Chemistry in exploration of a geothermal field

Abstract

Chemistry principles are some of the scientific techniques used in exploration for geothermal resources. The methods used include sampling of surface discharge from potential target areas and soil gas sampling followed by chemical analysis of the samples and finally data interpretation. The data obtained is used to assist in locating potential drill sites for geothermal generation, estimating the subsurface temperatures where the discharges are coming from and characterising the geothermal fluids using the chemistry to assess their usability for the intended purposes. This technique was used in exploration for geothermal resources in Menengai field, Kenyan Rift Valley. The results indicated availability of geothermal fluids at temperatures of up to 250 o C. The reservoir was defined by both high CO2 and Rn-222 measured in the soil gas and also high gas content in the fumarole discharges and the high volatile constituents in the fumarole steam condensates. Three deep exploration wells were proposed to be drilled in Menengai caldera using the chemistry of the surface discharges.