Complicated medium seismic wave field continuation method with high precision and stable computation

Abstract

The invention relates to a complicated medium seismic wave field continuation method with high precision and stable computation, which is characterized in that a computational format of a space-wavenumber domain is built through combining a Fourier integral operator and a finite difference operator, and a computational format of a time domain is built through combining a symplectic algorithm after splitting. The complicated medium seismic wave field continuation method specifically comprises the steps of building an integral operator of the space-wavenumber domain so as to improve the applicability of a complicated medium; splitting the space-wavenumber domain integral operator so as to reduce the computation amount of a hybrid domain; building a finite difference computational format in the space direction and discretely solving a space partial derivative in seismic wave field continuation so as to improve the computation precision; and building a symplectic format and a Fourier finite difference computational format in the time direction so as to realize seismic wave field continuation with high precision and stable computation. The complicated medium seismic wave field continuation method can be applied to upgrading seismic exploration technologies such as seismic forward modeling, seismic imaging (reverse-time migration) and seismic inversion, and has important practical significance and application values for high-precision seismic exploration of complicated oil and gas reservoirs.

Description

technical field [0001] The invention belongs to the field of exploration geophysics, and in particular relates to a seismic wave field continuation method carried out by using a Siegel Fourier finite difference method. Background technique [0002] Seismic wavefield continuation is the basis of seismic forward modeling, seismic imaging (reverse time migration) and seismic inversion. The spectral method is one of the most commonly used seismic wavefield continuation methods, which has the characteristics of high precision and small numerical dispersion. Considering the variation of medium velocity in space, the spectral operator can be written as a Fourier-type integral on the space-wavenumber mixed domain, and the computation cost of directly solving this integral operator is about O(N 2 ), where N represents the number of grid points in the calculation area, such a large amount of calculation is unbearable in seismic exploration. In this regard, researchers have developed...

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Problems solved by technology

[0004] In order to solve the problems of unstable calculation and low precision in the continuation of wavefields with large time steps under complex media conditions, the failure of seismic forward modeling simulation and the distortion of seismic imaging results, etc., the present invention proposes a high-precision, stable calculation It is applicable to the continuation method of seismic wave field in complex media—the symplectic Fourier finite difference method. By using the symplectic algorithm to realize the discrete solution of time partial derivatives, the calculation stability is improved. By combining the Fourier integral operator and the finite The combination of differential operators realizes the discrete solution of spatial partial derivatives, improves the calculation accuracy and the applicability to complex media, and finally realizes the seismic wave field continuation with high precision and stable calculation, which can improve the stability of forward modeling technology in seismic exploration and improve the complexity. Accuracy of Seismic Imaging of Geological Structures

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