Boreal Laser Gasfinder AB

Many of the world’s major natural gas transmission pipelines cross undeveloped and sparsely populated land. Natural vegetation quickly grows back after a pipeline has been laid, making it practically impossible to implement ground based survey programs to detect leaks. However, there are critical safety and economic reasons that such pipelines be surveyed on a routine basis to identify and repair leaks.

Leaking natural gas can cause explosions leading to loss of life and property. Loss of product through undetected leaks dramatically reduces a pipeline operator’s profitability. In some parts of the world, it is estimated that such losses exceed 15%. Fortunately, Boreal Laser’s GasFinderAB system makes it possible to routinely and inexpensively survey pipelines for leaks.

Mounted in either a fixed-wing or helicopter aircraft, GasFinderAB can immediately detect the presence of elevated levels of methane in the air above a pipeline. GasFinderAB was developed to be used within normal visual inspection flight parameters. Sampling 3 times per second, measurements are updated for every 10m of ground covered. Unlike other optical methods which can be confused by other gases present in air, the laser technology in GasFinderAB responds only to methane. With over 5 years of experience, and thousands of kilometers of pipeline surveyed, Boreal’s GasFinder has detected many pipeline leaks that would not otherwise have been detected.

Benefits

• CH4 specific – no interferences
• 3 readings per second.
• Robust, reliable, proven technology
• Self-calibrating—no calibration needed
• Easy set-up, alignment and use.
• No consumables and no maintenance
• Built-in data-logger and self diagnostics

How the Airborne CH4 GasFinder works

The GasFinderAB system comprises a GasFinderFC CH4 gas analyzer, and external airborne probe, and some accessories. The GasFinderFC houses a laser diode, drive electronics, and microcomputer subsystems. Fibre-optic cable carries the laser light to the external probe (see photo below). The laser light makes four passes through this probe and is focused on a photo-detector. The resulting photo current is returned to the GasFinderFC control unit via coaxial cable for analysis. The measurement probe has an effective path length of 2m, which yields a methane sensitivity of better than 1 ppm at three sample readings per second. The probe employs a robust mechanical design with simple, stable optical components. It is provided with a foam shroud that prevents dust and debris entering the path, but allows free passage of ambient air into the measurement zone. A portion of the laser beam is passed through a stable built-in reference cell inside the GasFinderFC to provide a continuous calibration update. The measure and reference signals are compared to determine the actual concentration of gas in the probe. This value can be viewed on a display unit and is transferred via serial interface to a data logging PC. The serial data signal also includes comprehensive system diagnostics. A GPS system provides spatial coordinates to the data-logging PC once a second, which enables CH4 data to be mapped along the flight profile.