可控源海洋电磁响应数值模拟与空气波压制方法研究

The project mainly focuses on the subject of "Study on the numerical simulation methods of controlled source marine electromagnetic response and the airwave mitigation method". The research topics include three aspects of numerical simulation methods and analysis of response characteristics in MCSEM, and interaction mechanism of airwave and other signals from under sea formations and their mathematical descriptions, and the separation and mitigation method of the airwave from the total EM field components. The first item of numerical simulation and analysis of electromagnetic responses of MCSEM covers investigation and comparison of the effective simulation methods of MCSEM responses both in time domain and frequency domain, analysis of the composition and interaction of different EM signals in stratified formations in shallow water，study of the characteristics of the EM fields in complex undersea formations. The second item of study on interaction mechanism of airwave and other signals from under sea formations and their mathematical descriptions include the interaction modes among airwave and other signals and the physical mechanism of airwave formation, and the coupling relations among airwave and other EM field components and their approximate expressions. The third item of research on the separation and mitigation methods of airwave from total EM wave fields covers the decomposition method of the EM field components into different modes, analysis of the factors that affect the leading term of the airwave and how to express leading term effectively and accurately, and investigation of particular measuring mode voiding of airwave effect. The project will begin with the numerical simulation methods of the electromagnetic responses, and adopt methods of EM mode decomposition and of mathematical approximation of the airwave, through the implementation of the separation and mitigation of the airwave from the total EM field, to fulfill the aim of improving the expressible accuracy of the effective signals, and of accurately evaluating the electric properties of undersea formations.

研究可控源海洋电磁(MCSEM)响应数值模拟方法与空气波作用机制和压制方法。研究内容有MCSEM电磁响应的数值模拟方法和响应特征分析、空气波与海底地层等信号的相互作用机制及数学表达、空气波的分离和压制方法三个方面。MCSEM的电磁响应数值模拟方法研究和特征分析包括：时间域和频率域MCSEM电磁响应高效计算方法研究与对比、层状介质中浅水域电磁信号的相互作用与构型分析、复杂海底介质的电磁响应特征分析；空气波与海底地层等信号的相互作用机制及数学表达包括：空气波信号的作用方式与形成机制、空气与其它信号的耦合关系及近似数学表达；空气波信号的分离和压制方法研究包括：电磁场响应的模拟与分离方法、空气波主导项的影响因素分析与近似数学表达、无空气波测量方式研究。本项目从电磁波响应的数值模拟入手，利用波场分离和近似数学表达的方法，实现空气波的分离与压制，达到提高有效信号表达精度的目标，以准确评价海底地层电性。

研究了可控源海洋电磁(MCSEM)响应数值模拟与空气波作用机制和压制方法。在响应特征数值模拟方面，研究了1D层状介质解析解、2.5维有限元和3D交错网格有限差分数值模拟对MCSEM电磁响应的高效计算；空气波与海底地层等信号的相互作用机制及其数学表达方面，实现了浅水域电磁信号的相互作用与构型分析；在基于崎岖海底模型，开展了复杂海底介质的电磁响应特征模拟，分析了空气波与海底地层等信号的相互作用机制，建立了空气与其它信号的耦合关系及近似数学表达式；在空气波的分离和压制方法方面，研究电磁场响应的模式分离方法，建立了空气波主导项的影响因素分析方法与近似模拟的数学关系，开展了无空气波测量方式研究。通过三方面本项目从电磁波响应的数值模拟入手，利用波场分离和近似数学表达的方法，实现空气波的分离与压制，达到提高有效信号表达精度的目标，以准确评价海底地层电性参数，对于海洋资源与能源的勘探开发具有重要的意义。