Elliptic window direction band-pass amplitude-preserved filtering data processing method in geophysical prospecting

Abstract

The invention discloses an elliptic window direction band-pass amplitude-preserved filtering data processing method in geophysical prospecting technology. The method comprises the following steps: gridding the gravity and magnetic data by an interpolation method; performing supplementary edging by use of the low-precision gravity and magnetic data, and performing fast Fourier forward transform; rotating the coordinate system so that the filter has directivity; calculating an elliptic window function so that the filter is an elliptic window in the coordinate system of a wave number domain; calculating an initial Hanning window filter and compensating for the initial Hanning window filter; in the wave number domain, multiplying the spectrum of the gravity and magnetic data by a band-pass filtering frequency response function to obtain the filtered wave number domain result; and performing Fourier inverse transform and anti-edging processing to obtain the gravity and magnetic data subjected to band-pass filtering. In the invention, the signal of the filter in a pass band is subjected to amplitude preservation but is totally inhibited in a stop band; the gravity and magnetic abnormal low-frequency background and high-frequency noise can be suppressed, and an intermediate-frequency useful signal is highlighted; and the method is especially suitable for highlighting the intermediate-frequency useful signal in the wave number domain which is an elliptic window.

Description

technical field [0001] The invention relates to the technical field of geophysical exploration, in particular to a data processing method for band-pass amplitude-preserving filtering in the direction of an elliptical window in geophysical exploration. Background technique [0002] Geophysical prospecting includes gravity, magnetic force, electrical method, seismic prospecting, etc. Gravity and magnetic force are two geophysical methods with the earliest development, mature theory and wide application. Gravity and magnetic methods cover a wide area and are economical and fast, and are widely used in various fields such as oil and gas, solid mineral resource exploration, regional and deep structure research, environmental and engineering surveys, etc. Gravity and magnetic prospecting include three parts: data acquisition, processing and interpretation. [0003] Digital filtering is to filter signals in the case of digital signals. In signal digital processing, low-pass, high-...

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Problems solved by technology

There are three main problems with other filters other than compensating smooth filtering. One is that the filter is not a continuous function, that is, there is a sudden break between the passband and the stopband, which causes the Gibbs phenomenon; the other is that it is not suitable for highlighting in The wave number domain is an intermediate frequency useful signal with an elliptical window; the third is that the attenuation area between the passband and stopband of the filter is relatively large, and the passband and stopband are not completely separated. The in-band signal is not completely suppressed, which not only affects the subsequent qualitative analysis, but more seriously affects the quantitative analysis

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