During laying operations from a pipelay vessel, the pipeline integrity shall be guaranteed until complete deployment onto the seabed. Harsh environmental conditions, pipeline transit load bearing structures, e.g. S-Lay stinger, vessel motion can induce local deformations that may develop into major damage, e.g. local buckling, with possible critical consequences both during and after laying operations. Hence, online monitoring of the pipeline can be crucial for early detection of anomalies. Currently, the offshore industry uses circular mechanical gauges positioned inside the pipe at the touchdown point and connected to the vessel via wire cable. The management of the wire cable is cumbersome in deep waters on long pipeline projects.
Saipem has developed a novel tool (IAU: Integrated Acoustic Unit) based on a non-invasive acoustic technology, with the aim at detecting deformations of the internal section of pipes. The IAU is based on the EAR (Extended Acoustic Radar) technology. The tool can remotely investigate long stretches (up to some km) of the line, classifying and quantifying the measured anomalies. It is also able to localize solid unexpected objects and obstacles (e.g. pigs, inline items). Further it can detect and track any water intrusion. It is basically composed of loudspeakers, microphones and dedicated acquisition and controlling units.
This paper gives an overview of recent developments on buckle detection, and it describes the IAU structure, its basic working principle and the expected benefits of this novel technology. The prototyping and validation phases are described and results are presented specifically referring to recent and near to come projects.