Our global telecommunications infrastructure consists of millions of kilometers of fiber optic cables. These include terrestrial and subsea networks that ensure that information travels across the planet. With the increased use of subsea cables to connect different continents and countries, the need to accurately monitor these critical assets has become apparent. In recent months, subsea cable incidents have made more common appearances in the news cycle. This is due to the large impact that a cable failure can have on various telecommunication services.
Some of the failures can be due to geohazards like ground movement and landslides. Other ones can be due to human causes like anchors, dredging and potentially, intentional ones aimed at disrupting our infrastructure.
In addition to our telecom assets, there are offshore facilities like wind farms, pipelines and oil and gas platforms that are instrumented with cables that include fiber optics lines. All of this optical infrastructure, combined with the large telecom one, provides a unique opportunity for distributed fiber optic sensing (DFOS).
Using this antenna can complement existing sensing tools like ocean bottom nodes
This technology effectively turns existing fiber optic cables into sensors that can detect tiny anomalies of vibration and acoustics (DAS), temperature (DTS) and strain (DSS) along their entire length with fine spatial resolution and density. The use of these tools provide real-time detection of third-party intrusions, power cable failures and precise cable fault localization, amongst others.
These same cables are also being used to image the subsurface. The use of DAS turns the cable into a permanent seismic sensor. Both natural and induced earthquakes, and active seismic sources are now being recorded with the technology. Recent work from the North Sea reveals that the seismic data from DAS provides images of PP and PS reflections.
Operators are using cables connecting the platform or umbilicals turning them into permanent receivers on the ocean floor. Using this antenna can complement existing sensing tools like ocean bottom nodes or PRM systems. Furthermore, they enable seismic imaging with high receiver density in areas where nodes are too expensive to deploy.
Fiber optic sensing technology gives the opportunity to use the same tools for various purposes, hence reducing overall operation costs. Leveraging it for our critical and expensive subsea assets not only allows us to monitor their integrity, but also allows us to illuminate the subsurface for exploration and geohazard mapping purposes.
