Application of Sodium Benzoate in Surface Water Flow Measurements in Mindanao Geothermal Production Field, Philippines

Abstract

The tracer dilution method has gained acceptance in the geothermal industry as a substitute to the conventional James Lip Pressure Method for bore output measurement. The former type of measurement in quantifying the water flow along the two-phase and reinjection lines has been adopted by PNOC-EDC. Sodium benzoate was analyzed using UV-Vis spectrophotometer and results compared to those from a more expensive instrument such as HPLC. Field trials using a fabricated delivery system were conducted and were also compared to the commercially available tracer flow test equipment. Results of the initial tests showed good precision of concentration and water flow data. Water flow data obtained through flow test set-up, which used a metering pump, were also compared and gave maximum acceptable variance of 3.6 %. Variations in water flow with time have been used as an aid in reservoir management.