Displacement of marine pipelines

Khoza, Tenele Prosperity (2022-04)

Thesis (MEng)--Stellenbosch University, 2022.

Thesis

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.

AFRIKAANSE OPSOMMING: Mariene pypleidings word gebruik om seewater, uitvloeisel en grootmaat olie- en gasprodukte te vervoer. Hul potensiële verplasing is beduidend omdat dit die pyplynnetwerk se integriteit in 'n baie uitdagende omgewing beïnvloed. Die hoofdoel van hierdie studie is om die verskillende metodes wat gebruik word om mariene pyplyn verplasing te bereken te assesseer en die mees geskikte opsie te kies. 'n Oorsig word gegee van twee materiale wat gebruik word vir die vervaardiging van mariene pypleidings: metaal- en nie-metaalpype. Die metaalpype word gewoonlik van koolstofstaal gemaak, maar hulle kan in sommige moeilike diensomstandighede van vlekvrye staal of 'n dupleks vervaardig word. Die mees gebruikte nie-metaalpype in die olie- en gasbedryf is HDPE, GRP en GRE. Hulle is meer algemeen vir pypleidings met 'n groot deursnee wat met kragstasie-verkoelingswater geassosieer word. Ongebonde nie-metaalpypleidings is standaard saamgestelde pypleidings in die olie- en gasbedryf, terwyl gebonde nie-metaalpype geassosieer word met tenkwalaai- en aflaaiaktiwiteite. Beton is ook 'n materiaal wat in pypkonstruksie gebruik word. Dit word egter nie in hierdie studie bespreek nie. Hierdie studie fokus op agt metodes: Die Kragbalansmetode, die DNV-RP-E305-kode se Vereenvoudigde Stabiliteitsanalise, Algemene Stabiliteit en Dinamiese Analise, die DNV-RP- F109-kode se Absolute Laterale Statiese Stabiliteitsmetode, Veralgemeende Laterale Stabiliteitsmetode en Dinamiese Laterale Stabiliteitsanalise en laastens die Skandinawiese Metode. Al hierdie metodes word bespreek, ontleed, met mekaar vergelyk, en 'n riglyn word gegee vir hul toepassings Die primêre metodologie vir die vergelyking van die agt metodes was die gebruik van die resultate van 'n gevallestudie wat sy pype se verplasing deur die Skandinawiese Metode bepaal het. Die pyp-eienskappe (hoofsaaklik deursnee) van daardie projek is dan gebruik om die verplasings te bepaal wat deur die ander metodes geproduseer sou word. Daar word ook berekeninge gedoen oor die vereiste pypgewig vir die pyp deur elke metode te gebruik. Die resultate wat deur elke metode geproduseer is, is met mekaar vergelyk, en gebruik as insette vir 'n Multi-Kriteria Analise (MCA) wat ook op die Metodes uitgevoer is. Aanbevelings is gemaak op grond van die resultate van die MCA. Die twee Dinamiese Analise-metodes is uitgesluit van hierdie hele afdeling omdat hulle eindige-element-analise en dinamiese modellering sou vereis het, wat uitgesluit is van die bestek van hierdie studie. In die aanbevelings word die DNV-RP-F109-kode se algemene laterale stabiliteitsmetode voorgestel aangesien dit die hoogste in die MCA behaal het. Dit is egter onderhewig aan die voorwaarde dat aan al die metode se vereistes voldoen word, en die metode is eintlik relevant tot die spesifieke gevallestudie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/124722
This item appears in the following collections: