Atteris was initially engaged to perform a review of survey data for the PoG flowline spoolpieces to evaluate for signs of axial walking. During this process it was determined that as-built dimensions were not used in the original survey comparison, resulting in considerable discrepancy in the survey results originally provided to Woodside. Using a combination of the survey data and as-installed coordinates of fixed references, Atteris derived the correct as-built dimensions of the spools, and using this information, were able to accurately assess the flowlines for signs of axial walking.
Based on the results of this work, detailed engineering assessments have been performed on two spoolpieces. A combination of Abaqus and Autopipe Finite Element Analysis (FEA) softwares were used to accurately model the behaviour of the flowline during shutdown/startup cycles, and the effect that these cycles had on the spoolpieces
Through the use of as-built material properties, challenging of original design criteria, recent pipeline surveys and the operational history of the assets, Atteris was able to provide the client reassurance on the current state of the PoG assets, as well as recommendations on the future operation of the field.