Key learning outcome: Distributed Acoustic Sensing (DAS) enables real-time monitoring over long distances. Implementation to reduce risk of cable incidents and ensuring submarine assets security.

Protecting submarine cables, umbilicals and pipelines is challenging: These assets are difficult to access, can cover long range e.g. >100 km, with limited surveillance capabilities for both the sea surface and submarine environments. When fibre optics is integrated in the cable system, state-of-the-art fibre sensing technologies enables the cable itself to act as a sensitive detector. Utilising variations in backscattered light, a DAS interrogator connected to one end of the optic fibre delivers a real-time measurement of cable interactions, densely sampled in space (metre-scale) and time (kHz). These measurements detect any movement of or physical contact with the cable or umbilical, which can be used to raise alerts for anomalous conditions. Moreover, wavefields related to vibrations and sound in the environment couple to the fibre. Signal processing on the topside DAS interrogator unit then determines the location and type seabed interference, for example an anchor dragged along the seabed at 3 km away from the cable. In this presentation, we will demonstrate how DAS technologies enable real-time surveillance of cables and umbilicals (e.g. DC/FO) for proactively mitigating cable incidents and damage. Moreover, the subsea sensing data will reveal activity not publicly tracked, for example vessels operating seabed gear and not reporting by the Automatic Information System (AIS). DAS cable monitoring lets operators update the risk by informing about all events in the cable environment.