Oil, gas, petro-chemical, and energy industries rely on vast networks of pipelines to transport and distribute large quantities of hydrocarbon fuels in liquid and gaseous forms to industrial users and customers. Over the decades, millions of miles of pipeline were built on land, underground, and off shore. These pipeline networks often traverse remote area which is subject to harsh weather conditions. As key infrastructures, these pipelines are important to national security and economic vitality. Pipeline accidents could cause human deaths, serious injuries, and material costs. It is therefore very important to develop a comprehensive monitoring scheme to protect their integrity from external threats such as malicious intrusion, tempering attempts, illegal tapping, construction accidents, and natural disasters, as well as from internal structural degradation including corrosion/erosions, due to aging and wear from weather.
Presently, pipeline monitoring and protection is often performed by expensive and laborious physical inspection methods such as helicopter or vehicle patrols. However, fiber optic distributed acoustic systems permit the supervision of long-distance pipelines using fiber optics. Since fiber optic cables are usually laid along the modern pipelines, no additional investment in equipment installation is needed.
The placement of the sensing cable is a critical part of the design. it must be buried sufficiently deep to avoid being uncovered by running surface water or by burrowing animals, and yet the deeper it is sited below the surface, the more high-frequency waves are attenuated and therefore, the signal bandwidth becomes more narrow.With only one fiber optic cable laid along the pipeline, FOTAS can detect third party intrusions like digging or excavations, the pressure waves of a pipeline leakage, ground movement and structural variations. Its length and operation as a distributed sensor make it a solution for a highly dense distributed sensing system for monitoring pipelines. FOTAS is also a reliable system for detecting and identifying leaks, and it is used for early detection of leaks in pipelines transporting liquid or gas. FOTAS looks for the noise generated by the fluid escaping the pipe, which then vibrates the pipe wall that the fiber is connected to.
FOTAS was implemented at a site of BOTAŞ Petroleum Pipeline Corporation, which is the state-owned crude oil and natural gas pipeline and trading company operating the national gas grid of Turkey, and the system has been successful.