Azimuthally Anisotropic 3D Velocity Continuation

Burnett, William; Fomel, Sergey

doi:10.1155/2011/484653

Cited by 22 publications

(3 citation statements)

References 37 publications

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“…A continuação da velocidade descreve como uma imagem sísmica é alterada, devido a uma mudança na velocidade de migração. Essa descrição é um processo de propagação de ondas, no qual as imagens mudam ao longo do eixo de velocidade [6].…”

Section: Introductionunclassified

Equação da onda imagem na análise sísmica do subsolo

Teixeira

Bortoli

2021

INTERMATHS

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Neste trabalho, estuda-se a equação da onda imagem e sua utilização para o problema de remigração na profundidade através de métodos numéricos. O problema consiste na reconstrução de uma imagem das camadas geológicas do subsolo a partir de uma imagem previamente migrada com um modelo de velocidade. O principal objetivo é a investigação de métodos numéricos para solução da equação da onda imagem, e para isso realizou-se investigação teórica e análise numérica. Os testes numéricos mostram que o método de diferenças finitas com aproximações centradas é o mais eficiente. Além disso, as implementações mostram a similaridade, tanto do aspecto físico como analítico, com a equação da onda clássica. Esta semelhança é útil, pois podemos considerar métodos já conhecidos e extensivamente estudados para a equação da onda clássica, e aplicá-los às investigações da equação da onda imagem para o problema de remigração na profundidade.

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Section: Introductionunclassified

Equação da onda imagem na análise sísmica do subsolo

Teixeira

Bortoli

2021

INTERMATHS

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“…OVC involves the continuous propagation of slope-decomposed seismic images along their characteristics over different time migration velocities [30,31]. Other continuation operators exist, for example Burnett and Fomel [32] proposed a method for applying azimuthally anisotropic velocity continuation to zero-offset data. The slope-decomposed partial images produced by OVC are equivalent to dip-angle gathers [33], enabling us to compute gather semblance and other pathintegration weights.…”

Section: Introductionmentioning

confidence: 99%

A Probabilistic Approach to Seismic Diffraction Imaging

Decker

Fomel

2021

Lithosphere

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We propose and demonstrate a probabilistic method for imaging seismic diffractions based on path-integral imaging. Our approach uses oriented velocity continuation to produce a set of slope-decomposed diffraction images over a range of plausible migration velocities. Utilizing the assumption that each partial image in slope is independent enables us to construct an object resembling a probability field from the slope-decomposed images. That field may be used to create weights for each partial image in velocity corresponding to the likelihood of a correctly migrated diffraction occurring at a location within the seismic image for that migration velocity. Stacking these weighted partial images over velocity provides us with a path-integral seismic diffraction image created using probability weights. We illustrate the principles of the method on a simple toy model, show its robustness to noise on a synthetic, and apply it to a 2D field dataset from the Nankai Trough. We find that using the proposed approach creates diffraction images that enhance diffraction signal while suppressing noise, migration artifacts, remnant reflections, and other portions of the wavefield not corresponding to seismic diffraction relative to previously developed diffraction imaging methods, while simultaneously outputting the most likely migration velocity. The method is intended to be used on data which has already had much of the reflection energy removed using a method like plane-wave destruction. Although it suppresses residual reflection energy successfully, this suppression is less effective in the presence of strong reflections typically encountered in complete field data. The approach outlined in this paper is complimentary to existing data domain methods for diffraction extraction, and the probabilistic diffraction images it generates can supplement existing reflection and diffraction imaging methods by highlighting features that have a high likelihood of being diffractions and accentuating the geologically interesting objects in the subsurface that cause those features.

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“…Therefore, the reflection energy can be suppressed by a method known as planewave destruction (Claerbout, 1992;Fomel, 2002). Separation and imaging of diffractions using plane-wave destruction in the poststack domain is proposed by Fomel et al (2007) and extended by Al-Dajani and Fomel (2010) and Burnett and Fomel (2011).…”

Section: Introductionmentioning

confidence: 99%

Separation and imaging of seismic diffractions using migrated dip-angle gathers

2012

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Common-reflection angle migration can produce migrated gathers either in the scattering-angle domain or in the dip-angle domain. The latter reveals a clear distinction between reflection and diffraction events. We derived analytical expressions for events in the dip-angle domain and found that the shape difference can be used for reflection/ diffraction separation. We defined reflection and diffraction models in the Radon space. The Radon transform allowed us to isolate diffractions from reflections and noise. The separation procedure can be performed after either time migration or depth migration. Synthetic and real data examples confirmed the validity of this technique.

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Azimuthally Anisotropic 3D Velocity Continuation

Cited by 22 publications

References 37 publications

Equação da onda imagem na análise sísmica do subsolo

Equação da onda imagem na análise sísmica do subsolo

A Probabilistic Approach to Seismic Diffraction Imaging

Separation and imaging of seismic diffractions using migrated dip-angle gathers

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