A Finite-Difference Seismic Wavefield Simulation Method with Deep Uniform Sampling Trapezoidal Grid

A finite-difference and uniform sampling technology, applied in the field of seismic wavefield forward modeling and depth uniform sampling trapezoidal grid finite-difference seismic wavefield simulation, which can solve the problems of interpolation false reflection wavefield recursion, small calculation amount, instability, etc.

CN108802819BActive Publication Date: 2019-11-08XI AN JIAOTONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2019-11-08

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Abstract

A finite difference seismic wave field simulation method adopting depth uniform sampling trapezoid grids comprises the steps as follows: firstly, the transformational relation between the coordinationpositions under a trapezoid coordinate system and coordinate positions under a rectangular coordinate system is determined, then, the expression form of a 2D wave equation in the trapezoid coordinatesystem is derived, and finally, as the wave equation in the trapezoid coordinate system has space mixed partial derivation, the mixed partial derivation is solved into non-mixed partial derivatives through coordinate rotation transformation, then, the wave equation under the trapezoid coordinate system is solved, and a simulation wave field is obtained. By means of the method, false reflection produced by transition of different sizes of grid areas can be avoided, and oversampling of traditional fixed grid finite difference for deep high-speed areas can be effectively reduced. The shallow simulation accuracy of the trapezoid coordinate system wave field is high, the deep horizontal response range is wide, and the number of finite difference grids can be effectively reduced.
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Description

technical field

[0001] The invention belongs to the technical field of seismic exploration, and relates to a seismic wave field forward modeling method, in particular to a depth uniform sampling trapezoidal grid finite difference seismic wave field simulation method. Background technique

[0002] Seismic wave field simulation provides the response information of the subsurface medium within a period of time after the source is excited by solving the wave equation, which is an important means to understand the propagation characteristics of seismic waves in complex media. Accurate and efficient solution of the wave equation is crucial in many seismic exploration applications, such as observation system design, multiple wave suppression, seismic data interpretation, high-precision imaging and modeling, etc. (Etgen and O'Brien, 2007; Ren et al., 2011). At present, seismic wave field simulation is mainly divided into finite difference method, finite element method, pseudospectr...

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Embodiment Construction

[0089] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0090] Aiming at the general characteristic that the seismic wave propagation velocity increases gradually with depth, the present invention proposes a wave field simulation method of finite difference wave equation in a two-dimensional trapezoidal coordinate system. The invention uses finite difference to solve the wave equation under the trapezoidal coordinate system, and realizes a finite difference seismic wave simulation method in which the sampling interval of the physical transverse grid increases with depth. Firstly, the conversion relationship between the coordinate position in the trapezoidal coordinate system and the coordinate position in the rectangular coordinate system is determined, and then the expression form of the two-dimensional wave equation in the trapezoidal coordinate system is deduced. Finally, since the space mixed partial derivatives appea...