Viscoelastic medium seismic inversion method based on Zoeppritz equation

Abstract

The invention provides a viscoelastic medium seismic inversion method based on a Zoeppritz equation. The method comprises the following steps: acquiring seismic data and logging data; obtaining angle-dependent seismic wavelets according to the obtained seismic data; obtaining prior data of a geologic horizon model according to the obtained logging data; obtaining geologic horizon model parameter initial values according to the obtained prior data; obtaining geologic horizon model parameters according to the obtained geologic horizon model parameter initial values, the angle-dependent seismic wavelets and a preset viscoelastic medium Zeoppritz reflection coefficient equation, and obtaining an inversion result according to the obtained model parameters; according to the method, inversion is carried out based on the accurate Zeoppritz equation of a seismic pre-stack viscoelastic medium AVO, the inversion calculation precision is high, the inversion parameter purposiveness is high, and accumulative errors caused by step-by-step inversion or indirect calculation are avoided.

Description

technical field [0001] The present disclosure relates to the technical field of seismic inversion, in particular to a method for seismic inversion of viscoelastic media based on the Zoeppritz equation. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] Seismic inversion is an effective method to obtain internal images of subsurface media and describe reservoirs in detail, and it is also the final form of high-resolution seismic exploration. Seismic data inversion greatly improves the value of reservoir characterization. As the focus of seismic research shifts from exploration to development, and from conventional oil and gas to unconventional oil and gas, especially shale gas, the fine distribution characteristics of underground oil and gas reservoirs are revealed through seismic inversion and other means, and the oil and gas reservoirs Th...

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Problems solved by technology

[0004] The inventors found that the linear inversion method based on the approximate Zoeppritz equation can stably solve ill-conditioned inversion problems or local extremum problems. large error, failed to make full use of the rich pre-stack information, and could not meet the fine characterization requirements of actual reservoirs in terms of inversion accuracy, especially for actual 3D large offset seismic data

For isotropic viscoelastic media, the traditional approximate reflection coefficient based on the Zoeppritz equation is an expression that includes elastic parameters and attenuation factors. Although it can be re-expressed as a linear expression of five model parameters through equivalent rewriting, the five unknown The ill-conditioned inversion problem caused by the parameter limits the application of the method

Moreover, the elastic parameters obtained by conventional inversion are difficult to directly characterize the attenuation characteristics caused by reservoir fluid, and step-by-step inversion or indirect calculation will introduce cumulative errors

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