基于多自由度系统的深水钻井隔水管紧急解脱反冲响应

深水钻井隔水管紧急解脱后的反冲响应是隔水管系统设计分析的重要内容之一。基于多自由度质量—弹簧—阻尼系统，建立了深水钻井隔水管紧急解脱后反冲响应分析的力学模型和控制方程，采用子空间迭代法求解了系统振动的固有频率和主振型，获得了隔水管底部组合（LMRP）紧急解脱后的振动响应曲线，并讨论了张紧器活塞运动振幅及运动频率、解脱初相角、水深和隔水管壁厚对LMRP振动响应时程曲线的影响。结果表明：随着作业水深和张紧器运动幅值的增加，LMRP与水下防喷器发生碰撞的可能性增大；解脱初相角对隔水管反冲响应具有较大影响；顶部张紧器活塞存在某一运动频率最不利于深水钻井隔水管的紧急解脱；壁厚对隔水管反冲特性的影响不大。

Recoil response of deepwater drilling riser during emergency disconnection based on a multi-degrees-of-freedom system

The recoil response of deepwater drilling riser after emergency disconnection is an important factor for the design and analysis of the drilling riser system. Based on a mass-spring-damping system with multi-degrees-of-freedom, this study establishes the mechanical model and control equation for the recoil response analysis of deepwater drilling riser during emergency disconnection. It solves the natural frequency and main vibration mode of the vibration system using the subspace iteration method, obtains the vibration response curve of the Lower Marine Riser Package (LMRP)of the drilling riser after emergency disconnection, and explores the impacts of piston motion amplitude and frequency of the tensioner, initial phase angle of disconnection, water depth and wall thickness of riser on the time history curve of LMRP vibration. The results show that the possibility of collision between the LMRP and the Blowout Preventer (BOP)increases with the increase of water depth and the movement amplitude of the tensioner during operation. The initial phase angle of the emergency disconnection has a great impact on the recoil response of riser. The piston of the top tensioner has a certain movement frequency that is the most unfavorable for the emergency disconnection of the riser. The wall thickness has little effect on the recoil characteristics of the riser.