Hydrocarbon Seepage Survey of Australia's Northwest Marine Margin

AGSO's 1998 marine survey collected 4,788 line kilometers of water column geochemical 'sniffer' data to detect natural hydrocarbon seepage. The program, conducted from the vessel TSMV Pacific Conquest, covered the Northern Carnarvon Basin, Yampi Shelf, and Southern Bonaparte Basin. It recorded concentrations of methane and ethane, identifying areas of weak to strong seepage.

Use Cases

• Map methane and ethane concentration anomalies to identify potential hydrocarbon seep zones along the survey lines.
• Correlate geochemical seepage data with seismic lines, such as S165, to validate subsurface hydrocarbon leakage where regional seals thin.
• Compare 1998 ethane and methane readings with 1996 survey S176 data to analyze temporal repeatability of seepage signals.
• Analyze spatial patterns of hydrocarbon concentrations across distinct survey areas like Skua, AC/P20, and Wandoo B Platform to assess basin-scale seepage activity.

Strengths

• Substantial spatial coverage with 4,788 line kilometers of acquired data.
• Multi-basin survey covering the Northern Carnarvon Basin, Yampi Shelf, and Southern Bonaparte Basin.
• Provides specific concentration levels (weak, moderate, strong) for key hydrocarbons like methane and ethane.

Limitations

• Data is from a single survey in 1998, offering only a historical snapshot with no recent updates.
• Specific row counts, sample densities, and detailed columnar data schema are unavailable.
• Analysis is confined to 160 specific survey lines, leaving gaps in spatial interpolation.

Provenance

Source

Australian Geological Survey Organisation (AGSO), now Geoscience Australia, via the Australian Ocean Data Network.

Collection Method

Regional water column geochemical 'sniffer' program conducted from the contract vessel TSMV Pacific Conquest.

Time Range

Survey conducted from 21 September to 23 October 1998.

Freshness

Historical dataset from a 1998 survey; metadata was last updated in 2026.

Geography

NW Australian Margin, from Dampier to west of Darwin, covering the Northern Carnarvon Basin, offshore Canning Basin, Yampi Shelf, and Southern Bonaparte Basin.