深海钻井隔水管紧急脱离反冲平台偏离效应

Effect of Platform Offset on Recoil Dynamics of a Deep-Water Drilling Riser after ED

建立深海隔水管横向和纵向反冲响应耦合有限元模型,探究钻井平台的横向偏离效应。相比于一维模型,考虑横向位移可更加准确地计算系统的潜存势能;同时,引入悬挂隔水管单摆运动可更接近作业实际并可对顶端挠性接头转角等因素进行分析。研究发现,顶端平台横向偏离使低端总成与井口在反冲过程中最小距离增大,有利于避免与井口相撞,但可能导致挠性接头转角及张紧器液压缸冲程超限。钻井平台偏离效应对选择最佳紧急断开时刻(即垂荡相位角)也有重要影响。该成果可为优化深海隔水管反冲响应特性预报程序及抗反冲控制系统提供支持。

A coupled finite element model of the lateral and longitudinal recoil response of deep-sea riser is established to explore the lateral deviation effect of drilling platforms on recoil dyanmics after ED(Emergenchy Disconnect).In recoil simulations,the researchers typically employ one-dimensional(1-D)models(i.e.,only the heave direction)and the platform offset effect is neglected.A 2-D finite element model for the coupled longitudinal and transverse motions of a recoiling riser is established,which can calculate the potential energy of the riser system with more accuracy.Moreover,the new model introduces a pendulum motion of the suspended riser and the influential factors such as the angle of the upper flex joint can be examined in recoil analysis.The results show that with the increase of platform offset,the minimum distance of LMRP and BOP in the recoil process which help avoid collision.However,it may cause the upper flex joint angle and the tensioner cylinder piston stroke exceeds the limits.The study can be a workbench for recoil analysis after ED and anti-recoil control optimization for drilling riser system operating in deep-waters.