Transient electromagnetic method

- Apr 11, 2019-

Transient electromagnetic method is to use a non-grounded return line or a grounding wire source to emit a pulsed magnetic field to the ground. During a pause of a pulsed magnetic field, the secondary induced eddy current field caused by the underground medium is observed by a coil or a grounding electrode to detect the dielectric resistivity. One way. The basic working method is to set a transmitting coil with a certain waveform current on the ground or in the air, thereby generating an electromagnetic field in the surrounding space and generating an induced current in the underground conductive rock ore body: after the power is turned off, the induced current is lost due to heat loss. And decay with time.

Transient electromagnetic detection has the following advantages

(1) Due to high construction efficiency, pure secondary field observation and sensitivity to low-resistance bodies, it has become the preferred method in current coalfield hydrogeological exploration;

(2) Transient electromagnetic method is the most sensitive method for finding low-resistance geological bodies in high-resistance surrounding rock, and has no terrain effect;

(3) Using the same point combination observation, it has the best coupling with the detection target, the abnormal response is strong, the shape is simple, and the resolution ability is strong;

(4) The profile measurement and sounding work are completed at the same time, providing more useful information.