GEDCO Stack-3D Volume Analysis

This tutorial shows how to create a stacked SEGY data volume for footprint analysis. In this
analysis traces are stacked based on the offsets provided by the survey design and script. You
can examine amplitude variability from bin to bin at your time of interest. These analyses are
particularly useful for comparing footprint characteristics for two or more candidate designs.
There are several options for calculation. One option allows you to ray trace over an OMNI
Target Model. Other options stack traces from an input CDP. OMNI 3D will compare the offsets
of traces in the input CDP to those for each shot in your survey script. It selects matching offsets
from the input and stacks them for output. We will demonstrate the use of a single SEGY NMO
corrected CDP as input.
Working with this Tutorial
Set parameters as described or shown in pictures. As you work, use OMNI 3D’s Popup Help to
see explanations of all available parameters. Hover your cursor over a parameter or click the
question mark in the upper right of a dialog and then click the parameter for Popup Help.
If you are new to OMNI 3D, please see the “Basic Land” tutorial before you use this tutorial. In
this advanced tutorial it is assumed that you can:
Start OMNI 3D
Create a project
Find and use menus in the Project Tree
Use Pop-Up Help in OMNI 3D’s menus and dialogs
Use right-click menus in the View tabs
Modify Color Bars
Create a survey
Create a script
Go to Help | Local Resources | Load Tutorial Solutions and open the Workshop Analyses
folder. The folder contains both the input data for this exercise and the completed solution
project. (Please see the end of this tutorial for information about working with the solution
project.)
To complete this set of exercises you will need these input files:
...\Tutorial\Workshop analyses\Stack 3D Example-data\Survey For Stack.osd
...\Tutorial\Workshop analyses\Stack 3D Example-data\sp203-agc-nmo.sgy

View Results
Results may be viewed in the Edit View, Chart View, 3D View, Volume View and SEGY
tabs. You may also use elements of these views to create custom montages on the Plot tab.
Edit View
Zoom in to a few bins somewhere near the center of the survey.
In the Project Tree, right click on the name of the analysis (Pattern 6×56-STCK-001) and select
Pattern 6×56-STCK-001Style. On the Bin Display tab set Color Mode to Amplitude. Under
Overlay place a check mark next to Draw Wiggle Wavelets, Draw VAR Wavelets and Draw
Timing Lines. Set the Window length to .15 seconds (150 milliseconds) and the Sample Scalar
to 2. (Notice that you can leave this dialog open as you work with different views. Just change
settings and press Apply.)
Go to the Slices tab. You are looking at a map slice through the analysis at 1 second. (OMNI
automatically displays a slice at one half the total length of the traces.) You may have noticed
that the colors for this slice are near the middle of the color bar range. That is because the color
scale is based on the minimum and maximum amplitude for the entire data volume.
Scroll to .600 seconds in the Map Slice list. Return to the Bin Display tab and turn on
Normalize Wavelets, set the Window length to .1 and the Sample Scalar to 1. Press Apply.

 

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