台风环境下深水钻井平台失控漂移后果分析及安全屏障研究

Research on consequences and safety barriers of the runaway drift-off for deepwater drilling platform under typhoon conditions

我国南海台风频度高、强度大,深水钻井平台存在失控漂移的风险。结合系统动力学方法,从系统角度整体分析平台-隔水管耦合模型在台风下的失控漂移过程,以漂移轨迹为顶部边界条件研究隔水管在不同状态下的力学响应,并利用因果回路图方法探讨防止平台漂移事故升级的各级安全屏障。研究结果表明:深水平台失控漂移轨迹随环境载荷方向变化明显,其中沿x方向漂移量呈现0°≈180°>45°≈135°>90°的特征,沿y方向漂移量规律相反且整体偏小;底部连接状态下隔水管等效应力大于断开状态,两种状态下隔水管分别在14s和100s左右超出应力限制;各级安全屏障存在显著交互关系,影响三级安全屏障性能的主要因素包括人员操作准确性、人员应急响应能力和紧急关断系统可靠性。本文研究结果可为台风下深水钻井安全作业提供理论依据和工程指导。

In view of the high intensity and high frequency of typhoon in South China Sea,the deepwater drilling platform faces the risk of runaway drift-off. Considering system dynamics,the developed dynamic coupling model of platform and riser was used to analyze the process of platform drift-off. The mechanical responses of the riser under different conditions were studied with the platform motion trajectory as the top boundary condition,and all levels of safety barrier performance to prevent the escalation of platform drift-off accidents were discussed combined with the causal loop diagram. The results show that the drift-off trajectory of deepwater platform changes obviously with the direction of environmental loads,and the drift-off displacement exhibits features of 0°≈180°>45°≈135°>90° along the x direction,but it shows the opposite law and lower value along the y direction. The equivalent stress of the riser under the bottom connected mode is higher than that under the disconnected mode as a whole and the stress of the riser exceeds the limit at the 14th second. However,in the disconnected mode,it requires 100 s. There are significant interactions among safety barriers of different levels. The main factors that affect the performance of three-level safety barriers are the operation accuracy of personnel,the capability of personnel emergency response and the reliability of emergency disconnection system. The results of this paper can provide a theoretical basis and engineering reference for deepwater drilling safety operations under typhoon conditions.