【作者】 陈宇；

【导师】 李焱骏；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 井下套管缺陷损伤检测一直是石油测井领域的重点,但国外的技术垄断导致现在国内常用的测井仪器一般只能检测套管内壁的情况,无法检测套管外壁。在“多频涡流套损检测仪的研制”项目中,本文设计出能够同时检测出套管内外壁损伤状态的远场涡流检测系统,该仪器能够在较为复杂的环境中进行长时间的测试工作,而且检测效率与精度均能达到较高水平。本文分析远场涡流检测的现象及原理,并根据电磁信号在传播过程中的变化,明确远场检测中电磁信号与套管损伤之间的关系。本文以快速计算检测信号的相位差为目标,并且讨论仪器参数对测试结果的影响。为了完成测试目标,文中讨论分析了三种计算检测信号相位差的方法,并对过零检测法的缺点进行了改进。在本文电路系统设计中,激励信号电路负责产生初始信号,控制高电压送入激励线圈使其产生远场涡流信号,并由信号处理电路对携带有套管缺陷损伤信息的信号进行调理与计算,最后得出检测信号相对于参考信号的相位差。然后本文对远场涡流检测系统进行了多方面的检测,测试并分析了电路系统上的信号,整支仪器的在温度升高环境中工作情况,以及实验套管的检测情况。多项测试的结果报告证明了多频涡流套损检测仪能够完成套管管壁缺陷损伤的检测目标,验证了本文设计和使用的测相方法和电路系统。更多还原

【Abstract】 The underground casing damage detection is always a focus in the field of oil well logging.But the current commonly used logging instruments can not detect the condition of casing’ outer wall but only the inner wall due to the overseas technology monopoly.In the "development of the multi-frequency eddy current detector of casing damage" project,this thesis has designed a far-field eddy current detection system which can be used to detect the inner and outer wall damage simultaneously.This instrument can work in a complex environment for a long period of time,and it has pretty good detection efficiency and precision.The thesis has analyzed the principle and phenomenon of far field eddy current detection,and the changes of the electromagnetic signal in the propagation.The relationship between the far field electromagnetic signal and the casing damage in the detection has been figured out.Then the thesis aims to calculate the phase difference of the detection signal quickly.And the effect of the instrument parameter on detection results also has been discussed.To accomplish the aim,three kinds of method to calculate phase difference of the detection signal have been discussed,and the thesis has improved disadvantages of the zero-crossing detection method.In the circuit system design of the thesis,the excitation signal circuit is responsible for generating initial signal.And the high voltage is controlled into drive coil to produce the far field eddy current signal by the initial signal.The signal processing circuit aims to improve the detecting signals that have carried the casing damage information.And finally the phase difference of the detection signal relatively to the reference signal is accomplished.Then in the thesis,the far field eddy current detection system has been tested in several ways.Test and analyze the signals in the circuit system,the statue of instrument in the high temperature environment,and the detection results of experimental casing pipes.The multi-frequency eddy current detector of casing damage is proved to accomplish the casing damage detection aim by these test reports,and the measurement method of signals’ phase and the circuit system are verified at the same time.更多还原