Keeping pipelines safe from environmental or malicious damage is a major challenge; the long distances, often through remote and hostile territory make the costs prohibitive for most conventional monitoring methods.
Protection of pipeline assets that span several hundreds or even thousands of kilometres has been a huge challenge for companies involved in oil and gas transportation. The companies suffer huge losses from pilferage by unscrupulous elements who surreptitiously tap the pipeline. Moreover, such activities can lead to accidents which pose serious threat to safety of people and the environment. Deliberate attempts at tapping are not the only risks to pipelines. In areas with increased development activity, pipelines are also accidentally damaged by construction, trenching and other installations near the pipeline.
Until now, the only way of monitoring third-party activity along the pipeline route was physical patrolling. It is impractical to install CCTV cameras or discrete sensors due to the sheer distance to be monitored, needless to mention the lack of power supply and provision for installation at frequent intervals in remote areas.
That has now changed with the advent of a new DISTRIBUTED SENSING technology for PIPELINE INTRUSION DETECTION. Commtel has partnered with Fotech Solutions (Hampshire, UK) to offer the Helios Distributed Acoustic Sensing system. By harnessing certain unique properties of the telecom optical fibre cable that runs along the pipeline, the distributed sensing system is able to detect, accurately locate and even identify any intrusion attempt along the entire monitored length in real time. The PIDS instrument itself is located in the control room and requires no installation in the field besides the existing OFC. The system works on the principle of Distributed Acoustic Sensing, where in acoustic signals generated by intrusion activities are picked up the optical probe pulses sent down the OFC. It consists of an interrogator that sends optical pulses from a highly coherent laser and detects back-scattered light. Each type of intrusion has a distinct “acoustic signature” by which it can be uniquely identified. Using specialized algorithms involving powerful computational techniques, the raw signals are processed to zero-in and precisely identify the type of activity.
Upon detection of an intrusion event, the system generates an alarm in REAL TIME and displays the exact location of the event with precise GPS coordinates on a map. The alarm indicates the type of intrusion event detected, such as walking, digging, etc. Alerts can be sent to concerned personnel over sms or e-mail so that a rapid response can be initiated. Unwanted background information, such as nearby vehicular traffic or industrial noise, is suppressed so that nuisance alarms are not generated.
A single PIDS instrument can cover 40 to 50km, and multiple instruments can be networked together to extend the detection range to hundreds or even thousands of kilometres of pipelines monitored from a single location. It is also possible to remotely monitor the system via the internet. Added functionalities include pig-tracking and leak detection. The position and speed of the pig along the pipeline can be detected in real time by the acoustic signal of the travelling pig which is picked up by the distributed sensing system. The system is a good alternative to conventional pig-tracking methods which involve painstaking procedures of physically “hunting” for the pig in the field with special equipment.
Leak detection is another application of the distributed sensing system. Depending on whether internal valve leaks or external leaks are to be detected, the optical fibre cable is laid in different patterns designed to pick up the acoustic signals emitted during a leak. It can be used for detection of gases and liquids.
The system can also be used for other applications in:
(A) Security and Tracking
The Optical Fibre-based Distributed Sensing System can also be used for perimeter protection, border security, and intrusion detection over extremely long distances such as grid power lines. It can also be used in the transportation sector such as railways and highways for security and tracking of train/automobile movement.
(B) Oil & Gas Exploration
Intelligence gathering is key to decision-making in the complex processes of exploration and production. Fibre-optic Distributed Acoustic Sensing is applied to a wide-range of solutions such as Hydraulic Fracturing, Borehole Siesmic Surveys, Gas-Lift, Flood-Front Monitoring and Downhole Leak Detection.
The Distributed Acoustic Sensing system provides the necessary information to optimize production and maximize recovery rates, while helping to mitigate unscheduled losses in scenarios involving a number of critical factors that are difficult to monitor. By providing accurate and detailed acoustic information from within wellheads or reservoirs to sub-meter accuracy in real time, the progress of production can be monitored and guided to the best path so that resources are utilized to the maximum.
In partnership with Fotech, Commtel Networks is able to provide end-to-end distributed acoustic sensing solution from requirement gathering, survey and design stages to installation and commissioning of the system. We invite you to contact us here to discuss your specific requirements.