Development and Application of Large-depth and Multi-function Electromagnetic Survey System

The large-depth, multi-function electromagnetic survey system is a kind of geophysical measurement system developed independently by Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences for more than ten years. It is suitable for resources and energy exploration, urban underground space exploration, deep geological structure exploration and three-dimensional geological mapping and other fields. The system is composed of the multi-function electromagnetic detection equipmentthe techniques for data acquisition and processing and the software for electromagnetic two or three dimensional positive inversion simulationAdopting distributed control, high precision GPS synchronization, large dynamic range 24-bit A/D sampling, single-frequency and multi-frequency waveform combination, m-sequence pseudo-random signal transmission, we have solved a series of key technology such as: accurate synchronization between instruments, self-calibration of instrument performance parameters, consistency & stability & reliability of instrument, and establishment of ultra-high power field source system. Accordingly the matched anti-jamming multi-parameter data extraction and processing interpreting technology of the multi-function electromagnetic system have been successfully re- solvedThe system has the measurement function of AMT, MT, CSAMT, CSEM and IPIts main technical index has reached the international level, such as the maximum power of high-power emission reaches 160 kW, and the receiver achieves multi-point coverage and high sensitivity synchronous observation. A good result has achieved in comparative trail between the system and the similar instruments abroad. As a resultwe have also made progress using the self-developed system in typical mine areas, Geological survey of the covered area, as well as geothermal, oil and gas resources and energy survey.