Velocity inversion by differential semblance optimization

Symes, William W.; Carazzone, James J.

doi:10.1190/1.1443082

Cited by 400 publications

(220 citation statements)

References 16 publications

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“…In DSVA, the perturbed image is computed by applying the fully automated differential-semblance operator (DSO) (Symes and Carazzone, 1991) to SODCIGs or ADCIGs. When applied to SODCIGs, DSO minimizes the energy not focused at zerooffset.…”

Section: Discussionmentioning

confidence: 99%

Migration-velocity Analysis Using Image-space Generalized Wavefields

Cardoso¹,

Biondi²

2011

73rd EAGE Conference and Exhibition Incorporating SPE EUROPEC 2011

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An accurate depth-velocity model is the key for obtaining good quality and reliable depth images in areas of complex geology. In such areas, velocity-model definition should use methods that describe the complexity of wavefield propagation, such as focusing and defocusing, multiple arrivals, and frequency-dependent velocity sensitivity. Wave-equation tomography in the image space has the ability to handle these issues because it uses wavefields as carriers of information. However, its high cost and low flexibility for parametrizing the model space has prevented its routine industrial use.This thesis aims at overcoming those limitations by using new wavefields as carriers of information: the image-space generalized wavefields. These wavefields are synthesized by using a pre-stack generalization of the exploding-reflector model. Cost of wave-equation tomography in the image space is decreased because only a small number of image-space generalized wavefields are necessary to accurately describe the kinematics of velocity errors and because these wavefields can be easily used in a target-oriented way. Flexibility is naturally incorporated into wave-equation tomography in the image space by using these wavefields because their modeling have as the initial conditions some key selected reflectors, allowing a layer-based parametrization of the model space.To use the image-space generalized wavefields in wave-equation tomography in the image space, the method is extended from the shot-profile domain to the image-space generalized-sources domain. In this new domain, the velocity updates are very fast. ER denotes Easily Reproducible and are the results of processing described in the paper. The author claims that you can reproduce such a figure from the programs, parameters, and makefiles included in the electronic document. The data must either be included in the electronic distribution, be easily available to all researchers (e.g., SEG-EAGE data sets), or be available in the SEP data library 2 . We assume you have a UNIX workstation with Fortran, Fortran90, C, X-Windows system and the software downloadable from our website (SEP synthetic data examples associated with this report are classified as NR because they were generated externally to SEP and only the results were released by agreement.Our testing is currently limited to LINUX 2.6 (using the Intel Fortran90 I thank Biondo Biondi, my adviser, for always being a source of encouragement and a reference on academic honesty. His attitude made clearer to me both the importance of obtaining good results and the usefulness of the bad ones, which deserve to be brought to light. I thank Jon Claerbout for initiating us students into the mysteries of inverse problems and for sharing his contagious enthusiasm for doing research. I admire his energy, curiosity, and serendipity. Bob Clapp has constantly been steps ahead of everyone in looking for computational solutions that best fit the type and size of geophysical problems we propose to solve. Also, his knowledge about ...

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Section: Discussionmentioning

confidence: 99%

Migration-velocity Analysis Using Image-space Generalized Wavefields

Cardoso¹,

Biondi²

2011

73rd EAGE Conference and Exhibition Incorporating SPE EUROPEC 2011

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“…[47]) or subsurface offset in the differential semblance approach (cf. [34]). The operators A we (α) are microlocally invertible under certain conditions on the ray geometry [48] (for small p).…”

Section: Velocity Continuation Of Common-image Point Gathers In the Pmentioning

confidence: 99%

“…We show an example, revealing the potential of the comprehensive theory presented here (Section 4). Velocity continuation of image gathers can directly be exploited in reflection tomography, the problem of determining the background velocity, see [34,35,32,36,37].…”

Section: Introductionmentioning

confidence: 99%

Evolution-equation approach to seismic image, and data, continuation

2008

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In reflection seismology one places point sources and point receivers on the earth's surface, forming an acquisition geometry. Each source generates acoustic waves in the subsurface, that are reflected where the medium properties vary discontinuously. The reflections that can be observed at the receivers are used to image these discontinuities or reflectors assuming a background medium. We analyze methods to circumvent the repeated imaging of reflectors under varying background media, or the repeated modelling of reflections under varying acquisition geometries. These methods involve the introduction of the notion of seismic continuation. Here, we develop the foundation of, and a comprehensive framework for seismic continuation while extending earlier approaches to allow for the formation of caustics. Traditionally, seismic continuation has been viewed from a geometrical (ray asymptotic) point of view; here, we introduce the notion of wave-equation continuation through the appearance of evolution equations.

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“…In the absence of other information one can use the DSO penalty function P  (x,)=|| (Figure 1a), shown to produce high-quality inversion results (Symes and Carazzone, 1991;Shen et al, 2005).…”

Section: D Asm-idt Theorymentioning

confidence: 99%

“…A key decision in the ASM-IDT inversion procedure is to specify a judicious penalty operator that eliminates energy already optimally focused in the extended image gather volume at the zero correlation lag and upweights that poorly focused at nonzero correlation lags. A common way to accomplish this is through applying a differential semblance operator (DSO) (Symes and Carazzone, 1991;Shen et al, 2005) that cancels out a perfectly focused image at the zero correlation lag. However, there are other classes of penalty functions that can be used in the ASM-IDT inversion procedure; e.g., ones that compensate for illumination irregularities (Yang et al, 2012) or more fully account for scattering theory (Albertin, 2011) The 4D ASM-IDT velocity estimation problem shares many similarities with -and may be regards an extension of -3D ASM-IDT inversion.…”

Section: Introductionmentioning

confidence: 99%