Wave Equation Depth Migration with the Optimum Split-Step Fourier Method In 3-D VTI Media

2005 ◽  
Vol 48 (2) ◽  
pp. 448-457 ◽  
Author(s):  
Li-Nong LIU ◽  
Hong-Wei GAO ◽  
Hong LIU ◽  
Jian-Feng ZHANG
Keyword(s):  
Wave Equation ◽  
Fourier Method ◽  
Depth Migration ◽  
Vti Media

Prestack wave-equation depth migration in VTI media

2005 ◽  
Vol 24 (6) ◽  
pp. 618-620 ◽  
Author(s):  
Jiaxiang Ren ◽  
Clive Gerrard ◽  
James Mcclean ◽  
Mikhail Orlovich
Keyword(s):  
Wave Equation ◽  
Depth Migration ◽  
Vti Media

Wave equation prestack depth migration in laterally varying VTI media

2005 ◽  
Author(s):  
Jiaxiang Ren ◽  
Clive Gerrard ◽  
James McClean ◽  
Mikhail Orlovich
Keyword(s):  
Wave Equation ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Vti Media

Hybrid Fourier finite-difference 3D depth migration for anisotropic media

Geophysics ◽  
2008 ◽  
Vol 73 (2) ◽  
pp. S27-S34 ◽  
Author(s):  
Tong W. Fei ◽  
Christopher L. Liner
Keyword(s):  
Wave Equation ◽  
Finite Difference ◽  
Acoustic Wave ◽  
Seismic Data ◽  
Transversely Isotropic ◽  
Acoustic Wave Equation ◽  
Near Surface ◽  
Depth Migration ◽  
Surface Distortions ◽  
Vti Media

When a subsurface is anisotropic, migration based on the assumption of isotropy will not produce accurate migration images. We develop a hybrid wave-equation migration algorithm for vertical transversely isotropic (VTI) media based on a one-way acoustic wave equation, using a combination of Fourier finite-difference (FFD) and finite-difference (FD) approaches. The hybrid method can suppress an additional solution that exists in the VTI acoustic wave equation, and it offers speed and other advantages over conventional FFD or FD methods alone. The algorithm is tested on a synthetic model involving log data from onshore eastern Saudi Arabia, including estimates of both intrinsic and layer-induced VTI parameters. Results indicate that VTI imaging in this region offers some improvement over isotropic imaging, primarily with respect to subtle structure and stratigraphy and to image continuity. These benefits probably will be overshadowed by perennial land seismic data issues such as near-surface distortions and multiples.

Depth migration from irregular surfaces with depth extrapolation methods

Geophysics ◽  
1991 ◽  
Vol 56 (1) ◽  
pp. 119-122 ◽  
Author(s):  
Moshe Reshef
Keyword(s):  
Wave Equation ◽  
Surface Topography ◽  
Time Shift ◽  
Extrapolation Methods ◽  
Irregular Surfaces ◽  
Depth Migration ◽  
Numerical Problem ◽  
Flat Interface ◽  
Interface Wave ◽  
Computationally Expensive

Nonflat surface topography introduces a numerical problem for migration algorithms that are based on depth extrapolation. Since the numerically efficient migration schemes start at a flat interface, wave‐equation datuming is required (Berryhill, 1979) prior to the migration. The computationally expensive datuming procedure is often replaced by a simple time shift for the elevation to datum correction. For nonvertically traveling energy this correction is inaccurate. Subsequent migration wrongly positions the reflectors in depth.

Fast acquisition aperture correction in prestack depth migration using beamlet decomposition

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. S67-S74 ◽  
Author(s):  
Jun Cao ◽  
Ru-Shan Wu
Keyword(s):  
Wave Equation ◽  
Correction Factor ◽  
Computing Time ◽  
Computation Time ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Wavenumber Domain ◽  
Amplitude Correction ◽  
Local Wavenumber ◽  
Local Angle

Wave-equation-based acquisition aperture correction in the local angle domain can improve image amplitude significantly in prestack depth migration. However, its original implementation is inefficient because the wavefield decomposition uses the local slant stack (LSS), which is demanding computationally. We propose a faster method to obtain the image and amplitude correction factor in the local angle domain using beamlet decomposition in the local wavenumber domain. For a given frequency, the image matrix in the local wavenumber domain for all shots can be calculated efficiently. We then transform the shot-summed image matrix from the local wavenumber domain to the local angle domain (LAD). The LAD amplitude correction factor can be obtained with a similar strategy. Having a calculated image and correction factor, one can apply similar acquisition aperture corrections to the original LSS-based method. For the new implementation, we compare the accuracy and efficiency of two beamlet decompositions: Gabor-Daubechies frame (GDF) and local exponential frame (LEF). With both decompositions, our method produces results similar to the original LSS-based method. However, our method can be more than twice as fast as LSS and cost only twice the computation time of traditional one-way wave-equation-based migrations. The results from GDF decomposition are superior to those from LEF decomposition in terms of artifacts, although GDF requires a little more computing time.

The case for applying wave equation depth migration in the North Sea

First Break ◽  
2004 ◽  
Vol 22 (8) ◽  
Author(s):  
R. Leggott ◽  
J. Cowley ◽  
R.G. Williams
Keyword(s):  
Wave Equation ◽  
North Sea ◽  
Depth Migration ◽  
The North ◽  
The North Sea
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