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

For more information go to www.dgb-group.com/ssis.html

info@dgb-group.comsupport@dgb-group.com