FJINNO proposes a joint monitoring method for vibration, strain, and temperature of pipeline companion optical cables based on the principle of fiber optic sensing, by utilizing communication optical fibers to perceive the vibration, strain, and temperature along the pipeline and achieve monitoring and localization of threat events along the pipeline. Using vibration data for length alignment and third-party activity monitoring, strain data for lateral displacement monitoring, temperature data for leakage monitoring and other abnormal operation analysis, multi-dimensional monitoring data after spatial length alignment and time alignment for joint analysis and interactive verification can further reduce false alarm rates, ultimately achieve line state perception in complex pipeline environments, and provide decision support for safe pipeline operation.
According to statistics, in recent years, the operational risks of pipelines mainly include third-party damage, natural geological disasters, manufacturing and installation defects, corrosion, and other line risks. The core of intelligent pipeline construction is to enhance the ability of pipeline risk prevention and control through perception, ensuring the safe, efficient and stable operation of pipelines. In order to transmit pipeline production data, communication optical cables are laid in the same trench along the pipeline to form a dedicated network. Utilizing redundant fiber cores in pipeline companion communication optical cables for distributed sensing of vibration, strain, and temperature, in order to achieve monitoring and localization of third-party damage, geological hazards, and leaks along the pipeline.
The vibration based fiber optic warning system of FJINNO has been implemented in industrial applications in multiple customer pipeline monitoring cases, effectively solving the safety protection problems of third-party construction along the pipeline, and following the industry standard SY/T 6827 Technical Specification for Oil and Gas Pipeline Safety Warning System. The temperature measurement along the pipeline based on fiber optic temperature measurement has undergone strict on-site testing and can achieve the measurement of temperature trends along the pipeline.
The principle of fiber optic temperature measurement in pipelines
During normal pipeline transportation, the temperature of the pipeline transportation generally does not change suddenly. Only after a long period of shutdown and heat exchange with the environment can significant changes in the temperature of the pipeline transportation medium occur. In the event of an accident, leakage of pipeline products can cause temperature changes. For example, if a natural gas pipeline leaks, due to the Joule Thomson effect, the temperature around the pipeline rapidly decreases. The optical cable can sense this change and accurately locate it. Third party construction excavation can affect the temperature field around the pipeline, causing local temperature fluctuations. Optical cables can achieve detection and positioning of third-party excavation. By monitoring the temperature along the pipeline, online monitoring of abnormal pipeline transportation can be achieved. Once the optical cable detects a sudden temperature change, it can be determined that an abnormal event has occurred at that location.
Measurement range of fiber optic pipeline monitoring system
Based on different principles of fiber optic scattering, pipeline companion optical cables can perceive various parameter information such as vibration, strain, and temperature along the pipeline. The vibration perception of optical cables can achieve correspondence between fiber length and ground position through active ground vibration excitation, and combined with electronic maps, it can achieve spatial positioning of third-party activity events along pipelines. The strain sensing of optical cables can be achieved by establishing mathematical models, and ordinary loose tube optical cables can also perceive soil movement and lateral thrust. Fiber optic cable temperature sensing can achieve the perception of temperature sudden changes along pipelines by measuring temperature changes. After aligning the three orthogonal parameters of vibration, strain, and temperature in time and space, joint analysis can be carried out for interactive verification, further reducing the false alarm rate of individual parameter perception and improving the accuracy of event judgment in pipeline line status monitoring in complex environments. It is possible to collect data from the same event in different spaces, and further improve the accuracy of event recognition through technologies such as big data and artificial intelligence. Ultimately, online monitoring and identification of various pipeline operation risks such as third-party activities, geological disasters, leaks, and pipeline anomalies can be achieved through companion optical cables, providing decision support for safe pipeline operation.