Body-wave radiation patterns and AVO in transversely isotropic media

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Geophysics

DOI:https://doi.org/10.1190/1.1443876· OSTI ID:118785

Tsvankin, I ^[1]

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1. Colorado School of Mines, Golden, CO (United States). Center for Wave Phenomena

The angular dependence of reflection coefficients may be significantly distorted in the presence of elastic anisotropy. However, the influence of anisotropy on amplitude variation with offset (AVO) analysis is not limited to reflection coefficient. AVO signatures (e.g., AVO gradient) in anisotropic media are also distorted by the redistribution of energy along the wavefront of the wave traveling down to the reflector and back up to the surface. Significant anisotropy above the target horizon may be rather typical of sand-shale sequences commonly encountered in AVO analysis. Here, the author examines the influence of P- and S-wave radiation patterns on AVO in the most common anisotropic model--transversely isotropic media. A concise analytic solution, obtained in the weak-anisotropy approximation, provides a convenient way to estimate the impact of the distortions of the radiation patterns on AVO results. The anisotropic directivity factor for the incident wave may be of equal of greater importance for AVO than the influence of anisotropy on the reflection coefficient. Therefore, interpretation of AVO anomalies in the presence of anisotropy requires an integrated approach that takes into account not only the reflection coefficient but also the wave propagation above the reflector.

• DOE Contract Number: FG02-89ER14079
• OSTI ID: 118785
• Journal Information: Geophysics, Journal Name: Geophysics Journal Issue: 5 Vol. 60; ISSN GPYSA7; ISSN 0016-8033
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
ALGORITHMS
ANISOTROPY
DATA PROCESSING
ELASTIC SCATTERING
EXPLORATION
PETROLEUM DEPOSITS
SEISMIC SURVEYS
SEISMIC WAVES
WAVE PROPAGATION