The Numerical Stress Analysis Of Deepwater Semi-Submersible Platform Key Pipelines

With the rapid development of world economy, the sources of energy and resourceissues have become increasingly prominent. Because the land and offshore oil and gasresources are gradually reduced, in order to meet the growing demand for energy, theworld’s advanced states focus on the deep sea oil gas resource development, so thedeepwater semi-submersible platform emerge as the times required. The sixth generation ofdeepwater semi submersible platform is a typical representative, its operating water depthis3000meters, drilling depth is10000meters, which is an important technical equipmentfor the development of offshore oil and gas resources, also is an important reflection of anational equipment manufacturing integrated technology level, So the research, design andmanufacture of semi submersible platform have very important significance.The pipeline is a very important part of the deepwater semi-submersible platform, dueto the platform floating on the sea, bad environmental conditions, complex stress, coupledwith the system is complex and numerous, and higher working pressure, the pipeline stressanalysis of the platform become a key point in the platform’s design and construction.This article use CAESAR II software to analyze the pipelines stress of semisubmersible platform, the pipelines mainly include high pressure mud system, highpressure air system, drilling hydraulic system and FRP ballast water system, the mainresearch contents are as follows:1、This paper summarize the meaning and purpose of the semi submersible platformkey pipelines’stress analysis. In the pipe stress analysis theory, a detailed description ofstandard B31.3stress analysis criterion, given primary stress and secondary stress checkcondition. Combing the pipe stress analysis tasks and process, and each link of the analysisprocess were discussed in detail.2、This paper use CAESAR II to establish the models of the semi-submersibleplatform key system, and calculate the result to check the primary stress and secondarystress levels, verified the feasibility of the design current.3、Aiming at the importance of ballast water system, this article carry out ballast watersystem water hammer load dynamic and ballast water centrifugal pump import and exportload assessment, improved system security.4、Finally, as an extension to high pressure mud system, this paper implement staticfatigue analysis of high pressure system, loading system expected cycle numbers, setting three fatigue conditions. Through the three fatigue conditions alone and cumulative effectsanalysis, obtained the system stress in a reasonable range.In conclusion, this paper preliminarily explored some feasible semi submersibleplatform piping stress analysis method and obtained some useful conclusions, which laid agood foundation for engineering application and further study in future.