Water production is naturally inevitable since the initial gas-water contact moves up as reservoir pressure is depleted during entire production period. In multi-layered gas reservoirs, gas productivity could be decreased by water production which may cause water blockage or cross flow and even the well can be killed if gas production rate is less than the minimum velocity to prevent liquid loading. Therefore, water management is essentially required as a top priority for reservoir management. However, an analytical approach to estimate water influx from each zone has uncertainties due to the complexity of fluid flow in multi-layered reservoir and in highly deviated wells. For that reason, production logging is commonly carried out to directly measure production contribution for each zone although it makes high cost. In this study, production logging data is reviewed and analyzed to estimate productivities of each zone and to select the best matched flow correlation then, the results are utilized to construct a production well model. The model is validated with well test data and a sensitivity analysis for water cut is carried out using multi-phase flow simulator in order to estimate water entry zone and to predict water production behavior in the future