FIBRE-OPTIC sensing systems firm Fotech Solutions has installed what it says is the world’s first “dedicated downhole distributed acoustic optical fibre system”.
It is based on the Scottish firm’s proprietary Helios distributed acoustic monitoring system and is installed in a coal-bed methane well in Scotland’s central belt for Composite Energy. The system was installed in August and has already provided valuable data, including:
Downhole pump condition monitoring.
Location of water level.
Flow profiles across the production intervals.
Vibrations at the wellhead.
Gas flow.
Fotech says other potential benefits of the system include:
Monitoring of, and locating, sand production.
Casing/tubing integrity.
Cross flow.
The system comprises two elements – a simple low-cost telecoms-grade optical-fibre cable and the company’s interrogator, which is the heart of the Helios system.
In essence, it provides acoustic or vibration information along the entire length of the installed optical fibre to provide multiple-event information, event characterisation and highly accurate event location.
An acoustic signal is recorded for each metre along the fibre. The system can therefore detect and position an event to an accuracy of one metre and can distinguish separate events more than two metres apart. It also has remote-control capability. The fibre can be laid near a pipeline or installed in a borehole.
Don Sharples, technical manager, Composite Energy, said: “Initial results from the Fotech fibre are very encouraging. The Fotech Distributed Acoustic technology collects data which is not available from other downhole sensors and will give Composite the ability to determine which coals are producing in any given well.”
Alan Piesse, a co-founder of Fotech, said: “Our vision for Helios was to provide sound at the speed of light and its successful deployment has really changed the game in the global monitoring sector.
“We see a strong future for the system in monitoring gas flow in coal-bed methane wells and other applications. For the first time, flow can be seen and heard entering and moving in the well and quantified in real time.”
The firm holds 21 licences covering coalfields in Scotland, England and Wales.