The Velocity Conversion process can:
- accurately resample velocities, and
- convert velocities between formats.
It uses a strategy that minimises the effect on the time-depth relationship:
- Convert input velocities to T-Z (time values sampled in depth) or Z-T (depth values sampled in time) consistent with the input vertical sequence.
- Linearly interpolate the time (depth) values to the output depth (time) sequence.
- Convert the interpolated result to the output velocity format.
Resampling in the Z-T domain preserves the time-depth relationship.
Time/depth conversion using arbitrary velocity formats works in a similar fashion (see How it Works (Time-Depth Conversion)).
Create velocity conversion process
- In the Control Panel, open the Process tab.
- At the tab header, click the Add icon and select New Process.
- Double-click Velocity Conversion.
- Type a name for the process and click OK.
Select input velocity to be converted
- In the Input Velocity section of the Details Panel, select the velocity volume to be converted at Velocity Volume. The conversion process supports both 2D and 3D velocity volumes.
- At Velocity Type, select the type of velocity you want to convert from. By default, this setting is based on the class of the input velocity volume.
- Select the unit of the input velocity at Velocity Units.
Define output velocity settings
- In the Output Settings section, select the type of velocity you want to convert to at Velocity Type.
- Define the Velocity Units.
- Type the vertical extent values and the increment for the output velocity. This is optional.
- A new velocity volume is available in the Volume tab.
Note: The output volume’s class by default is based on the Output Velocity Type you have selected in the velocity conversion process.
Tip: To quickly open the output volume, right-click the process item in the Process tab and click Open Child Volume. Vice versa, you can also open the process from the Volume tab directly. To do this, right-click the volume which was created from a process (indicated in italics) and click Open Parent Process.
The following example shows the conversion of a velocity volume from interval velocity (time) to interval velocity (depth):