Abstract: The success rate of drilling for fault structure traps in not high in the Pearl River Mouth Basin, and the study of fault sealing is particularly important for enhancing the success rate. In recent years, the technical progress of fault sealing study is mainly reflected in the aspects of consideration of stress factors, quantitative study of shale smears, and consideration of the three-dimensional shape of the sections. A typical fault trap, the Oilfield A in the Lufeng sag, is selected as an example for such an integrated assessment following the ideas mentioned above. The key reasons for the success or failure of the different fault blocks has been analyzed individually. It is found that the stress difference, SGR difference, appearance difference on section are the reasons to cause the failure in one fault block. The experiences provided by the case is valuable for drilling in similar fault structure traps.