DEVELOPMENT OF ELECTRICAL AND ELECTROCHEMICAL PROBES FOR DOWN HOLE AND IN-LINE CHEMICAL ANALYSIS OF HIGH PRESSURE, HIGH TEMPERATURE GEOTHERMAL FLUIDS (Interim Report - Period Ending October 1977)

Abstract

The objectives of this program are to develop probes that can determine the water chemistry of high temperature geothermal fluids. The entire probe system includes a high temperature reference electrode, oxidation potention (redox potential) , conductivity probe, pH, corrosivity, and specific ion probe (sulfide). The objective of this study for FY 1977 was to develop a reference electrode and conductivity probe that would operate in the geothermal environment and provide data. This work also involved a study of sealing materials. A high temperature-pressure, thermodynamic reference electrode was developed which was demonstrated to be operative in a simulated geothermal environment up to 250°C containing the contaminants that would affect its operation. An electrodeless conductivity probe was developed for use in the geothermal environment. This design is particularly resistant to the effects of scale deposition. A large number o f sealing materials were investigated for use in the 250°C geothermal environment. From this study, PNL has developed a spring-loaded seal that may have other applications in the geothermal industry.