Abstract: There is a typical gas cloud area in the L Oilfield of Bohai Bay, and the gas cloud area accounts for about 30% of the trap area. The quality of seismic data in gas cloud area is poor, which is characterized by weak amplitude and weak continuity on the seismic profile. Consequently, it is difficult to interpret the faults in the gas cloud area. In order to further understand the fault distribution of 1N block and improve the development effect, we have studied the geological reservoir response of the potential faults in the gas cloud area of 1N area, and identified the position and extension direction of two possible faults by fine stratigraphic contrast and the correlation analysis of injection and production wells, thus reducing the geological uncertainty, improving well pattern and ensuring injection safety.