Elastic wave forward simulation technology based on space-time dual-variable grid

Abstract

The invention discloses an elastic wave forward simulation technology based on the space-time dual-variable grid, comprising the following steps: determining the stability conditions of the target area and the background area according to the speed parameter and the elasticity parameter of the underground medium aiming to the known earthquake geological model so as to calculate the size of the space grids with different dimensions and perform the discretization process to the speed field; obtaining the space arbitrary precision difference formula of the grid point variables with different dimensions by using the Taylor's formula and the finite difference technology, which is the arbitrary even order accuracy space difference formula of the space constant grid operator and the space variable grid operator, and calculating the wave field values of the precise division area, the rough division area and the middle transitional belt area by using the deduced space difference formula; in the wave field extrapolation process of the time layer, using different time sampling intervals to different grid division areas and meet the partial stability condition, obtaining the wave field value of the precise grid point in the precise time layer and the wave field value of the rough grid point in the global time layer; in each global time layer, transmitting the wave field value of the precise grid division area to the rough grid division area, thereby obtaining the space wave field value of the whole speed field at the said moment; performing the wave field extrapolation on each time layer by the said method and obtaining the forward simulation record of single cannon. The partial stability condition of the shallow layer can be met, so as to avoid the frequency dispersion noise.

Description

Technical field [0001] The invention belongs to the basic application field of seismic exploration, and is a high-efficiency seismic wave forward modeling simulation technology for complex underground media. Background technique [0002] With the deepening of seismic exploration and development, the exploration field has gradually transitioned to a double complex structural environment with complex surface and complex geological structure. At this time, the effectiveness of seismic exploration depends to a large extent on the adaptability of the developed technology to the complex actual medium model. Therefore, the complexity of the surface and deep layers of the model is unavoidable when performing seismic wave forward modeling based on an actual model. The traditional finite-difference seismic wave simulation method is based on a regular rectangular grid, which is an effective method for dealing with inhomogeneous media, especially continuous inhomogeneous media. Howeve...

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Problems solved by technology

[0005] The purpose of the present invention is to propose a complex seismic geological model with high calculation efficiency and The elastic wave forward modeling technology based on the time-space double-variable grid of simulation accuracy adopts a more reasonable multi-scale grid discretization scheme for the complex velocity model, and adopts fine grid division locally, thus avoiding the use of fine grid for the entire model. Over-sampling caused by grid subdivision will take a long time to calculate and occupy a lot of memory.

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