stratal slicing using 3d model-driven chronostratigraphy g. de bruin
TRANSCRIPT
Stratal Slicingusing 3D Model-driven Chronostratigraphy
G. de Bruin
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
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
Introduction
Geological situation Shifting lower horizonShifting upper horizon
Stratal-slicing
Decrease of horizon quality
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
Seismic: Wheeler transformation
Seismic Domain Wheeler Domainm s
Geo-
tim
e
A horizon in the seismic domain is represented by a time-slice in the wheeler domainTherefore: 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.
Workflow
Track or import 2 horizons
Calculate chronostratigraphy
Create Wheeler volume
Load Volume in Wheeler scene
Required Software: OpendTect Base SSIS plugin
Track 2 horizons
http://www2.opendtect.org/rel/html/index.html
1. Track 2 horizons*
2. Make sure to fill all holes
3. Check for crossing horizons
* Consult OpendTect user-documentation
Calculate Chronostratigraphy
1. Read the 2 horizons
2. Set both to isochronous
3. Set spacing
4. Give a name
SSIS > Chronostratigraphy > new
Create Wheeler Cube
SSIS > Chronostratigraphy > Select
SSIS > Create Wheeler Cube
1. Select a seismic volume
2. Give a name
Load Volume in Wheeler
SSIS > Add Wheeler Scene
Add Volume in Wheeler Scene
Time-slice through volume
Drag the time-slice for stratal slicing