Changes

==AVO scanning==

==AVO scanning==

[[file:amplitude-versus-offset-avo-analysis_fig5.png|left|thumb|{{figure number|5}}Gas well AVO model, involving blocked well logs and calibrated (wavelet-processed) seismic data.]]

[[file:amplitude-versus-offset-avo-analysis_fig5.png|300px|thumb|{{figure number|5}}Gas well AVO model, involving blocked well logs and calibrated (wavelet-processed) seismic data.]]

The computer can efficiently measure the change in [[amplitude]] across the offsets of a [[CDP gather]] for each time sample and can produce a single number that is the best fit slope to that change in amplitude. This collection of numbers can be plotted like a seismic cross section to yield an amplitude versus offset gradient section. The gradient section can then be interpreted, and AVO anomalies can be correlated to the [[stack section]], on which an interpreter has already identified key horizons and potential structural or stratigraphic trapping areas. The purpose of this step is to identify quickly regions of anomalous AVO behavior, which can then be studied further with detailed modeling and rock physics calibration.

The computer can efficiently measure the change in [[amplitude]] across the offsets of a [[CDP gather]] for each time sample and can produce a single number that is the best fit slope to that change in amplitude. This collection of numbers can be plotted like a seismic cross section to yield an amplitude versus offset gradient section. The gradient section can then be interpreted, and AVO anomalies can be correlated to the [[stack section]], on which an interpreter has already identified key horizons and potential structural or stratigraphic trapping areas. The purpose of this step is to identify quickly regions of anomalous AVO behavior, which can then be studied further with detailed modeling and rock physics calibration.

[[file:amplitude-versus-offset-avo-analysis_fig6.png|thumb|{{figure number|6}}Comparison of calibrated seismic data and the gas well AVO model.]]

[[file:amplitude-versus-offset-avo-analysis_fig6.png|300px|{{figure number|6}}Comparison of calibrated seismic data and the gas well AVO model.]]

==AVO modeling==

==AVO modeling==