Time-varying mixed-phase seismic wavelet extraction method based on time-frequency spectrum simulation

Abstract

The invention discloses a time-varying mixed-phase seismic wavelet extraction method based on time-frequency spectrum simulation. The method is characterized in that on the basis that improved generalized S transformation is carried out on a non-stationary seismic record, a time-frequency filter is introduced for the first time to filter a time-frequency spectrum of the seismic record, then a wavelet amplitude spectrum at each moment is estimated according to the spectrum simulation method, a mixed-phase spectrum of the wavelets is reconstructed in the seismic record with the time-varying wavelet amplitude spectrums removed according to the bispectrum method of high-order cumulants under the assumed condition that the phases of the wavelets are time-invariant, and the amplitude spectrums and the phase spectrum are combined to achieve extraction of the time-varying mixed-phase wavelets. Compared with a conventional stage extraction method, the time-varying wavelet extraction method has the advantages that the assumption that stages of the wavelets are stable is not needed, the time-varying wavelets can be accurately estimated even though the attributes of the wavelets at adjacent stages vary greatly, the mixed phase of the extracted wavelets is more consistent with the reality and seismic data can be analyzed and processed more finely and more accurately. The method has great application value in improving the resolution of the seismic data.

Description

Technical field: [0001] The invention belongs to the field of seismic signal processing. Background technique: [0002] Seismic wavelet estimation is one of the key issues in seismic signal processing, and it is the basis of seismic processing techniques such as seismic forward modeling, seismic inversion and deconvolution. The increasing difficulty of oil and gas exploration makes the requirements for seismic data processing and interpretation more stringent. In order to obtain high-resolution seismic data, non-stationary components in seismic records cannot be ignored. This is because under the action of formation absorption and filtering, the amplitude and energy of the wavelet are gradually absorbed during the propagation of the subsurface medium, and the high-frequency components are gradually attenuated. Therefore, the wavelet to be estimated has dynamic attenuation. In recent years, the time-varying wavelet Wave extraction has become an important research topic to b...

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Problems solved by technology

[0009] The present invention is characterized in that it fully retains the non-stationary components in the seismic records, and does not need to assume white noise for the reflection coefficient sequence, and solves the problem of large changes in the wavelet attributes of adjacent layers in the conventional segmentation extraction method , the problem of inaccurate wavelet estimation, to achieve more precise time-varying seismic wavelet estimation; the high-order bispectrum method is used to extract the mixed phase of wavelets, which broadens the assumption of zero phase or minimum phase of wavelets in traditional wavelet extraction methods , the extracted wavelet phase attributes are more realistic; in terms of improving the resolution of seismic data, this method does not need to study the dynamic attenuation mechanism of seismic records, and directly processes seismic data, avoiding error accumulation; the introduction of time-frequency filters, The time resolution is greatly improved, and the influence between adjacent reflective layers due to the dispersion phenomenon is eliminated during time-frequency analysis. On this basis, subsequent processing can be performed more accurately

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