Collection of biostratigraphic data from petroleum wells (known as STRATDAT database)

Geoscience Australia’s biostratigraphic database (STRADAT) provides information about the biozonation of sedimentary rocks that were intersected by offshore petroleum wells. The basic unit of biostratigraphy is the biozone, a geological unit formally defined on the basis of the fossil groups contained within. Widely used taxa include trilobites, brachiopods, conodonts, dinoflagellate cysts, foraminifera, graptolites, spores and pollen, as well as nanofossils. Such units are typically defined by either the first appearance (range base) and apparent extinctions (range top/last appearance), or abundance of fossil index species. These fossil indices should ideally be relatively abundant, short-lived taxa that are easy to recognise and as geographically widespread as possible. Zonal schemes based on several different fossil groups can be used in parallel, and the zones can be calibrated to the absolute geological timescale (i.e., Geologic Time Scale 2004, 2012, 2020). Biozones allow the identification of spacial—temporal relationships and the distribution of lithostratigraphic units within and across sedimentary basins. They facilitate the understanding of subsurface geology and identification of source, reservoir and seal rocks, key elements of petroleum systems. These biostratigraphic data originate from well completion reports and destructive analyses reports that are submitted by the petroleum industry under the Offshore Petroleum and Greenhouse Gas Storage Act (OPGGSA) 2006 and previous Petroleum (submerged Lands) Act (PSLA) 1967. These data are also sourced from biostratigraphic studies by Geoscience Australia and its predecessor organisations, the Australian Geological Survey Organisation (AGSO) and the Bureau of Mineral Resources (BMR), as well as from state and territory geological organisations. Other open file data from publications, including university theses, are also captured. The database structure has evolved over time and will keep changing as different types of geological timescales data become available and the delivery platform changes. Data was initially delivered through the Petroleum Wells web page, http://dbforms.ga.gov.au/www/npm.well.search, which is in the process of being decommissioned. The biostratigraphic data will be available for viewing and download via the Geoscience Australia Portal Core, https://portal.ga.gov.au/.