Drillships are used for exploratory drilling operations in a water depth above 3000 m. Design variants in the new-generation drillships include flexible internal storage and payload capacity. While their operations are quite satisfactory in moderate weather conditions, response under metocean hurricane conditions to preserve operation versatility poses challenges. The design and operation of drillships, which are intricate and domain-specialized vessels, need attention. This study examines the motion characteristics of a drillship for different sea states and environmental conditions. Their stability across critical sea states is also assessed. Based on the numerical studies, it is seen that they experience a modest degree of instability due to excessive roll and pitch under extreme environmental loads. While preliminary checks under mild heave motion showed that the coupled heave–pitch motion dominates the design shear and longitudinal bending, they are critically influenced by the pitch motion. The forces of second-order steady drift in the far field and the near field are compared in the frequency domain. This study identifies parameters that influence its strength and stability, and the results are useful for improving the operational safety and reliability of drillships under challenging offshore conditions.

钻井船用于水深3000米以上的勘探钻井作业。新一代钻井船的设计变体包括灵活的内部存储和有效负载能力。虽然它们在温和天气条件下的操作相当令人满意，但在气象海洋飓风条件下保持操作多功能性的响应提出了挑战。钻井船是复杂且专业的船舶，其设计和操作需要引起注意。本研究研究了钻井船在不同海况和环境条件下的运动特性。还评估了它们在关键海域的稳定性。根据数值研究，可以看出，由于极端环境载荷下过度的横滚和俯仰，它们会经历适度的不稳定。虽然轻微升沉运动下的初步检查表明，耦合升沉-纵摇运动主导着设计剪力和纵向弯曲，但它们受到纵摇运动的严重影响。在频域中比较了远场和近场中的二阶稳态漂移力。这项研究确定了影响其强度和稳定性的参数，其结果有助于提高钻井船在具有挑战性的海上条件下的操作安全性和可靠性。