Abstract

Ultrasonic gas leak detection (UGLD) is gaining broader acceptance in the oil and gas industry as a means for detecting combustible gas leaks. UGLD responds to high pressure leaks by measuring the airborne ultrasound emitted, which when detected by the sensor, provides a measure that is proportional to the leak rate. A principal advantage of the technology is that it does not require gas to be transported to the detector and provides coverage for a relatively large area, up to 20 m in radius, suggesting UGLD is suitable for detecting gas releases in open, well ventilated sections of offshore platforms.

Despite such advantages, the location criteria and commissioning and routine maintenance procedures for UGLD are not as well understood as those for conventional gas detectors. A reason might be that UGLD requires the establishment of an ambient ultrasonic background noise level to decide the alarm level and assist with selection of optimal location, a requirement that has no parallel with point IR or catalytic sensors. Location of ultrasonic gas leak detectors is also based on identifying the potential sources of leaks and taking into account acoustic reflections and interferences caused by continuous or short timescale background ultrasonic noise.

Such newness might be enough to give a few would be users pause. They may believe that UGLD is for people with high technical competence or that mapping, commissioning, and maintenance are best left to UGLD equipment manufacturers. Experience by one of the authors of this monograph suggests the contrary. Ultrasonic gas leak detection, for its reliance on ultrasound as a proxy for a gas leak, is a simple concept to understand. Over the course of over 3,000 installations during the last 10 years, offshore platform personnel have developed best practices that reduce the time and cost required for installing and commissioning ultrasonic gas monitors and that ease the burden on maintenance. In this report, we examine several of these procedures and highlight the simplicity of installation and maintenance of this method of gas detection.

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