Time-varying Mixed-Phase Seismic Wavelet Extraction Method Based on Time-Spectrum Simulation

Abstract

The invention discloses a time-varying mixed-phase seismic wavelet extraction method based on time-frequency spectrum simulation, which is characterized in that: on the basis of generalized S-transformation improved on non-stationary seismic records, a time-frequency filter is introduced for the first time to the seismic records The time-frequency spectrum is filtered, and then the spectrum simulation method is used to estimate the wavelet amplitude spectrum at each moment. Under the assumption that the wavelet phase is time-invariant, the high-order cumulant bispectral method is used to remove the time-varying wavelet amplitude spectrum. The mixed phase spectrum of the wavelet is reconstructed from the seismic record, and finally the amplitude spectrum and the phase spectrum are combined to realize the extraction of the time-varying mixed phase wavelet. Compared with the conventional segmentation extraction method, the time-varying wavelet extraction method proposed by the present invention does not require the assumption that the wavelet is segmentally stable, and can accurately estimate the time-varying wavelet when there is a large change in the wavelet properties of adjacent layers , and the extraction of mixed phase of wavelet is more in line with the actual situation, it can analyze and process seismic data more finely and accurately, and has good application value in improving the resolution of 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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