Project summary

1. Consortium and funding

ChainTest is a collaboration between the following organisations: TWI Ltd (UK), Miltech Hellas SA, Greece, TSC Inspection systems Ltd, (TSC) UK, Bytest, Italy, INTERLAB IEC, UK, NES Ltd (NES), UK, Vicinay Cadenas, Spain, Petrobras, Brazil, ZENON, Greece, NDT Consultants (NDT Con) UK. The project is co-ordinated and managed by TWI Ltd and is partly funded by the EC under the Co-operative Research programme ref: COOP-CT-2005-018236.

2. Summary

Floating platforms must be moored to the seabed. The integrity of the mooring system is critical, because the consequences of failure could be oil pollution on a catastrophic scale. Floating structures are designed, in common with all offshore structures, to survive the 15m waves derived statistically from the '100 year storm' principle However, there is evidence of much larger freak waves. Also, climate change suggests that storms will become more frequent and severe in the future, increasing the risk of damage to offshore structures. Breaks often go unnoticed, increasing the probability of multiple breaks and total mooring system failure. There is, therefore, an urgent need to improve the integrity management of mooring systems. One issue is the inspection of chain links. Regulatory visual inspection is currently done with the cable chain brought up on deck, or, for greater sensitivity to defects using non-destructive tests (NDT), with the cable chain taken on-shore. Increasingly, interim 'swim-by' inspections of the chain in-situ are being conducted from Remote Operated Vehicles. The inspection, however, is unreliable and susceptible to human error, because of the hundreds of metres of chain involved and the short times allowed for inspection. Industry recognises the need for more effective inspection.

The 'ChainTest' project proposes to address these problems. The approach is to develop a robotic crawling vehicle for testing the chains in situ below water. The vehicle will be automated, and sensitive to fatigue cracks, corrosion, bent chains and abrasion.

3. Objectives

To overcome the limitations of current inspection working practices on chains used in the mooring systems for floating offshore oil and gas production platforms by -

obviating the need for human inspectors, therefore increasing inspection reliability;
developing an autonomous vehicle that will crawl along the chain below water, carrying out inspection tasks while the chain is in-situ, eliminating the need to bring the chain on board;
developing a cleaning system to remove sufficient marine growth and rust scale from the surfaces of the chain for inspection;
developing a vision system that can measure chain link dimensions and conduct visual inspection;
using novel non-destructive techniques that will detect fatigue cracks and corrosion with the minimum of surface preparation and probe scanning and on surfaces hidden between chain links.

4. Concept diagram

5. Timescales

The project began on 26 September 2005 and has a 2-year duration, being due for completion on 14 March 2008.



Project summary 1. Consortium and funding ChainTest is a collaboration between the following organisations: TWI Ltd (UK), Miltech Hellas SA, Greece, TSC Inspection systems Ltd, (TSC) UK, Bytest, Italy, INTERLAB IEC, UK, NES Ltd (NES), UK, Vicinay Cadenas, Spain, Petrobras, Brazil, ZENON, Greece, NDT Consultants (NDT Con) UK. The project is co-ordinated and managed by TWI Ltd and is partly funded by the EC under the Co-operative Research programme ref: COOP-CT-2005-018236. 2. Summary Floating platforms must be moored to the seabed. The integrity of the mooring system is critical, because the consequences of failure could be oil pollution on a catastrophic scale. Floating structures are designed, in common with all offshore structures, to survive the 15m waves derived statistically from the '100 year storm' principle However, there is evidence of much larger freak waves. Also, climate change suggests that storms will become more frequent and severe in the future, increasing the risk of damage to offshore structures. Breaks often go unnoticed, increasing the probability of multiple breaks and total mooring system failure. There is, therefore, an urgent need to improve the integrity management of mooring systems. One issue is the inspection of chain links. Regulatory visual inspection is currently done with the cable chain brought up on deck, or, for greater sensitivity to defects using non-destructive tests (NDT), with the cable chain taken on-shore. Increasingly, interim 'swim-by' inspections of the chain in-situ are being conducted from Remote Operated Vehicles. The inspection, however, is unreliable and susceptible to human error, because of the hundreds of metres of chain involved and the short times allowed for inspection. Industry recognises the need for more effective inspection. The 'ChainTest' project proposes to address these problems. The approach is to develop a robotic crawling vehicle for testing the chains in situ below water. The vehicle will be automated, and sensitive to fatigue cracks, corrosion, bent chains and abrasion. 3. Objectives To overcome the limitations of current inspection working practices on chains used in the mooring systems for floating offshore oil and gas production platforms by - obviating the need for human inspectors, therefore increasing inspection reliability; developing an autonomous vehicle that will crawl along the chain below water, carrying out inspection tasks while the chain is in-situ, eliminating the need to bring the chain on board; developing a cleaning system to remove sufficient marine growth and rust scale from the surfaces of the chain for inspection; developing a vision system that can measure chain link dimensions and conduct visual inspection; using novel non-destructive techniques that will detect fatigue cracks and corrosion with the minimum of surface preparation and probe scanning and on surfaces hidden between chain links. 4. Concept diagram 5. Timescales The project began on 26 September 2005 and has a 2-year duration, being due for completion on 14 March 2008.

THE SIXTH FRAMEWORK PROGRAMME	European Commission