Research On Affecting Factors Of Pipeline Bending Deformation Monitoring Based On Distributed Optical Fiber Sensing Technology

The security running of oil and gas pipelines has been the focus of people's attention. Through the analysis of domestic and international long-distance pipeline failure accidents, found that the large deformation accounted for a large proportion in causing pipeline failure, which is one of the important factors that threats to the safety running of long-distance pipelines. The traditional methods of monitoring pipe deformation is consuming both in time and human energy. And it is difficult to grasp the real-time running status of long-distance pipeline, leading the potential problems to the long-pipeline. In response to these problems, we propose using distributed optical fiber sensing technology for monitoring long-distance pipeline deformation. It breaks out the limitations of conventional methods,realizing long-term deformation monitoring. The topic is carried out, funding by the 12th Five-year National Scientific and Technical Support Plan(Project Number: 2011BAK06B01-13)":The research on key technologies of monitoring and evaluating long-distance pipeline deformation". A number of basic researches are conducted in this dissertation and the achieved results are as followes:(1) Retrieved and pursued the literature on oil and gas pipeline failure modes and monitoring methods,and layed rational research guidelines and technology program.(2) Combined the failure modes of oil and gas pipeline with the failure accident statistics, bending deformation is secleted for monitoring. Analyzed the basic deformation of pipeline and the common form from engineering. Summarized the common monitoring methods of pipeline and pointed out the disadvantages on them.A method of optical fiber sensing technology based on briliouin scattering was proposed for monitoring pipeline deformation.(3) In comparison with several common distributed optical fiber sensing technologies in sensing principle and performance,adopted BOTDA optical fiber sensing technology monitoring pipe deformation. Analyzed the effects of temperature and strain on Brillouin scattering spectrum. Established the physical mode of SBS, adopted the finite difference method solving the coupled wave equations, simulated strain and temperature effects on Brillouin scattering spectrum.(4) With ten tons of multi-channel loading machine, the deformation loading experiments are performed. At the same time,the distributed optical fiber sensing technology based on BOTDA and strain gauges are applied to monitor pipeline deformation. And analyzed the strain distribution when the pipe in tension and compression. Then compared the results. Verified the distributed optical fiber sensing technology based on BOTDA is an effectived method to monitor the deformation of pipeline.