Method and system for prestack seismic trace q compensation in frequency domain

Abstract

A frequency domain pre-stack seismic trace Q compensation method and system are disclosed. The method may include: calculating the frequency spectrum and normal moveout of the offset pre-stack seismic trace, setting the regularization parameter, regularization operator and initial Q value; for each reflection point of the offset pre-stack seismic trace, performing the following Described steps: Step 1: Obtain the offset pre-stack seismic trace after compensation for each offset of the reflection point; Step 2: Determine the offset pre-stack after compensation for each offset of the reflection point Whether the frequency spectrum of the seismic trace meets the set standard, if not, use the updated Q value as the initial Q value, and repeat steps 1‑2. The present invention directly obtains the compensated seismic trace by adopting the least square regularization inversion method, the calculation is simple and the compensation amount is small, and the formation Q compensation based on the normal time difference of reflected waves for pre-stack seismic traces with different offsets is directly realized.

Description

technical field [0001] The present invention relates to the field of seismic exploration, more specifically, to a method and system for pre-stack seismic trace Q compensation in the frequency domain. Background technique [0002] Energy attenuation and accompanying velocity dispersion in the process of seismic wave propagation are the basic characteristics of seismic wave propagation in underground media. Energy attenuation causes the amplitude of seismic waves to decrease with the increase of propagation time and frequency, and the velocity dispersion associated with energy attenuation causes the phase of seismic waves to change with the change of propagation time, and seismic wavelets have wavelet stretching, phase distortion, etc. Phenomenon. The attenuation theory proposed by Futterman (1962) and Kjartansson (1979) - the constant Q model (Q is the formation quality factor), which laid the theoretical foundation for the Q compensation of seismic data. In seismic explora...

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Problems solved by technology

The existing prestack seismic gather formation Q compensation method is mainly aimed at the Q absorption compensation of the whole process of seismic wave ray propagation, using the recursive method of wave field continuation compensation point by point (layer) according to time (depth), and the formation Q The requirements for the establishment of the sum and velocity are high, and the recursive process is prone to large cumulative errors. Due to the large compensation distance of seismic waves, the stability and accuracy of the compensation results are difficult to effectively guarantee (Wang.Y.H(2008), SEISMIC INVERSE Q FILTERING[M], First published 2008 by Blackwell Publishing Ltd)

Although Li Guofa et al. (Petroleum Geophysical Exploration, 2014, 49(1): 89-94.) proposed the influence of formation absorption related to offset on AVO analysis and its compensation method, only compensation related to offset Attenuation, the stability of compensation is improved by reducing the compensation distance, but the recursive method of wavefield continuation and point-by-point (layer) compensation based on time (depth) is still used. When the formation Q is small, the signal-to-noise ratio of seismic data is low , the cumulative error problem generated by the recursive process is still difficult to ignore

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