基于物性指数的大地电磁信号多维度耦合正演与工程试验

Multi-dimensional coupling forward modeling and experiment of magnetotelluric signals based on physical property index

为了采集和识别携带地层岩性信息的超低频大地电磁信号,在超低频大地电磁理论的基础上,系统分析了影响大地电磁信号的地层因素和干扰因素;建立物性指数模型,拟合波形和岩性的对应关系,从波形上提取岩层物性信息并赋值,纳入物性指数模型进行多维度耦合计算,有效减小了干扰因素对采集信号的影响。根据物性指数模型,设计了双层阵列扫频式传感器和大地物性探测仪,并开发出了相应的数据处理程序。经现场试验,仪器对地层完整性和富水区反应敏感,可对采空区、地下工程、地质构造、富水区等进行探测和识别,实现目标地质体的精细探测。

In order to collect and identify the ultra-low frequency magnetotelluric signal carrying the lithology information of strata,based on the theory of ultra-low frequency magnetotelluric,the stratigraphic factors and interference factors affecting the magnetotelluric signal were systematically analyzed;the physical property index model was established,and the waveform and rock were fitted.The corresponding relationship between the sexes was extracted from the waveform and the physical property information of the rock layer was extracted and assigned to the physical property index model for multi-dimensional coupling calculation,which effectively reduced the influence of interference factors on the acquired signal.According to the physical property index model,a two-layer array swept sensor and a geophysical detector were designed,and the corresponding data processing program was developed.After field test,the instrument was sensitive to the integrity of the formation and the reaction of the water-rich zone.It could detect and identify the goaf,underground engineering,geological structure and water-rich zone to achieve fine detection of the geological target.