Changes

==Step 2: Pick seismic horizons==

==Step 2: Pick seismic horizons==

[[file:interpreting-seismic-data_fig12-12.png|left|thumb|{{figure number|1}}(a) Representative line from the Glenn Pool data volume with sonic overlay and tracked events; (b) Horizon amplitude and time structure maps for the Wilcox. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-12.png|left|thumb|{{figure number|1}}(a) Representative line from the Glenn Pool data volume with sonic overlay and tracked events; (b) Horizon amplitude and time structure maps for the Wilcox. From Liner.<ref name=Liner_1999>Liner, Chris, Elements of 3-D Seismology: Tulsa, PennWell. Courtesy PennWell.</ref>]]

For 2-D data, only the traveltime to each event of interest is recorded with its coordinate along the line ''t''(''x''). For 3-D data, both traveltime and amplitude at each (''x, y'') are available from the seismic data cube, ''t''(''x, y'') and ''a''(''x, y''). The traveltimes form a time structure map, and the amplitudes are a horizon slice. [[:file:interpreting-seismic-data_fig12-12.png|Figure 1A]] shows a representative line from the Glenn Pool data volume with sonic overlay and tracked events. Horizon amplitude and time structure maps for the Wilcox are shown in [[:file:interpreting-seismic-data_fig12-12.png|Figures 1B, C]].

For 2-D data, only the traveltime to each event of interest is recorded with its coordinate along the line ''t''(''x''). For 3-D data, both traveltime and amplitude at each (''x, y'') are available from the seismic data cube, ''t''(''x, y'') and ''a''(''x, y''). The traveltimes form a time structure map, and the amplitudes are a horizon slice. [[:file:interpreting-seismic-data_fig12-12.png|Figure 1A]] shows a representative line from the Glenn Pool data volume with sonic overlay and tracked events. Horizon amplitude and time structure maps for the Wilcox are shown in [[:file:interpreting-seismic-data_fig12-12.png|Figures 1B, C]].

==Step 3: Calculate depth conversion velocity==

==Step 3: Calculate depth conversion velocity==

[[file:interpreting-seismic-data_fig12-13.png|thumb|{{figure number|2}}Hypothetical well with important reference points; average velocity map for the Wilcox Formation in the Glenn Pool survey. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-13.png|thumb|{{figure number|2}}Hypothetical well with important reference points; average velocity map for the Wilcox Formation in the Glenn Pool survey. From Liner.<ref name=Liner_1999 />Courtesy PennWell.]]

Calculate depth conversion velocity at locations where both well and seismic time picks exist. The wells used as control do not need velocity or density logs but must penetrate the event of interest. The event depth ''z'' (measured from seismic datum) is known from well control, and the vertical reflection time ''t'' is known from the previous item. The depth conversion velocity is given by

Calculate depth conversion velocity at locations where both well and seismic time picks exist. The wells used as control do not need velocity or density logs but must penetrate the event of interest. The event depth ''z'' (measured from seismic datum) is known from well control, and the vertical reflection time ''t'' is known from the previous item. The depth conversion velocity is given by

==Step 4: Convert time to depth==

==Step 4: Convert time to depth==

[[file:interpreting-seismic-data_fig12-14.png|left|thumb|{{figure number|3}}Process and result for the Glenn Pool Wilcox horizon. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-14.png|left|thumb|{{figure number|3}}Process and result for the Glenn Pool Wilcox horizon. From Liner.<ref name=Liner_1999 /> Courtesy PennWell.]]

Convert time to depth by multiplying the time structure map and the depth conversion velocity map, i.e.,

Convert time to depth by multiplying the time structure map and the depth conversion velocity map, i.e.,

==Step 5: Contour map==

==Step 5: Contour map==

[[file:interpreting-seismic-data_fig12-16.png|thumb|{{figure number|4}}zoom of the central area in the maps in Figure 5. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-16.png|thumb|{{figure number|4}}zoom of the central area in the maps in Figure 5. From Liner.<ref name=Liner_1999 /> Courtesy PennWell.]]

Contour or grid the integrated structure map with the same technique used for the wells-only depth map. This allows head-to-head comparison ([[:file:interpreting-seismic-data_fig12-16.png|Figure 4]]).

Contour or grid the integrated structure map with the same technique used for the wells-only depth map. This allows head-to-head comparison ([[:file:interpreting-seismic-data_fig12-16.png|Figure 4]]).

==Integrated map==

==Integrated map==

[[file:interpreting-seismic-data_fig12-15.png|thumb|{{figure number|5}}Comparison of the first depth map from well control only and the seismic plus well integrated depth map. Copyright: Liner, 1999; courtesy PennWell.]]

[[file:interpreting-seismic-data_fig12-15.png|thumb|{{figure number|5}}Comparison of the first depth map from well control only and the seismic plus well integrated depth map. From Liner.<ref name=Liner_1999 /> Courtesy PennWell.]]

The final product ''z''(''x'', ''y'') is called an integrated structure map. It honors all well-control depth points (by definition) and uses the seismic events to interpolate between these points. [[:file:interpreting-seismic-data_fig12-15.png|Figure 5]] is a comparison of the first depth map from well control only and the seismic plus well integrated depth map.

The final product ''z''(''x'', ''y'') is called an integrated structure map. It honors all well-control depth points (by definition) and uses the seismic events to interpolate between these points. [[:file:interpreting-seismic-data_fig12-15.png|Figure 5]] is a comparison of the first depth map from well control only and the seismic plus well integrated depth map.

* [[Mapping structure with seismic data]]

* [[Mapping structure with seismic data]]

* [[Preparing seismic data for mapping]]

* [[Preparing seismic data for mapping]]

==External links==

==External links==