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深海半潜式钻井平台码头系泊数值计算与模型试验研究

Numerical Calculation and Model Test Study on A Quay Mooring Deep Water Semi-submersible Drilling Platform

【作者】 吴小鹏

【导师】 杨建民;

【作者基本信息】 上海交通大学 , 船舶与海洋结构物设计制造, 2010, 硕士

【摘要】 迅猛发展的经济使国内能源需求量不断增加,开发和研制用于深水油气勘探、开采的重型装备已成为中国政府的战略决策之一。为此,外高桥造船有限公司正在建造我国首艘深海半潜式钻井平台。由于半潜平台的舾装周期较长,舾装期间甚至可能经历台风天气,有必要对该半潜平台的舾装码头系泊系统进行数值计算和模型试验研究。相对于常规大型船舶的码头系泊系统,半潜平台的码头系泊系统有其自身特殊性。平台舾装时纵横受风面积都较大,其所受到的风载荷要大于常规船舶。舾装状态的半潜平台其吃水接近下浮体高,干舷很低,也不同于常规船舶。平台立柱上装有锚架,系泊时需考虑如何保护以防止其与码头发生碰撞。考虑上述因素后,半潜平台的码头系泊一般采用在平台与码头问垫入驳船的系泊方式,驳船在平台与码头问传递载荷,并起到保护锚架的作用。但这种系泊方式对系泊缆的布置有着重要影响,也使整个系统的响应特性复杂化。本文通过借鉴常规船舶的码头系泊指南的相关建议,结合外高桥码头的具体情况,首先开展了基于风、流载荷静力计算研究。通过研究初步系泊方案、对系泊缆的预张力和刚度进行参数影响分析等方法,总结该平台的码头系泊规律。在此基础上,对根据码头实际情况设计的正常系泊方案作多次优化,形成最优方案。同时,也设计了利用抛锚定位的台风系泊方案,为模型试验的制定提供计算依据。随后,在上海交通大学海洋工程国家重点实验室进行了缩尺比为1:50的模型试验研究。试验包括风流静载荷试验,用于研究静力计算结果的可靠性;同时也包括风浪流共同作用的试验,用于考察系泊系统的动态响应。结合风浪流试验结果,本文最后还对平台的台风系泊方案进行动力计算分析。本文根据对深水半潜式钻井平台所作的数值计算与模型试验研究,总结出一些平台的码头系泊规律,能为以后类似系泊系统的设计提供参考。

【Abstract】 With the fast development of economy, the energy resource imbalance between needs and supplies in China is getting larger. Design and manufacture heavy equipments for deep water oil and gas exploration has become one strategic choice of the Chinese government. As a result, the first deep water semi-submersible drilling platform of China is presently under construction in Shanghai Waigaoqiao Shipbuilding Co.Ltd (SWS).The out-fitting cycle of the SEMI when it is moored at the quayside is very long, which indicates that it may have to experience and survive a typhoon. It is necessary to acquire a reasonable quay mooring layout of the SEMI by numerical calculation and model test study.Compared with the quay mooring system of conventional huge ships,the one of a SEMI has its own specialty. Due to its huger wind areas in both transverse and longitudinal directions,a moored SEMI will experience larger wind loads than conventional ships.Besides,the draft of a SEMI in out-fitting condition is near the depth of its pontoons, which will lead to its very low freeboard. On the other hand, the anchor bolsters installed on the columns of a moored SEMI need to be well protected from the quayside.Considering such factors,a barge is usually applied between the SEMI and the quayside in a SEMI quay mooring system, acting as a force transmission and a anchor bolters protector. However, it has crucial effect upon the layout of the mooring lines and will complicate the dynamic response of the whole mooring system.Using the quay mooring guidelines of conventional vessels for reference and taking the practical condition of the SWS quayside into consideration, this paper firstly investigates the quay mooring layout based on static wind and current loads. According to the study on the preliminary layouts, together with the sensitivity analysis of the mooring line’s pretension and stiffness,rules of the SEMI quay mooring system are obtained. Based on these rules, the quay mooring layouts in normal condition are compared and optimized. As for the typhoon condition, a layout applying four anchors is designed. The above investigations have laid a very good foundation for the model test study.Afterwards, model test with the scale of 1:50 is conducted for both normal and typhoon conditions in the basin of Shanghai Jiao Tong University. The wind-current-static model tests are performed to verify the reliability of the previous static calculation results.Wind-current-wave-dynamic model tests are also performed, in order to acquire the dynamic response of the SEMI quay mooring system. At last, a dynamic analysis of the quay mooring system in typhoon condition is carried out.Several principles for quay mooring layout of a semi-submersible drilling platform have been concluded. These conclusions can be used to support the design of similar systems in the future.

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