Topic:
How to copy a horizon to another survey that has different line numbers.

Description:
You want to copy a horizon interpreted in one survey to another that has been
reprocessed or acquired recently in order to compare amplitudes of the surveys.
The survey is numbered differently or has different line spacings or is offset
from the original survey coordinates.       

Solution:
If the coordinates are different and the numbering is different, you have to 
renumber the 3D survey, then export and import the horizon to the new survey.
Use the override option to import to the new survey. Importing horizons is based
on line and cdp values of the survey and does not use xy locations.

If the coordinates are the same but line spacings are different, or renumbering
the survey is not an option, use the surface cut (horizon to grid transfer )
capability to load the horizon into the new survey before extracting amplitudes.
This method is described below.

1) You need to transfer the "Z" attribute of each horizon to a grid using the
IESX Data Manager>Interpretation>Surface>Horizon Attribute => Grid option.
This needs to be done for each horizon that you want to see in the new survey.
Don't grid before the operation so that any uninterpreted data areas will remain
so. You will not be adding to your interpretation in error or by accident.

2) In the Basemap window, Gridding>Grid Operations>Single>Scale and Bias.  
Use the defaults (Bias 0.0, Scale 1.0) and click on .  The newly scaled grid
will post.

3) Click on Gridding>Save As>Create New Surface.  Type in the new surface name
and make it a seismic horizon.  Type in a grid name.

4) In the IESX Data Manager>Interpretation>Surface, select the newly created
surface, select the grid, type "Z" (for the seismic time attribute, this is a
must do, no quote marks), click on Add to Transfer list, click on the survey
that you want the horizon to be cut back to (also important), Transfer.

5) Select a line from the desired survey and post the interpretation.  To see
amplitudes, they must be extracted.  You can perform amplitude extraction with
the Areal operations function in the Seis3DV/2DV window.  There are no
amplitudes associated with the surface after the horizon is transferred.  You
may want to perform areal snap first in order to better align with the data or
to snap to new parameters if you change them for this horizon in the new survey.



Last Modified on: 19-MAY-00