1. Stratal Slicing using 3D Model-driven Chronostratigraphy
G. de Bruin

2. Introduction
Horizon based attribute analysis can reveal sedimentary and structural features
Since horizon-tracking is time-consuming, only the key horizons are typically tracked. Therefore, only a small part of the available data is usually analyzed

3. Introduction
To analyze more data, horizons are often shifted, which is in most cases only valid in the vicinity of the original horizon
Proportional slicing or stratal slicing enables a more accurate analysis
Decrease of
horizon quality
Geological situation
Shifting lower horizon
Shifting upper horizon
Stratal-slicing

4. Introduction
Stratal slicing or proportional slicing is possible in OpendTect, through the use of the linear interpolation option of the SSIS plugin
Stratal slicing is performed in the chronostratigraphic or Wheeler domain

5. Seismic: Wheeler transformation
Seismic Domain
Wheeler Domain
Geo-time ms
A horizon in the seismic domain is represented by a time-slice in the wheeler domain
Therefore: time-slicing in the Wheeler domain is horizon / stratal slicing in the seismic domain
We analyze the data on time-slices in the Wheeler-domain, simply because it is much easier to display a time-slice than a horizon. Horizons have a geometry, time-slices don’t. Thus more data can be displayed and this is done faster.

6. Workflow Track or import 2 horizons Calculate chronostratigraphy
Create Wheeler volume
Load Volume in Wheeler scene
Required Software: OpendTect Base SSIS plugin

7. Track 2 horizons Track 2 horizons* Make sure to fill all holes
Check for crossing horizons
* Consult OpendTect user-documentation

8. Calculate Chronostratigraphy
SSIS > Chronostratigraphy > new
Read the 2 horizons
Set both to isochronous
Set spacing
Give a name

9. Create Wheeler Cube SSIS > Chronostratigraphy > Select
SSIS > Create Wheeler Cube
Select a seismic volume
Give a name

10. Load Volume in Wheeler SSIS > Add Wheeler Scene
Add Volume in Wheeler Scene

11. Time-slice through volume
Drag the time-slice for stratal slicing