Atteris conducted a Level 2 Span Assessment of the pipelines. This included a thorough rationalisation of through life survey datasets to determine span configurations and determine behavioural trends of spans over the life of the asset and these in to the future for remaining. Allowable span lengths were re‑calculated based on the revise metocean data and the fatigue life of critical spans was assessed. Sensitivity analysis to marine growth was also performed. A number of spans were identified for rectification.
Project management was provided on an as-needed basis to scope and tender the rectification works. Novel subsea rock installation methods were identified from previous experience that allowed cost effective rectification whilst ensuring pipeline integrity. FEA analysis of dropped object scenarios was used to assess the risk of a loss of containment event.
