Currently Kengen Olkaria hosts five major power plants with several well head units that utilize the geothermal steam to generate power. These plants have single flash condensing turbines type with enormous condensate volumes per hour being reinjected into the cold reinjection wells. The production wells separation also result in several tones of brine being dumped into the hot reinjection wells which in turn recharges the reservoir. Once the steam has driven the turbines it is condensed and further cooled at the cooling towers with part of it being re-injected and some maintained as circulating cooling water component. The pH of the condensed steam is usually very low, (pH 2.5-3.0) due to the dissolution of gases such as CO2, H2S, and SO2, this brings about acidic environment that results in corrosion of carbon steel pipe works, cold re-injection wells master valves and the downhole well profile. The brine pH is alkaline in the pH range of (8 -10). Currently, Soda Ash is used to adjust the condensate pH from (2.5 – 3.0) to 6.0-8.0 for condensate re-injection purposes and also to accommodate Biocides efficacy pH range. There is also considerations to adopt the use of Caustic (NaOH) as an alternative to condensate pH adjustments. The current dosing plan seems to have several challenges ranging from pump breakdowns and lack of spares, soda ash stock runouts, and manual solution preparations which faces manpower issues and long stoppage of dosing. As a result, six cold reinjection wells have been completely lost and new wells drilled for the condensate reinjection in the Olkaria field. This proposal seeks to find a local solution based on the resources available and minimize on operational cost by mixing brine from wells and condensate from power stations at proportions capable of adjusting the pH to a neutral range before reinjection. Two potential mixing sites have been identified as a case study. Olkaria well OW-710C which is a cold reinjection well for Olkaria II power station and Brine from well OW-710. Lake Ngare Brine (OW-39, 37) and OIAU overflow condensate containment pond will be used to simulate the behavior of the mixing tendencies before reinjection at OW-R12. Expected benefits include saving cold re-injection wells from the frequent corrosion and leaks, improve on our re-injection efficiency and prevent condensate drain into the ponds due to low pH hence sustaining the reservoir. Reduce operational cost on drilling new reinjection wells, Soda ash consumptions, repairs and maintenance as a result of corroded pipe works, pumps and other auxiliaries.

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