谐振Q模型介质地震波场数值模拟  

Numerical modeling of seismic wave field in viscoelastic resonance Q media

作　　者：罗伟平[1,2] 李洪奇 石宁[1,2] 王海平 

机构地区：[1]中国石油大学(北京)地球物理与信息工程学院 [2]石油数据挖掘北京市重点实验室(Z121109009212008)

出　　处：《地球物理学进展》2014年第4期1727-1734,共8页Progress in Geophysics

基　　金："十二五"国家科技重大专项;近海大中型油气田地震勘探技术(2011ZX05023-005-006)

摘　　要：由于时间域内粘弹性介质的本构方程是一种卷积积分形式,无法将它直接离散化数值求解.本文采用GSLS模型逼近谐振Q模型介质的粘弹性;推导了粘弹性介质中实现纵波和横波分解的等价波动方程.同时给出了等价方程的完全匹配吸收边界(PML)条件公式及相应的交错网格任意偶数阶精度有限差分格式.最后应用交错网格高阶有限差分法,求解等价波动方程.实验显示GSLS模型逼近精度高,吸收边界效果好,能够实现纵、横波的完全分离,可以得到高精度的波场快照和合成记录;并且波场快照和合成记录能较好的反映谐振Q模型介质的粘弹性特征.结果证明GSLS模型能够精确地逼近谐振Q模型的粘弹性.Due to the anelastic stress-strain relation has the form of a convolution integral in the time domain,it is impossible to discrete the seismic wave equation in a numerical computation directly.In order to get the numerical solution,the paper uses the GSLS model to approximate the resonance Q medium.As well as derived the equivalent of the wave equation separate the P and S wave directly in the time domain.At the same time,equations of the perfectly matched layer（PML）are derived for the equivalent equations in the resonance Q medium.At last we use the staggered grid high-order finitedifference scheme to solve the equivalent equation.Results of numerical modeling indicate that the modeling precision is high;the absorbing boundary condition is suitable for the numerical modeling and obtained the completely separated fields of pure P wave and pure S wave,as well as high-precision snapshots of wave field and synthetic seismograms which reflect the characteristic of Viscoelasticity.We can get the conclusion that the GSLS model can accurately approximate the resonance Q medium.

关 键 词：GSLS模型 谐振Q模型 纵横波分解 数值模拟 

分 类 号：P631[天文地球—地质矿产勘探]