Project objectives

The scientific and technical objective is 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. The inspection should be conducted by three people at most. This imposes a weight restriction of 45kg (each person lifting no more than 15kg). It is assumed that these people will be subcontractors.
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. It is believed that the inspection will take two minutes per link.
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. This system will be able to measure the elongation to within 5% of total length, and twisted links to within 20% of tolerance.
Developing novel non-destructive techniques, sensors and systems that will detect fatigue cracks and corrosion with the minimum of surface preparation and probe scanning and on surfaces hidden between chain links. The system will be able to detect fatigue cracks in the flash weld of each link. ACFM will be used to find surface breaking cracks, while ultrasonics will be used for volumetric cracks. Thinning due to corrosion will also be detected by ultrasonics.

The economic objectives are:

To eliminate losses due to interruption of well production during critical stages in removal of mooring chains, and extra stand-by support vessels for inspection. For 800 floating production platforms world-wide, each with an average of 8 mooring lines and each inspected once over a 4 year period this amounts to a cost saving of 640 million Euro per annum.
To replace annual swim-by and remotely operated vehicle (ROV) inspections of floating production storage and offloading (FPSO) mooring systems costing 50,000 Euro per day. For average 5 day inspection duration on 180 FPSOs, this amounts to a saving of 18 million Euro over 4 years.
To avoid the risk of one catastrophic event every four years due to failure of production platform mooring system and rupture of oil pipeline causing 1 million tonne release of oil into the ocean with subsequent clean up costs of 500 million Euro.
To produce a total return on investment ratio over 4 years of 80:1.

The wider societal objectives are:

Elimination of dangerous underwater labour intensive and monotonous inspection tasks.
Elimination of the need for inspectors/surveyors to work in hazardous and dangerous spaces where they are exposed to dangerous heavy lifting machinery and noise.
Elimination of operator/surveyor stress and error caused by the need for great attention to detail and NDT process variability.
Elimination of subjective data interpretation.
Enhancement of quality improvement in structural integrity of floating structures.
Increased skill levels of NDT operators from using analogue, manual and subjective inspection systems to automated and robotic inspection systems.



Project objectives The scientific and technical objective is 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. The inspection should be conducted by three people at most. This imposes a weight restriction of 45kg (each person lifting no more than 15kg). It is assumed that these people will be subcontractors. 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. It is believed that the inspection will take two minutes per link. 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. This system will be able to measure the elongation to within 5% of total length, and twisted links to within 20% of tolerance. Developing novel non-destructive techniques, sensors and systems that will detect fatigue cracks and corrosion with the minimum of surface preparation and probe scanning and on surfaces hidden between chain links. The system will be able to detect fatigue cracks in the flash weld of each link. ACFM will be used to find surface breaking cracks, while ultrasonics will be used for volumetric cracks. Thinning due to corrosion will also be detected by ultrasonics. The economic objectives are: To eliminate losses due to interruption of well production during critical stages in removal of mooring chains, and extra stand-by support vessels for inspection. For 800 floating production platforms world-wide, each with an average of 8 mooring lines and each inspected once over a 4 year period this amounts to a cost saving of 640 million Euro per annum. To replace annual swim-by and remotely operated vehicle (ROV) inspections of floating production storage and offloading (FPSO) mooring systems costing 50,000 Euro per day. For average 5 day inspection duration on 180 FPSOs, this amounts to a saving of 18 million Euro over 4 years. To avoid the risk of one catastrophic event every four years due to failure of production platform mooring system and rupture of oil pipeline causing 1 million tonne release of oil into the ocean with subsequent clean up costs of 500 million Euro. To produce a total return on investment ratio over 4 years of 80:1. The wider societal objectives are: Elimination of dangerous underwater labour intensive and monotonous inspection tasks. Elimination of the need for inspectors/surveyors to work in hazardous and dangerous spaces where they are exposed to dangerous heavy lifting machinery and noise. Elimination of operator/surveyor stress and error caused by the need for great attention to detail and NDT process variability. Elimination of subjective data interpretation. Enhancement of quality improvement in structural integrity of floating structures. Increased skill levels of NDT operators from using analogue, manual and subjective inspection systems to automated and robotic inspection systems.

THE SIXTH FRAMEWORK PROGRAMME	European Commission