[OpendTect_Users] Deriving 3D horizon from 2D horizon: big holes

[Farrukh Qayyum]

Dear Randall,

>>On another horizon along the exact same lines, I have no such problem.

Your issues seems to be data related. Thanks to the earlier reply by
Julien. If his suggestions do not help soliving this issue, please do not
hesitate to contact OpendTect support at support at opendtect.org.

A part from this, I would like to share another idea which is only for 3D
surveys. We internally developed a plug-in that utilizes Dip Steering
Plugin to grid a 3D horizon. Attached images show the results. What
normally we do is that we map a 3D survey with a loose grid (10 by 10 steps
of inlines / crosslines) and then we try to do auto-tracking if the horizon
is phase consistent or we do gridding if the horizon cannot be
auto-tracked. The gridding step in 90% of cases is necessary and very
common in our workflows. However, the conventional gridding algorithms do
not follow the structure / stratigraphy that is always available in our
seismic data. Furthermore, we always see gridding artifacts and often the
interpolation method doesn't follow the background seismic (as highlighted
in the attachment).

Dip Steering plugin allows us to collect dip/azimuth information at each
sample location. We use such information to do
interpolation/gridding. Therefore, we are trying to use the seismic
dip/azimuth information while gridding a 3D horizon such that the output is
structurally as well as stratigraphically consistent.

We will release this plugin very soon to public, and it will require a Dip
Steering licence. I hope that most of you would like this in near future as
it would save a lot of your time and would output a superior grid.

Cheers and thanks for your attention.

-- 
Best regards,

*Farrukh Qayyum*,
Geoscientist,
dGB Earth Sciences B.V., Nijverheidstraat 11-2, 7511 JM Enschede, The
Netherlands.
Tel: +31 53 4315155
Fax: +31 53 4315104
http://www.dgbes.com
mailto: farrukh.qayyum at dgbes.com
http://www.facebook.com/OpendTect
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On Wed, Oct 3, 2012 at 1:18 PM, Julien Moreau <julien.moreau at geo.ku.dk>wrote:

>  Hi Randy,
>
> The interpolation is made according to the grid parameter, i.e. from the
> survey geometry. Unlike most of the 2D horizons, 3D horizons are clipped
> within the frame of the survey which is a sugarbox. Their coordinates are
> relative to the survey, not to the real seismic space.
> If you don't have any 3D horizons derived from a seismic cube you can try
> to play with the survey parameters. If you do have a cube, the horizons
> will be distorted and you will have to pick them again. You can try to dump
> your 2D line into a temporary survey if you have a mixed dataset.
> So:
> First all your lines should be within the survey
> Secondly, try to have a coarse spacing, meaning your u,v increment of the
> grid (the Xline-inline increment of the survey) with something quite large
> (equivalent to 4 times trace spacing?).
>
> You should get some 3D surface. You will be able to tune that to get some
> meaningful results by optimising your survey geometry.
>
> Best regards,
>
> Julien
>
> Julien Moreau, PhD
> Assistant Professor, Applied Geophysics
> Department of Geography and Geology, University of Copenhagen,
> Øster Voldgade 10, 1350 København, Denmark
> Office: +45 353-24168
>
>  ------------------------------
> *From:* users-bounces at opendtect.org [users-bounces at opendtect.org] on
> behalf of Randy Hunt [rl_hunt at yahoo.com]
> *Sent:* 02 October 2012 21:45
> *To:* users at opendtect.org
> *Subject:* [OpendTect_Users] Deriving 3D horizon from 2D horizon: big
> holes
>
>   Hi everybody, I have been using OpenDtect and appreciate what it can
> do.   In some areas, it's a little "rough", like when I go to derive a 3D
> horizon from a 2D one.  No matter what parameters or gridding algorithm I
> use, I only get values interpolated along the 2D lines, nothing in the gaps
> between lines.   On another horizon along the exact same lines, I have no
> such problem.   Has anyone seen this issue, and what can I do to fix it?
>
>  Any ideas much appreciated.   Thanks to everybody who has worked to
> provide such a great open source tool for geophysicists everywhere.
>
>  regards
>
>  Randall Hunt
>  Pittsburgh, PA
>
>
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