Overcoming challenges in the performance validation of fiber-optic pipeline leak detection systems

Proceedings Publication Date:

07 May 2020
Presenter
Dr. Chris Minto
Presenter
Company
Author
Chris Minto, Alastair Godfrey, Alasdair Murray
Part of the proceedings of
Abstract

External Leak Detection systems based on distributed fiber optic sensors (DFOS) offer the exciting potential to significantly reduce the overall amount of spilled product before a leak is detected and localized. As an external system, the validation of system performance and equally the verification of an operational installed system is a known challenge since, unlike in a conventional system, leaks cannot easily be simulated. As an example, the detection of a negative pressure pulse – a key detection mode for a Rayleigh based system requires test facilities >500m extent with leaks created at operational pressure in a full-bore pipeline. As a result, industrial focus has traditionally been deployed on lower level research-oriented test data rather than full scale validation.

OptaSense® have worked with the industry test facility CTDUT in Brazil to establish a unique test bed where realistic pipeline leaks can be created in full flow conditions. The results from this have been used to validate a realistic performance basis of small 15 lpm leaks detected via their negative pressure pulse in ~10 seconds and larger 150 lpm leaks detected by multiple modes in ~1 minute. Valid automated detection of NPP was observed down to 1mm holes in the pipe – a leak rate of only 1.5 lpm. The use of the negative pressure pulse is shown as a compelling detection method but needs care to deploy in testing since the use of a valve to create a pulse is shown to be inferior in comparison to burst disks due to the increased valve-opening time that gives rise to a reduced amplitude pressure pulse. This paper argues for the necessity of large-scale validation approaches to performance bound acoustic-based leak detection systems and presents established options for in-field verification on customer owned systems

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