Browsing by Author "Khoza, Tenele Prosperity"
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- ItemDisplacement of marine pipelines(Stellenbosch -- Stellenbosch University, 2022-04) Khoza, Tenele Prosperity; Schoonees, Koos; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.ENGLISH ABSTRACT: Marine pipelines are used to transport seawater, effluent, and bulk oil and gas products. Their potential displacement is significant because it affects the pipeline network's integrity in a very challenging environment. The main purpose of this study is to assess the different methods used to calculate marine pipeline displacement and select the most appropriate option. An overview is given of two materials used for the manufacture of marine pipelines: metal and non-metal pipes. The metal pipes are commonly made of carbon steel, but they can be constructed from stainless steel or a duplex in some harsh service conditions. The most used non-metal pipes in the oil and gas industry are HDPE, GRP, and GRE. They are more common for large diameter pipelines associated with power station cooling waters. Unbonded non- metal pipelines are standard oil and gas industry composite pipelines, while bonded non-metal hoses are associated with tanker loading and unloading activities. Concrete is also a material used in pipe construction. However, it is not discussed in this study. This study focuses on eight methods: The Force Balance Method, the DNV-RP-E305 code's Simplified Stability Analysis, Generalized Stability, and Dynamic Analysis, the DNV-RP-F109 code's Absolute Lateral Static Stability method, Generalized Lateral Stability Method and Dynamic Lateral Stability Analysis and lastly, the Scandinavian Method. All these methods are discussed, analysed, compared to each other, and a guideline is given for their applications. The primary methodology for comparing the eight methods was using the results of a case study that determined its pipes’ displacement through the Scandinavian Method. The pipe characteristics (mainly diameter) of that project were then used to determine the displacements that would have been produced by the other methods. There are also calculations done on the required pipe weight for the pipe by using each method. The results produced by each method were compared to each other and used as inputs for a Multi-Criteria Analysis (MCA) which was also performed on the Methods. Recommendations were made based on the results of the MCA. The two Dynamic Analysis methods were excluded from this entire section because they would have required finite element analysis and dynamic modelling, which are excluded from the scope of this study.