Australia's Petroleum Potential

Geoscience Australia has adopted the internationally benchmarked US Geological Survey (USGS) World Petroleum Assessment (2000) (see Table 5) to represent the oil and gas likely to be discovered in Australia's major offshore hydrocarbon bearing basins.

Limitations in knowledge mean that the assessment of undiscovered petroleum resources is limited to those accumulations whose existence is conceivable and which might be brought into production over the next 30 years. Hence, there may be other accumulations that cannot be conceived of or assessed. There may also be considerable additional petroleum in accumulations that would, if discovered, be regarded as uneconomic to produce using existing technology.

Geoscience Australia undertakes its own assessment of undiscovered hydrocarbons using a very different methodology to that used by the USGS. The methodology is a 'discovery forecast', one that enables the results to be incorporated in a production forecast. These discovery forecasts are only for the medium term (10 to 15 years) so they are not a measure of ultimate potential. Updated forecasts for the Bonaparte Basin (Oil & Gas Resources of Australia 2001), the Browse Basin (Oil & Gas Resources of Australia 2002), the Dampier Sub-basin/Rankin Platform (Oil & Gas Resources of Australia 2003) and the Exmouth Sub-basin (Oil & Gas Resources of Australia 2004) have been released and are available through the Geoscience Australia website.

Table 5: Assessment of Australia's Undiscovered Resources of Crude Oil, Gas and Condensate.

Unit
 Probability
95%
Average
5%
Crude Oil
million barrels
1 577
5 030
9 846
Condensate
million barrels
1 740
6 035
11 870
Gas
trillion cubic feet
33
114
228

Source: Powell, 2001 APPEA Journal

The extent of exploration drilling in Australia is relatively low compared with other regions in the world. By the end of 2005, over 9000 exploration and development wells had been drilled in Australia's vast onshore and offshore areas (see Table 6). Australia has about 16 million square kilometres of sedimentary basins. By comparison over 60,000 wells have been drilled in the Gulf of Mexico - an area smaller than the Carnarvon Basin off the north-west coast of Australia. By any measure, Australia is underexplored.

Table 6: Total of Petroleum Exploration and Development Wells Drilled in Australia up to 31 December 2005

Exploration Development Total
Onshore
4 550
2 282
6 832
Offshore
1 472
798
2 270
Total
6 022
3 080
9 102

Source: Geoscience Australia, Department of Industry, Tourism and Resources, 2006.

In 2005, 67 exploration wells were drilled in offshore Australian waters. This was up from the 42 wells drilled in 2004 (Oil & Gas Resources of Australia 2005). Table 7 shows the new field wildcat success rates for 2003 to 2005. Table 3 lists the offshore oil and gas discoveries from 2004 to October 2006. Table 4 lists the offshore petroleum development projects in Australia as of November 2006.

Table 7: New Field Wildcat success rates 2003, 2004 & 2005

Onshore Offshore Combined On/Offshore
2003
1:2.5
1:3.9
1:3.3
2004
1:1.9
1:2.5
1:2.8
2005
1:3.4
1:2.4
1:2.8

Source: Geoscience Australia, Department of Industry, Tourism and Resources, 2006.