[Users] import 2D segy

[Geert de Bruin]

Dear Vikram,

On the OpendTect website http://www2.opendtect.org/faq/opendtect/i- 
have-problems-loading-a-seg-y-file.html you can find an explanation  
on SEG-Y files and how to import them into OpendTect. The following  
section is taken from that FAQ:

In OpendTect  click 'import-seismics-SEGY-3D' (or 2D), and click the  
"define.." button. Then a rather large window pops up which allows  
you to:

* Select the SEG-Y file
* Click on 'Examine'
* Define where to find the correct byte locations in the file (see  
above or press the help button to find out what's what)
* Overrule certain things that may be incorrect
* Scan the file and check the result (and redo this workflow if  
necessary by changing the byte locations)

Note 1: examine the file first, then set what you think are the  
correct settings, only then you can do a meaningful scan.
Note 2: The help button on the window will lead you to the help for  
this window (yes, there is documentation).

When you think you have everything right, you press OK. Then you can  
subselect part of the data, specify an output format, scale the data  
etc. Now enter a name for the output cube (or line set) and then  
pressing OK should start the loading process.

Before you can load anything, you have to have a good survey setup.  
If all you have is one or a few similar SEG-Y files, you often want  
to setup the survey exactly according to the boundaries, coordinates  
and steps present in the SEG-Y file(s). For that, there is an option  
to set up the survey from a scan of a SEG-Y file.In the survey  
selection window, press 'New', then in that dialog, select 'Scan SEG- 
Y file' and press 'Go'. You'll have to define the bits and pieces  
like described above. Make sure inline, crossline aswell as  
coordinates are correct!

That's about it. There are many details and things that can go wrong,  
like extra headers (Rev.1 can have those which are handled nicely but  
there are also just bad SEG-Y files) or Rev.1 tape labels ending up  
in your file (your SEG-Y file then starts with 128 garbage bytes  
which you need to get rid of). Bad programs write coordinates as  
floating point numbers (very much against the SEG-Y standard), ignore  
the start time, trace scaling, Rev.1 flag, etc. etc.

You can also refer to the user-documentation http:// 
www2.opendtect.org/rel/html/x1496.htm#AEN1512

Best regards,

Geert


On Jul 11, 2007, at 1:33 PM, Vikram Unnithan wrote:

> Dear users,
> Let me apologise for the trivial question before I formulate it.
>
> Does one of you  have a quick "how-to" to import 2D segy into  
> opendtect, assuming you do not know anything about the segy file  
> i.e. no extents. I am often provided with 2D segy lines and would  
> like to quickly have a look at them. Normally, I do not have any  
> details apart from the fact that they are from the North Sea or  
> perhaps the Norwegian margin. It would be great, if I could load  
> the file and use the descriptors to define the working region.
>
> thanks for your help,
>
> with regards
> Vikram Unnithan
>
>
> -- 
> Dr. Vikram Unnithan <v.unnithan at jacobs-university.de>
>
> School of Engineering and Science
>
> Jacobs University Bremen gGmbH *
>
> Campus Ring 1, 28759 Bremen, Germany
>
> Office: Research III, Room 120
>
> Telephone: +49 421 200-3161
>
> Fax: +49 421 200-3229
>
> Web Address: http://www.jacobs-university.de
>
> And
>
> College Master, Mercator College
>
> Jacobs University Bremen gGmbH*
>
> College Ring 6, 28759 Bremen, Germany
>
> Telephone: +49 421 200-5300
>
> Telephone: +49 421 200-5306
>
> Web Address: http://www.mercator-college.org
>
> ---* Formerly, International University Bremen---
>
> _______________________________________________
> Users mailing list
> Users at opendtect.org
> http://lists.opendtect.org/mailman/listinfo/users

-- Geert de Bruin
-- Geoscientist
-- dGB Earth Sciences B.V.
-- Nijverheidstraat 11-2
-- 7511 JM Enschede, The Netherlands
-- geert.debruin at dgb-group.com
-- http://www.dgb-group.com
-- Tel: +31 534315155 , Fax: +31 534315104




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opendtect.org/pipermail/users/attachments/20070712/8ad6fcd2/attachment.html>