Unconventional Hydrocarbons Project
In Australia, onshore sedimentary basins that host coal seam gas (CSG), shale gas and oil, and tight gas and oil have attracted considerable recent exploration interest. These unconventional hydrocarbon resources occur within low-permeability reservoirs that require technology-intensive methods such as horizontal drilling and fracture stimulation (fraccing) to liberate the oil and gas.
Australia’s unconventional gas resource endowment is likely to be considerably greater than its currently estimated total conventional gas resources. Some basins are also likely to have a significant unconventional oil potential. Although many onshore basins in Australia are potentially prospective for unconventional gas and oil, most of these basins remain underexplored, with the exception of CSG in the eastern states.
Currently available resource estimates have some major shortcomings, including:
- the widespread use of deterministic volumetric methods, which may result in the inclusion of technically unrecoverable resources in the estimates, and do not fully account for the uncertainties around the estimates
- the lack of a nationally consistent approach, resulting in variable methodology, coverage and quality of resource assessments being carried out across Australia.
To fill this gap, the Onshore Hydrocarbons Section at Geoscience Australia has commenced an assessment of the unconventional hydrocarbon potential of Australian basins, in collaboration with the state and Northern Territory authorities and the United States Geological Survey (USGS).
The main objectives of this activity are to:
- screen Australia’s onshore sedimentary basins for their unconventional hydrocarbon prospectivity
- undertake basin studies (stratigraphy, petrography, geochemistry, tectonic history, petroleum systems modelling) to underpin resource assessments, commencing with the Georgina and Cooper basins
- produce systematic assessments of Australia's undiscovered unconventional hydrocarbon resources using a nationally consistent methodology
- provide advice regarding the location, spatial extent and geology of unconventional hydrocarbon resources.
The resource assessments use a methodology developed by the USGS, which provides a standardised and reproducible workflow based on statistically estimated gas and oil recovery for a given unconventional hydrocarbon play. The estimated recovery is derived from actual production data, or basin analogues in data-poor areas. The statistical approach quantifies the uncertainty around predicted resource volumes, thus providing a range of likely scenarios regarding the resource volume for a given basin. The USGS assessment methodology has been tested in over 100 unconventional gas and oil plays in North America and is currently being applied globally. The assessments will be complemented by the analyses of hydrocarbon, water and source rock samples, collected in collaboration with the exploration industry, at Geoscience Australia’s laboratories. The analytical results will assist in building up a geologic knowledge base on unconventional hydrocarbon resources, and can be accessed via Petroleum Wells Search.
The Geoscience Australia assessments will:
- inform the government, industry, public and other key stakeholders on the location and volumes of unconventional hydrocarbon resources in Australia
- provide precompetitive and baseline geologic information on unconventional hydrocarbon resources.
Achievements to Date
A National Unconventional Hydrocarbon Resource Assessment Strategy workshop was held in August 2011 at Geoscience Australia. The workshop was attended by representatives from state geological surveys, and established the current status of unconventional resource assessment across Australia. A major outcome was an agreement by the participants on developing a unified national approach to future assessments.
Collaboration with the USGS commenced in March 2012 with a training workshop by Dr Donald Gautier (World Energy Project, USGS, Menlo Park) at Geoscience Australia. The workshop was also attended by representatives from state geological surveys. It provided an overview of the USGS unconventional hydrocarbon resource assessment methodology, which is currently being applied to the Geoscience Australia assessments.
Overviews of Geoscience Australia unconventional hydrocarbon prospectivity and resource assessment programme have been presented at the Central Australian Basins Symposium III, RIU Good Oil Conference and Eastern Australasian Basins Symposium IV.
Topic contact: firstname.lastname@example.org Last updated: October 4, 2013