[OpendTect_Users] New survey from VSP data

[Paul de Groot]

Hello Mircea,

I have no experience with VSP's in OpendTect but I assume that the key
question here is whether the VSP is a 2D object (or set of 2D objects) or a
3D object. This is because OpendTect makes a distinction between 2D and 3D
where it comes to co-ordinate handling.

In 2D OpendTect uses X,Y co-ordinates to display the elements in their
proper position. Inline and cross-line positions are only used to display
the survey boundary box and to convert 2D horizons to 3D horizons. In this
case you have complete freedom how to define your inline, crossline grid.
However, for practical reasons I would setup the grid such that the 2D
sections fall more or less inside the survey box and with a grid spacing
that is optimized for converting 2D grids to 3D grids.

If the object is 3D than OpendTect works with inline, crossline positions
to manipulate and display data. Each X,Y position has a unique inline,
crossline position according to the transformation defined in the survey
set up window. To set up the survey and to calculate the transformation
from X,Y to inline, crossline numbers you can use the option in which you
specify three corner points, two of which need to be on the same inline.

Survey set up and co-ordinate transformations are discussed in this
webinar: http://www.opendtect.org/tutorials/Webinar_Data_Loading/

I hope this helps. Best regards,

Paul.

-- 
*Paul de Groot
President
dGB Earth Sciences, Nijverheidstraat 11-2, 7511 JM Enschede, The
Netherlands.
Tel. +31 53 43 15 155, Fax +31 53 43 15 104.
paul.degroot at dgbes.com, www.dgbes.com, www.opendtect.org.

*
On Sat, Feb 2, 2013 at 7:53 PM, Mircea Cozma
<mircea.stefan.cozma at gmail.com>wrote:

> Hello all.
> Does anyone knows how to start a new survey only fro VSP data?
> The flow seems to be straightforward: Survey > Select/Setup... > New... >
> Range\coordinate settings > Scan SEG-Y file(s)
> However, things are not that simple: which is (if any) the in-line and
> cross-line here?
> The in-line and cross-line bytes plus the X-coordinate and Y-coordinate
> bytes shouldn't be a problem from a segy file structure point of view. I am
> running some proprietary data and converting them to segy format is up to
> me, as far as I was writing the conversion programs. The segy output
> file(s) has been already verified by some other programs,
> like SegYDetective and SEGY Viewer from PETRA. So the segy file is not an
> issue.
> But the in-line and cross-line (and their correspondence to the X and Y
> coordinates) is.
> Does anyone have some experience with this problem?
> Many thanks in advance.
> Mircea
>
>
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