Introduction
Depth conversion of time data into depth data can also be performed for 2D seismic lines. It utilizes in principle the same basic techniques as desribed in Depth Conversion of time surfaces. In addition extra attention is paid to transforming the wavelets into a new wavelets form using spline based algorithms.
On this page:
Formula for depth conversion
Depth conversion applies the formula
Standard formula for depth conversion:
- Seismic_lines_in_depth = Seismic_lines_in_time x Velocity
The seismic linesare depth converted according to the corresponding velocity field. The velocity field describing the input velocity can be:
Velocity options:
- Time-velocity cube
- Stacking velocity data along the same line
- Lookup curve fory (time) to x(depth)
- Constant velocity in meter per second
Command menus for seimic depth conversion
Seismic lines (or seismic sections as they are also called) is organized under a folder having the schema Seismic Data. The seismic lines themselves have schema Seismic Line.
The following command menus for depth conversion of seismic lines are present:
- seismic lines in a folder->Depth conversion of seismic in a folder
- seismic line->Seismic depth conversion
Depth conversion of seismic
H2. Specify to which depth value depth conversion is to be performed.
Enter values for new vertical resolution if needed. Normally one could have a finer resolution for the depth converted seismic grid. The really fine resolution should only be used for powerful machines or low memory data types. Try to keep the new grid size below 30-40Mb if possible in the normal case.
To achieve a satisfactory depth conversion apply a smooth velocity field or a smooth velocity cube. It is assumed that the velocity data is covering the seismic outline. If not, the depth conversion will use the nearest velocity data that is covered by the outline.
A new outline is generated after depth conversion. This new outline makes a rectangular frame from top to the specified depth.
All seismic sections are depth converted and saved back into the project.
The default option is to create a new folder bearing the same name with the extension _depth.
Only seismic sections that are depth converted will be saved in the new folder.
Otherwise one can override the input time seismic with the depth seismic. In that case, make sure that you work on copies of the original seismic sections in time.
It is thus necessary to take a copy of the complete folder with seismic sections and run this command object on the folder doing a depth conversion on all seismic sections in the folder.
Seismic sections that are not depth converted if they are outside the cube are listed in the message area.