Determination of Calcite Scaling in OW-903, OW-911 and OW-914 of the Olkaria Domes Field, Kenya

Abstract

Determination of Calcite Scaling in OW-903, OW-911 and OW-914 of the Olkaria Domes field, Kenya By Ruth Wamalwa Olkaria Geothermal field has been in use for geothermal power generation since 1983. For ease of development, the field has been divided into 7 sectors; namely Olkaria East production field (EPF), Olkaria North East production field (NEPF), Olkaria Domes (OD), Olkaria Central production field (CPF), Olkaria South East (SE), Olkaria South East (SE). To date the field has six power plants operational; two of which having a capacity of 280Mw having being commissioned currently. An updated geochemical model indicates that NEPF and EPF have predominantly Na-Cl waters with EPF having slightly elevated Sulfate in the discharge fluids whereas the CPF is predominantly carbonate waters. The OD also has Na-Cl waters types except areas around OW-903, OW-911 and OW-914 which have carbonate waters. Though the impacts of calcite depositions associated with these water types are apparent especially with the blockage of OW-202 in the CPF due to calcite scaling, there exists a gap in that there has not been any studies meant to simulate the changes that may take place in wells OW-903, OW-911 and OW-914 during production in the bicarbonate water type reservoirs. This paper therefore seeks to bridge this gap by simulating the chemistry of these wells in an attempt to discern the most likely scenario during production at the existing production conditions. Key words: Geochemistry, simulations, calcite scaling