Weir-Jones Group

Solutions more information Oil & Gas, Energy, Mining more information Pipeline Strain Monitoring

Fully Distributed Fibre Optic Sensing (Brillouin)

A distributed system will provide an equivalent of a discrete sensor for every meter of fibre installed.  Distributed strain monitoring allows for continuous sensing along 10’s of kilometers of a loop of single mode optical fibre.  The ends of the fibre are terminated at the input and output ports of a Brillouin Optical Frequency Domain Interrogator, the optical pulse is generated at the interrogator and analyzed upon its return. 

Weir-Jones utilises a Brillouin Optical Interrogator manufactured by fibrisTerre of Germany.   More information regarding their technology can be found on their website http://www.fibristerre.de/

The tight fibre, shown below, is coupled to the protective jacket and thus to the surrounding ground, allowing for strain transfer of up to ± 3% (±30,000µε) from the medium in which it is installed.  Due to the cost of the monitoring equipment, systems tend to only be cost effective at large monitoring lengths (>1km) and several hundred measuring points.

Source: Brugg Cables Direct Burial Fibre Optic Line

Advantages/Disadvantages Fully Distributed Brillouin Sensing:

+ Ability to instrument 10’s of kms with continuous data.
+ No need to remove pipe coating: Directly applied.
- Difficult to apply to existing lines, since complete line length must be exposed.