Abstract: In view of the problems of offshore condensate gas reservoirs, such as fewer wells, more combined production wells, difficulty in stabilizing production, and urgent need to find new reserves, taking X gas field in East China Sea as an example, the integration research of geology and gas engineering was carried out. The fine characterization of reservoir A was carried out by using the method of seismic geology, dynamic and static integration, and relying on the modeling digital model technology. The horizontal and vertical spatial distribution characteristics of reservoir were implemented, which effectively solved the contradiction between geological cognition and production dynamics, quantitatively characterized the production situation and residual gas potential of each reservoir, and verified by new drilling.This study can better solve the quantitative characterization problem of remaining gas under complex geological conditions with few wells on the sea, and has reference significance for tapping the potential of similar gas reservoirs.