Many of the onshore sedimentary basins in Australia are underexplored with respect to hydrocarbons. 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 of some frontier onshore sedimentary basins for energy resources, including hydrocarbons, uranium, thorium and geothermal energy. The basins studied in this project include the Burke River Structural Zone of the Georgina Basin (northwest Queensland), the Yathong Trough in the eastern Darling Basin (western New South Wales), and the Arrowie Basin (South Australia). The interpretation of deep seismic reflection profiles and petroleum systems maturation modelling was undertaken in these basins to increase the understanding of their petroleum potential. The Arrowie Basin seismic data shows an asymmetrical basin architecture, with the basin fill being ~3800 m at its thickest. Several sequence boundaries are mapped in this seismic section, and are correlated with the sequence boundaries between the major Neoproterozoic stratigraphic groups in the Adelaide Rift System. In the easternmost part of the seismic section, a series of east-dipping thrust faults disrupt the stratigraphic section. The petroleum systems maturation modelling shows that potential Cambrian source rocks are likely immature to mature for oil generation. In contrast, potential Neoproterozoic source rocks are likely to be mature to overmature for oil generation, and immature to mature for gas generation. With hydrocarbon systems clearly present in the Arrowie Basin as shown by bitumen in shallow exploration wells drilled in the 1950's, future work, possibly with a focus on unconventional hydrocarbons, would be warranted. The Burke River Structural Zone of the Georgina Basin seismic data shows the basin is ~65 km wide, with a half-graben geometry, being bounded in the west by a rift border fault. The succession in the basin has a maximum thickness of ~2800 m, with the stratigraphy being relatively flat lying, and thickening towards the west. The petroleum systems maturation modelling shows potential Cambrian source rocks are likely to be oil mature. Significant generation and expulsion probably occurred early in the burial history, in response to Cambrian-Ordovician loading. Expulsion occurred after trap formation in the Neoproterozoic-Cambrian, but before later trap formation in the Devonian. The required long preservation time and unroofing are the major risk factors within the basin. The Yathong Trough of the Darling Basin seismic data interpretation shows that the basin fill consists of a thick succession characterised by alternating high and low amplitude seismic reflections, interpreted to represent the expected Devonian succession mudstones and sandstones. The basement units below the Yathong Trough are interpreted to be Ordovician turbidites and Ordovician-Silurian granites, considered to be part of the Lachlan Orogen. The petroleum systems maturation modelling shows that potential Lower and Middle Devonian source rocks are likely to be overmature for oil generation and mature for gas generation. Generation and expulsion from Lower and Middle Devonian potential marine source rocks occurred early during their burial history, prior to Carboniferous uplift and erosion, and thus, major trap formation. Later burial during the Permian and/or Cretaceous may have resulted in minor gas generation and expulsion from a Middle Devonian potential source rock.

Gravity surveys were conducted of the Gippsland Lakes district during 1949 and 1951. Both surveys showed an anomaly immediately to the north of Lake Wellington, the magnetic anomaly being a little displaced to the north-west of the gravity anomaly. The size and nature of the magnetic anomaly suggested that it might be due to rocks with higher than normal magnetic susceptibility in the basement complex. The gravity anomaly might be due to a buried hill in the Jurassic or basement, perhaps associated with the same feature which is responsible for the magnetic anomaly. Such a buried hill could result in a geological structure favourable to the accumulation of oil being present in the overlying Tertiary rocks, and in order to test whether or not a favourable structure existed a seismic reflection survey was undertaken by the Bureau. This report deals with the results of the seismic survey. Two north-south traverses and one running east-west and crossing the other two were surveyed.

A seismic survey, consisting of a main north-south reflection traverse and several short supplementary reflection and refraction traverses, was made in the Gosses Bluff area, of the Amadeus Basin,Northern Territory by a seismic party of the Bureau of Mineral Resources, Geology and Geophysics between March and July 1962. The purpose of the survey was to obtain information on the lli.ssionary Plain Syncline, the Gosses Bluff uplift; the fault at the northenl flank of the Gardiner Range, and the tectonic features relative to the Archaean/sedimentary contact at the northern edge of the Missionary Plain. The seismic reflection method proved to be an excellent exploratory tool in the undisturbed parts of the sedimentary basin. The Missionary Plain Syncline was shovm. to have a maximum thickness of sediments of 33,000 ft, nine miles north of Gosses Bluff. The results indicate that Gosses Bluff is a diapiric structure of the salt dome type, where the Proterozoic Bitter Springs Limestone has provided the necessary mobile material. The Gardiner Range Fault was shown to be overthrust from the south vdth a hade of 15 to 20 degrees. The problem regarding the Archaean/sedimentary contact was not solved.

A four and a half month seismic survey has been carried out in the Poole Range area of the Fitzroy Basin by C. G. G. where both the reflection and refraction methods have been tested. Reflection experiments lead to a high multiplication of geophones and shot-holes patterns. However, tests were too limited and too scattered to allow for definite conclusions regarding the best recording procedure. The refraction method has been used to provide information regarding the extension at depth of Poole Range surface anticline. The same method was used for a reconnaissance survey on the regional gravity anomaly 16 A. Besides shallow markers, two and sometimes three deep markers were followed simultaneously. The results obtained during the survey indicate that: Poole Range surface structure has no extension at depth; - Two high zones, separated by a narrow trough appear to correspond to the gravity anomaly 16 A. The eastern high zone is a wide dome with a closure of about 4,000 ft at the level of the deeper marker. The western high zone corresponds to a shelf-like area of the deeper marker. It is overlain by sedimentary formations where facies changes are suggested by rapid variations of the marker's velocities. This is the shallowest area of the survey with a 15,000 ft/ sec marker at a depth of less than 10,000 ft. Delimination of the most interesting structural locations would require the carrying out of supplementary traverses. A tentative interpretation makes the deeper marker a probable Proterozoic level with depths ranging from 15,000 feet to 30,000 feet. The two others might represent Devonian and Ordovician formations.

Seismic reflection studies in the Perth Basin, between the coast and the Darling Range, 30 miles north of Perth, were conducted in an attempt to derive a suitable recording technique for obtaining reflections when shooting on the Coastal Limestone formation, to investigate geological structure in the basin,and to supplement hydrological studies being madeby the Geological Survey of Western Australia. Experimental work occupying half of the survey period failed to yield a technique for obtaining seismic reflections on the Coastal Limestone, but led to reflections being obtained across the major part of the basin, Record quality with a fairly heavy technique was poor to fair in the western half of the basin off the Coastal Limestone but improved considerably to the east. A complex geological section in the west gave way to a more concordant thick synclinal section in the east, terminated at its eastern end by the Darling Fault. Of interest is an apparent anticlinal reversal of dip in beds lying deeper than 7000 ft,with the reversal axis near the centre of the major gravity 'low' of the basin.

The Vibroseis method of seismic exploration was first introduced into Australia during 1963. In accordance with the programme for accelerated oil search, the Bureau of Mineral Resources employed a Vibroseis seismic party to demonstrate the performance of the method in various problem areas within the Otway and Sydney Basins, the locations of which are indicated on the regional map. The Experimental Vibroseis Seismic Survey was conducted by Seismograph Service Limited. Party 243. on behalf of the Bureau of Mineral Resources, Geology and Geophysics during the period from 11th May to 3rd October, 1964. The broad objective of the survey was to demonstrate the capabilities of the Vibroseis method in selected areas where previous conventional seismic surveys had experienced difficulties in obtaining results and where various seismic problems had been defined. The main aim of the survey was to obtain good quality results rather than a high production rate yielding poorer quality data. However, as a secondary objective, some short production traverses were recorded USing the optimum field technique developed during the course of the survey for comparison e with normal shot hole production techniques.

Some experimental geophysical work was undertaken by the Bureau of Mineral Resources at the Moura Coalfield in Queensland in order to investigate the structure of coal seams which lie within 1000 feet of the surface. The aim of the survey was to evaluate the use of geophysical techniques for locating faults of small displacement. Most of the effort was concentrated on shallow seismic reflection techniques but additional techniques (magnetic, gravity, resistivity, electromagnetic and induced polarization) were used. The whole area of the survey was covered with a close-spaced grid of gravity and magnetic stations. A lesser effort was devoted to resistivity, electromagnetic, and induced polarization methods, the object being to take advantage of the opportunity to tryout these relatively inexpensive methods in the hope that they might give some indications of fault locations. These methods will be evaluated in a separate Record; this one deals- with the results of the seismic work. Encouraging results were obtained from seismic reflection work. The uppermost economic coal seam was mapped to within 300 feet of the surface and areas of faulting could be deduced from time differences and lack of continuity in reflections.

A deep crustal seismic reflection survey, conducted at Gundary Plains near Canberra, to test a digital seismic recording system, produced additional data for interpretation of seismic refraction profiles in the Lachlan Fold Best. Good reflections were recorded down to the probable Moho, at an estimated depth of 41 km. The intracrustal reflections are characterised by bands of seismic energy, which probably represent velocity transition zones within the crust.

<p>Geoscience Australia conducted a seismic survey in the central Eromanga Basin in Queensland in 1981. This survey was a continuation of the work undertaken in 1980 to investigate the structure, stratigraphy, geological and tectonic evolution, and petroleum potential of the area. The survey obtained 438 km of six-fold Common-Depth-Point seismic reflection data, in the Quilpie Trough and over the Cooper and Thomson Synclines.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74971</b>

<p>Geoscience Australia with assistance from the Geological Survey of Queensland conducted a seismic survey in southeast Queensland form April to December 1984. The survey set out to investigate deep structures within the earth's crust and is the first of the Australian Continental Reflection Profiling (ACORP), initiatives to study critical transects of the Australian lithosphere. The survey obtained 798 km of six-fold seismic reflection data over the Westgate Trough, Nebine Ridge, Surat Basin, Kumbarilla Ridge, and Clarence-Moreton Basin.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74969</b>