Simulation Study On Magnetic Field Distribution Of Electromagnetic Method For Damage Of Buried Pipeline Coating

Nowadays long distance oil&gas transporting pipelines distribute throughout China,95%of which are buried underground. Corrosion occurs to these buried pipelines easily since that after long time buried underground, the pipelines may come across various conditions, such as, cracking, aging, stripping, etc.; what’s even worse is that serious accident may happen, for instance, explosion, spill or fire, which can cause huge economic losses, casualties and environmental pollution. Thus, the detecting work is important to ensure safe operation. The technology that based on electromagnetic method is universally used to detect the anticorrosive coating of underground pipes. However, the study that focus on distribution characteristic of the relevant magnetic field during its detecting process is lacked, which is worthy being studied. This paper has certain guiding significance in the field buried pipeline coating detecting application.This paper studied this electromagnetic technology based on the research of all detecting technologies, analysis the factors that affect the electromagnetic detecting results; utilize the finite element simulation about various pipe and default conditions, obtain the distribution characteristic of the relevant magnetic field through the data selected from simulation results; match the data with simulation results, obtain the relation equation between the magnetic field intensity attenuation and the default area under the condition od different pipe diameters; prove the results by field experiments. Meanwhile, put forward an evaluation scheme based on the combination of field data and results analysis, which has a certain significance to the application of underground pipeline detecting, as a guide.The main study procedure and achievements are as following:(1)Make a deep theoretical research on buried pipeline detecting technology, analyze the internal factors affect the electromagnetic detecting signal, which is different default area and different pipe diameter.(2) Using finite element simulation method, establish the finite element model of a variety of defects situation, making comparison of different areas of the default and different pipe diameters, obtain the distribution characteristics of the magnetic field, support the application of this detect technology in the field.(3) Using the finite element simulation method, analyze the simulation results under the condition of different default areas and different pipe diameters, match the results with the data, get the relation equation between the magnetic field intensity attenuation and the default area.(4) Design field experiments to verify the simulation results. The experiment results proved that the simulation results is reliable, which can be used in the future research.(5) Through field survey and statistical analysis, combined with the relation equation between the magnetic field intensity attenuation and the default area, put forward the evaluation scheme about local3PE anticorrosive default detecting based on electromagnetic method, in which the area of default is a significant criterion.