[CCoE Notice] Dissertation Defense: Leakage and Impact Detection of Subsea Pipelines using Fiber Brag Grating Sensors

[Grayson, Audrey A]

Master’s Thesis Defense
Saeid Amiri
Leakage and Impact Detection of Subsea Pipelines using Fiber Brag Grating Sensors
Defense Date: Monday, November 23 2015 Time:11:00 AM  Location: ME Large Conference Room
Committee Members: Dr. Gangbing Song, Dr. Jae-Hyun Ryou, Dr. Gino J. Lim, Dr. Michael Siu Chon Ho

Subsea pipelines are widely used for the transport of a large variety of fluids, such as natural gas, across long distances. Third party damage to Subsea pipelines can be catastrophic if undetected. This damage may result in steep financial losses, environmental pollution and loss of life.
Therefore  the  timely  detection  and  location  of  damages  along the  pipelines  will  play  a  key  role  in  the  overall  integrity  management  of  a pipeline system
In this thesis, a novel method is proposed to calculate the leakage and impact location of the pipelines using FBG sensors, one common and well used type of Fiber Optic sensors. Detection for leakage was accomplished through the measurement of the negative pressure wave (NPW) resulting from sudden and rapid depressurization of a gas pipeline. FBGs installed at the ends of the pipeline will detect the wave at a time differential. Thus based on the time differential and the speed of the wave, the location of the leakage can be estimated. An experiment was performed on a model PVC pipeline (180 ft) with five manually controlled leakage points. Leakage was detected with 6-20% error, with higher error skewed towards the ends of the pipeline due to reflective boundary conditions. Meanwhile, impact points on the pipeline were detected and localized using a similar algorithm. However, impact-induced stress waves were used instead of NPW. Similar to leakage detection, accuracy was affected by pipeline length and also sampling frequency. Results in this thesis set the foundation for future fiber-optic based pipeline monitoring systems.
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