Intersection determination method of sensitive reference frequency in AVO frequency dispersion parameter inversion depending on frequency

Abstract

An intersection determination method of a sensitive reference frequency in AVO frequency dispersion parameter inversion depending on a frequency is an oil-gas seismic exploration data processing and interpretation technology. Intersection analysis is used to directly guide a selection method of a sensitive reference frequency in the AVO frequency dispersion parameter inversion depending on the frequency. Firstly, in a seismic effective frequency band scope, all frequencies are used to carry out vertical and horizontal wave frequency dispersion property parameter inversion on pre-stack angle gathering; then known logging interpretation data is fully used to carry out constraint and a vertical and horizontal wave frequency dispersion property of all the frequencies containing a fluid reservoir section is projected to a frequency-frequency dispersion property intersection plane graph; finally through intersection analysis, a frequency corresponding to a vertical and horizontal wave frequency dispersion property parameter maximum value containing a fluid reservoir and a frequency or a frequency range corresponding to a condition when a vertical and horizontal wave frequency dispersion property difference of different fluid reservoirs is maximum are determined. The above frequency and the above frequency or the above frequency range are a sensitive characteristic frequency. The frequency is taken as a sensitive optimal reference frequency so as to carry out the AVO vertical and horizontal wave frequency dispersion property parameter inversion depending on the frequency on the pre-stack angle gathering. Therefore, seismic frequency dispersion abnormity containing the fluid reservoir can be protruded maximumly and the frequency dispersion difference of the different fluid reservoirs can reach a maximum value so that distinguish and identification of different fluids are realized.

Description

technical field [0001] The invention relates to the field of oil and gas seismic exploration data processing and interpretation, and is a method to determine the reference frequency of the inversion through the intersection analysis method in the frequency-dependent AVO dispersion parameter inversion, so as to use this frequency as a sensitive reference frequency, and to Dispersion parameter inversion is performed on seismic prestack angle gathers to maximize the difference in seismic P- and S-wave dispersion when reservoirs contain different fluids, to distinguish different fluid reservoirs to the greatest extent, and to highlight the seismic dispersion anomalies of oil and gas reservoirs. Background technique [0002] AVO (Amplitude Versus Offset) uses the Zoeppritz equation to describe the variation of seismic wave reflection amplitude with incident angle (or offset), and is used to extract information about reservoir lithology, physical parameters and pore fluid. The tra...

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Problems solved by technology

However, at present, in the process of frequency-dependent AVO dispersion inversion using seismic pre-stack angle gathers, the method of selecting the reference frequency is usually the "manual observation method": first, the instantaneous spectral decomposition of the post-stack seismic data in the work area is performed, and several Common frequency profile, manually observe the characteristics of the instantaneous spectrum energy of the known oil and gas reservoirs changing with different frequencies in the common frequency profile, generally choose the frequency that is close to the main frequency of seismic data and the corresponding frequency of the oil and gas reservoir instantaneous spectrum energy is relatively strong as the reference frequency , this determination method is prone to strong human subjectivity; in addition, the dispersion anomaly information of different fluids reflected in the pre-stack angle gathers is easily distorted or weakened in the post-stack seismic data, so the use of post-stack data is not conducive to accurate Determining the more hydrocarbon-sensitive reference frequencies in prestack angle gather seismic data limits the accuracy and reliability of frequency-dependent AVO dispersion parameter inversions

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