A method for frequency extension processing of pre-stack crp gathers

Abstract

The invention provides a method for pre-stack CRP trace gather frequency-broadening processing. The method can maintain a good signal to noise ratio while improving the resolution of a seismic time profile according to spectrum characteristics of seismic waves, and can enable the resolution and the signal to noise ratio to be well combined. The method comprises the following steps of step one: using logging information and seismic traces by a well to perform inversion of a target layer section; step two: calculating a seismic wavelet according to the target layer number in the step one; step three: calculating the energy and frequency distribution range of an initial CRP trace gather; step four: obtaining the type of noise according to the energy and frequency distribution range of the initial CRP trace gather; step five: selecting a typical trace and determining an effective wave main energy distribution space; step six: determining a CRP frequency-broadening operator according to the energy and frequency distribution range of the initial CRP trace gather and the effective wave main energy distribution space; and step seven: performing CRP trace gather frequency-broadening processing according to the seismic wavelet, the type of noise and the CRP frequency-broadening operator. The method can maintain a good signal to noise ratio, and is high in reliability, good in stability and substantial in effect.

Description

technical field [0001] The invention belongs to the field of oilfield exploration, and relates to a gather processing method, in particular to a CRP gather frequency extension processing method, in particular to a pre-stack CRP gather frequency extension processing method. Background technique [0002] With the improvement of exploration and development of peripheral oilfields, seismic data processing objects are becoming more and more complex, especially Fuyang oil layer, with complex oil-water relationship, scattered distribution of sand bodies, thin thickness, no obvious response in seismic data, especially T2 The "shielding effect" of the reflective interface screen should be particularly prominent, and it is difficult to describe the spatial distribution characteristics of thin reservoirs in terms of seismic attributes. How to improve the seismic prediction accuracy of such reservoirs has always been the "bottleneck" problem faced by oilfield exploration and development ...

AI Technical Summary

Problems solved by technology

[0003] As a new method of reservoir prediction, pre-stack inversion has been popularized and applied in oil fields at home and abroad. Many theoretical methods of pre-stack inversion are mainly various approximate expressions for Zoeppritz equations. The basic process is to use CRP gather data , it is impossible to obtain high-quality CRP gather data using traditional processing techniques. How to improve the resolution of pre-stack seismic data has become a hotly discussed issue. The resolution of seismic data is low, which is manifested in the frequency domain. missing; although the "spectral whitening" processing and "blue spectrum correction" processing methods that have been developed can better solve the problem of insufficient high-frequency components in the "effective bandwidth" of seismic data, those frequencies outside this frequency band However, it must be compensated by some method;

[0004] The traditional CRP gather processing technology cannot solve the problem of maintaining a good signal-to-noise ratio and resolution on the seismic time section. The traditional CRP gather processing is only to improve the signal-to-noise ratio on the seismic time section. This approach is a loss Many effective frequency components of the seismic wave are eliminated. The result obtained by the traditional method is that the signal-to-noise ratio is improved, but the signal-to-noise ratio is greatly reduced.

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