Scaling Potential Assessment in the Domes Wellfield, Olkaria-Kenya

Abstract

Scaling is a major setback in the harnessing of geothermal resources. This paper presents results from a study aimed at assessing the potential of scale formation that can occur during utilization of geothermal fluid from the Domes wellfield, Olkaria-Kenya. The chemical composition of geothermal fluids from 4 selected high-temperature geothermal wells was determined. Data on the chemical composition liquid water and vapour discharged from these wells have been used to reconstruct the composition and species distribution in the initial aquifer fluid using the Phase Segregation Model for wells with excess discharge enthalpy. Aquifer fluid was then modelled to predict scaling occurrence when the fluid is cooled. Concentrations of reactive gases in relation to their approach to equilibrium with respect to selected mineral-gas reactions have also been examined. The results indicate that scaling potential of aquifer fluids at Domes wellfield differ from well to well and therefore each well need to be taken into consideration during planning of resource utilization for effective management.