Plane wave source composition: An accurate phase encoding scheme for prestack migration

Liu, Faqi; Stolt, Robert H.; Hanson, Douglas W.; Day, R.S.

doi:10.1190/1.1816854

Cited by 38 publications

(26 citation statements)

References 4 publications

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“…Então, cada campo de onda plana sintetizado (seção p s )é o resultado da superposição de todos os tiros do experimento sísmico. Como no método "Areal Shot" (Romero et al, 2000) ou "Delayed-shot Migration Method" (Liu et al, 2002;Zang et al, 2003), que são também métodos de migração de ondas planas baseados em soluções da equação da onda, precisamos somar um número razoável de seções de ondas planas migradas, para reduzir a influência dos termos-cruzados e conseguir uma imagem de boa qualidade de todo o modelo de subsuperfície.…”

Section: Migração De Ondas Planas -Método Kirchhoffunclassified

“…Mais recentemente, os métodos de migração utilizando ondas planas têm sido bastante empregados visando aumentar a eficiência computacional da extrapolação dos campos de ondas (Rietveld et al, 1994;Duquet et al, 2001;Pestana et al, 2001;Liu et al, 2002;Zhang et al, 2003;Zhang et al, 2005;Moreira Neto et al, 2005). Nesses métodos os registros de fonte pontual são sintetizados em dados sísmicos de fonte de onda plana, antes do processo de migração.…”

Section: Introductionunclassified

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Migração Kirchhoff em profundidade de seções de ondas planas

Pestana¹,

Neto²

2007

Rev. Bras. Geof.

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ABSTRACT. We present a migration method for plane wave source data based on the Kirchhoff integral. Plane wave migration has been employed to increase the efficiency of the wavefield extrapolation. Point source records are synthesized into a plane wave and the resulting plane wave data can be migrated using the same scheme as the one for conventional shot-record migration. Plane wave migration reduces the migration computation time, because the extrapolation does not need to be done for all the individual shot records, but only for the constant plane wave sections. Here we have developed a version of the plane wave migration method based on the Kirchhoff integral. To calculate the traveltimes for the point source and also for plane wave we used a eikonal solver. Once all plane waves section are migrated independently of the others, the final image is obtained by stacking all common images gathers. Integral methods are easier than the wave equation methods to adapt to different recording geometries and also allow large and small models to be treated in the same way. Also, with the aid of the Asymptotic Ray Theory (ART), integral methods can be extended to handle arbitrary velocity structures without any dip limitation. In this paper the SEG-EAGE salt model example and a real dataset from Gulf of Mexico are used to test the theory and show that Kirchhoff plane wave depth migration can produce images comparables in quality to those obtained with Kirchhoff migration and also a reduced computation cost when comparable with the Kirchhoff migration of common shot gathers.Keywords: pre-stack migration, Kirchhoff migration, plane wave, plane wave migration. RESUMO.Recentemente novos métodos de migração utilizando ondas planas têm sido desenvolvidos com o intuito de aumentar a eficiência computacional da etapa de extrapolação dos campos de ondas durante o processo de migração. Nesses métodos os dados de fonte pontual são sintetizados em registros de fontes de ondas planas antes do processo de migração. Em seguida, os campos de ondas planas resultantes podem ser migrados usando qualquer um dos esquemas de extrapolação utilizados nas migrações convencionais de tiro comum. Assim, a migração de ondas planas consegue reduzir o número de extrapolações durante o processo de migração, uma vez que a extrapolação nãoé mais feita para todos os tiros individualmente, mas apenas para as seções de ondas planas sintetizadas. Na migração de ondas planas faz-se necessário também a continuação para baixo do campo de onda da fonte, que no casoé uma onda plana, bem como a depropagação dos campos de ondas planas sintetizados. Com este trabalho buscamos melhorar ainda mais a eficiência computacional do método de migração de ondas planas e, para tanto, estamos propondo a sua implementação através de operadores de propagação baseados na Teoria Assintótica do Raio. A nossa versão Kirchhoff de migração para dados sísmicos sintetizados em onda planasé implementada utilizando os tempos de trânsito tanto da onda plana como da fonte pontual, calculado...

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Section: Migração De Ondas Planas -Método Kirchhoffunclassified

Section: Introductionunclassified

Migração Kirchhoff em profundidade de seções de ondas planas

Pestana¹,

Neto²

2007

Rev. Bras. Geof.

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“…One of these technologies is blended imaging, where multiple shotgathers are combined together by applying an amplitude or phase-encoding prior to migration (Romero et al, 2000). This process reduces the number of migrations that are needed to produce a final image (Liu, 1999;Morton, 1999;Romero et al, 2000;Soubaras, 2006;Zhang et al, 2007;Berkhout et al, 2009;Perrone and Sava, 2009). The encoding process introduces additional noise into the image, called cross-talk (Romero et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Blended source imaging by amplitude encoding

Godwin

Sava

2010

SEG Technical Program Expanded Abstracts 2010

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The computational cost of conventional imaging is large for today's wide-azimuth seismic surveys. One strategy to reduce the overall cost of seismic imaging is to migrate with multiple shot-gathers at once, a technique which is known as blended source imaging. Blended source imaging trades the reduced cost of imaging with the presence of artifacts (cross-talk) in the image. We show that a theoretical framework using a matrix representation of the imaging process adequately describes conventional, and blended source imaging. Furthermore, the matrix representation predicts both the quantity and strength of cross-talk artifacts prior to imaging, thus allowing us to decide a priori the trade off between cross-talk and speed. By exploiting our theoretical framework, we are able to design an amplitude encoding scheme, referred to as Truncated Singular Vector (TSV), that trades a significantly reduced cost of imaging with spatial resolution and cross-talk noise. The TSV encoding allows us to reduce the cost of imaging by at least an order of magnitude relative to conventional shot-record migration. Overall, we provide a framework for finding blended source encoding schemes, that produce good quality images at lower computational cost.

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“…Combining the plane wave shot record migration with the target-zone controlled illumination technique, Rietveld et al (1992) and Rietveld and Berkhout (1994) have successfully processed the Marmousi model and marine data. Recently, the phase code algorithm was developed based on the plane wave shot migration (Liu et al, 2002;Jing et al, 2000;Morton and Ober, 1998;Romero et al, 2000) which greatly improved image efficiency. The ray parameter selection method (Stork.…”

Section: Introductionmentioning

confidence: 99%

Plane wave shot PSDM and controlled illumination techniques

Cui

et al. 2007

Appl. Geophys.

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The Pre-Stack Depth Migration (PSDM) method based on wavefield continuation is the most reliable method for imaging complex structure in the subsurface, although there are large computational costs and poorly adaptive geometry. Plane wave shot migration is another method to perform exact wave equation prestack imaging with high computational efficiency and without the migration aperture problem. Moreover, wavefield energy can be compensated at the target zone by controlled illumination. In this paper, plane wave shot PSDM was implemented by the control of the plane down-going wavefield and selection of number and range of the raypaths in order to optimize the imaging effect. In addition, controlled illumination techniques are applied to enhance the imaging precision of interesting areas at different depths. Numerical calculation indicates that plane wave shot imaging is a rapid and efficient method with less computational cost and easy parallel computation compared to the single-square-root operator imaging for common shot gathers and doublesquare-root operator imaging for common midpoint gathers.

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Plane wave source composition: An accurate phase encoding scheme for prestack migration

Cited by 38 publications

References 4 publications

Migração Kirchhoff em profundidade de seções de ondas planas

Migração Kirchhoff em profundidade de seções de ondas planas

Blended source imaging by amplitude encoding

Plane wave shot PSDM and controlled illumination techniques

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