Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis
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...
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| Format: | Journal Article |
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Society of Exploration Geophysics
2011
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| Online Access: | http://hdl.handle.net/20.500.11937/16761 |
| _version_ | 1848749268640202752 |
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| author | Pevzner, Roman Gurevich, Boris Urosevic, Milovan |
| author_facet | Pevzner, Roman Gurevich, Boris Urosevic, Milovan |
| author_sort | Pevzner, Roman |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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. |
| first_indexed | 2025-11-14T07:18:14Z |
| format | Journal Article |
| id | curtin-20.500.11937-16761 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:18:14Z |
| publishDate | 2011 |
| publisher | Society of Exploration Geophysics |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-167612018-09-07T01:26:13Z Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis Pevzner, Roman Gurevich, Boris Urosevic, Milovan vertical seismic profile (VSP) shear wave (S-wave) anisotropy 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. 2011 Journal Article http://hdl.handle.net/20.500.11937/16761 10.1190/geo2010-0290.1 Society of Exploration Geophysics fulltext |
| spellingShingle | vertical seismic profile (VSP) shear wave (S-wave) anisotropy Pevzner, Roman Gurevich, Boris Urosevic, Milovan Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title | Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title_full | Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title_fullStr | Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title_full_unstemmed | Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title_short | Estimation of azimuthal anisotropy from VSP data using multicomponent S-wave velocity analysis |
| title_sort | estimation of azimuthal anisotropy from vsp data using multicomponent s-wave velocity analysis |
| topic | vertical seismic profile (VSP) shear wave (S-wave) anisotropy |
| url | http://hdl.handle.net/20.500.11937/16761 |