Analysis of Reservoir and Steam Flow Data in Olkaria Domes Geothermal Field, Kenya

This study evaluates reservoir performance and steam production in the Olkaria Domes Geothermal Field, Kenya, over the period 2019-2023, with a focus on key wells supplying Olkaria IV, Olkaria V, and wellhead power plants. Monitoring data from wells such asOW-914, OW-916, and OW-921 show stable wellhead pressures ranging from 6.5 to 9.8 bar, and discharge enthalpies between 1400 and 2650 kJ/kg, consistent with production from a high-temperature liquid-dominated reservoir. Reinjection rates remained above 48%, helping maintain reservoir pressure. However, evidence of cooling and dilution was observed in wells like OW-923 and OW-926, where enthalpy values dropped by up to 250 kJ/kg, and silica concentrations declined from 470 ppm to 410 ppm, suggesting the encroachment of colder reinjection fluids. Using discharge test data and pressure logging, mass flow rates, pressure trends, and thermodynamic conditions were analyzed. The findings underscore the necessity for continuous reservoir monitoring and the need to optimize reinjection design to avoid long-term pressure drawdown and thermal degradation. These insights are vital for sustaining steam supply and ensuring the long-term viability of geothermal energy production in the Olkaria Domes field.