Changes

==Example==

==Example==

In the figure below, a sonic log has been converted to time and velocity. Note that the time axis on the seismic section and the converted sonic log are linear, while the depth tick marks on the sonic are nonlinear. The geological horizons annotated on the sonic log are located via the depth tics from picks on other logs (electric, gamma ray, etc.). It is important to realize that a sonic log never goes to the surface; there is always a gap for the surface casing. So we do not expect time zero on the converted log to fit at time zero on the seismic section. In practice, the log is placed over the seismic section and shifted vertically until we are satisfied with the fit.

In [[:file:interpreting-seismic-data_fig12-8.png|Figure 1]], a sonic log has been converted to time and velocity. Note that the time axis on the seismic section and the converted sonic log are linear, while the depth tick marks on the sonic are nonlinear. The geological horizons annotated on the sonic log are located via the depth tics from picks on other logs (electric, gamma ray, etc.). It is important to realize that a sonic log never goes to the surface; there is always a gap for the surface casing. So we do not expect time zero on the converted log to fit at time zero on the seismic section. In practice, the log is placed over the seismic section and shifted vertically until we are satisfied with the fit.

[[file:interpreting-seismic-data_fig12-8.png|thumb|{{figure number|12-8}}. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-8.png|thumb|{{figure number|1}}. Copyright: Liner, 1999; courtesy PennWell.]]

==See also==

==See also==