Grid data

[アルヒルナ]

What Grid data  can be showed in Opendtect?

[Paul de Groot]

Dear アルヒルナ,

Grids in OpendTect are the same as 3D horizons. These are surfaces that can be displayed with different attributes (Z, amplitude, similarity, ...) in a stack of display layers. Each layer has its own color bar that controls colors and transparency of value ranges. Transparency can also be controlled on a layer-by-layer basis from the tree menu.

Please note that if you interpret a 3D horizon in a grid of inlines and crosslines and you want to see the data in between these interpreted lines, you should apply a gridding algorithm to fill in the uninterpreted parts. OpendTect supports various gridding algorithms in the free version and additional algorithms in the Pro version. One special algorithm is called Extension. This is used for display purposes only. It copies the value at the interpreted line to traces perpendicular to the line and in that way create strips of a certain width. We use this amongst others to display UVQ waveform segmentation results on 2D seismic.

Gridding is also needed when you work on 2D seismic. Here, you first have to convert the 2D horizon to a 3D horizon (option Derive 3D horizon ...) before gridding the derived 3D horizon.

I hope this helps. 

Best regards,

Paul.

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

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On Mon, Sep 8, 2025 at 9:14 AM アルヒルナ <aruh...@gmail.com> wrote:

What Grid data  can be showed in Opendtect?

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[アルヒルナ]

Thank you for the explanation. I might give less notes. The grid data that I mean is like what petrel can show. Here I attach Its figure:

That grid visualization clearly shows the 3D stratigraphic of the horizon as well as the fault that is denoted by the "black" line in the left side. Can I visualizate It in Opendtect? Thank you in advance.

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[アルヒルナ]

Is it valid that adopting "HorizonCube Attribute" Plugins is one of the solution? Thank you

[Paul de Groot]

Yes, you can make displays like this in OpendTect as well. From the image you sent, it is not clear whether the fault gap is empty or that it is displayed as an overlay with the same color as the background (black). Either way, you can do this in OpendTect. If you mapped the horizon using the auto-tracker, faults probably already have gaps. These gaps can be made cleaner if you mapped the associated fault planes and use the "Trim horizons against faults" tool in the Faults & Fractures plugin. If you want to display fault gaps as overlays, you have to draw polygons around these gaps. (I would use the latter option only for making final displays and displaying these results in the basemap or in a top view of the 3D scene with perspective view toggled off.)

Best regards,

Paul.

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

----------------------------------------------------------------------------------------------------------------------- 

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[Paul de Groot]

Is it valid that adopting "HorizonCube Attribute" Plugins is one of the solution? Thank you

Yes and no. A HorizonCube is a dense set of horizons. You cannot trim all horizons in a HorizonCube against faults as we can do with individual horizons. But we do have something called the 3D HorizonCube Slider. This tool allows slicing the seismic data in a geologically meaningful manner, i.e. along (Relative) Geologic Time lines. For example, we use the slider to see how the structure changes over geologic time (displaying Z on the horizons), how depocenters shift (visualizing iso-chron thicknesses between pairs of horizons) and how attributes change. If we display Fault Likelihood or another fault attribute like similarity on the slider's horizons, we have something that looks like your image. The difference with your image is that we do this not for one but for hundreds (even thousands) of horizons that are movie-style inspected as we move the slider through geologic time.

Best regards,

Paul.

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

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To view this discussion visit https://groups.google.com/a/opendtect.org/d/msgid/users/4a02d69d-156b-46cf-a95a-aaeed865fe83n%40opendtect.org.