The inspection of subsea pipelines in particular flow lines and gathering lines has recently moved into the focus of offshore integrity engineers. Contrary to most long-distance export pipelines many of these lines are unpiggable. While some of these lines can be inspected with tethered internal inspection tools the only inspections options until recently for the majority of lines were visual testing, CP-surveys and local defect monitoring. With the MEC-Combi crawler system it is now possible to gather integrity information to a level of accuracy that can be compared to in-line inspection. This level of accuracy permits carrying out defect assessment on the inspection data alone. It does not require any further verification as compared to general defect screening methods.
In this presentation several case studies are highlighted. The focus of the inspection and the inspection methodology varies from corrosion in rigid pipelines to threats in flexible riser. The operational conditions and possibilities of deployment of inspection equipment are discussed. The applied inspection technology in particular the Magnetic Eddy Current (MEC) principle is shown. The possibilities for further data assessment are also presented.