b'AEGC 2021Short abstractsexpanding coverage to include the whole of Australia. The EFTFof geological structures, which highlight the importance of energy component aims to improve our understanding of thegeology for geomechanical assessment of the basins.petroleum potential of frontier onshore Australian basins and has acquired significant pre-competitive datasets, including163: Application of facies based seismic inversion in the recently drilled Waukarlycarly 1 deep stratigraphic well in Western Australias Canning Basin (in partnership with thedeveloping shallow gas fields in Cooper-Eromanga Geological Survey of Western Australia), and the just completedBasinCarrara 1 deep stratigraphic well in the South Nicholson region of the Northern Territory (in partnership with the MinEX CRC).Mr Satyabratamishra 1, Mr Shane Squire1 and Mr Thomas These are the first stratigraphic wells drilled by GeoscienceMassey1Australia in a petroleum basin since its formation in 1997 from1 Santos Ltdits predecessor agencies, and both were sited along major new two-dimensional, deep crustal seismic surveys acquired byThis paper presents a case-study of the application of facies-Geoscience Australia as part of EFTF, providing stratigraphicbased seismic inversion in the Cooper-Eromanga Basin, control for the imaged geology. South Australia. The technique has been used to support the development of shallow gas fields in the Cretaceous reservoirs The Waukarlycarly 1 and Carrara 1 wells intersected significantof the Coorikiana Sandstone.successions of sedimentary fill and were both extensively cored and logged with a broad suite of wireline tools,Key features of the Coorikiana gas play are polygonal faults that providing substantial new data in two frontier areas. Thesecompartmentalise the field and Class II/IIp seismic amplitude data provide insights into regional stratigraphy and localvariation with offset/angle. The field compartmentalisation lithology. Geochronology, petrographic, organic and inorganicposes a significant challenge in development. Forward seismic geochemistry, petrophysical rock properties, petroleum systemsmodelling explained the impact of various aspects of the elements, palaeontological and fluid inclusion studies have beengeology and fluid types on the seismic wave-forms. A facies-undertaken that allow for inferences on regional prospectivitybased inversion was undertaken to support field development to be made in these data-poor regions. Moving into the nextplanning and it ultimately provided a better definition of the phase of EFTF, these crucial wells provide a template for newcompartments. A retrospective value of information analysis pre-competitive data acquisition by Geoscience Australia,showed that value is maximised by combining the new seismic expanding our knowledge of frontier regions and attracting newinversion information with the prior seismic knowledge (seismic investment for resource development. amplitude).162: The present-day state of tectonic stress in eastern164: Australian Proterozoic Thermal Aureole Gold Australia mineral systems: The critical role of high crustal geothermal gradients and the insights of Vic WallDr Mojtaba Rajabi 1Prof Lesley Wyborn 11 School of Earth and Environmental Sciences, The University of Queensland 1 Research School of Earth Sciences/Australian National UniversityKnowledge of the present-day stress is important to understandThirty years ago, Wall (1990) proposed the name Thermal the dynamics of earthquakes, and to manage the safe andAureole Gold (TAG) for a distinctive class of pluton-related gold sustainable usage of the underground during storage anddeposits (now more commonly known as Intrusion-related Gold exploitation. Eastern Australia hosts several sedimentary basins(IRG)). Initially based on the Pine Creek, Tanami and Paterson with large coal-seam gas reserves as well as mines that areProvinces, Wall (2005) later included significant deposits such critical for Australias energy and resources. Some of the easternas Murantau, Obuasi, Campbell-Red Lake, Fort Knox, and Pogo, Australian basins such as the Surat, Gippsland and Otway basinsshowing it is not just restricted to the Australian Proterozoic.have been proposed as potential CO 2storage sites. In addition, the Sydney Basin in New South Wales is one of Australias mostRevisiting the Pine Creek, Tanami and Telfer areas, a specific seismically active areas. type of granite is spatially associated with these Au-dominant This paper examines the state of present-day stress in easterndeposits. The granite type is fractionated, has dominantly Australia from variety of sources including wellbore data, focal65 wt% SiO 2and anomalously high concentrations of K, Th, mechanism solution of earthquakes, hydraulic fracturing andU and Rb: pluton compositions are variable. These granites overcoring tests. In particular, this paper presents the stateare believed to have formed at 30 kms as a product of of stresses in the Bowen, Surat, Clarence-Moreton, Sydney,anomalously high regional geothermal gradients of between 30 Gunnedah, Gippsland, Galilee, Cooper, Eromanga, Darling andto 60 degrees per km.Otway basins. Analysis of stress data in northeastern Australia (i.e.,Gold is commonly related to magnetite-bearing granites, but Bowen and Surat basins) shows a regional orientation of NNE- as Wall noted (2005), IRG deposits are often associated with SSW for the maximum horizontal stress (SHmax), which rotatesreduced granites (e.g., Pine Creek, Tennant Creek and Telfer). to ENE-WSW in the Clarence-Moreton, Gunnedah, and SydneyThis phenomena is common where granites intrude reduced basins. The SHmax orientation is E-W in the Galilee, Eromangahosts, particularly carbonaceous rocks, indicating that there and Cooper basins, and rotates to NW-SE in the Gippsland andhas been interaction between the granite and its host rock. The Otway basins in southeastern Australia. In addition to regionalhigh geothermal gradients, combined with anomalously high variability, significant stress changes (both orientation andregional heat flow suggests that once hydrothermal fluids leave magnitudes) at local scales have been observed due to presencethe granite they may mix with free convecting meteoric fluids AUGUST 2021 PREVIEW 90'