VSP seismic data frequency-varying Q value estimation and inverse Q filtering method

Abstract

The invention provides a VSP seismic data frequency-varying Q value estimation and inverse Q filtering method, which is characterized by firstly transforming a seismic record signal to a time-frequency domain by utilizing generalized S transformation; constructing a quadratic polynomial fitting relationship between a time-frequency spectrum ratio and an inverse quality factor Q-1 value for each frequency, and when a frequency Q value is calculated, calculating a spectrum ratio change slope in a small frequency interval taking the frequency as a center to obtain a central frequency Q value soas to realize VSP data frequency change Q value estimation; based on an inverse Q filtering method which is provided by Hale based on a Futterman mathematical model and uses series expansion as approximate high-frequency compensation, obtaining a relationship between the inverse Q filtering output frequency spectrum and the input seismic record frequency spectrum, the quality factor and the frequency and Hilbert transform, and revising a constant Q value in the relationship into a frequency-variable Q value to realize inverse Q filtering of the frequency-variable Q value. According to the method, the oil and gas reservoir can be predicted by utilizing the Q-value frequency dispersion attribute, and meanwhile, the imaging resolution and the signal-to-noise ratio are improved.

Description

technical field [0001] The invention relates to a Q value (quality factor) analysis and energy compensation method of VSP (vertical seismic profile method) seismic records, in particular to a frequency-varying Q value estimation and inverse Q filtering method for VSP seismic data. [0002] technical background [0003] In seismic exploration of oil and gas reservoirs, mineral resources, engineering geology and environmental geology, seismic wave attenuation, that is, quality factor Q value analysis technology, is an important and necessary link in seismic data processing and interpretation. VSP seismic exploration is a well-ground combined seismic exploration, which plays an irreplaceable and important role in seismic imaging and attribute extraction. The quality of Q value calculation and inverse Q filtering directly affects the VSP seismic imaging accuracy and seismic attribute interpretation. At the same time, the quality factor Q of seismic wave propagation, as an import...

AI Technical Summary

Problems solved by technology

However, the current research on VSP seismic Q value analysis technology has not yet reported frequency-dependent Q-value extraction and frequency-dependent inverse Q filtering technology. The method of Q value extraction and energy compensation (inverse Q filter), such as the method of estimating medium quality factor using zero-offset VSP data[J], Acta Geophysics, 2007,50(4):1198-1209., and time-based Quality factor estimation of variable wavelet[J], Petroleum Geophysical Exploration, 2018, 53(1): 136-146.

In fact, the Q value parameter obtained by frequency-independent Q value estimation and inverse Q filtering method does not change with frequency, and the energy compensation does not consider the dispersion effect of Q value, which will lead to insufficient deep energy compensation in VSP seismic data imaging, and even The waveform is distorted, and at the same time, the frequency-varying characteristics of the Q value cannot be better used for oil and gas indication analysis

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