EXPLORATION AND ITS RESPONSE TO DIVERGENT INFLUENCES

1975 ◽  
Vol 15 (1) ◽  
pp. 153
Author(s):  
W. G. H. Maxwell
Keyword(s):  
Technological Factor ◽  
South Australia ◽  
Sedimentary Basins ◽  
Social Background ◽  
Petroleum Exploration ◽  
Social Trends ◽  
Oil Boom ◽  
Third Phase ◽  
Political Events ◽  
Fluctuating Course

Petroleum exploration in Australia has evolved through three distinct phases and is now entering a fourth. It began with the wild, speculative flurries that culminated in drilling on the Coorong, South Australia in 1892, it was revived by the accidental discovery of gas near Roma at the turn of the century leading to the oil boom from 1926 to 1933, and it reached its peak in 1962-72 in the third phase, after which exploration activity has gone into decline. Examination of the economic, political and social background to the industry reveals that, on the national scene, political events rather than economic and social trends have had greater impact on the fluctuating course of its development. International influences also appear, in many instances, to be of greater significance than domestic factors. Much time and effort have been devoted by industry, government and academics to the analysis of economic, political and social influences on Australia's petroleum exploration but it is quite obvious that the basic determinant Is still the oft-forgotten geologic-technological factor. The condition of the domestic industry depends primarily on the potential of Australia's sedimentary basins and the quality of the technology used to explore them. In the long term, all other influences are temporary in their impact and subordinate in their ultimate effect.

Mapping geology beneath volcanics using magnetic data

2018 ◽  
Vol 58 (2) ◽  
pp. 821
Author(s):  
Irena Kivior ◽  
Stephen Markham ◽  
Leslie Mellon ◽  
David Boyd
Keyword(s):  
South Australia ◽  
Sedimentary Basins ◽  
Seismic Signal ◽  
Petroleum Exploration ◽  
Seismic Survey ◽  
Source Distribution ◽  
Magnetic Data ◽  
Large Area ◽  
Magnetic Susceptibilities ◽  
Passive Seismic

Volcanic layers within sedimentary basins cause significant problems for petroleum exploration because the attenuation of the seismic signal masks the underlying geology. A test study was conducted for the South Australia Government to map the thickness of volcanics and sub-volcanic geology over a large area in the Gawler Range Volcanics province. The area is covered by good quality magnetic data. The thickness of volcanics and basement configuration was unknown as there has only been a limited amount of drilling. The Automatic Curve Matching (ACM) method was applied to located magnetic data and detected magnetic sources within different rock units, providing their depth, location, geometry and magnetic susceptibility. The magnetic susceptibilities detected by ACM allowed the differentiation of the volcanics and the underlying basement. The base of volcanics and the depth to the top of basement was mapped along 75 km NS profiles, that were spaced 1 km apart over a distance of 220 km. The volcanic and basement magnetic susceptibilities and the magnetic source distribution pattern were used as key determinants to interpret the depth to the two interfaces. The results for each interface were gridded, and images of the base of volcanics and depth to basement were generated. The mapped volcanics thickness was validated by comparison with the results from drilling, with the volcanics thickness matching very well. After project completion, a passive seismic survey was conducted in part of the test area, indicating a base of volcanics of ~4 km, which further confirmed the results.

RECONNAISSANCE GRAVITY SURVEY OF AUSTRALIA

Geophysics ◽  
1976 ◽  
Vol 41 (6) ◽  
pp. 1337-1345 ◽  
Author(s):  
A. R. Fraser ◽  
F. J. Moss ◽  
A. Turpie
Keyword(s):  
Bouguer Anomaly ◽  
South Australia ◽  
Mineral Resources ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Aerial Photographs ◽  
Gravity Survey ◽  
State Governments ◽  
Anomaly Map ◽  
Considerable Benefit

The Australian Bureau of Mineral Resources, Geology and Geophysics, completed a 15 year systematic reconnaissance gravity survey of Australia in 1974. Using helicopters, gravity stations were established at 11 km spacing over most of the continent, and at 7 km spacing in South Australia and Tasmania. Station elevations were measured barometrically and station positions were marked on aerial photographs and transferred to 1:250,000 photocenter base maps. Gravity and elevation controls were maintained by ties to specially established control networks. A Bouguer anomaly map of Australia has been compiled from the reconnaissance data, and from information from other gravity surveys by state governments, petroleum exploration companies, and academic institutions which together cover about 15 percent of the total area. The compilation uses a total of about 170,000 gravity observations. The accuracy of Bouguer anomaly values, taking account of errors in the gravity, elevation, and position measurements, is estimated to be better than ± 2.0 mgal. The Bouguer anomaly fields over Australia are divided into nine regional gravity divisions, in each of which the gravity contour pattern has some degree of uniformity, or is such as to imply tectonic affinities between the sources of individual gravity features. The gravity divisions can be correlated with various metamorphic complexes and orogenic provinces, ranging in age from Archaean to Paleozoic, which also form the basements to extensive sedimentary platform covers. The reconnaissance gravity results have been made public as the survey has progressed to assist in regional geologic studies and the search for petroleum and minerals. They have proved to be of considerable benefit in delineating regional structures and in providing leads for more detailed geophysical investigations. Predictions of the structures of sedimentary basins have been made and possible extensions to mineral provinces have been indicated. The results have also been used in deep crustal and upper mantle studies and in geodesy.

SELECTING THE WINNING BID

2002 ◽  
Vol 42 (1) ◽  
pp. 523
Author(s):  
E. Alexander ◽  
J. Morton
Keyword(s):  
Scoring System ◽  
Net Present Value ◽  
South Australia ◽  
Petroleum Exploration ◽  
3D Seismic ◽  
Management Philosophy ◽  
Work Program ◽  
Single Target ◽  
2D And 3D ◽  
Selection Of

Work program bidding is established as the favoured method of allocating petroleum exploration tenements in offshore Australian waters and most of onshore Australia. However, the selection of winning bids can be complicated by the ranking of 2D versus 3D seismic, seismic versus drilling, program timing issues etc. On occasion the selection of the winning bids has been contentious. This paper summarises the process developed by the Petroleum Group in South Australia to select the winning work program bids for prospective onshore blocks for which bids have been gazetted. No other Australian jurisdiction has yet publicly released their detailed bid assessment processes.Onshore acreage releases with work program bidding have been used in South Australia since the 1980s by Petroleum Group to:focus industry onto specific prospective areas of the State (e.g. the Cooper Basin post expiry of PELs 5 and 6 in 1999); maximise exploration commitments; and achieve competition policy.The South Australian Petroleum Act 2000 allows cash or work program bidding to be used depending on the acreage. Acreage releases are announced by Ministerial press release. Associated clear bid assessment criteria are published together with promotional material to aid applicants. The date and time for close of bidding are also established, usually allowing a 6–9 month acreage evaluation period, the timeframe depending on the volume of data involved, i.e. the exploration maturity of the area.Applications received as a result of a gazettal process (i.e. competing bids) are assessed by a process designed to ensure probity and to achieve the over-arching aim of the bidding process i.e. the suitability of the applicants proposed work program for evaluating the prospectivity of the licence area and discovering petroleum.A scoring system has been developed which establishes, for each bid what is effectively a risked net present value in well equivalents. In this system, guaranteed work scores higher than non-guaranteed work; early work scores higher than later work; wells with multiple targets are scored higher than single target wells; 2D and 3D seismic and other exploration activity is converted into well equivalents; and loading of the later, non-guaranteed years of work programs are heavily discounted.The scoring system may also take into account differences in the amount and density of exploration data and minor variations may be made to the system to take this into account. It is intended that details of the scoring system to be used in bid assessment will be published each time bids are sought to ensure transparency and a level playing field.Comparisons are made with acreage management philosophy and processes used by other regulatory regimes in Australia and internationally.

NEW PETROLEUM MODELS IN THE PEDIRKA BASIN, NORTHERN TERRITORY, AUSTRALIA

2002 ◽  
Vol 42 (1) ◽  
pp. 259 ◽  
Author(s):  
G.J. Ambrose ◽  
K. Liu ◽  
I. Deighton ◽  
P.J. Eadington ◽  
C.J. Boreham
Keyword(s):  
Oil And Gas ◽  
South Australia ◽  
Sedimentary Basins ◽  
Poor Quality ◽  
Northern Territory ◽  
Early Jurassic ◽  
Source Rocks ◽  
Late Triassic ◽  
Hydrocarbon Expulsion ◽  
Migration Pathways

The northern Pedirka Basin in the Northern Territory is sparsely explored compared with its southern counterpart in South Australia. Only seven wells and 2,500 km of seismic data occur over a prospective area of 73,000 km2 which comprises three stacked sedimentary basins of Palaeozoic to Mesozoic age. In this area three petroleum systems have potential related to important source intervals in the Early Jurassic Eromanga Basin (Poolowanna Formation), the Triassic Simpson Basin (Peera Peera Formation) and Early Permian Pedirka Basin (Purni Formation). They are variably developed in three prospective depocentres, the Eringa Trough, the Madigan Trough and the northern Poolowanna Trough. Basin modelling using modern techniques indicate oil and gas expulsion responded to increasing early Late Cretaceous temperatures in part due to sediment loading (Winton Formation). Using a composite kinetic model, oil and gas expulsion from coal rich source rocks were largely coincident at this time, when source rocks entered the wet gas maturation window.The Purni Formation coals provide the richest source rocks and equate to the lower Patchawarra Formation in the Cooper Basin. Widespread well intersections indicate that glacial outwash sandstones at the base of the Purni Formation, herein referred to as the Tirrawarra Sandstone equivalent, have regional extent and are an important exploration target as well as providing a direct correlation with the prolific Patchawarra/Tirrawarra petroleum system found in the Cooper Basin.An integrated investigation into the hydrocarbon charge and migration history of Colson–1 was carried out using CSIRO Petroleum’s OMI (Oil Migration Intervals), QGF (Quantitative Grain Fluorescence) and GOI (Grains with Oil Inclusions) technologies. In the Early Jurassic Poolowanna Formation between 1984 and 2054 mRT, elevated QGF intensities, evidence of oil inclusions and abundant fluorescing material trapped in quartz grains and low displacement pressure measurements collectively indicate the presence of palaeo-oil and gas accumulation over this 70 m interval. This is consistent with the current oil show indications such as staining, cut fluorescence, mud gas and surface solvent extraction within this reservoir interval. Multiple hydrocarbon migration pathways are also indicated in sandstones of the lower Algebuckina Sandstone, basal Poolowanna Formation and Tirrawarra Sandstone equivalent. This is a significant upgrade in hydrocarbon prospectivity, given previous perceptions of relatively poor quality and largely immature source rocks in the Basin.Conventional structural targets are numerous, but the timing of hydrocarbon expulsion dictates that those with an older drape and compaction component will be more prospective than those dominated by Tertiary reactivation which may have resulted in remigration or leakage. Preference should also apply to those structures adjacent to generative source kitchens on relatively short migration pathways. Early formed stratigraphic traps at the level of the Tirrawarra Sandstone equivalent and Poolowanna Formation are also attractive targets. Cyclic sedimentation in the Poolowanna Formation results in two upward fining cycles which compartmentalise the sequence into two reservoir–seal configurations. Basal fluvial sandstone reservoirs grade upwards into topset shale/coal lithologies which form effective semi-regional seals. Onlap of the basal cycle onto the Late Triassic unconformity offers opportunities for stratigraphic entrapment.

Review of the 2009 offshore petroleum exploration release areas

2009 ◽  
Vol 49 (1) ◽  
pp. 465
Author(s):  
Thomas Bernecker
Keyword(s):  
Deep Water ◽  
South Australia ◽  
Northern Territory ◽  
Data Availability ◽  
Petroleum Exploration ◽  
Release Date ◽  
North West ◽  
The North ◽  
Release Area ◽  
Block Sizes

The Australian Government formally releases new offshore exploration areas at the annual APPEA conference. This year, 31 areas plus two special areas in five offshore basins are being released for work program bidding. Closing dates for bid submissions are either six or twelve months after the release date (i.e. 3 December 2009 and 29 April 2010), depending on the exploration status in these areas is and on data availability. The 2009 release areas are located in Commonwealth waters offshore Northern Territory, Western Australia, South Australia and Victoria, comprising intensively explored areas close to existing production as well as new frontiers. As usual, the North West Shelf features very prominently and is complimented by new areas along the southern margin, including frontier exploration areas in the Ceduna Sub-basin (Bight Basin) and the Otway Basin. The Bonaparte Basin is represented by one release area in the Malita Graben, while five areas are available in the Southern Browse Basin in an under-explored area of the basin. A total of 14 areas are being released in the Carnarvon Basin, with eight areas located in the Dampier Sub-basin, three small blocks in the Rankin Platform and three large blocks on the Northern Exmouth Plateau (these are considered a deep water frontier). In the south, six large areas are on offer in the Ceduna Sub-basin and five areas of varying sizes are being released in the Otway Basin, including a deep water frontier offshore Victoria. The special release areas are located in the Petrel Sub-basin, Bonaparte Basin offshore Northern Territory, and encompass the Turtle/Barnett oil discoveries. The 2009 offshore acreage release offers a wide variety of block sizes in shallow as well as deep water environments. Area selection has been undertaken in consultation with industry, the states and Territory. This year’s acreage release caters for the whole gamut of exploration companies given that many areas are close to existing infrastructure while others are located in frontier offshore regions. As part of Geoscience Australia’s Offshore Energy Security Program, new data has been acquired in offshore frontier regions and have yielded encouraging insights into the hydrocarbon prospectivity of the Ceduna-Sub-basin.

THE EVOLUTION OF THE BERNIER RIDGE, SOUTHERN CARNARVON BASIN, WESTERN AUSTRALIA:IMPLICATIONS FOR PETROLEUM PROSPECTIVITY

2004 ◽  
Vol 44 (1) ◽  
pp. 241 ◽  
Author(s):  
A.M. Lockwood ◽  
C. D’Ercole
Keyword(s):  
Seismic Data ◽  
Large Scale ◽  
Sedimentary Basins ◽  
Early Carboniferous ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Large Igneous Province ◽  
Satellite Gravity ◽  
Tectonic Events ◽  
Carnarvon Basin

The basement topography of the Gascoyne Platform and adjoining areas in the Southern Carnarvon Basin was investigated using satellite gravity and seismic data, assisted by a depth to crystalline basement map derived from modelling the isostatic residual gravity anomaly. The resulting enhanced view of the basement topography reveals that the Gascoyne Platform extends further westward than previously indicated, and is bounded by a northerly trending ridge of shallow basement, named the Bernier Ridge.The Bernier Ridge is a product of rift-flank uplift prior to the Valanginian breakup of Gondwana, and lies east of a series of small Mesozoic syn-rift sedimentary basins. Extensive magmatic underplating of the continental margin associated with this event, and a large igneous province is inferred west of the ridge from potential field and seismic data. Significant tectonic events that contributed to the present form of the Bernier Ridge include the creation of the basement material during the Proterozoic assembly of Rodinia, large-scale faulting during the ?Cambrian, uplift and associated glaciation during the early Carboniferous, and rifting of Gondwana during the Late Jurassic. The depositional history and maturity of the Gascoyne Platform and Bernier Ridge show that these terrains have been structurally elevated since the mid-Carboniferous.No wells have been drilled on the Bernier Ridge. The main source rocks within the sedimentary basins west of the Bernier Ridge are probably Jurassic, similar to those in the better-known Abrolhos–Houtman and Exmouth Sub-basins, where they are mostly early mature to mature and within the oil window respectively. Within the Bernier Ridge area, prospective plays for petroleum exploration in the Jurassic succession include truncation at the breakup unconformity sealed by post-breakup shale, and tilted fault blocks sealed by intraformational shale. Plays in the post-breakup succession include stratigraphic traps and minor rollover structures.

ENVIRONMENTAL IMPACT OF SEISMIC OPERATIONS IN THE OTWAY BASIN, SOUTH AUSTRALIA

1994 ◽  
Vol 34 (1) ◽  
pp. 741 ◽  
Author(s):  
M. L. Williams ◽  
A. J. Boulton ◽  
M. Hyde ◽  
A. J. Kinnear ◽  
C. D. Cockshell
Keyword(s):  
Environmental Management ◽  
Environmental Impact ◽  
Vegetation Structure ◽  
South Australia ◽  
Petroleum Exploration ◽  
Seismic Exploration ◽  
Native Vegetation ◽  
Seismic Line ◽  
The Impact ◽  
Seismic Lines

The Department of Mines and Energy, South Australia (DME) contracted Michael Williams and Associates Pty Ltd to audit the environmental management of seismic exploration operations in the South Australian Otway Basin. The audit was carried out in early 1992 and covered petroleum exploration operators and DME environmental management systems. An innovative field sampling technique was developed to compare the environmental impact of two different seismic line clearing techniques. Recovery of native vegetation as measured by vegetation structure was also quantified.The audit found DME to have a dynamic and integrated environmental management system while company systems varied in standard. Wide consultation assisted the audit process.As a result of clearing for agriculture, native vegetation covers only six per cent of the Otway Basin. With the strict limitations to broad-scale vegetation clearance since the mid-1980s and the cessation since 1991, the greatest environmental impact of seismic exploration is the clearance of native vegetation for access by seismic vehicles. Native vegetation structure and associated abiotic variables on seismic lines and adjacent control sites, were subject to a classification and ordination analysis which compared the impact of seismic lines constructed by bulldozer or Hydro-ax (industrial slasher). Post-seismic recovery rates of three different vegetation associations were also determined. This analytical technique permits the effects of seismic line clearance to be compared with the natural variability of specific vegetation associations within a region. In interpreting the results however, there is a confounding effect of line type and year as most of the more recent seismic lines were constructed using a Hydro-ax. Results indicate that Hydro-ax clearing affects vegetation structure less than bulldozing. Most Hydro-ax sites recovered within a few years whereas some sites, bulldozed as early as 1971, particularly tussock grasslands, have not yet recovered.This study provides a significant break-through in the debate about the persistence of seismic impacts on native vegetation. As a rapid preliminary assessment, sampling vegetation structure rather than floristics, provides a cost-effective audit and monitoring technique which can be used by non-specialists in a range of petroleum exploration environments. Any significant structural differences may require more detailed analysis to determine if floristic composition also differed.

PROGRESS OF STUDIES, BASIN STUDY GROUP, BUREAU OF MINERAL RESOURCES

1970 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
K. G. Smith
Keyword(s):  
Cross Sections ◽  
Mineral Resources ◽  
Sedimentary Basins ◽  
Basic Data ◽  
Petroleum Exploration ◽  
Geological Survey ◽  
Study Group ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Contour Maps

The Basins Study Group is part of the Subsurface Section of the Bureau's Petroleum Exploration Branch and was formed in 1962 to collect and review available basic data on the sedimentary basins of Australia and Papua-New Guinea. The Core and Cuttings Laboratory forms the second part of the Subsurface Section, and the Laboratory's technical staff contribute to basin reviews by carrying out analyses of various kinds, and assist in the collection of data principally by providing thin sections of various sedimentary formations.Recent activities of the Basins Study Group include a review of the Sydney Basin, and an increased effort to assemble basic data on all sedimentary basins, with particular emphasis on the Canning and Carnarvon Basins.The review of the Sydney Basin is nearing completion. It was undertaken with the co-operation of the Geological Survey of New South Wales and received generous support from petroleum exploration companies active in the Basin. The review included detailed petrological examination of twelve wells and selected outcrop samples. The results confirmed the previously-held opinions that the reservoir characteristics of Sydney Basin sediments are generally unfavourable. At present there are no indications of untested onshore areas where an improvement in reservoir properties may occur. The Bureau petrologists detected the rare mineral dawsonite in eight wells; the mineral occurred mostly in Permian sediments, both in marine and non-marine rocks, but it was recorded also from Triassic rocks in the Kurrajong Heights No. 1 well. The review of geophysical data from the Sydney Basin was concentrated mainly on seismic work. The magnetic tapes of three surveys were replayed and considerable improvement in records was effected. Record sections of all seismic surveys were reduced photographically to a horizontal scale of 1:50,000 and the reductions were spliced to provide easily-managed cross-sections. The geophysical review is nearing completion and structure contour maps and isochrons are in preparation.The collection of basic data is done for each sedimentary basin as it becomes available, but present emphasis is on assembling data from Western Australian basins: all seismic traverses in the onshore parts of the Canning and Carnarvon Basins have been plotted at 1:250,000 scale, and with the co-operation of the Geological Survey of Western Australia, bibliographies of the Canning, Carnarvon and Perth Basins have been compiled for issue as Open-file Records. Bibliographies of the Papuan and Ipswich-Clarence Basins have also been compiled.

DEEP STRATIGRAPHIC CORE-DRILLING AS AN AID TO PETROLEUM EXPLORATION

1971 ◽  
Vol 11 (1) ◽  
pp. 80
Author(s):  
R. J. Allen
Keyword(s):  
Gamma Ray ◽  
Single Point ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Current Maximum ◽  
Drilling Cost ◽  
Exploratory Wells ◽  
Relationship Of ◽  
The Relationship ◽  
Representative Material

The Queensland Department of Mines has undertaken stratigraphic drilling to assist petroleum exploration since 1965. The primary purpose was to obtain core for palynological and petrological study, in order to facilitate correlation of strata met in deep exploratory wells with the type sections of outcrop.To the end of October, 1970, 61 bores have been completed for a total of 50,473 feet (15,394 metres), an average depth of 827 feet (252 metres).Average drilling cost ranged from about $5 per foot at shallow depths to about $15 per foot towards the current maximum capacity of 4,000 feet (1,220 metres), total cost was of the order of $400,000.All holes were fully cored from about 50 feet (about 15 metres) to total depth. With minor exceptions, all drilling has been with NX equipment, giving a core approximately 1.7 inches (4.3 centimetres) in diameter. The core barrel is 10 feet (3 metres) long; it is recovered by the wireline method. On completion, most holes have been logged electrically and radiometrically (spontaneous potential, single-point resistivity and gamma-ray).Drilling lias been undertaken in sediments of the Surat, Bowen, Moreton and Ipswich Basins, and the Esk Rift. In the Surat Basin, complete sections of the Jurassic have been obtained on both the western and eastern flanks, and the Cretaceous has been sampled completely near the middle of the basin; in addition, the Injune Creek Group (Jurassic) is being investigated in some detail. In the Bowen Basin, representative material has been obtained from the Triassic units (Rewan, Clematis and Moolayember); the Permian on the eastern flank has been sampled completely in a Departmental coal-exploration project. In the Moreton Basin, a series of regional lines was drilled, partly in order to establish the relationship of the Bundamba Group to the Jurassic of the Surat Basin.One hole was drilled in the Ipswich Basin, to sample the upper part of the Triassic succession there.The program has been especially effective in providing material for palynological studies, both descriptive and stratigraphic, particularly in sandstone units. By this means, several important stratigraphic problems were resolved. For example, the type Wandoan Formation of Union-Kern-A.O.G. Wandoan 1 well was shown to be equivalent in age to the lower and middle Clematis Sandstone of outcrop, whereas the so-called Wandoan elsewhere in the basin was shown to be equivalent to the uppermost Clematis and lower Moolayember Formation of outcrop. Again, the drilling has confirmed the lithological correlation of the Precipice Sandstone of the Surat Basin with the Helidon Sandstone of the Moreton Basin, and the Evergreen Formation and Hutton Sandstone (which overlie the Precipice) with the Marburg Sandstone (which overlies the Helidon); the remarkably persistent oolite marker in the Evergreen and Marburg has been shown to be of essentially the same age throughout.Extension of the project widely through the sedimentary basins of Queensland is warranted.Proposed work for 1971 includes drilling of the Permian on the western flank of the Bowen Basin, and of the Tertiary in the Hillsborough Basin.

Sign in / Sign up

Export Citation Format

Share Document