A reservoir assessment of the southeast part of Olkaria Domes geothermal field, Kenya

Abstract

The Kenyan rift has great geothermal potential. Fourteen geothermal prospect fields have been identified and about 202 MWe are now generated in one of these fields, Olkaria. This has been a success and, as a result, has called for more drilling to develop Olkaria Domes, a division in the Greater Olkaria area. Appraisal drilling in the Domes field has been completed and the production drilling target of a 140 MWe power plant is at an advanced stage. Warm-up profiles, injection pressure transient tests and discharge results from the wells were used to assess the southeast part of the Domes field. Logging revealed temperatures of over 300°C in the wells at a depth of about 1200 m. The reservoir is two-phase with temperature and pressure following the boiling point curve. The wells have cyclic mass flow but with high enthalpy. The effective permeability of the reservoir varies between 1.1 and 6.1 mD; negative skin is observed in most of the wells.