Transient electromagnetic detection method for determining geo-electrical interface based on field transformation

Abstract

Provided is a transient electromagnetic detection method for determining a geo-electrical interface based on field transformation. The method comprises the following steps: a) finishing emission of a transient electromagnetic primary field signal and reception of an induction secondary field signal, and keeping the obtained transient electromagnetic field information data; b) converting data of each transient electromagnetic detection point into wave field data, and keeping the obtained wave field data; c) displaying a wave field curve of each detection point under the condition of a wave field; d) calculating depth of the wave field data corresponding to different time according to propagation velocity of an equivalent vortex ring of the transient electromagnetic field; e) with the depth being a horizontal axis and amplitude being a vertical axis, drawing a waveform image of each detection point in the depth direction and carrying out imaging; and f) according to the imaging result, determining the boundary of a vertical amplitude abnormity obvious area as the geo-electrical interface. The method can eliminate adverse influences of a volume effect on result interpretation, improves accuracy of determination of the geo-electrical interface and meets detection requirements.

Description

technical field [0001] The invention relates to a transient electromagnetic detection method, in particular to a transient electromagnetic detection method for determining the geological electrical interface based on field transformation. Background technique [0002] The transient electromagnetic detection method is a detection method that uses an ungrounded return line or a grounded line source to emit a pulsed magnetic field underground, and uses a coil or a grounding electrode to observe the secondary induced eddy current field caused in the underground medium during the intermittent period of the first pulsed magnetic field. At present, it is widely used in the fields of head-on advance in ground and underground coal mine excavation, roadway roof and floor, working face roof and floor, and side water damage detection. However, due to the volume effect of the transient electromagnetic detection method, the accuracy of the detection and interpretation of the geological el...

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Problems solved by technology

However, due to the volume effect of the transient electromagnetic detection method, the accuracy of the detection and interpretation of the geological electrical interface is low, and the detection requirements cannot be met.

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