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demigration

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Journal Article
Journal: Geophysics
Published: 03 May 2019
Geophysics (2019) 84 (4): S229–S238.
... to parallelize. A powerful tool for time imaging consists of a series of prestack time migrations and demigrations. We have applied multiparameter stacking techniques to obtain an initial time-migration velocity model. The velocity model building proposed here is based on the kinematic wavefield attributes...
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Journal Article
Journal: Geophysics
Published: 29 July 2015
Geophysics (2015) 80 (6): WD27–WD36.
...Amr Ibrahim; Mauricio D. Sacchi ABSTRACT Stolt migration is a Fourier-domain imaging operator that assumes a constant-velocity media. We have developed a multivelocity version of the Stolt migration and demigration operators to derive a transform that can decompose seismic data into a sparse...
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Journal Article
Journal: Geophysics
Published: 22 May 2014
Geophysics (2014) 79 (3): WA97–WA105.
...Wiktor Waldemar Weibull; Børge Arntsen ABSTRACT The forward and inverse process of seismic migration and demigration or remodeling has many useful applications in seismic data processing. We evaluated a method to reobtain the seismic reflection data after migration, by inverting the common image...
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Journal Article
Journal: Geophysics
Published: 03 May 2010
Geophysics (2010) 75 (3): S111–S119.
... because we integrate for half of the time only (until t = 0 ). Equation 9 is not an exact result; note the approximation detailed in Appendix A . END This provides the initial migrated section, function of h : FOR EACH TIME DELAY DEMIGRATION IN THE INITIAL MODEL...
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Journal Article
Journal: Geophysics
Published: 07 February 2008
Geophysics (2008) 73 (2): S35–S46.
...Hervé Chauris; Truong Nguyen Abstract Curvelets can represent local plane waves. They efficiently decompose seismic images and possibly imaging operators. We study how curvelets are distorted after demigration followed by migration in a different velocity model. We show that for small local...
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Journal Article
Journal: The Leading Edge
Published: 01 July 2000
The Leading Edge (2000) 19 (7): 712–715.
... can be found in “Seismic modeling by demigration” in the July–August issue of G eophysics . A new process in seismic reflection imaging called demigration has been designed as the inverse of migration and is, thus, easily confused with forward modeling . This paper will clarify...
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Journal Article
Journal: Geophysics
Published: 01 January 2000
Geophysics (2000) 65 (4): 1281–1289.
...Lúcio T. Santos; Jörg Schleicher; Martin Tygel; Peter Hubral Abstract Kirchhoff-type, isochron-stack demigration is the natural asymptotic inverse to classical Kirchhoff or diffraction-stack migration. Both stacking operations can be performed in true amplitude by an appropriate selection of weight...
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Journal Article
Journal: Geophysics
Published: 01 December 1999
Geophysics (1999) 64 (6): 1793–1805.
...Herman H. Jaramillo; Norman Bleistein Abstract The Kirchhoff approximation provides a representation of seismic data as a summation of imaged data along isochron surfaces (demigration). The asymptotic inversion of this representation provides a migration as a summation of seismic data along...
Journal Article
Journal: Geophysics
Published: 01 February 1997
Geophysics (1997) 62 (1): 183–194.
...Joerg Schleicher; Peter Hubral; Martin Tygel; Makky S. Jaya Abstract The size of the aperture has an important influence on the results of (Kirchhoff-type) migration and demigration. For true-amplitude imaging, it is crucial not to have apertures below a certain size. For both the minimum migration...
Journal Article
Journal: Geophysics
Published: 01 March 1994
Geophysics (1994) 59 (3): 439–449.
... time interpretations are still used and are 'demigrated' using the Kirchhoff time migration equations. This backs out the effect of the time migration prior to a ray depth migration and enables the lateral shifts between the time migrated image and a depth migrated image to be quantified. These shifts...
Image
The shot gather of a source located at  x  = 15.6 km for (a) the observed d...
Published: 22 September 2022
Figure 22. The shot gather of a source located at x  = 15.6 km for (a) the observed data set, (b) the demigrated data using the RTM image, (c) the demigrated data using the LSRTM image, (d) the demigrated data using the deep LSRTM without transfer learning, and (e) the demigrated data using
Image
Comparison between the (a) true synthetic data obtained by <span class="search-highlight">demigrating</span> all ...
Published: 20 October 2021
Figure 6. Comparison between the (a) true synthetic data obtained by demigrating all SOGs and data-domain reconstructions using (b) 1, (c) 2, (d) 3, (e) 4, and (f) 5 components. Whereas to obtain panel (a) all 17 SOGs were demigrated, each subsequent panel required demigration only of its
Image
(a) A <span class="search-highlight">demigrated</span> CDP gather showing wrap-around artifacts close to the time...
Published: 15 May 2017
Figure D-1. (a) A demigrated CDP gather showing wrap-around artifacts close to the time zero. These artifacts are inherent to the forward modeling (i.e., demigration) operator, due to the nature of the inverse Fourier transform. (b) Migrated result of demigrated data in panel (a). The high
Image
Application of a single migration&#x2F;<span class="search-highlight">demigration</span> to remove ASDs. (a) Subsurfac...
Published: 05 January 2021
Figure 4. Application of a single migration/demigration to remove ASDs. (a) Subsurface reflections and two ASDs in the unmigrated domain, (b) the migration results of (a) using the velocity of light in air (3 × 10 8  m/s), (c) the extracted ASDs in the migrated domain, (d) subtraction of (c) from
Image
The workflow of the CNN training step. We generate the PSF via <span class="search-highlight">demigration</span> ...
Published: 27 June 2022
Figure 7. The workflow of the CNN training step. We generate the PSF via demigration of the scattering points and then migration. The deconvolution operator is obtained by deconvolving each scattered PSF. We use the PSF as the input and the deconvolution operator as the label.
Image
Marine data. Close-up of common-offset sections: (a) original data and (b) ...
Published: 03 May 2019
Figure 7. Marine data. Close-up of common-offset sections: (a) original data and (b) demigrated data. Main events are recovered in demigrated image (b).
Image
(a) Common-offset ( h =1000 m) data and (b) migrated data from a syncline-s...
Published: 12 January 2006
Figure 2. (a) Common-offset ( h =1000 m) data and (b) migrated data from a syncline-shaped reflector embedded in a constant-velocity ( v =2000 m/s) medium. (c) Demigrated and (d) migrated line elements superimposed on the data and migrated data, respectively. The excellent agreement between
Journal Article
Journal: Geophysics
Published: 11 March 2022
Geophysics (2022) 87 (3): A43–A48.
... after migration and demigration. One-way wave-equation migration would automatically damp high-slope components in the evanescent region while accurately handling the other components. Thus, the migration velocity can be tuned to naturally trap a given range of high-slope components into the evanescent...
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Image
Smooth velocity model used for <span class="search-highlight">demigration</span> of synthetic SOGs.
Published: 20 October 2021
Figure 5. Smooth velocity model used for demigration of synthetic SOGs.
Image
(a) The  Q -attenuated and (b) acoustic <span class="search-highlight">demigration</span> records.
Published: 07 July 2021
Figure 11. (a) The Q -attenuated and (b) acoustic demigration records.