水下生产设施吊装入水砰击动态模拟

Dynamic Simulation on the Water Entry Slamming in Subsea Production Device Lifting Operation

在采用工程船吊装水下生产设施过程中,入水面积较大的设施与水面接触瞬间易产生较大的砰击载荷,使吊机及其索具因受到的瞬时动载荷超过自身极限而引发安全问题。为解决该问题,对工程船及水下生产设施在吊装过程中受到的动载荷进行理论分析,并基于OrcaFlex软件对水下管汇的下放入水过程进行动态时域模拟;同时,对多种海况下吊索的动态放大系数等条件进行校核,确定该工程船吊装入水的安全作业窗口。此外,分析不同随机波列中下放速度对吊装作业动载荷的影响,结果表明:波浪对动载荷的影响主要体现在波高越大,动载荷越大,而波陡越小,对作业越有利;下放速度减小有可能会使动载荷增大,因此在实际作业过程中,不能盲目降低下放速度。

In the subsea production devices lifting operation,the large-size pieces tend to suffer relatively higher slamming forces in the moment of contacting the sea surface,which may cause safety issues if the transient dynamic loads exceed the limitation of the crane and its wires.To solve the issue,this paper theoretically analyzes the hydrodynamic loads both on the lifting vessel and the subsea production devices in lifting operation,and carries out dynamic simulations of manifold entering water in time-domain with OrcaFlex software.The dynamic amplification factors of the wire and other apparatus are checked in various sea conditions to determine the safe operation window for lifting operation.Moreover,the influence of different lowering speeds on the dynamic loads is analyzed under different random wave trains.The results show that the larger the wave height,the larger the dynamic loads,while small wave slopes are beneficial for the operation.Reducing the lowering speed might increase the dynamic loads,therefore blindly reducing the lowering speed is not recommended for practical operation.