Australian Petroleum Accumulations Report 7 Browse Basin

115 Pages·2015·24.52 MB·English

Record 2015/10 | GeoCat 82545
Australian Petroleum Accumulations
Report 7 Browse Basin
Western Australia and Territory of Ashmore and Cartier Islands
adjacent area, 2nd edition
Steve le Poidevin, Tehani Kuske, Dianne Edwards and Russell Temple
APPLYING GEOSCIENCE TO AUSTRALIA’S MOST IMPORTANT CHALLENGES www.ga.gov.au

Australian Petroleum Accumulations
Report 7 Browse Basin
Western Australia and Territory of Ashmore and Cartier Islands
adjacent area, 2nd edition
GEOSCIENCE AUSTRALIA
RECORD 2015/10
Steve le Poidevin, Tehani Kuske, Dianne Edwards and Russell Temple
Department of Industry and Science
Minister for Industry and Science: The Hon Ian Macfarlane MP
Parliamentary Secretary: The Hon Karen Andrews MP
Secretary: Ms Glenys Beauchamp PSM
Geoscience Australia
Chief Executive Officer: Dr Chris Pigram
This paper is published with the permission of the CEO, Geoscience Australia

© Commonwealth of Australia (Geoscience Australia) 2015
With the exception of the Commonwealth Coat of Arms and where otherwise noted, this product is
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ISSN 2201-702X (PDF)
ISBN 978-1-925124-64-4 (PDF)
GeoCat 82545
Bibliographic reference: Le Poidevin, S. R., Kuske, T. J., Edwards, D. S. and Temple, P. R. 2015.
Australian Petroleum Accumulations Report 7 Browse Basin: Western Australia and Territory of
Ashmore and Cartier Islands adjacent area, 2nd edition. Record 2015/10. Geoscience Australia,
Canberra. http://dx.doi.org/10.11636/Record.2015.010
Contents
Foreword................................................................................................................................................... 1
1 Introduction ............................................................................................................................................ 2
1.1 Hydrocarbon accumulation classification ......................................................................................... 2
1.2 Hydrocarbon show classification ..................................................................................................... 4
1.3 Hydrocarbon fluid properties ............................................................................................................ 5
1.4 Hydrocarbon resource classification ................................................................................................ 7
2 Regional geology ................................................................................................................................... 9
2.1 Basin setting .................................................................................................................................... 9
2.1.1 Yampi and Leveque shelves and Prudhoe Terrace ................................................................... 9
2.1.2 Caswell and Barcoo sub-basins ...............................................................................................10
2.1.3 Scott Plateau and Seringapatam sub-basins ...........................................................................10
2.2 Tectonic development ....................................................................................................................11
2.3 Stratigraphy ....................................................................................................................................14
2.3.1 Weaber and Kulshill groups .....................................................................................................14
2.3.2 Kinmore Group .........................................................................................................................18
2.3.3 Sahul Group .............................................................................................................................18
2.3.4 Troughton Group ......................................................................................................................19
2.3.5 Swan Group .............................................................................................................................20
2.3.6 Bathurst Island Group ..............................................................................................................21
2.3.7 Woodbine Group ......................................................................................................................23
2.4 Petroleum geology .........................................................................................................................24
2.4.1 Source rocks ............................................................................................................................25
2.4.2 Reservoirs and seals ................................................................................................................26
2.4.3 Hydrocarbon fluid composition .................................................................................................27
2.4.4 Gas, oil and source rock correlations .......................................................................................33
2.4.5 Petroleum systems ...................................................................................................................35
2.4.6 Basin history modelling ............................................................................................................39
2.5 Petroleum resources ......................................................................................................................40
2.5.1 Development and infrastructure ...............................................................................................41
3 Exploration history and accumulation descriptions .............................................................................43
3.1 Barcoo Sub-basin exploration and discoveries .............................................................................44
3.1.1 The Greater Lombardina structure residual accumulation .......................................................47
3.2 Caswell Sub-basin exploration and discoveries ............................................................................48
3.2.1 Caswell Accumulation ..............................................................................................................55
3.2.2 Marabou Accumulation .............................................................................................................56
3.2.3 Burnside Accumulation .............................................................................................................59
3.2.4 Ichthys Accumulation ...............................................................................................................59
3.2.5 Concerto Accumulation ............................................................................................................65
3.2.6 Mimia Accumulation .................................................................................................................67
3.2.7 Echuca Shoals Accumulation ...................................................................................................69
3.2.8 Adele Accumulation ..................................................................................................................71
3.2.9 Bassett Accumulation ...............................................................................................................72
Australian Petroleum Accumulations Report 7 Browse Basin iii
3.2.10 Lasseter Accumulation ...........................................................................................................72
3.2.11 Abalone Accumulation ............................................................................................................73
3.2.12 Argus Accumulation ...............................................................................................................74
3.2.13 Columba Accumulation ..........................................................................................................76
3.2.14 Crux Accumulation .................................................................................................................78
3.2.15 Hippolyte Accumulation ..........................................................................................................81
3.2.16 Heywood residual accumulation ............................................................................................82
3.3 Scott Reef Trend and Seringapatam Sub-basin exploration and discoveries ...............................82
3.3.1 Torosa Accumulation ................................................................................................................85
3.3.2 Brecknock and Calliance (Brecknock South) accumulations ...................................................86
3.3.3 Poseidon (including Kronos) Accumulation..............................................................................89
3.3.4 Crown Accumulation ................................................................................................................90
3.4 Prudhoe Terrace, Yampi Shelf and Leveque Shelf exploration and discoveries ..........................90
3.4.1 Gwydion Accumulation .............................................................................................................95
3.4.2 Cornea Accumulation ...............................................................................................................96
3.4.3 Focus Accumulation .................................................................................................................98
3.4.4 Sparkle Accumulation ...............................................................................................................99
3.4.5 Caspar Accumulation ...............................................................................................................99
3.4.6 Psepotus Accumulation ..........................................................................................................100
4 Acknowledgements ...........................................................................................................................101
5 References ........................................................................................................................................102
Appendices ...........................................................................................................................................109
iv Australian Petroleum Accumulations Report 7 Browse Basin
Foreword
The Browse Basin lies offshore from the remote Western Australia Kimberley region and hosts vast
reserves of gas, some of which are rich in ‘condensate’, making it Australia’s next major conventional
liquefied natural gas (LNG) province on the North West Shelf. A recent upgrade of the supergiant
Ichthys gas accumulation, located in the central Caswell Sub-basin, by operator Inpex Browse Ltd,
estimated that the field holds 12.8 trillion cubic feet (Tcf) of gas. This accumulation has a
condensate: gas ratio (CGR) of 60 bbl/MMscf within the Brewster Member of the Vulcan Formation at
Titanichthys 1, and is estimated to contain 530 million barrels (MMbbl) of liquids, making it the largest
hydrocarbon accumulation with recoverable liquids found in Australia since the discovery of the
Gippsland Basin oil fields and the Barrow Island oil fields in the Northern Carnarvon Basin during the
1960s. Similar amounts of gas, albeit drier (CGR 5–30 bbl/MMscf) are hosted in the Brecknock,
Calliance and Torosa accumulations (cumulative 15.9 Tcf gas, 436 MMbbl condensate) that are
primarily reservoired within the Plover Formation along the Scott Reef Trend.
The Browse Basin continues to be a focus of exploration in which both international companies
(Chevron Australia Pty Ltd, ConocoPhillips Australia, Inpex Browse E&P Pty Ltd, Shell Australia Pty
Ltd, and Sinopec Corp) and Australian explorers (BHP Petroleum Ltd, Nexus Energy Ltd, Santos Ltd
and Woodside Energy Ltd) are capitalising on Liquefied Natural Gas (LNG) opportunities. To assist
with the documentation of these ongoing exploration successes, the Browse Basin Australian
Petroleum Accumulation report provides a summary of petroleum accumulations, significant
hydrocarbon shows and reserves estimates collated from open-file data.
Australian Petroleum Accumulations Report 7 Browse Basin 1
1 Introduction
The purpose of the Australian Petroleum Accumulation (APA) series of publications is to provide an
introductory overview of each petroleum-bearing basin in Australia and, by reference to other
publications, a starting point for further enquiry.
The Browse Basin APA report (2nd edition) updates the previous version (Lavering & Pain, 1991) and
provides a summary of petroleum accumulations and data on all significant petroleum shows
encountered in wells drilled in the Browse Basin (Figure 1.1), from initial exploration results in the
1970s to those obtained until December 2014. These data were sourced from publicly available well
completion reports (available by contacting [email protected]) and other cited references.
Reserves data used in this report are publicly available from the Department of Mines and Petroleum,
Western Australia (DoMP, 2013) and industry presentations. The report also provides background
information on the regional geology, evolution and tectonic development, and the petroleum systems
of the basin.
Pipelines and field outlines used on some figures within this report are provided by Encom GPinfo, a
Pitney Bowes Software (PBS) Pty Ltd product. Whilst all care is taken in the compilation of the field
outlines by PBS, no warranty is provided regarding the accuracy and completeness of the information,
and it is the responsibility of the Consumer to ensure, by independent means, that those parts of the
information used by it are correct before any reliance is placed on them.
A glossary of petroleum-related terms and abbreviations used in this report can be found in
Appendix A.
1.1 Hydrocarbon accumulation classification
The Browse Basin Australian Petroleum Accumulation Report differs slightly from previous reports in
this series in that it documents an ‘inferred’ accumulation, whereas the other APAs reported only a
‘demonstrated discovery’; that is, a discrete, measured recovery of petroleum from a test undertaken
in an exploration well (Table 1.1). This additional classification has been necessary because of
modern advances in petroleum drilling techniques and evaluation technology, where many wells
known to contain hydrocarbons are no longer tested and discrete hydrocarbons are not recovered.
Such an accumulation is typically interpreted from wireline logs, and hence is referred to as being
‘inferred’. Inferred accumulations are reported in known petroleum provinces where reservoir
characteristics can be confidently extrapolated from other accumulations. Other important indications
of hydrocarbons, such as log indications, significant shows and residual hydrocarbons were also not
reported in previous APA reports. Changes in exploration practice, petroleum technology within the
industry, and in Geoscience Australia a focus on defining petroleum systems rather than solely listing
discoveries, necessitated a change in the reported information.
To this classification scheme, a further category of ‘residual accumulation’ has been added, to account
for reservoirs with either low hydrocarbon saturation (i.e. >~80% water saturation) and/or poor
physical properties. This is intended to indicate to explorers the presence of an effective petroleum
system and reflect the petroleum generation potential of the basin. These accumulation qualifiers are
defined in Table 1.1 and Appendix A.
2 Australian Petroleum Accumulations Report 7 Browse Basin
Figure 1.1 Browse Basin hydrocarbon accumulations.
Table 1.1 Classification of accumulations.
A flow or discrete recovery of petroleum was made on test of a reservoir
Demonstrated discovery unit (a recovery of residual petroleum or a flow under atypical testing
conditions are not included).
Inferred accumulation Measurements, typically from wireline logs, indicate the presence of
petroleum in a reservoir unit.
Residual accumulation Measurements, typically from wireline logs, coring or mud logs, indicate
the presence of petroleum at either low saturation and/or in tight
reservoirs.
Australian Petroleum Accumulations Report 7 Browse Basin 3
1.2 Hydrocarbon show classification
Geoscience Australia has revised its hydrocarbon show classification scheme from that previously
used in its publicly available RESFACS database (http://dbforms.ga.gov.au/www/npm.well.search)
and the new scheme has been adopted for this report (Table 1.2, Appendix B, Appendix C,
Appendix D). Hydrocarbon shows are classified from Level 0 to Level 5 according to the magnitude
and degree of confidence of the show, with a prefix of ‘G’ indicating natural gas and ‘L’ indicating
crude oil. These show classifications are applied to accumulations, wells, formations and individual
tests where hydrocarbons are encountered. The definitions for Level 2 to 5 are listed in Table 1.2 and
their corresponding symbols are defined in Table 1.3. The Level 0 and 1 classifications are necessary
to define the limit of the petroleum system, but they are not used to define an accumulation. This show
classification is described more fully in Appendix B.
In the hydrocarbon shows by formation summary sheets (Appendix C), the show for each formation is
the best combined result for all observations for that formation. The dry hole symbol signifies that a
formation was tested but hydrocarbons were not recovered (Table 1.3).
The significance of each level of hydrocarbon show is listed in Table 1.2, with shows of Level 3, 4 and
5 indicating a probable accumulation; Level 2 shows indicate a possible residual accumulation where
either a zone of continuous but low hydrocarbon saturation or a saturated, but tight, reservoir has
been encountered. Level 1 and 0 shows indicate migrated hydrocarbons (Appendix B).
Table 1.2 Classification system for oil and gas shows.
Level Hydrocarbon Show Type Measured flow rate of gas and/or clean* oil
5 Flow Measured flow rate of gas and/or clean* oil
4 Proven log zone Gas or oil zone with water saturation less than ~80%.
3 Recovery Discrete recovery of gas and/or clean* oil.
Unmeasured flow of either oil or gas without oil. Unmeasured
recovery of either oil or gas without oil. A recovery of either residual
petroleum or a flow under atypical testing conditions. Oil
spontaneously flowing from core and/or cuttings. Gas and/or oil zone
2 Show or residual log zone
with water saturation greater than ~80% or immobile fluids at higher
saturation. Significant mud gas readings in potential reservoir not
recorded elsewhere. Pressure measurements showing gas and/or oil
gradient(s).
* Representative crude oil, not an emulsion or oil-water/oil-drilling fluid mixture.
The show classifications are combined and represented by symbols, with Level 3, 4 and 5 shows
expressed as Oil and/or Gas, and Level 2 shows as Minor oil and/or Minor gas. These combinations
are shown in Table 1.3. Note that symbols on figures sourced from company well completion reports
and other documents may not follow this scheme. In this case, the show type for the well, as assigned
in this report, is listed in the relevant exploration and appraisal well tables and in Appendix C and
Appendix D.
4 Australian Petroleum Accumulations Report 7 Browse Basin