Abstract: TDS-11SA top drive drilling system on KANTAN Ⅱ, as an important part of well control in drilling operation, its working reliability of IBOP directly affects the safety of well control operations.Various kinds of faults frequently occur in IBOP during drilling operations. In order to eliminate and prevent the faults quickly, the structure and characteristics of the IBOP are introduced. From the perspective of equipment repair, combined with the field work experience, the common failure types of IBOP are listed and the points that are prone to failures are analyzed. This paper summarizes the methods for preventing faults and repairing measures, and aims to provide references for the maintenance personnel to solve similar problems.