Tracer Flow Testing: New Developments in Tracers and Instrumentation

Abstract

The chemical tracer flow test (TFT) technque for Wephase mass flow rate measurement has been in use since 1992 and is now employed routinely in the major geothermal fields of 6 countries. There have been continuous refinements in the TFT process over time, including introduction of new vapor and liquid tracers, and upgraded tracer metering equipment. Since F T is now used by many operators around the worfd, it is impottant to ensure that the technique is consistent and robust, and not site-specfic or sensitive to small deviations in methodology. Comparative data are presented for some of the various tracers, including recent tests on alcohol tracers. These tests show sulfur hexafluoride (*e) is the most versatile and accurate tracer for F T steam measurements, while alcohol can be used in limited applications. Sodium benzoate was until mentty the primary liquid-phase tracer, but is now being replaced by polyaromatic suhnate (PAS) tmcers. The SF6 and PAS tracers allow miniaturization of the tracer metering equipment, resulting in greater pottabilw and lower cost.