[Users] Setting up a 2-D survey

[Bert Bril]

Hello,


At support we've been getting some questions on how to set up a survey 
for 2-D seismics.

In OpendTect, 2-D and 3-D seismic data can live together in the same 
survey. The rule is: when you have 3-D data, set up the survey 
parameters for the 3-D data. Those parameters are important in the 3-D 
world and they are used at a lot of places in the system. Changing the 
survey parameters after you have done work can cause problems here and 
there.

For 'pure' 2-D surveys, this is much less of an issue. The survey 
parameters only define the boundaries of the display box, and in some 
situations they define where positions are snapped to regular grids. 
Another difference with 3-D is that lines can be partly (or completely) 
outside of the survey boundaries; they will still be usable.

Therefore, setting up a pure 2-D survey is actually pretty simple. When 
you use '2-D only' in the survey setup window, a N/S (or E/W) oriented 
survey setup will be created. You need to give some min/max coordinates, 
and an average trace distance, which can all be guessed values. 
Actually, a good idea would be to use values you also use for gridding 
horizons - then the survey setup is well suited for loading those, too. 
  BTW don't forget to fill in the Z range (time or depth) after using 
'2-D only'.

When you want your survey box to be oriented at an angle with North, you 
have to set up the survey as if you have a 3-D survey, using the 3 
points (or use the 'Advanced' option).

Currently, scanning a SEG-Y file or using the workstation link to set up 
a survey isn't implemented; but this shouldn't be that much of a problem 
because of the simplicity of setting up the survey in the first place.


Bert Bril

-- 
-- Bert Bril / OpendTect developer at dGB
-- Boulevard 1945 - 24, 7511 AE Enschede, The Netherlands
-- mailto:Bert.Bril at opendtect.org , http://www.opendtect.org
-- Tel: +31 534315155 , Fax: +31 534315104