Anisotropic reverse time migration method for quasi-P wave equation in transverse isotropy with a vertical axis of symmetry (VTI) medium

Abstract

The invention relates to an anisotropic reverse time migration method for a quasi-P wave equation in a transverse isotropy with a vertical axis of symmetry (VTI) medium. The method comprises the following steps of: (1) performing discrete differentiation on a first-order quasi-P wave equation in a two-dimensional VTI medium and a perfect matched layer (PML) absorption layer boundary equation by adopting staggered meshes to obtain high-order difference formats of forward continuation and reverse continuation of the two equations; (2) performing numeric calculation to obtain a forwards-continued wave field of a shot point and a reverse time continued wave field of a receiver point, and performing normalized correlation operation on the two wave fields to obtain a migration imaging result of each imaging point in a model; and (3) extracting common imaging point gathers from migration results to obtain a final migration profile. By the method, a problem about the migration imaging of intensive transverse speed variation and a high dip angle stratum can be solved; and the influence of anisotropy of the medium is also taken into account, and the good imaging effect of longitudinal wave data acquired from an anisotropic region can be achieved by an anisotropy-theory-based migration method.

Description

technical field [0001] The invention belongs to the technical field of seismic data processing in exploration geophysics, and is a pre-stack VTI medium quasi-P wave equation anisotropic reverse time migration method based on anisotropy theory. Background technique [0002] In recent years, with the continuous improvement of the precision and requirements of seismic exploration, the precise imaging of complex geological structures has attracted more and more attention from the industry. , buried deep, etc.; seismic migration technology is constantly developed and perfected to meet this demand. [0003] In the prior art, prestack depth migration methods mainly include Kirchhoff integral method, finite difference migration method based on one-way wave equation, frequency wavenumber domain migration method and reverse time migration method based on two-way wave equation; The time migration method is based on the accurate two-way wave equation, and allows the wave to propagate i...

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the disadvantages of conventional migration methods based on isotropy theory, such as low precision, inclination angle limitation, and inability to adapt to strong lateral velocity changes, etc., and develop a pre-stack reverse time depth based on anisotropy theory. Migration method to solve the problem of seismic wave migration and homing in anisotropic media, obtain the real structure of the underground, and provide amplitude and phase information for subsequent processing such as AVO analysis, attribute analysis, etc.

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