Static effect correction method and system based on magnetotelluric sounding

Abstract

The invention relates to a static effect correction method and system for magnetotelluric sounding. The correction method comprises the following steps: acquiring a magnetotelluric signal to be processed, wherein the magnetotelluric signal comprises five mutually orthogonal to-be-processed signals, and performing empirical mode decomposition on each to-be-processed signal to obtain a multi-order intrinsic mode function component corresponding to each to-be-processed signal; according to the multi-order intrinsic mode function component corresponding to each to-be-processed signal, determininga multi-order principal component of each to-be-processed signal by adopting a principal component analysis method; determining an effective signal component of each to-be-processed signal by adoptinga canonical correlation analysis method according to the multi-order principal components of all the to-be-processed signals; and reconstructing according to the effective signal component of each path of to-be-processed signal to obtain each path of corrected to-be-processed signal. According to the method, the static effect can be corrected, and the quality of the reconstructed signal is improved.

Description

technical field [0001] The invention relates to the field of signal correction, in particular to a static effect correction method and system based on magnetotelluric sounding. Background technique [0002] Magnetotelluric sounding (Magnetotelluric sounding, MT) is a geophysical exploration method that inverts the electrical structure of the subsurface by measuring mutually orthogonal electromagnetic field components on the surface. This method has the advantages of low economic cost, portable instrument, and large detection depth. However, when using magnetotelluric sounding to explore the underground geological structure, if there are uneven two-dimensional or three-dimensional geological bodies in the shallow strata, and the electromagnetic wave wavelength is much larger than the geometric size of the uneven body, a charge accumulation effect will be formed on the surface of the uneven body , so that the electric field is distorted, and the apparent resistivity curve ris...

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Problems solved by technology

[0004] Although the above traditional methods are theoretically feasible, when dealing with the field measured data of the magnetotelluric sounding, due to the complex and changeable underground structure, the smooth processing and correction method based on the assumption of a gentle change in the electrical structure in a large area is compatible with The correction method of the measurement results of adjacent measuring points often filters out the real underground fractures and steep deep anomalies

In addition, the method of using phase information to inversely calculate the apparent resistivity needs to ensure that the phase expression in the integration interval can be known, but the complex electrical structure in the field often cannot guarantee this, so this method is also limited to dealing with uniform underground electrical properties. , the case of simple construction

The correction method based on magnetic track information is different from the above three methods. The application effect of this method is not affected by the complexity of the underground structure. However, using the magnetic track data alone to estimate the underground electrical information needs to be carried out under the premise of known field source information. , so this method is limited to the correction of Controlled-Source Audio Magnetotelluric (CSAMT) results, and is not applicable to the magnetotelluric sounding method using natural field sources

In addition to the above, since these four types of traditional methods are only for static effects, the existence of other types of noise in magnetotelluric sounding will also interfere with the application effect of these methods

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