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Title: A preliminary survey of noble gases at Dixie Valley, Nevada

Conference ·
OSTI ID:494437
 [1];  [2];
  1. Lawrence Berkeley National Lab., CA (United States)
  2. Oxbow Geothermal Corp., Reno, NV (United States)

A preliminary survey of noble gas abundances and isotopic compositions in production fluids from four high pressure separator stations providing steam to the dual flash Dixie Valley Geothermal Plant has been completed. The atmospheric noble gases are dominated by dissolved gases introduced with the injection fluid, a mixture of flashed degassed brine and condensate equilibrated with air in the cooling tower. Excess helium, however, represents a primary reservoir fluid and variations in the amount of excess can be used to monitor the changing proportion of injectate in the production fluid. The helium component associated with the reservoir fluid has an isotopic composition (0.70 - 0.76 Ra) implying that {approximately}7.5% of the helium in the 1995 Dixie Valley reservoir fluid is mantle-derived. The Dixie Valley geothermal field is closely related to the range-front normal fault of the Stillwater Range. Assuming fluid transport along the fault from deeper sources and using a one-dimensional steady-state advection model, the helium content and isotopic composition of the reservoir fluid predicts an average fluid flow rate of virgin fluid from depth of {approximately} 7 mm/yr. This is significantly less than injectate flow rates within the reservoir estimated from tracer tests (i.e. 5 - 120 m/day).

DOE Contract Number:
AC03-76SF00098
OSTI ID:
494437
Report Number(s):
CONF-960913-; TRN: 97:002642-0114
Resource Relation:
Conference: Annual meeting of the Geothermal Resources Council, Portland, OR (United States), 29 Sep - 2 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of Geothermal development in the Pacific rim. Transactions, Volume 20; PB: 886 p.
Country of Publication:
United States
Language:
English