Lan Do gas field (Block 06-1 in Nam Con Son basin) started producing gas and condensate in October 2012. The cumulative production up to February 2018 was 6,854 billion cubic metres of gas and 0.09 million barrels of condensate which account for 62% and 41% of the reserve, respectively. At present, there is no water influx phenomenon in Lan Do production wells. However, it is necessary to forecast water influx period for reservoir production and management strategies. This paper analyses and forecasts this phenomenon for the production wells of Lan Do field and proposes optimal production strategy.