A methodology for the rigorous assessment of pipeline freespans is described, together with a description of its application to the Beryl Field network of pipelines.
The methodology is in two parts, each with two stages, and comprise preliminary stress and vibration frequency checks followed by detailed strain and fatigue life checks where appropriate. Comprehensive software, automatically linked to the inspection database, has been written to allow efficient use of the methodology.
The use of a new ROV based freespan rectification technique is also described.
Both the assessment and rectification techniques were successfully used in Mobil's Beryl field and the SAGE pipeline in 1992.