海洋发射电极的阻抗特性理论分析与实验研究

There is a great importance to solve the fundamental problems in the development progress of Marine controlled-source electromagnetic methods (MCSEM) for the exploration of oil and gas resources. During the MCSEM survey, the way to increase the transmission dipole source moment is to minus the resistance between electrodes. How many influence factors related to the resistance? What are the weights of these factors? What is the correct expression of the resistance? The design of the transmission system is influenced greatly by these questions. In this proposal, we try to execute the derivation of the formula from the basic theories and analysis these influence factors to get the rigorous results. We also should find the relationship between the flume and the ocean to get the new simulation guidelines for the experiment. And we will validate the theoretical derivation and experimental results by carrying out the marine experiments. The clear mathematical expressions of the resistance between the electrodes will provide the support for the MCSEM development in China.

解决海洋可控源电磁法（MCSEM）发展过程中的基础理论问题，对我国海域天然气水合物和油气资源的勘探有着重要的意义。在进行MCSEM勘探时，一般通过减小发射电极极间电阻的方式来增大人工源电磁场的激励能力，进而提高信噪比。而极间电阻的阻抗特性究竟与哪些影响因素有关，各个因素占据多少权重，正确的极间电阻计算公式又将是什么？这个前沿性的关键问题如果不解决，将影响整个系统的设计。本项目正是立足基础理论，对极间电阻的阻抗特性和众多影响因素展开深入分析，力争从基础理论推导得到严谨的计算结果，根据理论结果，指导室内外的模拟实验。另外提出新的模拟准则，探讨利用大小水槽模拟海洋环境的对应关系和规律。结合水槽、海边和海洋实验，验证理论推导和实验结果。最终得到清晰明了的数学表达式。极间电阻求取问题的解决，将会为我国MCSEM的发展提供积极的理论支撑。

本项目首次在国内深入研究了海洋发射电极阻抗特性的基础理论。围绕室内和海上模拟试验开展了大量的研究工作。通过理论推导和基础实验相结合的方式，解释了发射端间电阻随着发射电压和发射电流变化的影响规律，引入并探讨了双电层电容在供电时间轴上的影响，系统总结了发射极间电阻总体表达式，为MCSEM 的发展提供基础理论支持。不过由于供电空间、离子不扩散、大量沉淀、电极尺寸等因素的影响，以及所涉学科的基础理论和影响因素太多，未能得到利用水槽代替海洋环境下电极供电的模拟准则理论表达式。按时提交了年度技术报告。结合本项目的研究成果，以第一作者或通讯作者发表了5篇国际SCI检索源学术论文，1篇国内SCI论文，获得了3项发明专利授权，指导了多名本科及硕士研究生。