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

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.