how to apply ssis on 2d seismic g. de bruin. sequence stratigraphic interpretations the sequence...
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How to apply SSIS on 2D Seismic
G. de Bruin
Sequence stratigraphic interpretations
The sequence stratigraphic analysis comprises of 3 steps:
Setup and data preparation
Calculate the chronostratigraphy
Interpretation
Required Software: OpendTect Base v3.1.4, SSIS plugin, dip-steering plugin
Workflow
Setup projectI
&Load Seismic DataII
Filtered Seismic Data3
Create SteeringCube1
Create SteeringCube
Filter SteeringCube2(Optional)
Track bounding surfacesIII
Create SteeringCube1
Filter SteeringCube2
(Optional)
Calculate Chronostratigraphy5
Filter SteeringCube(Optional)
http://www2.opendtect.org/rel/html/dgb/index.html
http://www2.opendtect.org/rel/html/index.html
Consult dGB User Documentation
1: Chapter 2.2.22: Chapter 2.2.33: Chapter 5.25: Chapter 3.3
Consult OpendTect UserDocumentation
I: Chapter 3.1II: Chapter 4.3.1III: Chapter 3.2Sequence stratigraphic analysis
Please consult the user documentation on how to setup a survey and to load seismic data http://www2.opendtect.org/rel/html/index.html
Setup and data preparation
Select a key line & calculate a SteeringCube. Processing > Steering > Create
(BG-fast steering with a median filter is recommended)
Setup and data preparation
Apply dip-steered median filter to the seismic data
Processing >
Attributes…
Setup and data preparation
Dip steered median filteredoriginal
Filtered
Note: 2D seismic requires a larger step-out than 3D seismic. Test step-out for optimal results
Chapter 5.3
Create a seismic output of your dip-
steered median filtered seismic Processing > Create seismic output
Calculate a steering cube for the Filtered Data-set(Processing > Steering > Create :
Dip steered median filtered seismicFFT standard or Event-steering are recommended)
Setup and data preparation
Setup and data preparation
Track bounding surfaces (unconformities)
Start with two horizonsFor unconformities use “Draw between seeds”
Chapter 3.2
(tracked horizons)
There are 2 modes to calculate the chronostratigraphy
Calculate the Chronostratigraphy
*Requires: dip-steering plugin
Model Driven: in-between each pair of horizons the chronostratigraphy is calculated based on models
Data driven: in-between each pair of horizons the chronostratigraphy is auto-tracked by making use of a SteeringCube*
Calculate the Chronostratigraphy
Click on SSIS > Chrono stratigraphy > New
Select your key lineRead horizonsAssign diachronous or isochronous to
horizons
Select the SteeringCube or sampling rateGive a name to the chronostratigraphy
Isochronous Isochronous Linear interpolation
Isochronous Diachronous Parallel to upper
Diachronous Isochronous Parallel to lower
Diachronous Diachronous Data-driven
Top Base Mode
Display the Chronostratigraphy1) Select the Chronostratigraphy (SSIS > Chrono stratigraphy > select)2) Right click on the line in tree> add chronostratigraphy display
Display Chronostratigraphy
Add Chronostratigraphy Display
(tree) (Chronostratigraphy display)
Chapter 3.3
Evaluate Chronostratigraphy
Use the Chronostratigraphy-slider to QC result(right click Chronostratigraphy in the tree > options)
(Chronostratigraphy-slider)
Improve Chronostratigraphy
To improve chronostratigraphy:
Improve SteeringCube:– Test Event Steering, FFT Standard or BG-Fast algorithms and
vary parameters (see next 2 slides)– Test median filtering the steering cube (see next 2 slides)– Test dip-steered median filtering the seismic before calculating
chrono-stratigraphy– Iterate if necessary (SC -> filter SC -> filter seismic -> new SC
etc.)
Add or improve bounding surfaces
Model-driven chronostratigraphy:– Use model driven Chronostratigraphy for noisy sections
Improve Chronostratigraphy
Chronostratigraphy too erratic Improve SteeringCube
> Larger step-out
> Apply (more) Median filtering
Improve Chronostratigraphy
Chronostratigraphy too smooth Improve SteeringCube
> Smaller step-out
> Less Median filtering
Interpretation
Add a Wheeler SceneSSIS> Add Wheeler Scene
Add the 2D line in the Wheeler scene Tree scene 2
Display Seismic data
Interpretation
Make a Systems tracts interpretation
SSIS >interpretations > new
Interpretation
Assign a systems tractSub-divide into
systems tracts– Highlight the
interval– Click Insert– Provide a geotime /
index– Provide a name
TIP: Use the chronostratigraphy slider to get the exact geotime values
