Seismic wave attenuation compensation method in curvelet domain

Abstract

The invention relates to a seismic wave attenuation compensation method in a curvelet domain. The method comprises the following steps of (1) collecting a seismic signal and carrying out preprocessing to obtain a time domain signal x(t) of an earthquake, (2) carrying out curvelet transform on the time domain signal x(t) to obtain a curvelet domain signal psi j, l (omega j, Tk), (3) carrying out smoothing process on the curvelet domain signal psi j, l (omega j, Tk) to obtain a curvelet coefficient Phi j, l (omega j, Tk), (4) carrying out threshold iterative processing on the curvelet coefficient Phi j, l (omega j, Tk) to obtain a denoised signal Psi j, l (omega j, Tk), (5) carrying out pointwise recursion to obtain the deep and shallow layer energy ratio delta j, ll (omega j, Tk) of the denoised signal Psi j, l (omega j, Tk) in each frequency band compensation angle, (6) calculating all frequency band compensation factor coefficient matrices Dj, ll (omega j, Tk) in a compensation angle, (7) weighing the reciprocal values of the compensation factor coefficient matrices Dj, ll (omega j, Tk) in all frequency band compensation angles to obtain a signal Cj, l (omega j, Tk) after curvelet wave weighing, (8) carrying out inverse curvelet transform on the signal Cj, l (omega j, Tk) after the curvelet wave weighing to obtain a time domain signal xx(t) after frequency division directional compensation. The method can be widely applied to the seismic data processing.

Description

Technical field [0001] The invention relates to a seismic data processing method used in the process of petroleum exploration, in particular to a seismic wave attenuation compensation method in the curved wave domain. Background technique [0002] In the process of petroleum exploration, the absorption of seismic waves by the formation causes the source wavelet time variation, which reduces the resolution of the data, especially for deep-seated signals. Due to the low-pass filtering of the formation, high-frequency signals are attenuated seriously. Therefore, the reflected signals at different depths and their frequency bands recorded on the surface can no longer reflect the true underground conditions, which affects the subsequent processing and interpretation of seismic data, and also affects the accuracy of petroleum exploration results. In order to improve the resolution of seismic data, it is necessary to absorb and compensate the seismic wave attenuation. [0003] At present...

AI Technical Summary

Problems solved by technology

These three methods use time-frequency analysis and seismic wave attenuation characteristics to obtain the formation absorption coefficient, which can eliminate the time-varying influence of seismic wave attenuation on seismic records to a certain extent and improve the resolution of seismic data. There are certain requirements, while compensating for seismic wave attenuation, it also enhances the energy of noise and random interference

[0005] To sum up, the existing technologies have deficiencies in the processing of seismic wave attenuation compensation. For example, the conventional spherical divergence and absorption attenuation compensation method can only compensate for the energy attenuation that changes with time, but cannot compensate for the absorption attenuation with frequency; The Q value of the inverse Q filtering method is not easy to be accurate, and the signal-to-noise ratio of the seismic signal is reduced while processing; the conventional spectral whitening method is difficult to maintain the amplitude; the single-channel or multi-channel deconvolution method cannot compensate the absorption attenuation change point-to-point; The analytical absorption compensation method has certain requirements on the signal-to-noise ratio of seismic data, and it increases the energy of noise and random interference while compensating for seismic wave attenuation.

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