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Traveltime decomposition in practice

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Proceedings Papers

Paper presented at the 2017 SEG International Exposition and Annual Meeting, September 24–29, 2017
Paper Number: SEG-2017-17745788
... reflected traveltime inversion (WERTI). The reflection kernel analysis shows that mode decomposition can suppress the artifacts in gradient calculation. We design a two-step inversion strategy, in which PP reflections are firstly used to invert P wave velocity (Vp ), followed by S wave ve- locity (Vs...
Proceedings Papers

Paper presented at the 2018 SEG International Exposition and Annual Meeting, October 14–19, 2018
Paper Number: SEG-2018-2989356
... , 10.1190/segam2016-13778747.1 . Resnick , J. R. , 1993 , Seismic data processing for AVO and AVA analysis , in J.P. Castagna and M.M. Backus , eds ., Offset-dependent reflectivity: Theory and practice of AVO analysis : SEG , Investigations in Geophysics No. 8 , 175...
Proceedings Papers

Paper presented at the 2015 SEG Annual Meeting, October 18–23, 2015
Paper Number: SEG-2015-5903601
... the gradient is computed based on Born kernels and us- ing a matrix decomposition of the Fre´chet derivative. The traveltime sensitivity kernels The sensitivity kernels or the Fre´chet derivatives relate a per- turbation in the recorded data to a perturbation in the Earth model. The derivation of the...
Proceedings Papers

Paper presented at the 2018 SEG International Exposition and Annual Meeting, October 14–19, 2018
Paper Number: SEG-2018-2992555
... much harder. Conclusion We have derived the misfit sensitivity and traveltime inversion kernels for VTI elastic media for two sets of anisotropic parameters widely used in practice. Data at different offsets have different implications in the kernels. For near offsets, misfit sensitivity kernels...
Proceedings Papers

Paper presented at the 2011 SEG Annual Meeting, September 18–23, 2011
Paper Number: SEG-2011-1608
...- curate estimates of traveltimes, this still requires full (monopole) source coverage, a condition which is rarely met in practice. As a result, we generally recover only estimates of the true GF, which introduces uncertainties to the information recov- ered from these empirical (interferometric) Green s...
Proceedings Papers

Paper presented at the SEG International Exposition and Annual Meeting, September 15–20, 2019
Paper Number: SEG-2019-3215231
... practice, they are rarely adopted for their large computational costs and wavefield complexity. Accordingly, most anisotropic imaging algorithms are developed under the acoustic approximation (Alkhalifah, 1998, 2000). On the other hand, seismic wave propagation in viscoelastic media commonly suffers from...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 4–7, 1998
Paper Number: OTC-8759-MS
... depth requires processing algorithms that honor the physics of wave propagation and velocity models that accurately predict the traveltimes of seismic waves. Prestack depth migration algorithms have advanced in theory and in practice to the point where they are useful in making accurate images of...
Proceedings Papers

Paper presented at the 2017 SEG International Exposition and Annual Meeting, September 24–29, 2017
Paper Number: SEG-2017-17779992
... an efficient operator that based on Hilbert transform to improve the resolution of the 3D RTM. In the numerical example, the proposed 3D RTM with wavefield decomposition is applied to the two-layer model and SEG/EAGE salt dataset. The results show the effective wavefield decomposition operation...
Proceedings Papers

Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-1478
... general workflow of the analysis algorithm is to pick a window centered on the interpretation seed along the Z axis and then perform the spectrum decomposition in the window. In the practice, the window analysis works best when the interpretation target is almost flat and the signal wavelets travel along...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-1123
... in Fig- ure 2 represents z0 and which can be automatically or man- ually picked in practice. Each maxmum represents a curve in angle-domain CIGs denoted by the blue line in Figure 2a. Figure 2: (a). Angel-domain CIGs. (b). Semblance analysis panel. The blue dashed line in (a) represents the moveout...
Proceedings Papers

Paper presented at the 2013 SEG Annual Meeting, September 22–27, 2013
Paper Number: SEG-2013-1088
... traveltimes while an ideal full waveform inversion uses the complete seismic record, though in practice only a part of the record is used after some preprocessing. FWI provides higher resolution in theory but it is less robust than traveltime tomography in practice. Frequency-dependent traveltime tomography...
Proceedings Papers

Paper presented at the 2018 SEG International Exposition and Annual Meeting, October 14–19, 2018
Paper Number: SEG-2018-2995247
... arrivals and the reflection traveltimes simultaneously in the velocity inversion. The results of synthetic tests show that the joint MDLT can accurately recover some layered velocity models, with higher stability and accuracy than the first-arrival MDLT. true model raypath deformable layer...
Proceedings Papers

Paper presented at the 2008 SEG Annual Meeting, November 9–14, 2008
Paper Number: SEG-2008-2311
... practical tool for depth imaging, but conventional implementations suffer in areas of complicated geology, since only single arrivals are used in the implementation. In conventional approaches, rays are traced from a surface point to imaging points in the subsurface. The traveltime table for imaging points...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-1537
... SUMMARY Computation of multi-arrival traveltimes for angle-domain Kirchhoff migration is most simply performed by ray tracing from subsurface points. However, the high computational cost of this approach limits its feasibility in practice. Fortunately this ray-tracing procedure can be replaced...
Proceedings Papers

Paper presented at the 2009 SEG Annual Meeting, October 25–30, 2009
Paper Number: SEG-2009-4004
... to a synthetic example. Models consist of uniformly gridded cells in three dimensions with a constant velocity for each cell. Traveltimes of the model are calculated by applying finite-difference methods of the seismic-ray eikonal equation. The inversion minimizes a functional that includes a least...
Proceedings Papers

Paper presented at the 2014 SEG Annual Meeting, October 26–31, 2014
Paper Number: SEG-2014-0590
... Summary Decomposition of interfering wavefields is significant in VSP data processing. One of main strategies implementing multicomponent separation is using the difference of polarization directions of P-wave and SV-wave. We develop a wavefield decomposition method based on global...
Proceedings Papers

Paper presented at the 2003 SEG Annual Meeting, October 26–31, 2003
Paper Number: SEG-2003-2168
... ? ? ? ?Ll ,0,0 1 ? , where L is half a maximal offset shot-receiver. Let us minimize the objective ? ? ? ? dllablalaJ l 2 0 242 1 ? ?? . (3) From (3) it follows b l aa 7 5 21 . (4) Non-hyperbolic traveltime picking The estimate (4) is the LS one, but in practice, the coefficient standing at 2l is determined...
Proceedings Papers

Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-3242
... practice is based on the generation of offset gathers first, which are then converted to angle domain. The reason for this is that angle gathers are difficult to gener- ate; while methods for angle gather generation in WEM exists, due to the computational expense involved they are employed mostly in a...
Proceedings Papers

Paper presented at the 2003 SEG Annual Meeting, October 26–31, 2003
Paper Number: SEG-2003-2004
... basis functions for this vectorial space can be obtained by singular value decomposition (SVD). The new approximation is obtained in the form of a traveltime series t x , (1)1 1 2 2 3 3( ) ( ) ( ) ( ) c f x c f x c f x ? ? ? ? ? with exponent ? equal to 1 or 2. The functions fi are the basis functions...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-1522
... SUMMARY In complicated geologic environments with multipathing in traveltime fields, Kirchhoff migration can improve imaging results, if the integration is performed in the angle domain. Angle-domain migration operates on a traveltime table expressed as a function of image points and...

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