相关辨识技术在谱激电中的应用研究

A new spectrum induced polarization(SIP) method based on correlation identification technology is proposed to solve low efficiency and noise problems of SIP. By using conventional electrical exploration devices, correlation operation can be carried out with the transmitted pseudo-random sequence and received signal to suppress the random noise, and also obtain the transmission characteristics such as the impulse response and the frequency response of the underground media. With only two or three times of sendings and receivings we could obtain a wide bandwidth complex resistivity spectrum, whose width and the number of effective spectrum lines vary with the cycle and clock frequency of the transmitted pseudo-random sequence. Using theoretical research, numerical simulation and experimental verification, we plan to study the essential theories and key technologies of correlation identification SIP which include different characteristics of the electric field response in differen medium, the relation of the identification results (impulse response and frequency response) and underground electrical distribution, the method of apparent spectrum parameters and various electrical parameters deduced from recognition results. On this basis, a set of systematic observation scheme and data processing method are presented and verified through indoor experiment and field experiment.The above work will lay foundation for correlation identification technology in electric prospecting and provide solutions to develop lightweight, portable and efficient electric prospecting instruments. The proposed method has the advantages of time domain and frequency domain IP method at the same time and it is expected to become one of the key techniques and methods of energy and mineral exploration including minerals and groundwater, etc.

为了解决谱激电法的低工效和噪声问题，本课题提出在谱激电法中采用相关辨识技术：采用常规的谱激电装置，将发送的伪随机序列和接收的时间信号进行相关运算，在压制随机噪声的同时得到待勘查地下介质的冲激响应和频率响应；只要2-3次发送和接收就可以得到一条宽频带的复电阻率谱,并得到多个激电和电磁参数。拟采用理论研究、数值模拟和实验验证等手段，研究相关辨识技术在谱激电中应用的核心理论和关键技术，包括不同介质的电磁场响应特征、辨识结果（冲激响应和频率响应）与地下电性分布的关系、从辨识结果得到视谱参数和其他多种地电参数的方法。在此基础上形成一套体系化的观测方案和数据处理方法，并通过室内实验和野外实验进行验证。研究成果将为实用化的地电系统相关辨识方法提供理论依据，为研制轻便、高效的多功能电法仪器提供方案。该方法同时具有时间域和频率域激电法的优点，有望成为矿产资源、地下水等能源和资源普查以及详查的一项新技术。

本课题研究在谱激电法中采用相关辨识技术的理论和技术，以解决谱激电法的低工效和噪声问题。围绕这个研究目标，我们完成了以下研究内容：我们采用数值模拟方法计算了均匀大地介质、层状介质、有限规则体等电性结构对不同装置和不同收发距的冲激响应和频率响应，总结和归纳了冲激响应和频率响应的响应特征与地下介质的电性分布的对应关系，并且研究了从频率响应推出的复电阻率谱中获得各种激电参数和电磁参数的方法。.完成了实验用发送机和接收机的设计和制作，并且通过实验验证了仪器的性能；对相关辨识算法进行了全面优化，以提高辨识精度、效率和抗干扰能力。根据上述理论研究结果，确定了相关辨识谱激电法的最优观测方案、由辨识结果得到各种激电参数和电磁参数的数据处理方法以及信号处理算法和流程。通过室内和野外实验对上述观测方案和数据处理方法进行了验证，得到了实用化的方法体系。.本项目达到并超过了预期目标，为下一步利用统一的电磁法理论框架对得到的辨识结果进行系统地研究和精确地解释奠定了研究基础。同时，在项目执行过程中，培养了多名动手能力强、综合素质高的研究生。