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4. Geological and Geophysical Datasets
4.1. Geological data
Initial geological data compilation included petroleum, coal seam methane, water and Geological
Survey of Queensland (GSQ) stratigraphic wells. This project almost exclusively used petroleum
well data as it was the most suitable to assess the subsurface geology for the injection and storage of
CO 2 . A comprehensive quality control was carried out on the well location in order to maintain
confidence in the geological interpretation (Appendix 10.6.1).
From the petroleum well database of approximately 4000 wells, a subset of approximately 600
wells was utilised (Figure 4.1.; see Appendix 10.6.1 for well list). Wells were included in this subset
if the well:
• penetrated a depth greater than the 800 m required for supercritical storage of CO 2 ;
• could be integrated into a digital dataset. The electrical log dataset was obtained from the
Queensland Department of Natural Resources, Mines and Energy (QDNRME);
• was perceived as critical to the understanding of the area (i.e. wells in key areas, or well-tie
to seismic lines), and
• additional wells were added in areas lacking sufficient data to make a realistic assessment.
Once the key wells had been selected, all the available data associated with these wells was
collected and examined, including:
• well completion reports acquired from QDNRME QDEX (Queensland digital exploration)
database;
• approximately 400 wireline logs from QDNRME and approximately 20 wireline logs were
hand digitised, and
• approximately 60 drillcores from Geoscience Australia’s and QDNRME’s core stores.
Cross examination of the location of many of the wells selected from QDNRME’s database with a
database at Geoscience Australia indicated that many wells had a significant discrepancy in
geographic location, with some wells plotting up to 100 km apart. It was decided to examine all of
the 600 wells in the dataset and compare the location with that reported in the well completion
report. Many wells were found to have location errors, in particular the geographical datum in many
of the wells had been entered incorrectly, causing many of the location errors seen, and to a lesser
extent key stroke error was also responsible.
To prevent repeating work that had previously been conducted, formation tops were acquired from a
CD produced by the QDNRME / Geological Survey of Queensland (GSQ) Geoscience Data
Queensland Petroleum Geoscience Data. This CD contained a database with the GSQ formation
picks and another database with the formation picks the operator submitted with the well
completion report. These two databases were compared and a preferred formation picks set was
obtained from both sets. The lithostratigraphic tops were subsequently normalised into a single
“pseudo-sequence” stratigraphic name using the autho-stratigraphic chart of the Bowen Basin
(Appendix 10.1). The Wunger Ridge area picks were then checked against the composite log with
specific attention to the Showgrounds Sandstone, Snake Creek Mudstone and Rewan Formation.
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