A NEW HEALTH MONITORING TECHNIQUE ON SUBMARINE PIPELINE

摘要

Submarine pipeline system is a main pattern in collection and transmission of offshore oil and gas, which sends oil and gas from offshore to onshore terminal, and it plays an important role in offshore oil and gas development. Because of the complicated and harsh working condition in which pipeline system works, such as impulsion, corrosion and free-spanning vibration, failure of submarine pipeline system occurs occasionally, it causes oil leakage, environment pollution and economic losses. Health monitoring is a feasible and effective manner to ensure submarine pipeline safety and reliability during service life, especially when all factors affecting pipeline failure are not still entirely realized or controlled. The practical strategy of a new real-time monitoring system for long distance submarine pipeline is introduced in this paper, which has the function of diagnosis and auto-alarm. In this system, a new distributed optical fiber sensor (DOFS), which uses optical time domain reflectometry theory based on Brillouin backscatter, is applied to monitor the strain and temperature along the pipeline. In addition to, Wavelength Division Multiplex (WDM) technology and series DOFS are also applied to extend the measure scope for long distance submarine pipeline By using signal processing system to analyze the outcome data of sensor, the strain along the pipeline can be obtained. If the strain reaches the alarm setting, the system will send out caution and meanwhile accurately give the dangerous position, The system can also analyses vibration frequency of pipeline, if free-spanning vibration occurs, caution will also be given, so that the operator can take some measures in time to avoid the failure of pipeline. In this paper, the makeup and development principle of distributed optical fiber sensor are specified, the development, application and assembly of system in engineering are introduced as well. The brand new practical system can not only be used for submarine oil and gas pipeline but also for oil and gas transfer system in land, city coal gas transfer system, electricity-transmission cable, great span bridge, and so on. This system can also be widely used in many prospects of other industries.