Spatial Grid Size Limited by the Accuracy of Interface Represented by the Discrete Grid

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

Finite difference method (FDM) is widely used for seismic waveform modeling. Since the computational time is proportional to the number of grid points, many higher-order and optimized schemes were developed to increase the spatial grid size while maintaining the dispersion error below predefined levels. It has been reported that 3 or 4 points per wavelength (PPW) are enough for these higher-order and optimized schemes. But such statements are only valid for homogeneous velocity models. The efficiency of such schemes is questioned for velocity models with strong velocity interfaces since large error due to the interface may arise when large grid spacing is used. To solve this problem, various effective medium parameterization methods have been proposed, in which the media parameters on the grid points are set in such a way that makes the wavefield satisfies the weld condition across the interface as much as possible.

In this work, we systematically analyze existing different effective media parameterization methods and also develop a new TTI effective media parameterization method. Our results show that the proposed TTI effective media parameterization method can be used with higher-order and optimized scheme to utilize 4-6 PPW to produce satisfactory results for moderate complex velocity models.

Presenting Author: Luqian Jiang

Authors