Changes

* ''Detailed AVO modeling supported by well log data''—Provide base information upon which to judge and interpret the AVO study using well log data in the vicinity of an exploration target.

* ''Detailed AVO modeling supported by well log data''—Provide base information upon which to judge and interpret the AVO study using well log data in the vicinity of an exploration target.

* ''Elastic model inversion at prospective locations''—Identify potential reservoirs and describe them numerically prior to drilling.

* ''Elastic model inversion at prospective locations''—Identify potential reservoirs and describe them numerically prior to drilling.

Readers interested in additional information on AVO analysis should begin by consulting the work of Hilterman,<ref name=pt07r19>Hilterman, F. J., 1990, Is AVO the seismic signature of lithology? A case history of Ship Shoal-South Addition: Geophysics—The Leading Edge, June, p. 1522.</ref> Neidell,<ref name=pt07r38>Neidell, N. S., 1986, Amplitude variation with offset: Geophysics—The Leading Edge, March, p. 47–51.</ref> and Ostrander.<ref name=pt07r43>Ostrander, W. J., 1984, Plane-wave reflection coefficients for gas sands at nonnormal angles of incidence: Geophysics, v. 49, p. 1637–1648, 10, 1190/1, 1441571.</ref>

Readers interested in additional information on AVO analysis should begin by consulting the work of Hilterman,<ref name=pt07r19>Hilterman, F. J., 1990, Is AVO the seismic signature of lithology? A case history of Ship Shoal-South Addition: Geophysics—The Leading Edge, June, p. 1522.</ref> Neidell,<ref name=pt07r38>Neidell, N. S., 1986, Amplitude variation with offset: Geophysics—The Leading Edge, March, p. 47–51.</ref> and Ostrander.<ref name=pt07r43>Ostrander, W. J., 1984, Plane-wave reflection coefficients for gas sands at nonnormal angles of incidence: Geophysics, v. 49, p. 1637–1648, 10, 1190/1, 1441571.</ref>

==AVO feasibility studies==

==AVO feasibility studies==

[[file:amplitude-versus-offset-avo-analysis_fig2.png|thumb|{{figure number|2}}Brine sand model.]]

[[file:amplitude-versus-offset-avo-analysis_fig1.png|left|thumb|{{figure number|1}}Possible combinations of the acoustic and shear terms.]]

Whether or not there is an application for amplitude versus offset analysis in a given exploration setting is an often posed problem. The explorationist should ask several questions. Are the AVO phenomena that may be present large enough to overcome the various noises in the system? Are there sufficient differences between geological conditions and seismic expressions to distinguish between them?

Whether or not there is an application for amplitude versus offset analysis in a given exploration setting is an often posed problem. The explorationist should ask several questions. Are the AVO phenomena that may be present large enough to overcome the various noises in the system? Are there sufficient differences between geological conditions and seismic expressions to distinguish between them?

A reflection coefficient can be thought of as consisting of the sum of two components—an acoustic term and a shear term. The acoustic term depends only on the impedance of the two layers and the angle of incidence. The shear term depends on Poisson's ratio in the two layers and also on the angle of incidence.

A reflection coefficient can be thought of as consisting of the sum of two components—an acoustic term and a shear term. The acoustic term depends only on the impedance of the two layers and the angle of incidence. The shear term depends on Poisson's ratio in the two layers and also on the angle of incidence.