[Users] Simple procedure to generate empty cubes (and possibility to export them...) (cubes, not attribute)

[Jean-Francois DUTZER]

Hello all !
I have had the (strange) request to generate a SEGY seismic cube with empty/constant values all over the cube.
This is coming from people working in datarooms, where they just have the coordinates of the 3Ds, and they'd like
to see the data they gather (maps, sections,...) with a reminder of X,Y, Inline, Xline positions (also to check well
positioning...)
Opendtect is a target, but thay also want to use other tools (Petrel,...) so basically they need this SEGY file with just the
necessary
information (IL, XL, X, Y and structure)

I have a found a procedure to do that within Opendtect, but there may a simpler way.
(1) generate the survey within Opendtect with the collected information Inline min, Inline max, step,Xline,... time min, and
coordinates.
(2) call for "attributes", ask for "Maths", type in a constant value, save this attribute set.
(3) here comes the small trick : you may ask for this attribute to be displayed, but you cannot compute the corresponding
seismic cube
("create seismic output"), because your survey has no data loaded. Opendtect tells you that you have to import data first and
unfortunately
you don't have any (datarooms...). The trick is to fool Opendtect and let it believe that there is some.
      (3-1) get to your data directory, under the "Seismics" directory there is a file called .omf (Object Management File).
Edit it !
      (3-2) add the dummy line indicating that cvbs data has already been loaded. Typically it is some lines with :
Object Management file
Tue Sep 02 13:14:20 2008
!
ID: 100010`3
!
Seismics: 1
Seismic directory: dGB`Stream
$Name: Seismics
!
(it is rather empty because nothing has yet been computed. Add some lines and correct the numbering so that it will believe
something
with a cvbs format is available: (I am even not sure that the #type: Attribute line is necessary..., but the numbering has
some importance)
Object Management file
Tue Sep 02 13:14:20 2008
!
ID: 100010`3
!
dummy name: 1
Seismic Data: CBVS`Stream
$Name: dummy_name.cbvs
#Type: Attribute
#Data storage: 0 - auto
!
Seismics: 2
Seismic directory: dGB`Stream
$Name: Seismics
!

      (3-3) Save the file. You are now allowed to "create seismic output", with constant values for example.

(4) eventually (if you want to use that for other programs), you are also allowed to export your newly created attribute as
SEGY format, display images
(maps) at their locations, sections images if you have some scans,...   ;-)

If somebody has a simpler way to do so, please let me know.

Sincerely,

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Jean-François Dutzer
R&D Project Manager
Direction Exploration-Production
Département Géosciences
Service Projets Géosciences
361 Av. du Psdt Wilson - BP33 -
93211 StDenis La Plaine Cedex
France

tel :    33+(0)1 49 22 47 88
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