Seismic wave propagation forward modelling method and device

Abstract

The embodiment of the invention provides a seismic wave propagation forward modelling method and device. The method comprises the following steps: converting an irregular region on a preset geologicalmodel for seismic wave modelling into a regular region under a second coordinate system for differential computation based on a longitudinal coordinate conversion algorithm; solving physical quantityon each grid point in the rule region under the second coordinate system based on a staggered mesh high-order differential algorithm; converting the physical quantity on each grid point into the physical quantity under the first coordinate system and taking the physical quantity under the first coordinate system as the output of the wave equation forward modelling according to a mapping relationbetween the first coordinate system and the second coordinate system. The seismic wave simulation on the ragged surface and like surface model can be realized, especially for the forward first-arrivalwave. By utilizing the method provided by the embodiment of the invention, the analysis research on the statics correction effect can be performed, the waveform can be maintained, the modelling precision is high, and the numerical dispersion is small.

Description

technical field [0001] The invention relates to the field of exploration geophysics, in particular to a seismic wave propagation forward modeling method and device. Background technique [0002] Terrain undulations have a great influence on the propagation of seismic waves, making the propagation of seismic waves near the surface extremely complicated, resulting in changes in the vibration intensity of seismic waves and the mutual conversion between seismic wave types, causing the interaction between surface waves, scattered body waves, and multiple scattered surface waves. Resonant coupling. In addition, regional seismic wave energy anomalies in natural seismic detection, as well as low signal-to-noise ratio and "static correction" problems of seismic data in mountainous oil and gas exploration are all caused by terrain fluctuations and near-surface velocity anomalies. The existing numerical simulation methods of seismic wave propagation in the case of terrain undulation m...

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Problems solved by technology

[0003] Finite element (FE) simulation method: This simulation method has low calculation efficiency, but it is more convenient to deal with irregular surfaces, and has become an effective method for simulating seismic wave propagation under undulating surfaces

For this reason, some hybrid methods combining finite element and other methods have been developed. For example, when Moczo et al. used the discrete wave number method to simulate the source excitation and the propagation of seismic waves in the lower medium, they used the finite element method to simulate the propagation of waves along the undulating surface ( DW-FE); Huang Ziping et al. used the method of combining finite element and finite difference (FE-FD) to simulate the propagation of seismic waves on the undulating surface, but the problems in the aforementioned methods are: the FE simulation method combined with other methods to calculate the boundary of the area It is easy to produce artificial reflections, and the absorption boundary is not easy to deal with

This method is often used in the study of seismic wave propagation on undulating surfaces, but the semi-analytic nature of the BE method determines that this method cannot be applied to situations where the surface velocity changes greatly. more drastic, thus limiting the practical application of the BE method

[0005] Finite difference (FD) method: This method has high computational efficiency and is the most widely used in simulating seismic wave propagation in complex models, but an important defect of this method is that it is difficult to deal with complex terrain

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