Dip moveout in the frequency‐wavenumber domain

Geophysics ◽  
1987 ◽  
Vol 52 (12) ◽  
pp. 1718-1721 ◽  
Author(s):  
C. D. Notfors ◽  
R. J. Godfrey
Keyword(s):  
Velocity Analysis ◽  
Frequency Content ◽  
Reflection Point ◽  
Processing Industry ◽  
Seismic Processing ◽  
Wavenumber Domain ◽  
Processing Sequence ◽  
Zero Offset ◽  
Filtering Effect

In recent years dip moveout (DMO) has come into routine use in the seismic processing industry. The main benefits of including DMO in the processing sequence are that (1) stacking velocities after DMO are dip‐independent, and (2) “reflection point smear” associated with dipping events is eliminated by laterally shifting the reflection points to their zero‐offset position. These effects of DMO are also beneficial for estimation of stacking velocities by simplifying the interpretation of velocity analysis. Dip moveout also has an inherent dip filtering effect (Bolondi et al., 1984) by lowering the frequency content on the stacked section of steeply dipping aliased events, which leads to reduced migration noise.

scholarly journals Study on the Velocity Analysis Method of Low SNR Seismic Data

2021 ◽  
Vol 11 (1) ◽  
pp. 78
Author(s):  
Jianbo He ◽  
Zhenyu Wang ◽  
Mingdong Zhang
Keyword(s):  
Seismic Data ◽  
Fresnel Zone ◽  
Signal To Noise Ratio ◽  
Normal Wave ◽  
Curvature Radius ◽  
Velocity Spectrum ◽  
Velocity Analysis ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Zero Offset

When the signal to noise ratio of seismic data is very low, velocity spectrum focusing will be poor., the velocity model obtained by conventional velocity analysis methods is not accurate enough, which results in inaccurate migration. For the low signal noise ratio (SNR) data, this paper proposes to use partial Common Reflection Surface (CRS) stack to build CRS gathers, making full use of all of the reflection information of the first Fresnel zone, and improves the signal to noise ratio of pre-stack gathers by increasing the number of folds. In consideration of the CRS parameters of the zero-offset rays emitted angle and normal wave front curvature radius are searched on zero offset profile, we use ellipse evolving stacking to improve the zero offset section quality, in order to improve the reliability of CRS parameters. After CRS gathers are obtained, we use principal component analysis (PCA) approach to do velocity analysis, which improves the noise immunity of velocity analysis. Models and actual data results demonstrate the effectiveness of this method.

2-D continuation operators and their applications

Geophysics ◽  
1996 ◽  
Vol 61 (6) ◽  
pp. 1846-1858 ◽  
Author(s):  
Claudio Bagaini ◽  
Umberto Spagnolini
Keyword(s):  
Seismic Data ◽  
Real Data ◽  
Integral Form ◽  
Amplitude Distribution ◽  
Velocity Model ◽  
Velocity Analysis ◽  
Seismic Data Processing ◽  
Analysis Method ◽  
Standard Tool ◽  
Zero Offset

Continuation to zero offset [better known as dip moveout (DMO)] is a standard tool for seismic data processing. In this paper, the concept of DMO is extended by introducing a set of operators: the continuation operators. These operators, which are implemented in integral form with a defined amplitude distribution, perform the mapping between common shot or common offset gathers for a given velocity model. The application of the shot continuation operator for dip‐independent velocity analysis allows a direct implementation in the acquisition domain by exploiting the comparison between real data and data continued in the shot domain. Shot and offset continuation allow the restoration of missing shot or missing offset by using a velocity model provided by common shot velocity analysis or another dip‐independent velocity analysis method.

Velocity analysis using zero-offset attributes in common source domain

2015 ◽  
Vol 2015 (1) ◽  
pp. 1-4
Author(s):  
Mohammad Javad Khoshnavaz ◽  
Milovan Urosevic ◽  
Andrej Bona
Keyword(s):  
Common Source ◽  
Velocity Analysis ◽  
Source Domain ◽  
Zero Offset

Transformation to zero offset for mode‐converted waves

Geophysics ◽  
1992 ◽  
Vol 57 (3) ◽  
pp. 474-477 ◽  
Author(s):  
Mohammed Alfaraj ◽  
Ken Larner
Keyword(s):  
Seismic Data ◽  
Constant Velocity ◽  
Reflection Point ◽  
P Waves ◽  
S Waves ◽  
Nmo Correction ◽  
Converted Waves ◽  
Zero Offset ◽  
Correct Data

The transformation to zero offset (TZO) of prestack seismic data for a constant‐velocity medium is well understood and is readily implemented when dealing with either P‐waves or S‐waves. TZO is achieved by inserting a dip moveout (DMO) process to correct data for the influence of dip, either before or after normal moveout (NMO) correction (Hale, 1984; Forel and Gardner, 1988). The TZO process transforms prestack seismic data in such a way that common‐midpoint (CMP) gathers are closer to being common reflection point gathers after the transformation.

Ellipse evolving common reflection point velocity analysis and its application to oil and gas detection

2009 ◽  
Vol 6 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Qing-Chun Zhou ◽  
Huai-Shan Liu ◽  
V V Kondrashkov ◽  
Guo-Du Li ◽  
Yi-Hua Lin
Keyword(s):  
Oil And Gas ◽  
Gas Detection ◽  
Velocity Analysis ◽  
Reflection Point ◽  
Point Velocity

Wave-equation migration velocity analysis by focusing diffractions and reflections

Geophysics ◽  
2005 ◽  
Vol 70 (3) ◽  
pp. U19-U27 ◽  
Author(s):  
Paul C. Sava ◽  
Biondo Biondi ◽  
John Etgen
Keyword(s):  
Wave Equation ◽  
Migration Velocity ◽  
Velocity Estimation ◽  
Velocity Analysis ◽  
Depth Migration ◽  
Interval Velocity ◽  
Migration Velocity Analysis ◽  
Inversion Procedure ◽  
Velocity Information ◽  
Zero Offset

We propose a method for estimating interval velocity using the kinematic information in defocused diffractions and reflections. We extract velocity information from defocused migrated events by analyzing their residual focusing in physical space (depth and midpoint) using prestack residual migration. The results of this residual-focusing analysis are fed to a linearized inversion procedure that produces interval velocity updates. Our inversion procedure uses a wavefield-continuation operator linking perturbations of interval velocities to perturbations of migrated images, based on the principles of wave-equation migration velocity analysis introduced in recent years. We measure the accuracy of the migration velocity using a diffraction-focusing criterion instead of the criterion of flatness of migrated common-image gathers that is commonly used in migration velocity analysis. This new criterion enables us to extract velocity information from events that would be challenging to use with conventional velocity analysis methods; thus, our method is a powerful complement to those conventional techniques. We demonstrate the effectiveness of the proposed methodology using two examples. In the first example, we estimate interval velocity above a rugose salt top interface by using only the information contained in defocused diffracted and reflected events present in zero-offset data. By comparing the results of full prestack depth migration before and after the velocity updating, we confirm that our analysis of the diffracted events improves the velocity model. In the second example, we estimate the migration velocity function for a 2D, zero-offset, ground-penetrating radar data set. Depth migration after the velocity estimation improves the continuity of reflectors while focusing the diffracted energy.

3D generalized nonhyperboloidal moveout approximation

Geophysics ◽  
2017 ◽  
Vol 82 (2) ◽  
pp. C49-C59 ◽  
Author(s):  
Yanadet Sripanich ◽  
Sergey Fomel ◽  
Alexey Stovas ◽  
Qi Hao
Keyword(s):  
Time Domain ◽  
Functional Form ◽  
Seismic Imaging ◽  
High Accuracy ◽  
Velocity Analysis ◽  
Zero Offset ◽  
Independent Parameters

Moveout approximations are commonly used in velocity analysis and time-domain seismic imaging. We revisit the previously proposed generalized nonhyperbolic moveout approximation and develop its extension to the 3D multiazimuth case. The advantages of the generalized moveout approximation are its high accuracy and its ability to reduce to several other known approximations with particular choices of parameters. The proposed 3D functional form involves 17 independent parameters instead of five as in the 2D case. These parameters can be defined by zero-offset traveltime attributes and four additional far-offset rays. In our tests, the proposed approximation achieves significantly higher accuracy than previously proposed 3D approximations.

Shot gather DMO in the double log domain

Geophysics ◽  
1994 ◽  
Vol 59 (8) ◽  
pp. 1305-1307 ◽  
Author(s):  
Harald Granser
Keyword(s):  
Seismic Processing ◽  
Wavenumber Domain ◽  
Log Domain

Dip moveout (DMO) correction is applied routinely now in seismic processing. Over the years, numerous DMO methods have been developed for the frequency‐wavenumber domain (Hale 1991).

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