FBG Optical Sensing for Pipeline Structural Health Monitoring
Pipelines are naturally vulnerable to operational, environmental and man-made effects such as internal erosion and corrosion; mechanical deformation due to geophysical risks and ground movements; leaks from neglect and vandalism; as well as encroachments from nearby excavations or illegal intrusions. The actual detection and localization of incipient and advanced faults in pipelines is a very difficult, expensive and inexact task. Anything that operators can do to mitigate the effects of these faults will provide increased reliability, reduced downtime and maintenance costs, as well as increased revenues. Over the last few years, optical fiber sensors have seen an increased acceptance and more widespread use for structural sensing and monitoring in civil engineering, aerospace, marine, oil & gas, electrical power, composites and smart structure applications. Given their immunity to electromagnetic effects and compatibility with outdoor use, fiber optic sensors have proven themselves to be rugged and long-lasting for installation along pipelines. Furthermore, with the advent of advanced, novel discrete and distributed fiber optic sensing techniques over the past decade, it has now been demonstrated that it is possible to perform on-line, real time pipeline condition monitoring as well as intrusion detection over routes extending 100s of kilometers and make measurements of pressure, temperature, strain, as well as vibration and acoustic signals. Such fiber optic sensing systems are a powerful tool in a pipeline’s operator’s arsenal to more effectively understand the mechanical behavior of pipeline assets under normal and abnormal operating conditions, as well as to predict and locate the start of an incipient fault. This talk will review the state-of-the-art of one of the most common and effective fiber sensor types—optical fiber Bragg gratings (FBG)—describing operation basics, common applications, associated advantages and benefits, as well as reviewing a number of real-life application examples of diverse instrumented pipelines.