Physical modeling and analysis of P-wave attenuation anisotropy in transversely isotropic media
DRS at CSIR-National Institute of Oceanography
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Title |
Physical modeling and analysis of P-wave attenuation anisotropy in transversely isotropic media
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Creator |
Zhu, Y.
Tsvankin, I. Dewangan, P. Van Wijk, K. |
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Subject |
Anisotropic attenuation
seismic anisotropy |
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Description |
Anisotropic attenuation can provide sensitive attributes for fracture detection and lithology discrimination. This paper analyzes measurements of the P-wave attenuation coefficient in a transversely isotropic sample made of phenolic material. Using the spectral-ratio method, the group (effective) attenuation coefficient of P-waves transmitted through the sample for a wide range of propagation angles (from 0 degrees to 90 degrees) with the symmetry axis is estimated. Correction for the difference between the group and phase angles and for the angular velocity variation help us to obtain the normalized phase attenuation coefficient A governed by the Thomsenstyle attenuation-anisotropy parameters epsilon sub(Q) and delta sub(Q). Whereas the symmetry axis of the angle-dependent coefficient A practically coincides with that of the velocity function, the magnitude of the attenuation anisotropy far exceeds that of the velocity anisotropy. The quality factor Q increases more than tenfold from the symmetry axis (slow direction) to the isotropy plane (fast direction). Inversion of the coefficient A using the Christoffel equation yields large negative values of the parameters epsilon sub(Q) and delta sub(Q). The robustness of our results critically depends on several factors, such as the availability of an accurate anisotropic velocity model and adequacy of the homogeneous concept of wave propagation, as well as the choice of the frequency band. The methodology discussed here can be extended to field measurements of anisotropic attenuation needed for AVO (amplitude-variation-with- offset) analysis, amplitude-preserving migration, and seismic fracture detection
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Date |
2007-04-09T07:37:06Z
2007-04-09T07:37:06Z 2007 |
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Type |
Journal Article
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Identifier |
Geophysics, vol.72(1), D1-D7pp.
http://drs.nio.org/drs/handle/2264/572 |
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Language |
en
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Rights |
©2007 Society of Exploration Geophysicists. All rights reserved. Authors and publishers may present or republish up to two figures or tables per SEG article or per SEG book without seeking written permission from SEG, provided that full acknowledgment of the source is provided in the new work. SEG considers this fair use. There are no fees associated with this permission. Authors who need documentation that SEG is extending this permission are encouraged to print this message and present it to their publishers. Those who require further documentation should contact the SEG publications director. SEG recommends that authors and publishers who intend to reuse SEG figures or tables also seek consent of the original work’s lead author, if possible. The member search on the SEG Web site might prove a helpful resource in locating these authors. Requests to use any portion of “Seismic Data Analysis: Processing, Inversion, and Interpretation of Seismic Data” should be directed to the SEG publications director. |
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Format |
631035 bytes
application/pdf |
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Publisher |
Society of Exploration Geophysicists
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