Abstract: The main exploration horizons in Xihu Sag are usually condensate gas reservoirs, are hard to be identified by conventional fluorescence logging. In addition, the fluorescent material added in the drilling fluid for the safety of well drilling also complicates the judgment of mud logging information. Due to the high sensitivity in detection, the three-dimension quantitative fluorescence logging technology has shown its specific advantage in the identification and interpretation of condensate gas layers in Xihu Sag. The plots for the interpretation of condensate gas, oil and gas, water-bearing gas layers established in the application of three-dimension quantitative fluorescence logging in many years provide effective technical support for the exploration of oil and gas in Xihu Sag.