Long-distance Pipeline Security Situation Grading And Its Protective Coating Trenchless Detection

The long distance transportation pipeline is the most economic and safest manner to transport petroleum and natural gas. As the characteristics of flammable, explosive toxicity, etc. the petroleum and natural gas transported might cause the malignant consequence easily, such as firing, exploding, poisoning, environmental polluting, etc. At once the accident of the pipeline happened, this kind of accident often causes the serious casualties, significant economic loss and bad influence of society and political at the same time. With the increase of social and public voice attention and request to the environment and the public safety, the effect intensity are also increasing more and more in today along with the economical and political globalization flourishing. So that, nil accident operation become the pursed goal to the pipeline profession.In order to guarantee the operation of the pipeline safety, reduce the accident probability, and lengthen the service life of the pipeline, the safe situation grade and the inspection to the pipeline outer coating which need not to be dug are regarded as the key research point in this paper.1, The harm factors to the pipeline have been studied detailed, and the evaluation method of safe situation grade of the pipeline has been proposed based on the risk assessment and fitness-for-purpose assessment, and referred to the classification methods of pressure vessel and industry pipeline safe situation grades. And aim at the characteristics of local corrosion occurred easily at the pipeline surface, a three-step assessment method to voluminal corrosion flaw assessment has been proposed which is convenient to in-site application.2, The advantages and disadvantages of non-dig examination technology had been studied detailed. With respect to the different lengths of the long distance trasportation pipeline and considering the needs of in-site examinations, an examination project of different lengths of pipeline and a synthesis examination method of mid-long pipeline have been proposed.