夏半年强风条件下波浪对平湖油气管道安全的影响分析

The Influence of Wave on Pinghu Submarine Pipeline under Extreme Weather Conditions

强风天气过程影响下的波浪近底层水体运动(波致底流速)是海底动力条件的重要驱动因素之一,因此,强风天气过程引起的波致底流速分布可能对海底管道冲刷和埋设状态变化产生潜在影响。本研究基于SWAN模式的海浪模型,对平湖油气管道区域波致底流速进行推算;将平湖管道区域波致底流速分布与管道埋深状况有机结合,探讨波浪对管道埋深状态变化的影响。结果显示,夏半年(7月~9月),因其近SE向为主的典型强风向和地形因素影响,波致底流速在舟山群岛靠外侧海域(约KP85~KP100段)形成明显的相对高值区。近年来,平湖油气管道裸露和悬空管道的增幅,主要出现在夏半年管道KP85~KP100段区域,该区域与波致底流速相对高值区基本重合。综合已有研究成果表明,夏半年的典型强风过程的波浪作用可能对管道KP85~KP100段区域动力条件产生一定的影响,使水体挟沙能力加强,对海底造成区域性冲刷,是造成该区域管道冲刷、管道裸露、悬空及埋深状态变化的重要原因。

The wave orbital motion near the bottom (Ubot)caused by strong wind is one of the most important factors in marine sediment dynamics.The Ubot may have potential influence on the submarine pipeline's scouring and status.Based on SWAN model,the Ubot in the area of the Pinghu pipeline may be calculated.Based on inspecting data in recent years,the vibration regularity of Pinghu submarine pipeline's status is analyzed.This article discusses the effect of wave action on submarine pipeline's scouring and status by synthesizing all kinds of factors.The resuIt shows that the formation of an apparent high value region of Ubot is on the outer surface of the Zhoushan Archipelagos (KP85-KP100) under strong SE wind in summer.The result also shows that the status of pipeline scouring in KP85-KP100has been aggravated during summer,causing the pipeline to be exposed.In conclusion,summer wind conditions may influence the wave-induced near-bottom orbit velocity in KP85-KP100section area,thus leading to pipeline's scouringrapidly,seriously affecting the submarine pipeline's exposing and suspending.