Tracer Calibration Tests at Wairakei Geothermal Field

Abstract

To investigate the potential for performing simultaneous tracer tests from multiple reinjection wells, calibration trials were done within the production area of the Wairakei geothermal field using a range of tracers. The tracers included fluorescent dyes, inert gases, organic compounds and radioactive isotopes. All tracers were injected into a non-productive well containing a natural inter-zonal flow using 6 capillary tubing. Tracer returns were monitored in the nearby production wells. All tracers showed similar first return times and relative to and the liquid tracers showed similar return patterns, but the return concentrations varied by up to For wells producing from the liquid zone of the reservoir, tracer return patterns from the xenon gas tracer was essentially the same as for the liquid tracers, but for one well producing from both steam and liquid feed zones the returns of the gas tracers greater than for the liquid phase tracers by four times. This difference is attributed to transfer of the gas from the liquid to vapour zones in the reservoir as the deeper liquid boils.