Assessment of geothermal reservoirs by analysis of gases in thermal waters
Gases were measured in fifty-one thermal wells and springs in New Mexico including sixteen wells in the Lightning Dock geothermal area. Correlation of gases with alkali geothermometry indicates CO/sub 2/ and He increase in abundance with reservoir temperature while N/sub 2/, Ar, NO, Kr and CH/sub 4/ show slight decreases. H/sub 2/S generally occurs in waters with reservoir temperatures >100/sup 0/C, however, H/sub 2/S is not present in all high temperature waters. Gas ratios, principally CO/sub 2//N/sub 2/, CO/sub 2//Ar, CO/sub 2//CH/sub 4/, He/N/sub 2/ and He/Ar correlate better with geothermometry than abundances of individual gases. This study indicates the gas data which could be used to identify waters from reservoirs of T > 100/sup 0/C are CO/sub 2/, CO/sub 2//N/sub 2/, CO/sub 2//Ar, CO/sub 2//CH/sub 4/, He/N/sub 2/ and He/Ar in well waters as well as CO/sub 2/, CO/sub 2//CH/sub 4/, CO/sub 2//N/sub 2/, and CO/sub 2//Ar in spring waters. A geothermometer based on CO/sub 2/-CH/sub 4/ ratio is proposed. Indications are that the CO/sub 2//CH/sub 4/ geothermometer works in temperature ranges of 50 to 300/sup 0/ and nearly as well as the other chemical geothermometer. Gases and gas ratios which correlate positively with reservoir temperature show a regular zonation pattern around the hot wells in the Lightning Dock geothermal area. This agrees with other studies which indicated that the hot wells are the point of upwelling thermal waters. It is concluded that gases in waters can be a valuable exploration tool to locate favorable sites for drilling in geothermal fields.
- Research Organization:
- New Mexico Inst. of Mining and Technology, Socorro (USA). Dept. of Geoscience
- OSTI ID:
- 5819904
- Report Number(s):
- NP-2901208; EMD-2-68-2305; ON: DE82901208
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOTHERMAL RESOURCES
RESOURCE ASSESSMENT
GEOTHERMOMETRY
THERMAL WATERS
GAS ANALYSIS
ARGON
CARBON DIOXIDE
HELIUM
HYDROGEN SULFIDES
METHANE
NEW MEXICO
NITROGEN
THERMAL SPRINGS
ALKANES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
FLUIDS
GASES
HYDROCARBONS
HYDROGEN COMPOUNDS
NONMETALS
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE GASES
RESOURCES
SOUTHWEST REGION
SULFIDES
SULFUR COMPOUNDS
USA
WATER SPRINGS
Geothermal Legacy
152004* - Geothermal Data & Theory- Isotope & Trace Element Studies
150302 - Geothermal Exploration & Exploration Technology- Geochemical Techniques & Surveys