Nonlinear Optimal Stacking Based on Shortest Path Ray Tracing for Enhancing Pre-Stack Seismic Data

2019 ◽  
Author(s):  
C. Wu ◽  
H. Wang ◽  
J. Hu ◽  
F. Luo ◽  
P. Xu
Keyword(s):  
Ray Tracing ◽  
Shortest Path ◽  
Seismic Data

Seismic complex ray tracing in 2D/3D viscoelastic anisotropic media by a modified shortest-path method

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. T331-T342
Author(s):  
Xing-Wang Li ◽  
Bing Zhou ◽  
Chao-Ying Bai ◽  
Jian-Lu Wu
Keyword(s):  
Ray Tracing ◽  
Shortest Path ◽  
Anisotropic Medium ◽  
Wave Energy ◽  
Seismic Data ◽  
Seismic Waves ◽  
Effective Means ◽  
Anisotropic Media ◽  
The Real ◽  
Complex Ray

In a viscoelastic anisotropic medium, velocity anisotropy and wave energy attenuation occur and are often observed in seismic data applications. Numerical investigation of seismic wave propagation in complex viscoelastic anisotropic media is very helpful in understanding seismic data and reconstructing subsurface structures. Seismic ray tracing is an effective means to study the propagation characteristics of high-frequency seismic waves. Unfortunately, most seismic ray-tracing methods and traveltime tomographic inversion algorithms only deal with elastic media and ignore the effect of viscoelasticity on the seismic raypath. We have developed a method to find the complex ray velocity that gives the seismic ray speed and attenuation in an arbitrary viscoelastic anisotropic medium, and we incorporate them with the modified shortest-path method to determine the raypath and calculate the real and imaginary traveltime (wave energy attenuation) simultaneously. We determine that the complex ray-tracing method is applicable to arbitrary 2D/3D viscoelastic anisotropic media in a complex geologic model and the computational errors of the real and imaginary traveltime are less than 0.36% and 0.59%, respectively. The numerical examples verify that the new method is an effective and powerful tool for accomplishing seismic complex ray tracing in heterogeneous viscoelastic anisotropic media.

Geometrical spreading in a layered transversely isotropic medium with vertical symmetry axis

Geophysics ◽  
2003 ◽  
Vol 68 (6) ◽  
pp. 2082-2091 ◽  
Author(s):  
Bjørn Ursin ◽  
Ketil Hokstad
Keyword(s):  
Ray Tracing ◽  
Seismic Data ◽  
Symmetry Axis ◽  
Transversely Isotropic ◽  
Analytical Approximation ◽  
Geometrical Spreading ◽  
S Wave ◽  
Weak Anisotropy ◽  
P Waves ◽  
Amplitude Versus

Compensation for geometrical spreading is important in prestack Kirchhoff migration and in amplitude versus offset/amplitude versus angle (AVO/AVA) analysis of seismic data. We present equations for the relative geometrical spreading of reflected and transmitted P‐ and S‐wave in horizontally layered transversely isotropic media with vertical symmetry axis (VTI). We show that relatively simple expressions are obtained when the geometrical spreading is expressed in terms of group velocities. In weakly anisotropic media, we obtain simple expressions also in terms of phase velocities. Also, we derive analytical equations for geometrical spreading based on the nonhyperbolic traveltime formula of Tsvankin and Thomsen, such that the geometrical spreading can be expressed in terms of the parameters used in time processing of seismic data. Comparison with numerical ray tracing demonstrates that the weak anisotropy approximation to geometrical spreading is accurate for P‐waves. It is less accurate for SV‐waves, but has qualitatively the correct form. For P waves, the nonhyperbolic equation for geometrical spreading compares favorably with ray‐tracing results for offset‐depth ratios less than five. For SV‐waves, the analytical approximation is accurate only at small offsets, and breaks down at offset‐depth ratios less than unity. The numerical results are in agreement with the range of validity for the nonhyperbolic traveltime equations.

The Study of Diffraction Ray Tracing on the Surface of Airplane

2012 ◽  
Vol 433-440 ◽  
pp. 6345-6349
Author(s):  
Li Peng Deng ◽  
Xiao Ying Zhao ◽  
You Feng Chen ◽  
Wang Jing
Keyword(s):  
Ray Tracing ◽  
Shortest Path ◽  
Convex Surface ◽  
Local Algorithm ◽  
Dijkstra Algorithm ◽  
End Point

This article makes the surface of airplane into quadrilateral gridding by using the method of discrete gridding generation, and calculates the data of gridding by using the classical Dijkstra algorithm (local algorithm) which can seek the shortest path from the start point and the end point. With that we can achieve diffraction ray tracing. This method can be used for any convex surface of the diffraction ray tracing.

scholarly journals Ray-tracing traveltime tomography versus wave-equation traveltime inversion for near-surface seismic land data

2017 ◽  
Vol 5 (3) ◽  
pp. SO11-SO19
Author(s):  
Lei Fu ◽  
Sherif M. Hanafy
Keyword(s):  
Wave Equation ◽  
Ray Tracing ◽  
Water Table ◽  
Seismic Data ◽  
Velocity Model ◽  
Water Table Depth ◽  
Seismic Survey ◽  
Near Surface ◽  
Traveltime Tomography ◽  
Initial Starting

Full-waveform inversion of land seismic data tends to get stuck in a local minimum associated with the waveform misfit function. This problem can be partly mitigated by using an initial velocity model that is close to the true velocity model. This initial starting model can be obtained by inverting traveltimes with ray-tracing traveltime tomography (RT) or wave-equation traveltime (WT) inversion. We have found that WT can provide a more accurate tomogram than RT by inverting the first-arrival traveltimes, and empirical tests suggest that RT is more sensitive to the additive noise in the input data than WT. We present two examples of applying WT and RT to land seismic data acquired in western Saudi Arabia. One of the seismic experiments investigated the water-table depth, and the other one attempted to detect the location of a buried fault. The seismic land data were inverted by WT and RT to generate the P-velocity tomograms, from which we can clearly identify the water table depth along the seismic survey line in the first example and the fault location in the second example.

A Fast Algorithm of the Shortest Path Ray Tracing

2006 ◽  
Vol 49 (5) ◽  
pp. 1315-1323 ◽  
Author(s):  
Mei-Gen ZHANG ◽  
Bing-Jie CHENG ◽  
Xiao-Fan LI ◽  
Miao-Yue WANG
Keyword(s):  
Ray Tracing ◽  
Shortest Path ◽  
Fast Algorithm

2D efficient ray tracing with a modified shortest path method

2009 ◽  
Vol 40 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Meigen Zhang ◽  
Liyun Fu ◽  
Xinfu Li ◽  
Xiaofan Li
Keyword(s):  
Ray Tracing ◽  
Shortest Path

Multiple weights in diffraction stack migration

Geophysics ◽  
1993 ◽  
Vol 58 (12) ◽  
pp. 1820-1830 ◽  
Author(s):  
M. Tygel ◽  
J. Schleicher ◽  
P. Hubral ◽  
C. Hanitzsch
Keyword(s):  
Ray Tracing ◽  
Seismic Data ◽  
Specular Reflection ◽  
Three Dimensional ◽  
Weight Vector ◽  
Reflection Coefficients ◽  
Dynamic Information ◽  
Data Set ◽  
Kirchhoff Migration ◽  
Multiple Weights

Three‐dimensional (3-D) prestack diffraction‐stack migration methods (often called Kirchhoff migration/inversion) play a fundamental role in seismic imaging. In addition to estimating the location of arbitrarily curved reflectors and the angle‐dependent reflection coefficients upon them, they can also be used to provide useful kinematic and dynamic information about the specular reflection ray that connects the source and receiver via the unknown reflecting interface. This is achieved by performing a diffraction stack more than once upon the same seismic data set using identical stacking surfaces but different weights. Some of these weights can be applied simultaneously, i.e., as a weight‐vector. The approach offers the possibility of determining various useful quantities that help to compute and interpret migrated reflections. The vector‐weighted diffraction stack is principally intended to economize the amplitude‐preserving migration that normally would require a large amount of dynamic ray tracing. A simple 2-D synthetic example shows how the method works in principle.

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