A high-amplitude shielding layer rejecting method based on seismic data instantaneous attributes

Abstract

The invention relates to a high-amplitude shielding layer rejecting method based on seismic data instantaneous attributes. The method is characterized by comprising the following steps: 1), fine interpretation of a high-amplitude shielding layer is carried out in terms of data after stack or offset; 2), the interpreted high-amplitude shielding layer is regarded as a center; a time window is designed, and seismic data in the time window is intercepted; time and amplitude information of the interpreted high-amplitude shielding layer is obtained, and the seismic data in the time window is subjected to Hilbert conversion to obtain frequencies and phases forming wavelets of the high-amplitude shielding layer; average wavelets are obtained through well seismic calibration; according to correlation coefficients between the average wavelets and different scale parameter theoretical wavelets, the scale parameters of the average wavelets are determined; Morlet wavelets approximating the high-amplitude shielding layer is constructed one by one; and 4) differences between a data body of the 1) step and the Morlet wavelets obtained in the 3) step are calculated one by one to obtain seismic records in which the high-amplitude shielding layer is rejected. In the invention, influences by the high-amplitude shielding layer in a seismic profile on the processed data can be effectively eliminated.

Description

technical field [0001] The invention belongs to the field of seismic data analysis and processing in oil and gas exploration, and relates to a seismic data processing method, in particular to a method for eliminating strong-amplitude shielding layers based on the instantaneous attributes of seismic data. Background technique [0002] There are often strong reflection axes in the actual seismic section, such as strong biological limestone reflection, strong coal seam reflection, etc. They are all formed due to the excessive difference in wave impedance between the upper and lower strata of the reflection layer, and because the amplitude of these strong amplitude events is too large , relatively speaking, the event energy below it will be relatively weaker, this is the shielding effect of the strong-amplitude energy event on the weak-amplitude energy-amplitude event. In seismic data interpretation, the traditional method for describing thin reservoirs under strong-amplitude sh...

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Problems solved by technology

[0003] At present, the existing methods for eliminating strong-amplitude shielding axes are all based on the multi-wavelet decomposition theory. The methods used in conventional seismic signal processing all assume that the seismic wavelet is single and fixed. This theoretical assumption is far from the actual situation. It often brings some unavoidable problems: the seismic records based on this assumption may cause some effective information with weak energy to be lost; at the same time, in the traditional filtering method, due to the overlapping part of the frequency of the interference wave and the effective wave, when filtering out the interference At the same time as the signal, the effective signal will also be attenuated to varying degrees

Although the above methods can reconstruct the strong shielding axis through multi-wavelet decomposition, if the above algorithm is only introduced into the strong amplitude shielding axis elimination, it does not make full use of the strong energy of the strong amplitude shielding axis, which is easy to distinguish in the section. characteristics, and the calculation efficiency is also low

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