Abstract:

The research of receiving the electromagnetic waves in Super Low Frequency (SLF) from the depth of the Earth has become a hot international issue in recent years. This paper introduces the field experiments and applications of the passiveexploration technology of SLF. Owing to its portability, simple surveying line arrangement, being little affected by the terrain and being sensitive both to low resistance and high resistance bodies, the passive SLF explorer presents a good performance and great development potential in the resource explorations. In this paper, the field experiments of passive SLF and the level of the technical specifications of SLF sensor are introduced first. From the introduction, we can see that the BD6 type of passive SLF electromagnetic detector has been improved greatly, such as the spectral resolution, SNR, the detection efficiency, etc. Furthermore, the influence of the source effects, the frequencydepth conversion and the resolution in the data acquisition and processing are also analyzed. Based on those analyses, we propose that the random noise caused by the source can be reduced by means of averaging the data, that the frequency depth conversion algorithm revised by the known geological and drilling data is more applicable to the data interpretation of some regions or targets, such as the coalbed methane, the groundwater, etc., and that the use of linear or nonlinear method (spectral analysis method or the fractal dimension method) is a new way for the data processing and interpretation.

Key words: passive SLF electromagnetic exploration, problem, data collection, data processing