基于时间辛格式的傅里叶有限差分地震波场正演

地震波场正演模拟是地震资料处理、解释中最为重要的技术之一。地震波场正演模拟在大时间步长、长时程的波场延拓中,存在计算不稳定的问题。本文基于声波方程的Hamilton表述,在波动方程求解中用辛差分格式进行时间网格离散,用傅里叶有限差分进行空间网格离散,提出一种新的保结构地震波场正演模拟方法一辛格式傅里叶有限差分法,在保证计算精度的同时提高计算的稳定性。利用声学近似处理空间-波数混合域的积分算子,将该方法推广至各向异性介质。给出各向同性和各向异性条件下的地震正演模拟的计算流程,并将本文方法用于BP盐丘、BP TTI等模型的波场正演模拟。数值算例表明本文开发的方法适用于速度变化剧烈的复杂介质地震波场...

Full description

Saved in:
Bibliographic Details
Published in应用地球物理：英文版 Vol. 14; no. 2; pp. 258 - 269
Main Author 方刚 巴晶 刘欣欣 祝堃 刘国昌
Format Journal Article
LanguageEnglish
Published 2017
Subjects
Hamilton系统
傅里叶有限差分
各向异性
地震正演
辛算法
Online AccessGet full text
ISSN1672-7975
1993-0658

Cover

More Information
Summary:地震波场正演模拟是地震资料处理、解释中最为重要的技术之一。地震波场正演模拟在大时间步长、长时程的波场延拓中,存在计算不稳定的问题。本文基于声波方程的Hamilton表述,在波动方程求解中用辛差分格式进行时间网格离散,用傅里叶有限差分进行空间网格离散,提出一种新的保结构地震波场正演模拟方法一辛格式傅里叶有限差分法,在保证计算精度的同时提高计算的稳定性。利用声学近似处理空间-波数混合域的积分算子,将该方法推广至各向异性介质。给出各向同性和各向异性条件下的地震正演模拟的计算流程,并将本文方法用于BP盐丘、BP TTI等模型的波场正演模拟。数值算例表明本文开发的方法适用于速度变化剧烈的复杂介质地震波场正演模拟,计算精度高,数值频散小,在各向异性介质正演中能够有效避免qSV波残余,在大时间步长的迭代计算中稳定性好。本文为在辛算法的框架下实现高精度地震正演模拟提供了一种新的选择。
Bibliography:Fang Gang1,2, Ba Jing3, Liu Xin-xin1,2, Zhu Kun4, Liu Guo-Chang5 （ 1. The Key Laboratory of Gas Hydrate, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China; 2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; 3. School of Earth Sciences and Engineering, Hohai University, Nanjing 211100, China; 4. School of Geosciences, China University of Petroleum （East China）, Qingdao 266580, China; 5. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing 102249, China.）
symplectic algorithm, Fourier finite-difference, Hamiltonian system, seismic modeling, anisotropic
11-5212/O
Seismic wavefield modeling is important for improving seismic data processing and interpretation. Calculations of wavefield propagation are sometimes not stable when forward modeling of seismic wave uses large time steps for long times. Based on the Hamiltonian expression of the acoustic wave equation, we propose a structure-preserving method for seismic wavefield modeling by applying the symplectic finite-difference method on time grids and the Fourier finite-difference method on space grids to solve the acoustic wave equation. The proposed method is called the symplectic Fourier finite-difference （symplectic FFD） method, and offers high computational accuracy and improves the computational stability. Using acoustic approximation, we extend the method to anisotropic media. We discuss the calculations in the symplectic FFD method for seismic wavefield modeling of isotropic and anisotropic media, and use the BP salt model and BP TTI model to test the proposed method. The numerical examples suggest that the proposed method can be used in seismic modeling of strongly variable velocities, offering high computational accuracy and low numerical dispersion. The symplectic FFD method overcomes the residual qSV wave of seismic modeling in anisotropic media and maintains the stability of the wavefield propagation for large time steps.
ISSN:1672-7975
1993-0658