Frequency Domain Electromagnetic Prospecting Method Based on Horizontal Electric Field and Magnetic Field to Obtain Resistivity

Abstract

The invention discloses a frequency-domain electromagnetic prospecting method based on a horizontal electric field and a magnetic field to obtain resistivity, comprising the following steps: S1, laying out an observation device: including a transmitter, two power supply electrodes A and B, and a measuring point with measuring electrodes , a receiver capable of simultaneously observing electric and magnetic fields; S2, making the observing device work normally, and the measuring equipment receives the electromagnetic response signal fed back from the measuring point, and sends it to the processing device; S3, the processing device according to the electromagnetic response signal , calculate the apparent resistivity of different frequencies at the location of the measuring point, and obtain formation information through qualitative analysis and quantitative calculation. Since this method has no azimuth restrictions on the electric field and magnetic field, it can realize electromagnetic ground detection with a wide azimuth angle, which greatly improves the efficiency of field construction; secondly, its apparent resistivity is strictly defined based on the electric field and magnetic field component formulas, which can not only accurately reflect geoelectric information, And it can eliminate the influence of field source emission efficiency on electromagnetic sounding.

Description

technical field [0001] The invention relates to the technical field of electromagnetic prospecting in the field of prospecting geophysics, in particular to a frequency-domain electromagnetic prospecting method based on horizontal electric fields and magnetic fields to obtain resistivity. Background technique [0002] The traditional artificial source electromagnetic method (CSEM) either simplifies the electromagnetic field formula or uses a single component when defining the apparent resistivity. For the controlled source audio frequency magnetotelluric method (CSAMT), the Carnia formula is used to calculate the apparent resistivity, and the high-order term of the electromagnetic field component is discarded, which is only suitable for far-field observations; secondly, two orthogonal electric and magnetic fields need to be strictly measured The weight restricts the efficiency of field construction and causes unnecessary human errors. [0003] For the wide-field electromagne...

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Problems solved by technology

[0003] For wide-field electromagnetic method (WFEM), any single component can be used to obtain apparent resistivity parameters, and it can be measured in a wide area. Its measurement range and exploration depth have greater development than CSAMT, but it is also subject to the influence of field source emission efficiency.

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