Linearized amplitude variation with offset "AVO… inversion with supercritical angles

Contrary to popular belief, a linearized approximation of the Zoeppritz equations may be used to estimate the reflection coefficient for angles of incidence up to and beyond the critical angle. These supercritical reflection coefficients are complex, implying a phase variation with offset in addition to amplitude variation with offset (AVO). This linearized approximation is then used as the basis for an AVO waveform inversion. By incorporating this new approximation, wider offset and angle data may be incorporated in the AVO inversion, helping to stabilize the problem and leading to more accurate estimates of reflectivity, including density reflectivity.

[1]  J. Downton,et al.  An Efficient Method For AVO Modeling of Reflected Spherical Waves , 2005 .

[2]  Paul G. Richards,et al.  Quantitative Seismology: Theory and Methods , 1980 .

[3]  G. C. Smith,et al.  Weighted stacking for rock property estimation and detection of gas , 1987 .

[4]  Fabio Rocca,et al.  Eigenvalues and eigenvectors of linearized elastic inversion , 1993 .

[5]  G. H. F. Gardner,et al.  FORMATION VELOCITY AND DENSITY—THE DIAGNOSTIC BASICS FOR STRATIGRAPHIC TRAPS , 1974 .

[6]  J. Downton,et al.  Seismic parameter estimation from AVO inversion , 2005 .

[7]  A. Buland,et al.  Bayesian linearized AVO inversion , 2003 .

[8]  C. Ursenbach,et al.  Spherical‐wave AVO‐modeling in elastic and anelastic transversely isotropic (VTI) media , 2005 .

[9]  Herbert W. Swan,et al.  Velocities from amplitude variations with offset , 2001 .

[10]  Laurence R. Lines,et al.  Three Term AVO Waveform Inversion , 2004 .

[11]  Milo M. Backus,et al.  Waveform-based AVO inversion and AVO prediction-error , 1996 .

[12]  Per Christian Hansen,et al.  Rank-Deficient and Discrete Ill-Posed Problems , 1996 .

[13]  L. Lines,et al.  Constrained three-parameter AVO inversion and uncertainty analysis , 2001 .

[14]  J. Claerbout.  Earth Soundings Analysis: Processing Versus Inversion , 1992 .

[15]  V. Červený,et al.  Seismic Ray Theory , 2001, Encyclopedia of Solid Earth Geophysics.

[16]  A. Rüger.  Reflection Coefficients and Azimuthal AVO Analysis in Anisotropic Media , 2002 .

[17]  Xiaoxia Xu,et al.  Geometrical spreading of P-waves in horizontally layered, azimuthally anisotropic media , 2005 .

[18]  J. Castagna,et al.  Relationships between compressional‐wave and shear‐wave velocities in clastic silicate rocks , 1985 .