Pipeline Failure Analysis For DPC-V-K2-18" Pipeline Based On Finite Element Method

Subsea pipeline has a long history of application of several decades for offshore oil & gas production system. The pipeline accidents such as leakage, fracture etc. increase largely once the pipeline operating period proceeds to its design life. Consequently, the pipeline failure analysis becomes important for the offshore oil industry today. Once pipeline accident, engineers have to do the failure anlaysis first to find out the accident reasons for the development of correct repairing plan. There are few offshore pipeline failure analysis examples in published documents, wherever in domestic or in exotic. Consequently, the pipeline failure analysis may be used as a practical reference for the pipeline engineering field.The objective of this thesis is to apply Finite Element Method (FEM) to the field of offshore pipeline failuress analysis. The study is based on a practical project of DPC-V-K2-18" subsea pipeline accident in Persian Gulf in 2008. The FEM was used to assess the whole procedures of V-K2-18-O pipeline failure, including pipeline installation, operation, concrete coating lossing, pipeline flooding, pipeline hydrotesting, adding four bags, and operating after four bags added. The condition of pipeline stress and strain are got through FEM analysis, based on which the reasons for pipeline failure are found together with the pipeline Fitness for Service (FFS) analysis per relevant rules. And the reasonable repair plan for pipeline was provided based on the discovered failure reasons and FEM analysis of.Based on the successful use of FEM for DPC-V-K2-18" Pipeline Failure Analysis, it is found that the potential application of FEM for pipeline analysis of intervention by human being or other accident are very huge.The content of pipeline FFS per the relevant rules include on-bottom stability analaysis, global lateral & upheaval buckling analysis, free-span anlaysis and Fracture analysis.