MEC-FIT – an advanced flexible riser Inspection system from Fugro Subsea Services and Innospection.
Over the past two years, Innospection has developed an external flexible riser inspection system. Last year, the company and Fugro Subsea Services agreed an alliance to interface the new technology with a modern work-class ROV, then to jointly market the technically advanced, reliable and comprehensive inspection solution.
Design engineers at Fugro’s subsea engineering and intervention tooling business line provided input into the design, with the result that the inspection tool was made lighter and easier to deploy by ROV. They also developed a deployment system.
After a full yard trial, which was witnessed by clients, the technology was successfully deployed on a flexible riser during a recent offshore intervention campaign. As a result, the MEC-FIT® system is now ready for use. The MEC-FIT® system was developed in response to market demand for general riser and flexible riser inspections operated from offshore installations. MEC-FIT® is a novel inspection tool which uses patented subsea electromagnetic eddy current technology. It offers rapid external scanning with the ability to penetrate into the various armoured layers of the flexible riser.
This technology offers fast external scanning with the ability to penetrate into the various armour layers of flexible risers, as well as the possibility of selecting specific layers to be inspected.
MEC-FIT® features a patented inspection technique which combines direct current magnetic field lines with eddy current field lines, allowing deeper penetration into the ferrite steel material. A modification from the standard eddy current technology already well established by Innospection, this technique enables the selection of the flexible riser pipe layers to be inspected, or alternatively allows the optimisation of the inspection for a specific layer from which a defect signal is received.
The key capability of MEC-FIT® is the detection of localised material defects, such as cracks and corrosion beneath the riser coating at the single wires or wire areas. Further potential of this tool is the detection and analysis of material property change (fatigue), as well as general wall loss.
Because the inspection method is electromagnetic, it measures the integrity in the armoured layers and detects corrosion, cracking and any other structural changes in these metallic layers. The system was recently demonstrated in offshore trials in the North Sea with Chevron on flexible risers, with a penetration of up to three metal layers from the outside of the riser.
The principle of the technique means that no “couplant or annulus flooding” is required for the inspection to be carried out. Other benefits of MEC-FIT® include the provision of instantaneous inspection results.
The system consists of a clamp-on cage which allows the scanning device to be attached to the outer surface of the riser around its full circumference.
The cage is deployed on to the riser via a ROV, and moves along the riser for inspection. The inspection head contains the permanent magnet unit, which can be controlled in its field strength by hydraulic valves, and the eddy current sensors which are connected to the ROV interface. From here, the signal data is transferred via the main ROV umbilical back to the inspection computer at the ROV control unit, where the information is received in real-time.
Based in Aberdeen, Fugro Subsea Services Limited operates within the geographical region of the North Sea, the Mediterranean and west Africa and is part of the global Fugro Subsea Services Group.
They operate a modern and diverse fleet of ROV vessels, ROV systems and intervention tooling supporting clients in a wide range of offshore projects. They offer teams of experienced project personnel, subsea engineers and ROV operators, ensuring clients receive a first-class service, delivered safely and on time.
Innospection Ltd is an independent advanced non-destructive testing company with a focus on electromagnetic inspection technologies, delivering successfully for over 10 years, advanced NDT solutions to process industries worldwide, including the on and offshore oil & gas industry. Innospection operates in-house developed topside and subsea inspection systems, which provide the industry with comprehensive integrity supporting data.
For more information about this innovative inspection tool, visit www.furgosubsea.co.uk and www.innospection.com
Fugro contact: David (Jock) Nicol – e-mail: D.nicol@fugro.com
Innospection contact: Andreas Boenisch – e-mail: a.boenisch@innospection.com and Alex Campbell – e-mail: a.campbell@innospection.com