Gas and Chemical Monitoring of the Mutnovsky (Dachny) Geothermal Field Exploitation (Kamchatka, Russia)

Abstract

Gas and chemistry sampling of the exploitation wells of the Dachny site Mutnovsky geothermal field (Kamchatka, Russia) were performed in 1999-2000 (before the 50 MWe power plant was put into operation) and again in 2003 (after exploitation started). Sampling from five principal exploitation wells (016, 26, 029W, 4E and 5E) was performed. Gas and macroelemental analysis was performed in the Institute of Volcanology Lab, sampling method was based on ASTM E 1675-95a. Microelemental analysis based on the ICP method (IRIS, Jarell Ash Corporation).
Drilling of deep wells and geothermal exploitation may cause chemical emissions of elements including arsenic, boron, lithium, silicon over their maximum allowable concentrations. The ecological impact of the gas emission (CO2, H2S) was estimated too. Since exploitation started, the following variations were detected: (1) fraction of meteoric gases increase in wells 016, 029W and 4E, (2) Na/K temperatures decrease in wells 4E and 029W, (3) SiO2 decrease in all wells.