半潜式钻井平台内波工况定位能力

Station Keeping Capacity of Semi-submergible Drilling Platform in Internal Wave Condition

采用MOSES软件建立动力定位半潜式钻井平台分析模型,在时域内模拟平台在钻井作业过程中遭遇内波作用的耦合动力特性,分析平台在不同流速内波作用下的定位能力,并对动力定位系统的关键因素进行敏感性分析。结果显示:在同等环境载荷强度下,平台在船宽方向出现最大偏移;当内波流速小于1.0 m/s时,平台可基本满足钻井作业的定位要求,而当内波流速达2.0 m/s时,平台出现大幅值的水平偏移和倾角,需要解脱隔水管系统;提升推进器推力和增加推力敏感因子都有助于提升平台的抗内波能力,但都无法明显减小平台的水平偏移。因此,在遭遇高流速内波作用时,推荐平台撤离或调整船体首向。

The analysis model of a semi-submergible drilling platform with Dynamic Positioning(DP)system is established by MOSES software,and the coupled dynamic characteristics of the platform under the action of internal waves during drilling operation are simulated in time domain.The station keeping capacity of the platform is evaluated under internal wave conditions with different velocities,and the effects of some key factors of DP system are studied by sensitivity studies.The results show that:under the same environmental load intensity,the maximum deviation occurs in the port/starboard direction of the platform;the platform can satisfy the stationing requirement for drilling operation when the velocity of internal wave is lower than 1.0m/s,when the velocity of internal wave reaches 2.0m/s,large horizontal offset and trim angle emerge and the drilling riser has to be released;the station keeping capacity of the platform will be enhanced by increasing the thruster force or sensitivity factors of thruster force but the offset can not be suppressed efficiently.Therefore,it is recommended to evacuate the platform or adjust yaw angle when the platform encounters internal wave condition with high velocity.