From Geoscience Australia
JSON format icon JSON RDF format icon RDF ISO19115-3 XML

South-eastern Australia Surface Geochemistry II: Light Hydrocarbon Geochemistry in Bottom-waters of the Gippsland Basin, Eastern Otway Basin, Torquay Sub-Basin and the Durroon Sub-Basin Vols 1 and 2

Created 17/10/2025

Updated 17/10/2025

JSON format icon JSON RDF format icon RDF ISO19115-3 XML

The Bureau of Mineral Resources (BMR) collected 1430 line-km of bottom-water Direct Hydrocarbon Detection (DHD) data during a survey aboard R.V. Rig Seismic in the Durroon Sub-basin, the Otway Basin, the Torquay Sub-basin, and the Gippsland Basin, during late September and early October of 1991. No significant bottom-water anomalies were detected in the Durroon Sub-basin. Anomalous concentrations of light C2+ hydrocarbons were detected in the eastern Otway Basin. The anomalies were not extensive, comprising only a few data points representing a few kilometres in extent. One anomaly (of methane, ethane and propane) was accompanied by high levels of the biogenic hydrocarbons, ethylene and propylene, suggesting in-situ biogenic activity in the water column. However, anomalous concentrations of C7 and C8 hydrocarbons were also found here and at three other locations, and are from an unknown 'source'. A weak bottom-water anomaly was detected in the Torquay Sub-basin in the same location as an anomaly detected during an earlier survey (Rig Seismic Survey 89), two years previously. The weakness of the anomaly prevents a confident interpretation of the potential 'source' of the hydrocarbon anomaly, but the data suggests it is derived from a gas/condensate, or dry thermogenic gas 'source'. Several strong bottom-water anomalies were detected in the Gippsland Basin. Bottomwater anomalies were found near the Sunfish and Tuna oil/gas accumulations, in similar locations to anomalies found on Rig Seismic Survey 89, two years earlier. However, another previously-detected anomaly (near Barracouta) was not reproduced. Additional anomalies were found near Flathead, and to the west of Wahoo. The anomaly west of Wahoo was weak and in a similar area to that detected on Survey 89. The composition of most bottom-water hydrocarbon anomalies in the Gippsland Basin are indicative of a liquid-prone hydrocarbon 'source', while one anomaly in the northern sector of the survey area is indicative of a gas/condensate 'source'.

Files and APIs

Tags

Additional Info

Field Value
Title South-eastern Australia Surface Geochemistry II: Light Hydrocarbon Geochemistry in Bottom-waters of the Gippsland Basin, Eastern Otway Basin, Torquay Sub-Basin and the Durroon Sub-Basin Vols 1 and 2
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/8530c786-de0c-4fc9-9163-ef3e441f7155
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage Australia
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "South-eastern Australia Surface Geochemistry II: Light Hydrocarbon Geochemistry in Bottom-waters of the Gippsland Basin, Eastern Otway Basin, Torquay Sub-Basin and the Durroon Sub-Basin Vols 1 and 2". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/south-eastern-australia-surface-geochemistry-ii-light-hydrocarbon-geochemistry-in-bottom-waters1