Application of Geochemical Methods in Geothermal Exploration in Kenya

AbstractThe major goals of geochemical exploration are to obtain the subsurface composition of the fluids in a geothermal system and to use this to obtain information on temperature, origin, and flow direction, which help in locating the subsurface reservoir. Subsurface waters have been classified into meteoric water, ocean water, evolved connate water, magmatic water, and juvenile water. Geothermal water is mostly meteoric and oceanic water, although andesitic waters near subduction areas often contain significant proportions of evolved connate and magmatic waters. Geothermal waters have been classified with respect to their anion and cation contents into alkali-chloride water, acid sulphate water, acid sulphate-chloride water, and bicarbonate water. Acid waters are generally unsuitable for elucidation of subsurface properties. Conservative constituents are used for tracing the origin and flow of geothermal fluids, stable isotopes (especially 2H and 18O), along with B and Cl being most important. Rock forming constituents SiO2, Na, K, Ca, Mg, CO2, and H2) are used to predict subsurface temperatures and potential production problems such as deposition and corrosion. Kenya is located on the Great Rift Valley in Eastern Africa and has a huge potential for geothermal production of power and other direct uses. In this paper, we report on the geochemical methods used in Kenya to explore, develop, and monitor the available geothermal resources for power production and other direct uses