Abstract: A quantitative evaluation of the fault sealing of Chenbao area in Gaoyou sag is made by applying synthetic fuzzy judgment integrated with shale smear factor method. The results are in accordance with actual situations from exploration. Study shows that great differences of fault sealing in different positions occur for such major faults as Wu-1 and Wu-2, with characteristic of deep opening and shallow closing, becoming the main passages for hydrocarbon migration and effective sealing for hydrocarbon fugitive emission. For the minor faults, they tend to forming fault-sealed reservoirs in it due to their good sealing properties.

Key words: Chenbao, fault sealing, shale smear, synthetic fuzzy judgment