120 to 140°i; in Y7, and from about 160 to 170*C in Y8.…”