Performing domain conversion

In instances where you need to transform data in a velocity model from time to depth, or depth to time, you can use the Domain Conversion tool (prepare > Seismic > Domain Conversion).

Time/depth conversion can be applied to the following objects:

  • 3D Seismic data (voxel grids)
  • Tri-meshes
  • Polyline sets
  • 2D Grids

The surfaces that you want to domain convert need to be in a seismic interpretation in the JewelExplorer. When you created a velocity model with the Velocity Model form (previous step of the workflow) you can select it here. Note that all surfaces within the seismic interpretation will be converted, for example also faults if you have them.

To transform surfaces in the time and depth domains

  1. Open the Domain Conversion form (prepare > Seismic > Domain Conversion).
  2. From the Source drop-down list, select the seismic interpretation that contains the surfaces you want to convert.

    3. Input

  3. Under Input, select one of the following ('Function' can only be used when converting from time to depth).
    • Velocity Model - Select this option if you want to use a velocity model for the conversion. See Defining velocity models for details on how to create one if you do not have a suitable one already. If you have a velocity model, select it under the Velocity model drop-down list. Continue under 'Output' further below.
    • Function (this option is only available when converting from time to depth). Select this option when you want a user-defined function to convert your surfaces from time to depth. Continue under 'Edit Function' below.

    4. Edit Function

    Edit Function can only be used for time to depth conversion (not for depth to time conversion).
    1. Click on the Edit Function button which will open the Edit Function form.
    2. Select one of the following methods for converting seismic times to depths:
      • Linear: z = Bt + A
      • Quadratic: z = Ct2 + Bt + A
      • Cubic: z = Dt3 + Ct2 + Bt + A
      When you make this selection, the corresponding conversion equation is displayed in the 'Resulting polynomial' field.
    3. Select 1-way travel time base formula if time in your function is OWT; select 2-way travel time based formula if time in your function is TWT.
    4. Enter the values for A, B, C and D in the entry fields on the form, depending on the degree of the polynomial. Click Apply changes on the form to apply A, B, C and D to the function that is displayed in the expression field below.
    5. Click Close when your function is finished.

    Output

  4. Convert to is for information only and shows you the domain to which the surfaces will be converted (if your selected source is in time, 'Convert to' is set to depth, and vice versa).
  5. From the Folder drop-down list, select a folder where the converted surfaces will be stored. This folder can only be the Data folder or a Seismic Interpretation.
  6. Check the Maintain watertight geometry between objects checkbox to set whether any watertight geometry between objects in the source domain should be preserved in the target domain.
  7. The Transform seismic volumes entry field shows the seismic volume(s) in the seismic volume folder of your selected seismic interpretation.

For more on domain conversion, see About domain conversion.