埋地管道防腐层破损点电磁法检测磁场分布特性仿真研究

发布时间：2018-02-14 17:29

本文关键词： 埋地管道防腐层破损点电磁法检测分布特性仿真研究　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前我国己建成的油气长输管道遍布全国,95%以上埋藏于地下。由于外防腐层长时间埋地,易出现破损、老化、剥离和脱落等现象,会发生管道腐蚀和穿孔,引发泄露、火灾、爆炸等事故,造成重大经济损失、人员伤亡和环境污染。及时掌握管道腐蚀程度,进行防腐层的检测工作是保证管道安全运行的重要环节。基于电磁法的埋地管道防腐层检测技术是目前国内外应用最广泛的检测技术之一,但现阶段针对其检测过程中产生的磁场分布特性的研究相对较少,是埋地管道防腐层电磁检测亟待进一步开展研究的问题。本文在调研国内外埋地管道电磁检测技术的基础上,开展了相关理论研究,提出了检测电磁信号的内部影响因素；采用有限元仿真技术,对防腐层存在不同面积缺陷和埋地管道不同管径情况进行了仿真分析研究,得到了磁场分布特性的变化规律；并针对仿真结果进行了数据拟合,得到了在不同管径情况下磁场强度衰减量与破损点面积的明确关系式,接着在现场进行了检测实验,验证了仿真结果及拟合关系式的合理性,最后在结合大量现场资料调研和分析结果的基础上,提出了防腐层局部破损点电磁检测的评价方案,研究成果对埋地管道防腐层电磁检测技术在现场的应用具有一定的指导意义。具体开展工作及取得成果如下： (1)对埋地管道防腐层电磁检测技术进行了阐述,针对其检测原理进行了深入理论研究分析,根据理论分析结果提出了电磁检测信号的影响因素,即防腐层破损点不同面积和埋地管道不同管径。 (2)利用有限元方法实现了埋地管道防腐层破损点电磁检测过程的仿真模拟,建立了防腐层存在不同面积破损点和埋地管道不同管径模型,通过仿真研究分别得到了各情况下的磁场分布特性变化规律,为该技术在现场的检测应用提供了有力的理论依据。 (3)利用有限元软件对埋地管道防腐层存在不同面积破损点及埋地管道不同管径两种情况进行了交叉仿真分析,对仿真结果进行了数据拟合,得到了在埋地管道不同管径情况下磁场强度衰减量与防腐层破损点面积的明确关系式,对现场实际检测评价工作有重大参考价值。 (4)开展了现场实地埋地管道防腐层破损点电磁检测实验,通过实验的方法进行研究,得到了与仿真及拟合结果相似的结论,从而验证了仿真模型、仿真结果及拟合公式的合理可行性,为进一步开展相关研究奠定基础。 (5)通过对大量的现场实际情况的资料调研及统计分析,并结合仿真和拟合得到的各个管径下磁场衰减量与破损点面积的关系式的基础上,提出了针对基于电磁法的埋地管道3PE防腐层局部破损点检测,以破损点的等效破损面积大小作为判据的分级评价方法。
[Abstract]:At present, more than 95% of the long distance oil and gas pipelines built in China are buried underground. Due to the long term burial of the external anticorrosion coating, it is easy to appear such phenomena as breakage, aging, stripping and shedding, etc., which will lead to pipeline corrosion and perforation, causing leakage and fire. Accidents such as explosions have resulted in major economic losses, casualties and environmental pollution. The extent of pipeline corrosion should be grasped in a timely manner, The inspection of anticorrosive coating is an important link to ensure the safe operation of pipeline. The detection technology of buried pipeline anticorrosion coating based on electromagnetic method is one of the most widely used detection technologies at home and abroad. However, there are few researches on the magnetic field distribution in the detection process, which is an urgent problem for the electromagnetic detection of buried pipeline anticorrosion coating. Based on the investigation of electromagnetic detection technology of buried pipeline at home and abroad, this paper has carried out relevant theoretical research, put forward the internal influencing factors of detecting electromagnetic signal, adopted finite element simulation technology, In this paper, the characteristics of magnetic field distribution are analyzed and analyzed by simulation, and the simulation results are analyzed, and the simulation results are simulated. The explicit relationship between the attenuation of magnetic field intensity and the area of the damaged point is obtained under different pipe diameters, and then the test results are carried out in the field to verify the rationality of the simulation results and the fitting relationship. Finally, based on the investigation and analysis of a large number of field data, an evaluation scheme for electromagnetic detection of local damage points of anticorrosive coating is proposed. The research results have certain guiding significance for the application of electromagnetic detection technology of buried pipeline anticorrosion coating in the field. The specific work carried out and the results achieved are as follows:. 1) the electromagnetic detection technology of buried pipeline anticorrosion coating is expounded, and the testing principle is studied and analyzed in theory. According to the theoretical analysis results, the influencing factors of electromagnetic detection signal are put forward. That is, different areas of damaged points and different pipe diameters of buried pipelines. 2) using finite element method to realize the simulation of electromagnetic detection process of corrosion protection point of buried pipeline, the model of different damage points and different pipe diameter of buried pipeline is established. Through the simulation research, the variation law of magnetic field distribution characteristics is obtained, which provides a powerful theoretical basis for the detection and application of the technology in the field. 3) using finite element software, the cross-simulation analysis is carried out on the two cases of different damaged points of corrosion protection coating and different pipe diameter of buried pipeline, and the simulation results are fitted with the data. The explicit relationship between the magnetic field intensity attenuation and the area of the damage point of the anticorrosive coating under different pipe diameters of buried pipeline is obtained, which is of great reference value to the field actual inspection and evaluation work. (4) the electromagnetic detection experiment of the damaged point of buried pipeline is carried out on the spot. The results are similar to those of simulation and fitting results, and the simulation model is verified by the method of experiment. The results of simulation and the reasonable feasibility of fitting formula lay a foundation for further research. 5) based on the investigation and statistical analysis of a large number of field data, and the relationship between the attenuation of magnetic field and the area of damaged points under various pipe diameters obtained by simulation and fitting, Based on electromagnetic method, this paper presents a hierarchical evaluation method for the detection of local damage points of 3PE anticorrosion coating of buried pipeline. The equivalent damage area of the damage point is taken as the criterion.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE988.2

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