The principal achievements of the FlexiRiserTest project were 1) The development of a marinised digital flat panel detector capable of operation at 20-50m water depth, 2) Underwater radiography trials using the marinised digital detector, and resulting digital radiographs showing flaws found in flexible risers, 3) Development of a robot crawler capable of deploying radiography inspection both in and out of water, 4) Automated defect detection algorithms capable of indicating suspected flaws visualised by the digital radiographs.
The resulting prototype has exceeded expectations and provides a proof in principal. Using DR for underwater inspection is a first. Prior to the FlexiRiserTest project, nowhere has it been reported about the deployment of a water-proof digital radiography detector for any application, let alone for inspection of flexible risers and other under water structures. Prior to the developments in the FlexiRiserTest project, only film and phosphor plates (used in CR) had been reported and used in underwater radiography. The main disadvantage of using film and plates is that, after exposure to radiation, it is then necessary for them to be returned topside to be developed and processed – a task that would normally be extremely time consuming and costly when operating in a sub-sea environment.
The individual components of the prototype can already be immediately deployed for inspections. In particular, the marinised digital detector can be used without further development to inspect man made underwater structures at up to 20m water depth. Likewise, the robot crawler also has immediate application for deploying inspection equipment along pipes from 20-50m water depth.
However, an important step in the further development of the prototype is the deployment of the prototype in sea trials. Sea trials are required in order to prove to Oil and Gas operators that the system as a whole can operate in real situations. This means testing and demonstrating radiography inspection in a sea environment. This is an important step in order to win funding from the Oil and Gas industry to be able to develop the FlexiRiserTest system further.
The prototype was designed in such a way as to minimise major development should sea trials become a possibility. As such, minimal re-engineering is required to integrate a real isotope holder in the prototype. Likewise, only minimal changes (extra pillars added within the vessel structure and/or the use of titanium instead of aluminium for the faceplates) are required to the marinised vessel to extend its underwater operation range to greater than 50m sea depth.
(C) FlexiRiserTest 2010. The FlexiRiserTest Project is a collaboration between the following organisations: Computerised Information Technology (CIT) Ltd, Technical Software Consultants (TSC) Inspection Systems Ltd, Naftosol SA, Wellstream International Ltd, Petrobras, EuroNDT Ltd, Zenon SA, Research Institute Juelich and TWI Ltd. This project is managed and co-ordinated by TWI Ltd, and is partly funded by the European Commission under the Horizontal Research Activities Involving SMEs: Cooperative Research Programme reference COOP-CT-2006-032680.