Arctic Pipeline Leak Detection using Fiber Optic Cable Distributed Sensing Systems

Abstract

Multiple offshore Arctic fields have been developed over the past three decades and the world demand for oil and gas will continue to drive hydrocarbon development in Arctic and sub-Arctic environments. Arctic pipelines are used for the safe and economic transportation of hydrocarbons. While pi pelines are designed not to leak, excessive strains due to the effect s of ice gouging, strudel scour, frost heave and p ermafrost thaw settlement along with other loading and failure mechanisms (i.e. corrosion, third party damage) could result in a leak. Failure to detect leaks in a timely manner could have severe safety, environmental, and economic impacts. Large leaks can easily be detected, but small chronic leaks may go undetected for a period of time, especially when pipelines are buried in remote locations or under seasonal ice cover.First, this paper reviews existing Leak Detection System (LDS) technologies for their potential use on Arctic and sub-Arctic pipelines. The technology evaluation based on regulatory requirements and functional criteria suggests that Fiber O ptic Cable (FOC) distributed sensing systems have a high pote ntial to be use d on Arcti c pipelines. Distributed sensing FOC can b e used to detect and locate leakages. Pipeline leakage would gen erate a local change in te mperature. These thermal anomalies can be captured by FOC Distributed Temperature Sensing (DTS) systems with good spatial and temporal resolution. Similarly, the acoustic signature generated by leaking fluid can be detected using FOC Distributed Acoustic Sensing (DAS) systems. Inelastic Brillouin and Raman backscattering principles are used for measuring temperature in DTS, whereas the Rayleigh backscattering principle is used for measuring acoustics in DAS. This paper presents information on a pplicable regulations, operating principles, optical budgets, system integration, sensor positioning, installation and maintenance assessment, technology status, risk an alysis using Failure Mode, Effec ts and Critic ality Analysis (FMECA) and field implementation challenges.

Application of fiber optics in water distribution networks for leak detection and localization: a mixed methodology-based review

“…When an abnormality is sensed by a fiber optics sensor, a signal is instantly sent to the receiver notifying the presence of abnormality. The analysis of the signal determines the location of the abnormality (Thodi et al 2014).…”

A Review of Hybrid Fiber-Optic Distributed Simultaneous Vibration and Temperature Sensing Technology and Its Geophysical Applications

“…Distributed FOS technology has the ability to measure vibration, temperature, and strain at thousands of points along a single fiber. Recent developments in DAS, DTS and DVTS technologies promise to provide cost-effective tools allowing monitoring critical parameters over tens of kilometers along the pipeline with a single distributed system [ 7 , 54 , 55 ].…”

“…However, excessive strain and temperature fluctuations triggered by ice gouging, strudel scour, frost heave and permafrost thaw along with other extreme loading and corrosions, could result in leaks. These leaks cause local anomalies in temperature and vibration signatures, which can be detected and monitored regularly using distributed sensing systems [ 54 ].…”

Chronic Pipeline Leak Detection Survey: A Description of Various Case Studies

“…Large or catastrophic leaks greater than 10mm can be detected using Dynamic pressure sensing, whereas medium to small leaks between 4 to 8mm is suited to RTTM and SPRT lead detection and location technology. Pipeline leaks greater than 4mm for onshore, arctic and subsea conditions were investigated however there is no published field data available which fully addresses chronic leaks less than 3mm [3][4][5]. Experimental and pilot scale studies using fiber optic leak detection highlighted key risks using DTS or DAS for arctic or subsea conditions [4].…”