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dc.contributor.authorPevzner, Roman
dc.contributor.authorGurevich, Boris
dc.contributor.authorUrosevic, Milovan
dc.date.accessioned2017-01-30T11:57:40Z
dc.date.available2017-01-30T11:57:40Z
dc.date.created2012-02-23T20:00:59Z
dc.date.issued2011
dc.identifier.citationPevzner, Roman and Gurevich, Boris and Urosevic, Milovan. 2011. Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis. Geophysics 76 (5): pp. D1-D9.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/16761
dc.identifier.doi10.1190/geo2010-0290.1
dc.description.abstract

Observation of azimuthal shear wave anisotropy can be useful for characterization of fractures or stress fields. Shear wave anisotropy is often estimated by measuring splitting of individual shear wave events in vertical seismic profile (VSP) data. However, this method may become unreliable for zero-offset (marine) VSP where the seismogram often contains no strong individual shear events, such as direct downgoing shear wave, but often contains many low-amplitude PS mode converted waves. We have developed a new approach for estimation of the fast and slow shear wave velocities and orientation of polarization planes based on the multicomponent linear traveltime moveout velocity analysis. This technique is applicable to zero-offset VSP data, and should take advantage of the presence of a large number of shear wave events with the same apparent velocity (which, for a horizontally layered medium, should be close to the interval velocity).The approach assumes that the VSP data are acquired in a vertical well drilled in an orthorhombic medium with a horizontal symmetry plane (including horizontal transverse isotropy). The main idea is to estimate the dominant apparent velocity for a given polarization direction by measuring the coherency of the seismic signal of a large number of events as a function of the apparent velocity. The algorithm was tested on marine three-component (3C) VSP acquired in the North West Shelf of Australia, and on land 3C VSP acquired with different sources in the same borehole located in Otway Basin, Victoria. These tests show good agreement between anisotropy parameters (magnitude and orientation) derived from the VSP and cross-dipole sonic log data.

dc.publisherSociety of Exploration Geophysics
dc.subjectvertical seismic profile (VSP)
dc.subjectshear wave (S-wave)
dc.subjectanisotropy
dc.titleEstimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis
dc.typeJournal Article
dcterms.source.volume76
dcterms.source.number5
dcterms.source.startPageD1
dcterms.source.endPageD9
dcterms.source.issn0016-8033
dcterms.source.titleGeophysics
curtin.note

Copyright © 2011 Society of Exploration Geophysicists.

curtin.departmentDepartment of Exploration Geophysics
curtin.accessStatusOpen access


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