Corrosive species and scaling in wells at Olkaria, Kenya and Reykjanes, Svartsengi and Nesjavellir, Iceland

Abstract

The Olkaria geothermal system in Kenya is located within the Okaria volcanic complex in the central sector of the Kenya Rift Valley. Reykjanes, Svarstengi and Nesjavellir geothermal fields are located in southwest Iceland and fall on a continuous earthquake epicentric line extending through the Reykjanes Penninsula that stretches northeast to Langjökull. These four geothermal fields are all high-temperature. Measured temperatures in Olkaria are as high as 350°C, Reykjanes 320°C, Svartsengi 240°C and Nesjavellir > 380°C. The reservoir waters in the four fields vary. The water type at Olkaria is mainly dilute near neutral pH sodium -chloride and sodium-bicarbonate waters with chloride ranging between 50 and 4000 ppm at atmospheric pressure. At Reykjanes and Svartsengi these are saline sodium-chloride waters with chloride being 20,000 and 13,000 ppm, respectively, while at Nesjavellir they are very dilute sodium chloride waters with chloride of ~ 150 ppm.