Recent Exploration and Development of the Olkaria Geothermal Field

Abstract

Exploration of the Olkaria geothermal field in Kenya was commenced 1956 with the drilling of two hot but unproductive shallow investigation wells and X-2, Fig.2). Between 1971 and 1972 a surface exploration program was funded by the Kenya Government and United Nations. This resulted the drilling of a number of further exploration wells during the period 1972 to 1976. The first of these (OW-1) was unsuccessful, however, the second (OW-2) encountered in an area now known as the Olkaria East Wellfield, OEW, a vapour zone at about 240 C. underlain by a dilute NaCl reservoir which deeper temperatures closely followed boiling point for depth conditions. Four exploration wells were subsequently drilled as from OW-2 with very similar conditions encountered. Following a feasibility study carried out in 1976, production drilling was commenced which progressed through to the staged commissioning between 1981 and 1985 of a 3 X 15 turbine power station the Olkaria East area. A detailed account of this initial phase of exploration and development is given Svanbjornsson et al. (1983).