Prestack depth migration with compensation for absorption and dispersion

Geophysics ◽  
1995 ◽  
Vol 60 (5) ◽  
pp. 1485-1494 ◽  
Author(s):  
Rune Mittet ◽  
Roger Sollie ◽  
Ketil Hokstad
Keyword(s):  
Phase Velocity ◽  
Optimization Algorithm ◽  
Design Criterion ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Dispersion Effects ◽  
Wavefield Extrapolation ◽  
Absorption And Dispersion ◽  
Attenuation And Dispersion ◽  
High Absorption

In prestack depth migration using explicit extrapolators, the attenuation and dispersion of the seismic wave has been neglected so far. We present a method for accommodating absorption and dispersion effects in depth migration schemes. Extrapolation operators that compensate for absorption and dispersion are designed using an optimization algorithm. The design criterion is that the wavenumber response of the operator should equal the true extrapolator. Both phase velocity and absorption macro models are used in the wavefield extrapolation. In a model with medium to high absorption, the images obtained are superior to those obtained using extrapolators without compensation for absorption.

3-D prestack depth migration by wavefield extrapolation methods

2003 ◽  
Vol 2003 (2) ◽  
pp. 1-4
Author(s):  
James Sun ◽  
Carl Notfors ◽  
Zhang Yu ◽  
Gray Sam ◽  
Young Jerry
Keyword(s):  
Extrapolation Methods ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Wavefield Extrapolation

Offset‐domain pseudoscreen prestack depth migration

Geophysics ◽  
2002 ◽  
Vol 67 (6) ◽  
pp. 1895-1902 ◽  
Author(s):  
Shengwen Jin ◽  
Charles C. Mosher ◽  
Ru‐Shan Wu
Keyword(s):  
Heterogeneous Media ◽  
Fourier Transforms ◽  
Data Migration ◽  
Computationally Efficient ◽  
Lateral Velocity ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Narrow Angle ◽  
Domain Phase ◽  
Wavefield Extrapolation

The double square root equation for laterally varying media in midpoint‐offset coordinates provides a convenient framework for developing efficient 3‐D prestack wave‐equation depth migrations with screen propagators. Offset‐domain pseudoscreen prestack depth migration downward continues the source and receiver wavefields simultaneously in midpoint‐offset coordinates. Wavefield extrapolation is performed with a wavenumber‐domain phase shift in a constant background medium followed by a phase correction in the space domain that accommodates smooth lateral velocity variations. An extra wide‐angle compensation term is also applied to enhance steep dips in the presence of strong velocity contrasts. The algorithm is implemented using fast Fourier transforms and tri‐diagonal matrix solvers, resulting in a computationally efficient implementation. Combined with the common‐azimuth approximation, 3‐D pseudoscreen migration provides a fast wavefield extrapolation for 3‐D marine streamer data. Migration of the 2‐D Marmousi model shows that offset domain pseudoscreen migration provides a significant improvement over first‐arrival Kirchhoff migration for steeply dipping events in strong contrast heterogeneous media. For the 3‐D SEG‐EAGE C3 Narrow Angle synthetic dataset, image quality from offset‐domain pseudoscreen migration is comparable to shot‐record finite‐difference migration results, but with computation times more than 100 times faster for full aperture imaging of the same data volume.

A simple design procedure for depth extrapolation operators that compensate for absorption and dispersion

Geophysics ◽  
2007 ◽  
Vol 72 (2) ◽  
pp. S105-S112 ◽  
Author(s):  
Rune Mittet
Keyword(s):  
Frequency Domain ◽  
Design Procedure ◽  
Simple Design ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Space Frequency ◽  
Absorption And Dispersion

I compensate for the effects of absorption and dispersion in deriving the space-frequency domain depth extrapolation operators by starting from the ones without such compensation. The procedure is simple and requires only trivial cosine transforms applied to the original noncompensating operators. I show that compensating operators enhance resolution as a function of depth when applied in prestack depth migration.

scholarly journals 3D prestack depth migration with compensation for frequency dependent absorption and dispersion

2010 ◽  
Vol 2010 (1) ◽  
pp. 1-4
Author(s):  
Yi Xie ◽  
Kefeng Xin ◽  
James Sun ◽  
Carl Notfors ◽  
Ajoy Kumar Biswal ◽  
...  
Keyword(s):  
Prestack Depth Migration ◽  
Frequency Dependent ◽  
Depth Migration ◽  
Dependent Absorption ◽  
Absorption And Dispersion

Multicomponent prestack depth migration by scalar wavefield extrapolation

Geophysics ◽  
2002 ◽  
Vol 67 (6) ◽  
pp. 1886-1894 ◽  
Author(s):  
Anning Hou ◽  
Kurt J. Marfurt
Keyword(s):  
Wave Equation ◽  
Single Shot ◽  
Complex Structures ◽  
Scalar Wave ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Polarization Filtering ◽  
Polarity Reversals ◽  
Wavefield Extrapolation ◽  
Propagation Velocities

We present a new multicomponent prestack depth migration methodology based on successive application of conventional scalar wave equation migration. We do not separate the data into PP‐ and PS‐waves; rather, we migrate each x‐, y‐, and z‐component of the data using both P and S propagation velocities, followed by polarization filtering in the depth domain. By generating intermediate images in the depth domain, we can account for polarity reversals of the PS reflection for all dips. Since the polarization angles are calculated from the data, it is straightforward to accommodate anisotropic effects (quasi‐P and quasi‐S) into multicomponent migration. The multicomponent migration results in our synthetic examples demonstrate that even for a single shot gather, we can obtain clean PP‐ and PS‐wave images over complex structures and resolve the problem of PS‐wave polarity reversals.

Kinematic interpretation in the prestack depth‐migrated domain

Geophysics ◽  
1997 ◽  
Vol 62 (4) ◽  
pp. 1226-1237 ◽  
Author(s):  
Irina Apostoiu‐Marin ◽  
Andreas Ehinger
Keyword(s):  
Signal To Noise Ratio ◽  
Velocity Model ◽  
Point Of View ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Velocity Models ◽  
Time Domain Data ◽  
And Migration ◽  
Point To Point ◽  
Homogeneous Media

Prestack depth migration can be used in the velocity model estimation process if one succeeds in interpreting depth events obtained with erroneous velocity models. The interpretational difficulty arises from the fact that migration with erroneous velocity does not yield the geologically correct reflector geometries and that individual migrated images suffer from poor signal‐to‐noise ratio. Moreover, migrated events may be of considerable complexity and thus hard to identify. In this paper, we examine the influence of wrong velocity models on the output of prestack depth migration in the case of straight reflector and point diffractor data in homogeneous media. To avoid obscuring migration results by artifacts (“smiles”), we use a geometrical technique for modeling and migration yielding a point‐to‐point map from time‐domain data to depth‐domain data. We discover that strong deformation of migrated events may occur even in situations of simple structures and small velocity errors. From a kinematical point of view, we compare the results of common‐shot and common‐offset migration. and we find that common‐offset migration with erroneous velocity models yields less severe image distortion than common‐shot migration. However, for any kind of migration, it is important to use the entire cube of migrated data to consistently interpret in the prestack depth‐migrated domain.

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