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Comparison of two algorithms for isotropic elastic P and S vector decomposition

Wenlong Wang, George A. McMechan and Qunshan Zhang
Comparison of two algorithms for isotropic elastic P and S vector decomposition
Geophysics (July 2015) 80 (4): T147-T160

Abstract

P- and S-wavefield separation is necessary to extract PP and PS images from prestack elastic reverse time migrations. Unlike traditional separation methods that use curl and divergence operators, which do not preserve the wavefield vector component information, we did P and S vector decomposition, which preserves the same vector components that exist in the input elastic wavefield. The amplitude and phase information was automatically preserved, so no amplitude or phase corrections were required. We considered two methods to realize P and S vector decomposition: selective attenuation and decoupled propagation. Selective attenuation uses viscoelastic extrapolation, in which the Q-values are used as processing parameters, to remove either the P-waves or the S-waves. Decoupled propagation rewrites the stress and particle velocity formulation of the elastic equations into separate P- and S-wave components. In both methods, the decomposition is realized during the extrapolation of an elastic wavefield. These algorithms could also perform P and S decomposition in x-t gather data by extrapolating the data downward from the receivers, during which the decomposition is performed, and then back upward to record the decomposed P- and S-waves at the receivers. Comparisons of the two methods in terms of efficiency, accuracy, and memory showed that both could separate P- and S-waves in the vector domain. The decoupled propagation is preferable in terms of speed and memory cost, but was applicable only to elastic propagation.


ISSN: 0016-8033
EISSN: 1942-2156
Coden: GPYSA7
Serial Title: Geophysics
Serial Volume: 80
Serial Issue: 4
Title: Comparison of two algorithms for isotropic elastic P and S vector decomposition
Affiliation: University of Texas, Dallas, Center for Lithospheric Studies, Richardson, TX, United States
Pages: T147-T160
Published: 201507
Other Date: 20150625
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 32
Accession Number: 2015-098632
Categories: Applied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendices
Illustration Description: illus. incl. 1 table
Secondary Affiliation: Repsol Services Company, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 201542
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