【作者】 王洋；

【导师】 秦洪德；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2010， 硕士

【摘要】 自升式钻井平台凭借其抗风暴能力强、机动性好、造价经济等优点,承担着大量中、浅海地区的石油钻探任务,因此,对其进行安全评估是十分必要的。目前,相关学者针对平台拖航过程中稳性、举持状态、风暴自存状态下结构动力响应及桩靴与土壤的相互作用进行了大量研究,然而针对平台在不同地点安装过程进行的研究却非常少。由于环境载荷及海底地质条件影响而导致的自升式钻井平台安装定位失效很可能带来巨大的经济损失及人员伤亡,而上述失效的直接原因往往是桩腿支撑管屈曲失效,此问题可以通过RPD(Rack Phase Difference)进行度量研究。本文主要目的是对自升式钻井平台升船过程中的RPD进行研究,记录升船过程中RPD及其它结构响应,并分析环境载荷(风载荷、波浪载荷)、海底边界条件对RPD的影响。本文的重点工作如下:1)引入RPD的定义、测量方法、成因、分类等基本概念,论述国内、外RPD的研究进展及研究方法,包括二维、三维有限元方法进行敏感性分析及时域分析等,并给出了相关结论。2)结合电动齿轮齿条升降装置的特点,设计RPD时域数值模拟程序,包括介绍有限元模型建立的准则、通过样条插值获得升降机构特性函数,以及设计通过应力提取进而实现模型位移控制的时域数值模拟程序。3)给出环境载荷(风载荷、波浪载荷)的计算方法、及时域加载方式,编制适用于RPD时域数值模拟的波浪载荷等效节点力计算程序;确定需要考虑的海底边界条件,以及不同海底边界条件在有限元模型中的表达。4)以F&G公司设计的L780 ModⅤ型自升式钻井平台为模型,应用前述方法研究风、浪及海底边界条件对平台升船过程中RPD的影响。更多还原

【Abstract】 Benefited from the movability, relatively low cost and good performance in storm, jack-up units are widely used in oil and gas industry for drilling. Although research about jack-up units are focused on stability during transit, spudcan-soil interaction and structural dynamic response in elevated and storm condition nowadays, structural behavior during installation is very important.For a jack-up unit, localized failure or structural collapse may happen if installation were taken in severe sea state or bad seafloor foundation, and the direct cause of above failure is buckling of brace members of leg between upper and lower guides. Rack phase difference (RPD) as an indicator of brace load is studied in this paper to assure the safety and avoid the tremendous loss for a jack-up unit in the design phase. The primary work included in this paper are:1) Introduce the background, definition, measurement, classification and cause of formation of RPD, and also a dissertation about state of art is given, such as sensitivity analysis of leg brace configuration with regard to RPD using 2D FEA model and time domain simulation of RPD during jacking operation, also conclusions are discussed in this paper.2) Establish the time-domain simulation program of RPD during jacking operation, including building principles of FEA model, method to simplify the jacking system as a function of vertical reaction force verse moving-up velocity, and also the way to control the model displacement using above function.3) Calculate environmental load and establish the way how the load be applied on FEA model in time domain; Define the boundary condition at seafloor point and how to consider it in the FEA model.4) Using L780 ModⅤas structural model, do sensitivity analysis of RPD during jacking operation with regard to wave load, wind load, and boundary condition at seafloor point.更多还原