Studies on Distributed Brillouin Scattering Technique for Monitoring of Lifeline Structures

Pipeline networks are the most efficient means for transporting large quantities of oil and gas through large distances. These pipelines cross different geographical terrains and are subjected to different manmade and natural hazards. Also these pipelines are prone to failures due to aging. Leakage in pipelines, particularly those carrying fuels is very dangerous as it leads to environmental pollution and also fatal accidents. The pipeline infrastructure industry has seen extensive growth in the recent years and hence there is a huge necessity for the development of real time pipeline monitoring technologies for reliable and safe operation of pipeline networks. Presently, health assessment and real time monitoring is gaining popularity among the researchers as it provides quality information on the performance of complex systems during its operation. There are different types of technologies developed for real time monitoring of pipelines using distributed fiber optic sensors, acoustic emission techniques and guided wave techniques. This paper presents in detail the theory of brillouin based distributed optical fiber sensing technology and studies carried out using the distributed fiber sensing for monitoring strain and temperature profiles through laboratory experimental investigations. Experimental investigations were carried out by simulating leakage in pipelines filled with hot water to study the performance of the distributed fiber sensors. Leakage was simulated in pipelines by drilling small holes at predetermined locations. Detection time was from 5 to 10 minutes and location of leakage was exactly detected with the spatial resolution of 80 mm. Brillouin based distributed fiber sensing system is a promising technique for monitoring long distance pipelines.