TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMultiphase wellhead flow measurements using the tracer technology method have been successfully applied to over 65 wells in the Dulang field, located offshore Malaysia. A large range of flow conditions were covered with gas rates ranging between 943 m3/d and 165,900 sm3/d, oil rates between 20 m3/d and 319 m3/d, and water rates up to 489 m3/d. The watercut varied between 0% and 93%. The results obtained using the tracer technique was used as a cross-reference to the results obtained from conventional well tests using the test separator and to a separate multiphase meter during a trial period.The present tracer method involves injection of selected tracers for oil, gas and water at a specific injection rate into the production stream followed by subsequent sampling of the fluids at a suitable downstream location. Measurement of the tracer dilution ratios allows the accurate determination of the individual fluid flow rates.The application has proven the tracer technology method to be a robust and accurate multiphase flow measurement technique over a wide range of flow conditions. In practice the tracer method is capable of measuring over a much wider range than most test separators and multiphase flow meters making the technique very well suited for in-situ verification and calibration of installed multiphase and wet gas flow meters.