Velocity Conversion

Description Safely resample velocity models and convert between formats.
Module(s) Insight
Requirements Velocity Model
Related Velocity Re-Datum, Velocity Model (From Well Checkshots)
Works with Velocity

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

Create velocity conversion process
  1. In the Control Panel, open the Process tab.
  2. At the tab header, click the Add icon and select New Process.
  3. Double-click Velocity Conversion.
  4. Type a name for the process and click OK.

Select input velocity to be converted

Select input velocity to be converted
  1. 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.
  2. 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.
  3. Select the unit of the input velocity at Velocity Units.

Define output velocity settings

Define output velocity settings
  1. In the Output Settings section, select the type of velocity you want to convert to at Velocity Type.
  2. Define the Velocity Units.
  3. Choose the Conversion method, either Interval Conversion (Blocky) or Interval Conversion (Smooth).
  4. Type the vertical extent values and the increment for the output velocity. This is optional.
  5. 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):