Broad earthquake wave impedance low-frequency information prediction method and system

Abstract

The invention discloses a broad earthquake wave impedance low-frequency information prediction method, comprising the steps of utilizing broadband overlapped earthquake information and earthquake wavelet to establish complex frequency domain earthquake impedance calculation; utilizing Bayesian inversion theory to calculate initial target function of earthquake wave impedance according to positive calculation of complex frequency domain earthquake impedance; adding initial model constraint to initial target function of earthquake wave impedance to get low-frequency prediction target function and work out the low-frequency prediction target function to get earthquake wave impedance low-frequency information. The method is only utilizes broadband earthquake materials to realize low-frequency prediction of earthquake wave impedance, that is to say, shaft information constraint is not required to measure, and low-frequency information prediction result can still be obtained if complicated geological conditions such as lenticle and strong change of physical property exist. The invention also discloses a broad earthquake wave impedance low-frequency information prediction system, having the above beneficial effect.

Description

technical field [0001] The invention relates to the field of oil and gas seismic exploration, in particular to a method and system for predicting low-frequency information of broadband seismic wave impedance. Background technique [0002] Seismic wave impedance inversion is the main way to obtain the wave impedance of subsurface medium. The low-cut frequency range of conventional seismic data is generally 8-10 Hz, lacking low-frequency components. When seismic inversion is used to obtain subsurface medium wave impedance, it is generally necessary to use logging data to establish an initial low-frequency model of elastic parameters. The initial low-frequency model directly affects the rationality and reliability of pre-stack seismic inversion results. [0003] At present, the establishment method of the initial low-frequency model of elastic parameters is mainly based on seismic interpretation horizons or sedimentary facies as lateral constraints, and the elastic parameters ...

AI Technical Summary

Problems solved by technology

However, it is difficult to use this method to establish an effective model when there are complex geological conditions such as lenses or drastic changes in physical properties between wells, especially when the well information is relatively sparse during the exploration stage.

Therefore, how to overcome the shortcomings of conventional low-frequency information prediction methods that cannot be accurately predicted under complex geological conditions such as lenses between wells or drastic changes in physical properties is a technical problem to be solved by those skilled in the art

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