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Stratal Slicing using 3D Model-driven Chronostratigraphy. G. de Bruin. Introduction. Horizon based attribute analysis can reveal sedimentary and structural features.
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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
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
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 Domain • 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 Geo-time ms 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 • Track 2 horizons* • Make sure to fill all holes • Check for crossing horizons * Consult OpendTect user-documentation http://www2.opendtect.org/rel/html/index.html
Calculate Chronostratigraphy • SSIS > Chronostratigraphy > new • Read the 2 horizons • Set both to isochronous • Set spacing • Give a name
Create Wheeler Cube • SSIS > Chronostratigraphy > Select • SSIS > Create Wheeler Cube • Select a seismic volume • 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