Study On Jack-up Platforms’ Environmental Parameters And Its Structural Safety

As the change of global climate, the design environmental parameters of jack-upplatforms, which are taken as the core design, are trending to increase and reasonableenvironmental parameters are essential to ensure the structural safety, economy and operatingrate of jack-up platform. In the paper, taking in-service and in-design platforms as researchobjects, the withstanding extreme environmental parameters and the applicable work areawere given via the efficient structural strength assessment for in-service platforms under thecurrent design standards and the level of marine technology. According to the characteristicsof environmental parameters in operation waters, the rapid approach for determining thedesign environmental parameters was proposed based on the different condition of in-designplatforms. The environmental parameters and the structural strength were studied together inthesis. The main contents were as follows,1) The environmental parameters and the relationship with structural strength of jack-upplatforms were focused on, and the main environmental parameters were commanded in fourdesign conditions as transit condition, lifting condition, working condition and survivalcondition. The determining approach, the factors considered and the general procedure ofenvironmental parameters were mainly researched.2) Based on the theory and method of joint probability, taken working position A of EPin South China Sea as an example, the rapid prediction of two variables was carried out, thenthe joint probability distribution of extreme wind velocity and significant wave height weredrawn, and the feasibility of the joint probability based design standards was investigated atlast.3) MYWORK (Mobility Workbench), a structural strength assessment program based onPATRAN, was developed by PCL and FORTRAN language for jack-up platforms.MYWORK greatly improved the efficiency of strength assessment and simplified the tediousprocess, which features simple, functional and high automation.4) Taken XJ23-1oilfield condition, survival condition as examples, on the basis of ABSguide for offshore structures, the Finite element method and MYWORK were applied toassess the structural strength of300feet jack-up platform, and its applicable work area weregiven via the efficient structural strength assessment. 5) The comprehensive application of the theory of environmental parameters, themethod of joint probability and the rapid assessment tools MYWORK are confirmed. Taken300ft jack-up platform as an example, the method determining its safety domain ofenvironmental parameters was analyzed emphatically and investigated on the basis ofstructural safety, the foundation for the analysis of jack-up platforms’ applicability tooperation waters was laid in this paper.