摘要
本文直接采用Thomsen导出的横向各向同性介质中的相速度、群角与相角、群速度与相速度的精确函数关系,提出了一种新的具有任意各向异性强度的横向各向同性介质中的初至波旅行时计算方法,它不同于Faria等人给出的采用群速度近似公式(Byun)的仅适应弱各向异性的初至波旅行时计算方法。该新算法在计算具有任意各向异性强度的横向各向同性介质中的初至波旅行时时,并不显著地增大计算时间。分析对比由新算法得到的初至波旅行时的等值线图和由交错网格有限差分波场模拟得到的波场快照表明,无论是对弱各向异性还是对强弱各向异性,新算法都具有较高的精度;随着各向异性强度的增大,新算法的计算结果与采用近似公式计算结果的差值也随之增大。
The paper directly uses the precious functional relationship among the phase velocity ,group angle and phase angle as well as group velocity and phase velocity in transversely isotropic medium deduced by Mr. Thomsen to present a new method for computing the traveltimes of seismic first breaks in transversely isotropic medium with arbitrary anisotropic strength that different from the computational method of traveltimes of seismic first breaks presented by Mr. Faria et al that uses approximation of group velocity and is only suitable for weak anisotropy. The new algorithm does not significantly increase computational times when computing the traveltimes of seismic first breaks in transversely isotropic medium with arbitrary anisotropic strength. It is shown by analysis and correlation between isochron sections of travel-times of seismic first breaks given by new algorithm and snapshots of wavefields simulated by staggering mesh finite-difference that the new algorithm has higher precision either in weak anisotropy or in strong-weak anisotropy; the difference of computational results between new algorithm and approximation increases along with the increase of anisotropic strength.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2006年第1期26-31,共6页
Oil Geophysical Prospecting
关键词
横向各向同性
初至波
旅行时
相速度
群速度
transverse isotropy,first breaks,traveltimes,phase velocity,group velocity
