How do I crop a seismic volume using a polygon?

Volume Sculpting and Volume Maths can be used to remove the area inside or outside a polygon.

A probe can also be used, but is limited to the shape of a cube.

Remove seismic outside polygon

  1. In the Process tab, create a Volume Sculpting process (see Volume Sculpting).
  2. Choose the volume and select a polygon to constrain the data inside the polygon. You can also constrain the vertical extents of the cropped seismic by selecting a constant time/depth or horizon.
  3. In the views, select the process volume to display.

This will create a process volume within the constrains of the polygon. Process volumes are updated on-the-fly and may be computationally intensive. Export this process volume to disk to improve performance (see Exporting a Volume).

Remove seismic inside polygon

  1. In the Process tab, create a Volume Sculpting process (see Volume Sculpting). Choose the volume and select a polygon.
  2. Create a Volume Maths process.
    • Select the original volume as v1 and sculpted volume as v2.
    • At Formula, type the following formula: if(!IsNaN(v2),NaN,v1)

This will create a process volume that omits the area inside the polygon. Process volumes may be computationally intensive. Export this process volume to disk to improve performance (see Exporting a Volume).

Alternatively...

Another way to remove the volume inside a polygon is to create a horizon with missing values inside the polygon (see Horizon Erase), and then select to Exclude traces where a horizon is missing during Volume Sculpting.

If either (you only technically need one) of the horizons used in Volume Sculpting have null values, the nulls will carry through into the process volume.