Volume Interpolation/Extrapolation creates a filled 3D region from input data, using interpolation and/or extrapolation as required.
Use this process to:
- Extrapolate velocity models (and other low frequency data)
- Interpolate missing traces and small areas of seismic data
- Interpolate/Extrapolate 2D data to a 3D region
- Output a seismic volume to a different survey (without exporting)
The algorithm is a combination of natural neighbour and inverse distance weighting, according to the parameters. By default, the output extents cover all the input volumes. Output must be made onto a 3D survey.
Note: All input volumes must have the same vertical extent and increment.
Create a volume interpolation/extrapolation process
- In the Control Panel, open the Process tab.
- At the tab header, click the Add icon and select New Process.
- Double-click Volume Interpolation/Extrapolation.
- Type a name for the process and click OK.
Interpolate/extrapolate 2D lines into 3D volume
- Select the input volume(s). Click the blue (+) icon to include one or more 2D volumes; or one 3D volume.
- Interpolate/extrapolate parameters (see How Interpolation Settings Work):
- At Max distance (m), enter the maximum distance to search for data. Any point further that this distance from the input data will be interpolated. During extrapolation, this parameter has no effect.
- Spreading power defines the weighting applied to the natural neighbour interpolation. Enter the value for the voronoi area weight used in the process. By default, this is set at 1.0. Use values more than 0.0 if circular artifacts appear in the result (caused by joints jumping in and out of the natural neighbour set).
- Smoothing power defines the inverse-distance weight. By default, it is set at 0.
- Strike direction (degrees) defines the direction to apply any strike vs dip weighting. E.g. To guide the result for data trending in a 45 degree direction, specify 45 degrees and increase the strike vs. dip weigth.
- The Strike vs dip weight defines the weighting factor applied in the strike direction, i.e. applying a value of 3 results in a point in the strike direction has three times more influence over another point the same distance away.
- Check Extrapolate to output data to the full extent and fill all gaps. The Max distance (m) field is disabled.
- Check Slowness to safely operate on velocity models. Calculations are performed in slowness (1/V) and converted back to velocity. This check box is selected by default if a velocity volume is selected.
Note: Always enable Slowness when workiing with velocities to accurately maintain the time-depth relationship. Consider using the Velocity Conversion Process to accurately resample and convert velocity data.
Define output parameters
- Select the output survey for the resulting volume.
- Enter the inline and crossline extents and increments for the output
- This process creates a new 3D volume in the Volume tab.
Note: Use Set Spacing to quickly set an inline/crossline sampling distance.