Quasi static design method for the structure of the lunar pool stabilizer on an ocean drilling vessel

The amplitude response of ocean drilling vessels is more severe than that of floating platforms, and there is a high risk of interference between the drilling string and the moon pool. To address this issue, a moon pool centralizer was designed. Considering the motion characteristics and load distribution of the drilling string, the overall structure of the moon pool centralizer was designed, and the offshore current load excitation was restored. The ultimate bearing capacity of the moon pool l centralizer was analyzed under three different operating conditions: drilling, casing running, and drifting of the drilling vessel. The load distribution and risk points for each condition were analyzed based on the failure mode under the ultimate state, and structural improvement schemes were then proposed. The research indicates that the failure-prone location of the moon pool centralizer is at the pin shaft; the moon pool centralizer is more dangerous under the condition of drifting of the drilling vessel; and by adjusting the position of the base pin shaft and adding a set of thrust bearing cylinders, the load distribution of the overall structure and the pin shaft can be reduced.The research results provide theoretical support for the subsequent research on the optimal design of the moon pool centralizer structure.