RiserSure: development of a digital radiographic-based system for subsea inspection of flexible risers


Flexible risers are typically used for transporting oil from the seabed to offshore platforms and Floating Production Storage and Offloading units. The risers can extend several hundred meters and their complex structure, comprising several layers of steel and polymer materials in order to withstand their harsh subsea operating environment within the Oil and Gas floating production operations, presents a challenge to most non-destructive testing techniques. With the growing demand for the use of these structures, it is becoming increasingly important that there is a robust inspection technique that can assess the effects of fatigue through all the layers in the riser as it ages.

Radiographic based solutions are the only viable methodology that is able to inspect the entire cross-section of a riser and digital radiography negates the time and expense limitations of traditional film radiography. The consortium of the H2020 EU funded project "RiserSure" present the development of an automated digital radiographic inspection system for in-service flexible risers. The RiserSure system utilises the novel concept of a subsea deployable linear detector array coupled with a gamma radiation source deployed on a bespoke robotic scanning system. The linear detector array, compared to flat panel detector solution, offers greater sea depth capability, in a smaller package, and the ability to cope with the high radiation energy demands of the Gamma source. The project first-year findings including shallow sea trial results and future intended work are presented.