This is a compilation of all proven and probably producing source rocks from Australia. These can be grouped into 15 intervals ranging in age from Late neoproterozoic to Late Cretaceous-Eocene.

The polar lipid and macromolecular compositions of three samples from the marine-influenced Heartbreak Ridge lignite deposit (Bremer Basin, Western Australia) were investigated for chemical changes wrought during early diagenesis. The results of Rock-Eval, microscope Fourier transform infrared spectroscopic and thermal extraction/pyrolysis-gas chromatography-mass spectrometric analyses indicate that the composition of the lignite and its extract are typical of immature Type III organic matter, and thus contain a high proportion of aromatic and oxygen-containing functionalities. Down-seam variation in the proportions of these functionalities, together with changes in the carbon preference index (CPI) of the pyrolysate n-alkenes, and the wax indices of straight chain n-alkyl pyrolysis products, is consistent with more pronounced degradation of the lowermost lignite horizon. This profile is also reflected in the diagenetic products of higher plant triterpenoids, identified in the lignite extracts by gas chromatography-mass spectrometry. The extent of aromatisation, demethylation, ring opening and defunctionalistion is recorded through this depth profile by the compositions of the free, sulfurised and oxygenated higher plant triterpenoids. In contrast, degradation of the extended hopanoids had come to a hiatus by the onset of sulfurisation in the Heartbreak Ridge lignite. Oxygen-containing lipids are implicated as the primary source of the sulfurised hydrocarbons, although not necessarily via direct sulfurisation of the identified oxygenated lipids, but through the formation of more reactive intermediate species. These results suggest that the onset of marine incursion and associated sulfur fixation inhibits, and through preservation illuminates, the typical biogeochemical transformation of lipids and biopolymers in coal-forming environments.

First paragraph of abstract: The importance of organic sulphur fixation in the preservation of organic matter in humic coal-forming environments is demonstrated in this thesis. The transgression of coal depositional systems by marine waters during their deposition and early diagenesis enables the production of reduced inorganic sulphur species by sulphate-reducing bacteria. The presence of these reactive sulphur species, in combination with the altered chemical and microbial regime, influences the preservation and petroleum potential of humic coal.

The transgression of coal depositional systems by marine waters enables the preservation of functionalised lipids, such as steranes, hopanes and higher plant triterpanes, via their reaction with reduced inorganic sulphides produced by sulphate-reducing bacteria. Using compound specific isotopic analysis, higher plant and microbial sources of these lipids can be identified. The carbon isotopic compositions of the lipids are invariant to differences in the degree or timing of marine incursion. This indicates that the introduction of marine waters at any stage of mire and peat development preserves the inherited lipid composition and does not overwhelm this biotic signature during sulphate reduction. Consequently, the selective preservation of certain biomarkers enables their use in the reconstruction of coal palaeoenvironments and facilitates oil-source rock correlations. The presence of these coal-derived chemical markers in crude oils is testament to the petroleum generation potential of marine-influenced coals.

This product is a Microsoft Access database which contains the raw data, calculated biomarker ratios and reporting output forms. This product includes 120 oils from the first Oils of Western Australia study (WOZ1) and 150 oils from the second Oils of Western Australia study (WOZ2). This database is one component of "The Oils of Western Australia II" product which comprises two other components: an interpretative report documenting the petroleum geochemistry of the oils in the study and assignment of each sample to an oil family, and an ArcView GIS CD containing coverages of North West Shelf regional geology and petroleum exploration themes, and oil family maps linked to graphs of specific chemical parameters which define the families. The Oils of Western Australia II report summarises the findings of a collaborative research program between Geoscience Australia and GeoMark Research undertaken on the petroleum geochemistry of crude oils and condensates discovered within the basins of western Australia and the Papuan Basin, Papua New Guinea prior to March 2000. The interpretations documented herein build on research that Geoscience Australia and GeoMark Research undertook previously in The Oils of Western Australia (AGSO and GeoMark, 1996) and The Oils of Eastern Australia (Geoscience Australia and GeoMark, 2002) studies. To make informed decisions regarding Australia's petroleum resources, it is important to understand the relationship between the liquid hydrocarbons within and between basins. This Study has geochemically characterised the liquid hydrocarbon accumulations of western Australian basins and the Papuan Basin into genetically related families. From a total of 316 samples, 33 oil/condensate families were identified in the western Australian basins; Bonaparte (10), Browse (2), Canning (4), Carnarvon (11) and Perth (6), as well as some vagrant and contaminated samples. Three oil/condensate families were recognised in the Papuan Basin. The geographic distribution of each oil/condensate family is mapped within each basin/sub-basin. Using the geochemical characteristics of each family, the nature of their source facies, thermal maturity level and degree of preservation has been determined. This Study used a set of standardised geochemical protocols that include bulk geochemical (API gravity, elemental analysis of nickel, vanadium and sulphur), molecular (gas chromatography of the whole-oil and gas chromatography-mass spectrometry of the saturated and aromatic hydrocarbons) and bulk stable carbon isotopic analyses. n-Alkane-specific 13C isotopic analyses were carried out on only a selected set of oils and condensates. Statistical analyses were performed on these data using the software Pirouette' provided by Infometrix. In addition to this report, the geochemical data acquired for the crude oils and condensates in this Study are provided in the accompanying Microsoft Access2000 database. These data may be viewed spatially and plotted on x-y cross-plots in the charting application included in the ESRI Australia GIS ArcView3.2 georeferencing package that also accompanies this report.

This product is an ArcView GIS CD containing coverages of North West Shelf regional geology and petroleum exploration themes, and oil family maps linked to graphs of specific chemical parameters which define the families. This product includes 120 oils from the first Oils of Western Australia study (WOZ1) and 150 oils from the second Oils of Western Australia study (WOZ2). This CD is one component of "The Oils of Western Australia II" product which comprises two other components: an interpretative report documenting the petroleum geochemistry of the oils in the study and assignment of each sample to an oil family, and a Microsoft Access database which contains the raw data, calculated biomarker ratios and reporting output forms. The Oils of Western Australia II report summarises the findings of a collaborative research program between Geoscience Australia and GeoMark Research undertaken on the petroleum geochemistry of crude oils and condensates discovered within the basins of western Australia and the Papuan Basin, Papua New Guinea prior to March 2000. The interpretations documented herein build on research that Geoscience Australia and GeoMark Research undertook previously in The Oils of Western Australia (AGSO and GeoMark, 1996) and The Oils of Eastern Australia (Geoscience Australia and GeoMark, 2002) studies. To make informed decisions regarding Australia's petroleum resources, it is important to understand the relationship between the liquid hydrocarbons within and between basins. This Study has geochemically characterised the liquid hydrocarbon accumulations of western Australian basins and the Papuan Basin into genetically related families. From a total of 316 samples, 33 oil/condensate families were identified in the western Australian basins; Bonaparte (10), Browse (2), Canning (4), Carnarvon (11) and Perth (6), as well as some vagrant and contaminated samples. Three oil/condensate families were recognised in the Papuan Basin. The geographic distribution of each oil/condensate family is mapped within each basin/sub-basin. Using the geochemical characteristics of each family, the nature of their source facies, thermal maturity level and degree of preservation has been determined. This Study used a set of standardised geochemical protocols that include bulk geochemical (API gravity, elemental analysis of nickel, vanadium and sulphur), molecular (gas chromatography of the whole-oil and gas chromatography-mass spectrometry of the saturated and aromatic hydrocarbons) and bulk stable carbon isotopic analyses. n-Alkane-specific 13C isotopic analyses were carried out on only a selected set of oils and condensates. Statistical analyses were performed on these data using the software Pirouette provided by Infometrix. In addition to this report, the geochemical data acquired for the crude oils and condensates in this Study are provided in the accompanying Microsoft Access2000 database. These data may be viewed spatially and plotted on x-y cross-plots in the charting application included in the ESRI Australia GIS ArcView3.2 georeferencing package that also accompanies this report.

A laboratory study has been conducted to determine the best methods for the detection of C10 to C40 hydrocarbons at naturally occurring oil seeps in marine sediments. The results indicate that a commercially available method using hexane to extract sediments and gas chromatography to screen the resulting extract is effective at recognizing the presence of migrated hydrocarbons at concentrations between 50 to 5,000 ppm. When the oil charge is unbiodegraded the level of charge is effectively tracked by the sum of n-alkanes in the gas chromatogram. However, once the charge oil becomes biodegraded, with the loss of n-alkanes and isoprenoids, the level of charge is tracked by the quantification of the Unresolved Complex Mixture (UCM). The use of GC-MS was also found to be very effective for the recognition of petroleum related hydrocarbons and results indicate that GC-MS would be a very effective tool for screening samples at concentrations below 50 ppm oil charge.

Collation of talks and posters completed under the APCRC Program 5 during June 1999-June 2001.

The molecular composition of fluid inclusion (FI) oils from Leander Reef-1, Houtman 1 and Gage Roads-2 provide evidence of the origin of palaeo-oil accumulations in the offshore Perth Basin. These data are complemented by compound specific isotope (CSI) profiles of n-alkanes for the Leander Reef-1 and Houtman-1 samples, which were acquired on purified n-alkane fractions gained by micro-fractionation of lean FI oil samples, showing the technical feasibility of this technique. The Leander Reef-1 FI oil from the top Carynginia Formation shares many biomarker similarities with oils from the Dongara and Yardarino oilfields, which have been correlated with the Early Triassic Kockatea Shale. However, the heavier isotopic values for the C15-C25 n-alkanes in the Leander Reef-1 FI oil indicate that it is a mixture, and suggest that the main part of this oil (~90%) was sourced from the more terrestrial and isotopically heavier Early Permian Carynginia Formation or Irwin River Coal Measures. This insight would have been precluded when looking at molecular evidence alone. The Houtman-1 FI oil from the top Cattamarra Coal Measures (Middle Jurassic) was sourced from a clay-rich, low sulphur source rock with a significant input of terrestrial organic matter, deposited under oxic to suboxic conditions. Biomarkers suggest sourcing from a more prokaryotic-dominated facies than for the other FI oils, possibly a saline lagoon. The Houtman-1 FI oil ?13C CSI data are similar to data acquired on the Walyering-2 oil. Possible lacustrine sources include the Early Jurassic Eneabba Formation or the Late Jurassic Yarragadee Formation. The low maturity Gage Roads-2 FI oil from the Carnac Formation (Early Cretaceous) was derived from a strongly terrestrial, non-marine source rock containing a high proportion of Araucariacean-type conifer organic matter. It has some geochemical differences to the presently reservoired oil in Gage Roads-1, and was probably sourced from the Early Cretaceous Parmelia Formation.

Legacy product - no abstract available