Abstract: We mainly introduces the composition and configuration of workover and drilling operation system capable of cylindrical floating production, storage and offloading system (FPSO), as well as the key heave compensator system. An operation system layout scheme which makes full use of the central moon pool area is demonstrated, and the frame structure which supports the operation system is analyzed. The analysis results show that the layout scheme is reasonable and feasible, which integrates workover or drilling well function on cylindrical FPSO successfully. This application research provides a new thought and the key technical reserves for the deepwater marginal oil field development.