Abstract
CO2 is a main component of gases in the Yangbajing geothermal field, usually higher than 85% in volume; others are N2, H02S, H2, CH4, etc. Helium R/Ra ratios, ranging from 0.14 to 0.46, indicate a crustal component to be dominant in the gases. δ13C-CO2 values and δ34 S-H2S values are in the range −7.72‰–−11.33‰ and 0. 2‰–8. 3‰, respectively. The gases are inferred to mostly derive from the partial melting of the Nyainqentanglha core complex. The gases of shallow and deep reservoirs are distinctive in chemical compositions and δ34S-H2S values, which shows their different flowing paths and physical-chemical processes. Sulphur does not approach isotopic equilibrium between H2S and SO-2 4 species in both reservoirs. Significance of steam chemical monitoring is also discussed.
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Zhao, P., Dor, J., Liang, T. et al. Characteristics of gas geochemistry in Yangbajing geothermal field, Tibet. Chin. Sci. Bull. 43, 1770–1777 (1998). https://doi.org/10.1007/BF02883369
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DOI: https://doi.org/10.1007/BF02883369