大地电磁测深三维反演系统及应用

3D Inversion System of Magnetotelluric Sounding and its Application

大地电磁测深是基于电磁感应原理,在地表采集正交的电、磁场来研究地壳乃至上地幔电性结构的地球物理方法,后期衍生出采集高频天然场信号的音频大地电磁测深和采集人工源信号的可控源大地电磁法。此类方法在深部构造研究、矿产资源勘查、油气资源探测等多领域得到了广泛应用。近几年来,虽然其野外工作趋近三维勘探水平,但其采集数据的处理和三维反演研究仍然存在不足,限制了地质解释的准确度和效率。针对这些问题,我们开发了大地电磁测深的三维反演软件系统,系统主要分为静位移校正、三维反演的初始模型构建和三维反演3个模块,有效地解决了数据处理中的静位移问题和数据解释中的三维反演问题,并且其中涉及的很多算法改进了现有技术,在计算精度、计算效率和成本节约方面有很大优势,具有良好的应用前景。

Magnetotelluric is a geophysics exploration method for studying the crust and upper mantle electrical structure, which measures the surface orthogonal electric and magnetic fields based on the electromagnetic induction and natural electromagnetic fields. Thereafter, the audio-frequency magnetotelluric method which collects the high frequency domain of natural field and controlled source audio-freguency magnetotelluric method which collects artificial source are derived. These methods are widely used in deep structure study, mineral resources exploration, oil and gas exploration, and so on. Though the field work achieves 3D level in recent years, 3D data processing and inversion are insufficient and the efficiency and accuracy of interpretation is limited. To solve these problems, we develop the 3D inversion system of magnetotellurie sounding which contains static shift correction, initial model design and 3 D inversion. The system effectively solves the static shift of data process and 3D inversion problem. A lot of algorithms in the system are improved which have advantages on calculation accuracy, efficiency and cost savings. And the system has a good application prospect.