To provide a regional assessment of the lithofacies associated with 5 formations from the Cooper Basin leading to improved prediction of reservoir, source and seal rocks.

To provide a regional assessment of the lithofacies associated with 5 formations from the Cooper Basin leading to improved prediction of reservoir, source and seal rocks.

These data, as displayed, result from an analysis of well log data over pre-determined intervals covering specific formations intersected in wells during petroleum exploration in the Cooper Basin. Formation tops are well documented in the PEPS-SA...

These data, as displayed, result from an analysis of well log data over pre-determined intervals covering specific formations intersected in wells during petroleum exploration in the Cooper Basin. Formation tops are well documented in the PEPS-SA database, but interpretation of specific lithologies from well logs is interpretive particularly when applying nominal cut-off values to distinguish between shale, silstone, sandstone and coal lithologies. An in-house software package called "Electrofacies" was used to derive the interpretations based on petrophysical cut-offs. Not all available wells were utilised in the study and a significant number of new drilling results are now available since the study was completed in 2004. However, results were deemed to be appropriate for a regional assessment to be made of the Cooper Basin area in terms of lithologies for the Nappamerri, Toolachee, Daralingie, Epsilon and Patchawarra Formations.
Petrosys mapping and interpretation software was utilised to display the derived data for both Isopach ( thickness) and Isolith (%)using a grid mesh of 250m*250m.
Final files produced and managed by Energy Resources Division, Dept. of State Development.
Positional accuracy:This is dependent on the grid mesh size - in the current project it was 250*250 metres. Original data points are considered reliable as all petroleum wells have surveyed locations submitted as part of their statutory requirements.
Attribute accuracy:Attribute data were derived from an analyses by "automatic routine" of well log data from 830 wells out of some possible 1200 wells. Limitations of the technique were identified and edits required. Total thicknesses of the formations studied are well documented in PEPS but the % of coal, shale, siltstone and sandstone which was the subject of this study are interpretitive.
Completeness:Updates to this project are recommended as there are numerous wells drilled subsequent to the completion of this project.

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