Extended abstract version of the abstract (Geocat#73747) submitted in March 2012 and accepted for an oral presentation at the symposium.

Geoscience Australia (GA) has been acquiring both broadband and long-period magnetotelluric (MT) data over the last few years along deep seismic reflection survey lines across Australia, often in collaboration with the States/Territory geological surveys and the University of Adelaide. Recently, new three-dimensional (3D) inversion code has become available from Oregon State University. This code is parallelised and has been compiled on the NCI supercomputer at the Australian National University. Much of the structure of the Earth in the regions of the seismic surveys is complex and 3D, and MT data acquired along profiles in such regions are better imaged by using 3D code rather than 1D or 2D code. Preliminary conductivity models produced from the Youanmi MT survey in Western Australia correlate well with interpreted seismic structures and contain more geological information than previous 2D models. GA has commenced a program to re-model with the new code MT data previously acquired to provide more robust information on the conductivity structure of the shallow to deep Earth in the vicinity of the seismic transects.

In 2009, as part of its Onshore Energy Security Program, Geoscience Australia, in conjunction with the Northern Territory Geological Survey, acquired 373 km of vibroseis-source, deep seismic reflection, magnetotelluric and gravity data along a single north-south traverse from the Todd River in the south to nearly 30 km north of the Sandover Highway in the north. This traverse, 09GA-GA1, is referred to as the Georgina-Arunta seismic line, extends from the northeastern Amadeus Basin, across the Casey Inlier, Irindina and Aileron provinces of the Arunta Region and Georgina Basin to the southernmost Davenport Province. Here, we report the results of an initial geological interpretation of the seismic and magnetotelluric data, and discuss some preliminary geodynamic implications.

The Onshore Energy Security Program, funded by the Australian Government, has been a five year program (2006-2011) conducted by Geoscience Australia in conjunction with the Australian state and Northern Territory geological surveys. Its aim was to provide new geological information on frontier onshore sedimentary basins in Australia, and, as part of this program, deep seismic reflection data have been acquired across several basins, to provide fundamental information on the stratigraphic and structural architecture of the basins and to stimulate hydrocarbon exploration. Reflection data were acquired over the Darling, Arrowie, Georgina (Queensland and Northern Territory), Amadeus, Arckaringa, Officer (Western Australia and South Australia) and southern Carnarvon Basins. This program also discovered and imaged a previously unknown basin, the Millungera Basin, in northwestern Queensland. Ranging from the Neoproterozoic to Cretaceous, these basins encompass segments of the Centralian Superbasin and later phases of basins that have built the Australia continent. Key results of this work include description of the architecture and internal geometries of each basin, settings imaged include mostly extensional basins, many which are later subject to contraction either by inversion (Arrowie Basin) or thrusting (Amadeus Basin) and, an example of a strike-slip basin, the Moorilyanna Graben, in the Officer Basin. The interpretation of stratigraphy used a sequence stratigraphic approach providing a basis for 1D petroleum systems modelling of the Millungera, Arrowie, Georgina (QLD) and Darling Basins. In total, 10 deep seismic profiles across 8 basins have been interpreted, hopefully contributing to an increase in onshore exploration activity.

The Georgina-Arunta deep seismic reflection line (09GA-GA1) has provided an image of the entire crust in this part of central Australia. At a first approximation, beneath the Neoproterozoic-Devonian sedimentary basins, the crust can be divided into four distinct regions, namely, the Aileron, Irindina and Davenport Provinces, and the Ooratippra Seismic Province. Each of these regions is separated from each other by major, crustal-scale faults. The observed crustal architecture has implications for geodynamic models for the evolution of the region, implying amalgamation of these crustal blocks in the Paleoproterozoic and major shortening and basin inversion in the Paleozoic.

Many of the onshore sedimentary basins in Australia are underexplored with respect to hydrocarbons. With domestic oil production in steady decline, and increasing offshore exploration costs, the Onshore Energy Security Program was funded by the Australian Government over five years (2006-2011), for Geoscience Australia to provide precompetitive geoscience data and assessments of the potential for onshore energy resources. As part of the Onshore Energy Security Program, deep seismic reflection data have been acquired across several frontier sedimentary basins to stimulate petroleum exploration in onshore Australia. The basins studied in this project include the Arrowie Basin (South Australia) and the Burke River Structural Zone of the Georgina Basin (northwest Queensland). The interpretation of deep seismic reflection profiles from these onshore sedimentary basins focussed on the overall stratigraphic and structural architecture of the basins. Petroleum systems maturation modelling was also undertaken to increase the understanding of the petroleum potential of these basins.

The Onshore Energy Security Program, funded by the Australian Government and conducted by Geoscience Australia, has acquired deep seismic reflection data, in conjunction with State and Territory geological surveys, across several frontier sedimentary basins to stimulate petroleum exploration in onshore Australia. Here, we present data from two seismic lines collected in South Australia and the Northern Territory. Seismic line 08GA-OM1 crossed the Carboniferous to Permian Arckaringa Basin is imaged as a series of depocentres forming the Phillipson and Penrhyn Troughs, with a much thinner succession connecting the depocentres, and extending well to the north. Seismic line 08GA-OM1 also crosses the Neoproterozoic to Devonian eastern Officer Basin. The basin is structurally complex in this area, being dominated by south-directed thrust faults and fault-related folds, providing potential for underthrust petroleum plays. Seismic line 08GA-OM1 also images the southern margin of the Amadeus Basin Seismic line 09GA-GA1 crossed the northeastern part of the Amadeus Basin and the complete width of the southern Georgina Basin in the Northern Territory. Structural and sequence stratigraphic interpretations of the seismic lines will be presented here, to be followed by an assessment of the petroleum potential of the basins. In the northeast, seismic line 09GA-GA1 crosses two parts of the basin separated by the Paleoproteroozic to Mesoproterozoic Casey Inlier. Seismic line 09GA-GA1 was positioned to cross that part of the southern Georgina Basin where the basin has a complex southern margin, with Neoproterozoic stratigraphy being thrust interleaved with basement rocks of the Arunta Region.

The CO2CRC Otway Project is Australia's first demonstration of geological storage of CO2 within deep underground reservoirs. The project has undergone many phases of implementation and the latest work program, Phase 2C, is aimed at injecting between 10,000 and 30,000 tonnes of CO2 into the saline Paraatte Formation located around 1,400m below surface. One of the key measures of success for Phase 2C is successful seismic detection of the injected gas stream. The geophysics team from Curtin University of Technology have previously conducted three 3D surface seismic surveys, and numerous smaller experiments, at the Otway CO2 re-injection site. These tests were completed during Phase 1 of the Otway Project whereby an (80-20%) CO2-CH4 gas mixture was re-injected into the depleted Warre-C gas reservoir. The feasibility of seismic monitoring of the CO2-CH4 gas mixture injected into the Paraatte Formation is expected to be improved over the Warre-C reservoir due to the increased fluid property contrast between brine and the CO2-CH4 mixture and the shallower depth of the reservoir. A comprehensive desktop feasibility study has been completed by the Curtin/CSIRO geophysics team to assess the probability of successful seismic detection and the preliminary results are encouraging. A Seismic Assurance Review workshop was completed incorporating seismic expertise from both academia and industry to assess the risk of unsuccessful seismic detection. The workshop was held on the 3rd and 4th of November, 2011, at Curtin University of Technology.

The Onshore Energy Security Program was funded by the Australian Government for five years (2006-2011) to provide geological information on some of the frontier onshore sedimentary basins in Australia, many of which are underexplored with respect to hydrocarbons. As part of the Onshore Energy Security Program, deep seismic reflection data have been acquired across several frontier sedimentary basins to stimulate petroleum exploration in onshore Australia. In 2009, Geoscience Australia, in conjunction with the Northern Territory Geological Survey, acquired a deep seismic transect 373 km long across (Figure 1) the Georgina Basin and northeast margin of the Amadeus Basin of the Northern Territory.

The Bureau of Mineral Resources, Geology and Geophysics (BMR) conducted a seismic survey in the Denison Trough, in the western part of the Bowen Basin in Queensland in 1979. The survey continued work commenced in 1978 aimed at delineating the configuration of the trough and providing stratigraphic information from the Permian sequence which, in conjunction with current Geological Survey of Queensland stratigraphic studies, would enable reliable stratigraphic correlations to be made throughout the trough. The survey obtained 265 km of digitally recorded mainly six-fold Common-Depth-Point seismic reflection data.