Practical aspects and applications of 2D stereotomography

Billette, Frédéric; Bégat, Soazig Le; Podvin, Pascal; Lambaré, Gilles

doi:10.1190/1.1581072

Cited by 122 publications

(124 citation statements)

References 36 publications

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“…We have applied the above technique of velocity model refinement to the Marmousoft data (Billette et al, 2003). These data were constructed by Born modeling in a smoothed version of the Marmousi model (Versteeg and Grau, 1990).…”

Section: Numerical Examplesmentioning

confidence: 99%

“…Even when the time migrated image is not convenient for structural interpretation, the so-constructed time-migration velocity model can still be used for the construction of an initial depth velocity model by means of time-to-depth conversion. This initial depth velocity model can then later be refined using more sophisticated depth migration-velocity analysis techniques like tomographic methods (Billette et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Coherence measures in automatic time migration velocity analysis

Maciel¹,

Costa²,

Schleicher

2011

SEG Technical Program Expanded Abstracts 2011

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Time-migration velocity analysis can be carried out automatically by evaluating the coherence of the migrated seismic events in the common-image gathers (CIGs). The performance of gradient methods for automatic time-migration velocity analysis depends on the the coherence measures used in the objective function. We compare the results of four different coherence measures, being conventional semblance, differential semblance, an extended differential semblance using more neighboring traces, and the product of the latter with conventional semblance. In our numerical experiments, the objective functions based on conventional semblance and on the product of conventional semblance with extended differential semblance provided the best velocity models, as evaluated by the flatness of the resulting common-image gathers. The method can be easily extended to anisotropic media.

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Section: Numerical Examplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coherence measures in automatic time migration velocity analysis

Maciel¹,

Costa²,

Schleicher

2011

SEG Technical Program Expanded Abstracts 2011

View full text Add to dashboard Cite

show abstract

“…It exploits the arrival time of locally coherent events within an automatic procedure to select a seismogram collection [27]. Some applications to synthetic and real data sets are shown in [7,8]. Finally, …”

Section: Existing Methodsmentioning

confidence: 99%

A parallel evolution strategy for an earth imaging problem in geophysics

et al. 2015

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In this paper we propose a new way to compute a rough approximation solution, to be later used as a warm starting point in a more refined optimization process, for a challenging global optimization problem related to Earth imaging in geophysics. The warm start consists of a velocity model that approximately solves a full-waveform inverse problem at low frequency. Our motivation arises from the availability of massively parallel computing platforms and the natural parallelization of evolution strategies as global optimization methods for continuous variables.Our first contribution consists of developing a new and efficient parametrization of the velocity models to significantly reduce the dimension of the original optimization space. Our second contribution is to adapt a class of evolution strategies to the specificity of the physical problem at hands where the objective function evaluation is known to be the most expensive computational part. A third contribution is the development of a parallel evolution strategy solver, taking advantage of a recently proposed modification of these class of evolutionary methods that ensures convergence and promotes better performance under moderate budgets.The numerical results presented demonstrate the effectiveness of the algorithm on a realistic 3D full-waveform inverse problem in geophysics. The developed numerical approach allows us to successfully solve an acoustic full-waveform inversion problem at low frequencies on a reasonable number of cores of a distributed memory computer.

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“…Although several numerical implementations ͑e.g., Chauris et al, 2002;Billette et al, 2003;Lambaré et al, 2004͒ of the stereotomographic velocity inversion are illustrated in practical applications, automatic picking of locally coherent events in prestack time domain remains a critical point for stereotomography. Lavaud et al ͑2004͒ proposed picking locally coherent events in poststack rather than in prestack domain.…”

Section: Introductionmentioning

confidence: 99%

Residual stereotomographic inversion

2006

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Depth migration requires highly accurate knowledge of the subsurface velocity field. Different traveltime tomographic methods are used for this purpose. Stereotomography is a tomographic method that uses local dip estimates in addition to traveltimes for velocity model estimation. We present a new methodology for velocity model updating. It combines poststack stereotomography and residual moveout velocity inversion. The former is used for initial model construction and the latter for updating the velocity model. Residual inversion is a kind of stereotomographic inversion applied to common reflection point ͑CRP͒ gathers after model-based moveout correction. Velocity analysis can be made more efficient by preselecting the traces that contribute to a series of CRP gathers and using only these traces for inversion. The algorithm is defined in a two-step procedure. First, ray tracing from the reflection point for nonzero reflection offsets defines the source and receiver locations of the data traces in the CRS gather. Then these traces are moveout corrected according to the calculated traveltimes and residual moveout is estimated. The interval velocity model is updated by fitting the velocity that minimizes estimated residuals. Application of the proposed technique demonstrates its robustness and reliability for fast and automatic velocity model estimation.

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Practical aspects and applications of 2D stereotomography

Cited by 122 publications

References 36 publications

Coherence measures in automatic time migration velocity analysis

Coherence measures in automatic time migration velocity analysis

A parallel evolution strategy for an earth imaging problem in geophysics

Residual stereotomographic inversion

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