The energy component of Geoscience Australia’s Exploring for the Future (EFTF) program aimed to improve our understanding of the petroleum resource potential of northern Australia. The sediments of the Mesoproterozoic South Nicholson Basin and the Paleoproterozoic Isa Superbasin on the northern Lawn Hill Platfrom (nLHP) are primary targets of the EFTF program, as they are known to contain highly prospective organic-rich units with the potential to host unconventional gas plays. A defining feature of shale gas plays is that they require technological intervention to increase bulk rock permeability and achieve commercial flow rates. The Egilabria prospect, intersecting nLHP sediments in northwest Queensland, flowed gas to surface from a fracture-stimulated lateral well, demonstrating a technical success. Elsewhere in the region, shale gas prospectivity is limited by a lack of well data. Shale rock brittleness in the nLHP part of the Isa Superbasin was analysed in two studies under the EFTF program. These studies showed that shale brittleness ranges from ductile to brittle; zones of brittle shales were present in all supersequences. Shale brittleness is controlled by increasing quartz and decreasing clay content, with carbonate content proving insignificant. Organic-rich target zones in the Lawn and River supersequences are demonstrated to be brittle and favourable for fracture stimulation. <b>Citation:</b> Bailey, A.H.E., Jarrett, A.J.M., Wang, L., Champion, D.C., Hall, L.S. and Henson, P., 2020. Shale brittleness in the Isa Superbasin on the northern Lawn Hill Platform. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

The South Nicholson region has the potential to host major petroleum and base metal mineral resources. The region is poorly understood compared with the neighbouring resource-rich areas of the McArthur Basin and the Mount Isa Province. A multidisciplinary study was undertaken as part of the Exploring for the Future program to improve our understanding of the petroleum potential of the region. Our work integrates newly acquired seismic data, geological mapping and geochronology, organic and inorganic geochemistry, petroleum systems modelling, and a shale gas assessment to build a better understanding of the region’s resource potential. The South Nicholson seismic survey imaged a new sub-basin, the Carrara Sub-basin—an approximately 1550 km2 depocentre that likely includes Meso- and Paleoproterozoic sedimentary rock. Successions within the Carrara Sub-basin are likely to be highly prospective for energy resources, significantly increasing the extent of the regional prospectivity fairway. New datasets and interpretation from this study have greatly improved understanding of the South Nicholson region, de-risking the region for future resource exploration. <b>Citation:</b> Jarrett, A.J.M., Bailey, A.H.E., Carr, L.K., Anderson, J.R., Palu, T., Carson C.J., Boreham, C., Southby, C., MacFarlane, S.K., Hall, L., Bradshaw, B., Orr, M., Munson, T., Williams, B., Simmons, J., Close, D., Edwards, S., Troupe, A., Gorton, J., Gunning, M. and Henson, P., 2020. A multidisciplinary approach to improving energy prospectivity in the South Nicholson region. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

Australia’s search for petroleum began in the onshore basins where extensive areas of Paleozoic marine sequences, with some high-quality source rock intervals and spectacular outcrop, encouraged sporadic exploration for many decades. For these efforts, there were some rewards, including the discovery of the Mereenie oil field in Ordovician rocks, the Amadeus Basin in 1960s, and the Blina discovery in Devonian carbonates in the Canning Basin during the early 1980s. Since the late 1980s, however, the focus of exploration has shifted offshore where more and larger discoveries were made in the Mesozoic marginal basins, which today contain about 90% or more of Australia’s conventional oil and gas. Now, however, the focus has shifted back to the onshore, recognising the potential for shale and tight gas and oil in these older rocks. The onshore basin area under exploration license has nearly doubled from 2010 to 2012; several major international companies have joined local explorers in testing the worth of Australia’s lower Paleozoic and Proterozoic petroleum systems, and new discoveries have been made in several basins. Geoscience Australia and its partners in the state and NT surveys are undertaking new assessments and studies across a number of these basins. Extended abstract and presentation prepared for the APPEA Conference & Exhibition 2013, Brisbane. Citation: Bradshaw, M., Carr, L., Edwards, D.S., Hall, L., Laurie, J.R. 2013. Unconventional hydrocarbons - Australia's old rocks prove their worth. The APPEA Journal 53(2) 472-472 https://doi.org/10.1071/AJ12083