Two eddy current-based inspection and monitoring techniques for offshore oil & gas structures are presented. First, ROV-based inspection solution for underwater structural elements and welds in difficult conditions, even in the presence of marine growth residues. Its characterization on ISO15548-2-compliant samples at up to 6mm distance shows an outstanding capability to cope with large coating and marine life thicknesses. Second, a permanent crack monitoring solution, based on a lightweight, compact and flexible sensor design is described. Applications of the monitoring solution for offshore structures are discussed, and a case study on the use of the monitoring solution for a highway bridge in Germany is exposed. The two inspection and monitoring solutions enable asset owners to reduce operational downtime, improve maintenance planning and asset integrity, and potentially extend asset life.


In the unpredictable environment created by the recent swings in oil price, it is more important than ever to be able to extend the lifetime of existing offshore infrastructure. We present two solutions based on the well know eddy current inspection technique to reduce operational downtime: a ROV-based weld and surface inspection procedure and a crack monitoring solution.

The inspection of the welds in offshore structures is particularly challenging because of the limited dexterity of underwater manipulators. Another challenge is the removal of marine growth and cleaning to bare metal, which tends to represent the dominant cost of an inspection campaign. We present an underwater ROV eddy current inspection solution designed from scratch to enable efficient, in-service inspection of welds in these difficult conditions, even in the presence of marine growth residues.

If a crack is found, the monitoring method presented here can be used to obtain conditional compliance by continuously measuring the crack length and showing it remains under a given safe threshold.


The inspection and monitoring solution we present here are based on the well-known eddy current (EC) inspection technique. The key advantage of this technique is that it does not require surface contact or preparation, which is why it is widely used for crack detection in the industrial and aerospace fields [1] [2].

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