What can deep seismic reflection data tell us about hydrocarbon prospectivity in onshore
Thomas Bernecker A and Jenny Maher AGeoscience Australia GPO Box 378 Canberra, ACT, 2601
The APPEA Journal 49(2) 598-598 https://doi.org/10.1071/AJ08071
Published: 2009
Abstract
Now in its third year, Geoscience Australia’s Onshore Energy Security Program has acquired several suites of regional geological and geophysical data. The data includes several deep seismic reflection surveys that have been designed to image:
basement provinces with high geothermal gradients that may contain uranium enrichments and are potential candidates for geothermal energy;
geological terrane boundaries; and,
sedimentary basins that are known to host petroleum system elements but are under-explored.
Seismic signals are recorded down to 20 seconds two-way-time (TWT) which corresponds to 25–35 km depth depending on dominant lithologies. Basinal sections normally extend down to 6–8 sec TWT and the data is of such high quality that any section of the seismic profile can be enlarged without significant loss of resolution. Deep reflection surveys are able to image the relationship between crystalline basement and overlying basin sequences very clearly and also allow interpretations of structural styles as well as impacts of deformational processes on the basin-fill.
A new basinal section was discovered beneath the Eromanga Basin suite of sediments. Named the Mullangera Basin,its structural style and basement relationship seem to indicate some affinity with the Georgina Basin, located further west. The succession is clearly composed of several sequences that contain both fine and coarse-grained sediments. If a geological relationship with the Georgina Basin can be ascertained, a new hydrocarbon prospective area could be delineated. Another new section was discovered beneath the Devonian section of the Darling Basin. Judging by the fast acoustic velocities, the entire basin-fill sequence appears to be very dense and therefore largely non-porous and of low permeability. While low poro-perm characteristics would normally be translated to low prospectivity for oil and gas, the potential for unconventional hydrocarbons such a tight-gas and shale-gas warrants further attention.
keywords: Deep seismic reflection data, vibroseis, Millungera Basin, Darling Basin, Arrowie Basin, basin architecture, hydrocarbon prospectivity
Thomas Bernecker is a sedimentary and petroleum geologist who holds an MSc from the University of Aachen, Germany and a PhD from Melbourne’s La Trobe University. After teaching undergraduate courses at the University of Melbourne, he worked for nearly ten years as a petroleum geologist in the Victorian Department of Primary Industries focussing on the regional geology and the hydrocarbon prospectivity of the Gippsland and Otway basins. Thomas joined Geoscience Australia in 2007 to manage the Onshore Petroleum Project as part of the Onshore Energy Security Program and has recently taken on the Offshore Acreage Release Project. He enjoys promoting Australia’s energy opportunities at national and international meetings. Member: PESA, SEPM, IAS and GSA. Tom.Bernecker@ga.gov.au |
Jenny Maher is the Leader of the Seismic Acquisition and Processing Project of the Onshore Energy & Minerals Division at Geoscience Australia. She is currently coordinating the seismic acquisition surveys for the Onshore Energy Security program. Jenny joined Geoscience Australia, known then as BMR, in 1985 after graduating from the University of Canberra. She has worked in many different areas within the organisation, including managing the Acreage Release and Petroleum Promotion Project, coordination petroleum databases and managing the digital seismic data collected under the Petroleum Submerged Land Act (PSLA). Jenny.Maher@ga.gov.au |
References
Huston, D., Blewett, R., Champion, D., Gibson, G., Henson, P., Korsch, R And Roy, I., in press—Building the northeastern margin of Australia; links between geodynamic evolution and energy potential. Abstracts, 2009 SGA Conference, James Cook University, Queensland, Australia.Mckirdy, D.M. (1994). Biomarker geochemistry of the Early Cambrian oil show in Wilkatana-1: implications for oil generation in the Arrowie and Stansbury basins PESA Journal 22, 3–17.
Tingate, P.R., Green, Pf, Lemon, N.M. And Mckirdy, D.M., 2007—Insights into the tectonic development and hydrocarbon potential of the Flinders Ranges, South Australia, based on AFTA® and organic maturity data from the Blinma–2 borehole. In: Munson, T.J. and Ambrose G.J. (eds) , Proceedings of the Central Australian Basins Symposium (CABS), Alice Springs, Northern Territory, 16–18 August, 2005. Northern Territory Geological Survey, Special Publication 2, 71–81.
Zang, W., Jago, J.B., Alexander, E.M. And Paraschivoiu, E., 2004—A review of basin evolution, sequence analysis and petroleum potential of the frontier Arrowie Basin, South Australia. In: Boult, P.J., Johns, D.R. and Lang, S.C. (eds), PESA’s Eastern Australasian Basin Symposium II, Adelaide 2004. PESA. Special Publication, 243–56.
