Untitled - Orkustofnun

Chloride conc. (ppm)NaK Temp. (°C)Olkaria reservoir response40Ofwona3501200Well OW-2Well OW-10Well OW-25300800250200400150Well OW-2Well Ow-10Well OW-2501980 1985 1990 1995 2000 2005Year1001980 1985 1990 1995 2000 2005YearFIGURE 19: Chloride variationsFIGURE 20: NaK geothermometer resultsOnly well OW-34 has had silica deposition problem on surface equipment but studies have shown thatthis problem is unique to this well and that this deposition has not affected the wellbore or its output.4. FUTURE RESERVOIR DEVELOPMENT IN OLKARIAOlkaria I plant and reservoir have been in operation since 1981 and have performed very well.Average plant availability factor and overall load factor has been over 96%. The plant is nowapproaching its design life of 25 years but is still in good condition. The only major repair done wasreplacement of unit 1 generator coil in 2003. Unit 2 generator coil is now being replaced. The wellscurrently have about 280 t/hr more steam than what is required to generate 48 MWe. The deepreservoir is still unexploited as has been proved by deepening of well OW-5 and has had very littlepressure drawdown. There is also evidence that it has good recharge from the periphery and an areafor expansion still exist to the south and to the east of the field. Currently, studies are beingundertaken to find ways of optimizing the generation and the reservoir. After the optimization study,it will then be decided whether to increase production from the reservoir and by how much or to keepthe current installed generation plants. However, because of the positive response of the reservoirduring its production history, it is felt that it is underutilized and increased production is expected inthe future. Production drilling in Olkaria Domes will also start soon and hot re-injection in Olkaria Iwill be enhanced.REFERENCESAmbusso, W.J., 1994: Results of injection and tracer tests in Olkaria geothermal field. Proceedings ofthe 19 th Workshop on Geothermal Reservoir Engineering, Stanford University, Ca, 155-160.Brown, P.R.L., 1984: Subsurface stratigraphy and alteration of the Eastern section of the Olkariageothermal field, Kenya. Proceedings of the 6 th New Zealand Geothermal Workshop, Universityof Auckland, NZ, 33-42.Glover, R.I., 1972: Chemical characteristics of water and steam discharges in the rift valley. U.N.Geothermal Exploration Project, report.