Accurate 3D frequency-domain seismic wave modeling with the wavelength-adaptive 27-point finite-difference stencil: a tool for full waveform inversion

08/19/2021
by   Hossein S. Aghamiry, et al.
0

Efficient frequency-domain Full Waveform Inversion (FWI) of long-offset/wide-azimuth node data can be designed with a few discrete frequencies. However, 3D frequency-domain seismic modeling remains challenging since it requires solving a large and sparse linear indefinite system per frequency. When such systems are solved with direct methods or hybrid direct/iterative solvers, based upon domain decomposition preconditioner, finite-difference stencils on regular Cartesian grids should be designed to conciliate compactness and accuracy, the former being necessary to mitigate the fill-in induced by the Lower-Upper (LU) factorization. Compactness is classically implemented by combining several second-order accurate stencils covering the eight cells surrounding the collocation point, leading to the so-called 27-point stencil. Accuracy is obtained by applying optimal weights on the different stiffness and consistent mass matrices such that numerical dispersion is jointly minimized for several number of grid points per wavelength (G). However, with this approach, the same weights are used at each collocation point, leading to suboptimal accuracy in heterogeneous media. In this study, we propose a straightforward recipe to improve the accuracy of the 27-point stencil. First, we finely tabulate the values of G covering the range of wavelengths spanned by the subsurface model and the frequency. Then, we estimate with a classical dispersion analysis in homogeneous media the corresponding table of optimal weights that minimize dispersion for each G treated separately. We however apply a Tikhonov regularization to guarantee smooth variation of the weights with G. Finally, we build the impedance matrix by selecting the optimal weights at each collocation point according to the local wavelength, hence leading to a wavelength-adaptive stencil.

READ FULL TEXT

page 10

page 11

page 12

page 14

page 16

page 18

page 20

page 23

research
04/14/2020

Iterative frequency-domain seismic wave solvers based on multi-level domain-decomposition preconditioners

Frequency-domain full-waveform inversion (FWI) is suitable for long-offs...
research
12/01/2022

Controlled-source electromagnetic modelling using high order finite-difference time-domain method on a nonuniform grid

Simulation of 3D low-frequency electromagnetic fields propagating in the...
research
02/07/2022

Elastic waveform inversion in the frequency domain for an application in mechanized tunneling

The excavation process in mechanized tunneling can be improved by reconn...
research
05/31/2023

Isogeometric Multi-Resolution Full Waveform Inversion based on the Finite Cell Method

Full waveform inversion (FWI) is an iterative identification process tha...
research
08/16/2022

Wave simulation in non-smooth media by PINN with quadratic neural network and PML condition

Frequency-domain simulation of seismic waves plays an important role in ...
research
06/13/2020

Alternating direction implicit time integrations for finite difference acoustic wave propagation: Parallelization and convergence

This work studies the parallelization and empirical convergence of two f...

Please sign up or login with your details

Forgot password? Click here to reset