Transient electromagnetic receiving coil observation potential correction method for spherical geologic body based on RL circuit

Abstract

The invention relates to a transient electromagnetic receiving coil observation potential correction method for a spherical geologic body based on an RL circuit, and belongs to the technical field ofgeological exploration. The method comprises the steps: carrying out the outdoor observation of a transient electromagnetic instrument which takes a receiving coil as a probe, and obtaining an observation potential VR of the receiving coil; carrying out the index fitting of observation time t for the observation potential VR, and obtaining a fitting expression of the observation potential VR; solving the VR first-order derivative (shown in the description) of the fitting expression of the observation potential VR to the observation time t, and obtaining the expression of the inductance potential VL of the receiving coil and the expression of an internal resistance potential Vr of the receiving coil through the observation potential VR and the VR first-order derivative (shown in the description); substituting the fitting expression of the observation potential VR, the expression of the inductance potential VL of the receiving coil and the expression of the internal resistance potentialVr of the receiving coil into a formula: Vi=Vr+VL+VR, and obtaining the expression of the inductance potential Vi of the geological body; substituting the observation time t into the expression of theinductance potential Vi, and calculating the inductance potential Vi. The method can improve the precision of the observation data of a transient electromagnetic method.

Description

technical field [0001] The invention relates to a method for correcting the observed potential of a transient electromagnetic receiving coil based on an RL circuit of a spherical geological body, and belongs to the technical field of geological exploration. Background technique [0002] Time-domain transient electromagnetic method, also known as transient electromagnetic method, abbreviated as TEM, is an artificial source electromagnetic detection method based on the principle of electromagnetic induction. Transient electromagnetic is widely used in resource exploration, engineering geophysical prospecting, hydrological prospecting and other fields, and is a widely used geophysical prospecting method. Most current TEM systems use the potential V across the matched resistor R As an observation potential to approximately replace the induced voltage Vi of the geological body on the receiving coil, this substitution is mathematically wrong, and it will produce a huge data error...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the deficiencies of the prior art, the present invention provides a method for correcting the observation potential of a spherical geological body based on a transient electromagnetic receiving coil based on an RL circuit, so as to solve the problem of matching the resistance at both ends of the receiving coil when using the transient electromagnetic method to detect underground geological bodies. The observation potential replaces the induced potential of the underground spherical geological body on the receiving coil, resulting in poor detection results

In order to obtain the induced potential Vi of the spherical geological body, the present invention adopts the exponential fitting method to obtain the observation potential V of the receiving coil R The fitting formula, thus avoiding the V R The unknown parameters contained in the theoretical expression solve the problem of poor detection accuracy caused by substituting the observed potential for the induced potential of the underground spherical geological body on the receiving coil

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