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RELEASE AREAS W13-1, W13-2 AND W13-3,
CASWELL SUB-BASIN, BROWSE BASIN,
WESTERN AUSTRALIA
HIGHLIGHTS
BIDS CLOSE 21 November 2013
 Adjacent to the Ichthys and Prelude gas field
developments.
 Development/production plans are underway
for the nearby Torosa, Brecknock and
Calliance gas fields
 Proximal to the recent gas discovery at
Crown 1
 Shallow water depths, 300–500 m
 Numerous proven structural and stratigraphic
plays
 Excellent quality reservoirs and seals, multiple
potential oil- and gas-prone source rocks and
active petroleum systems within the region
Figure 1 Location of the 2013 Release Areas in the
Caswell Sub-basin of the Browse Basin
 Special Notices apply, refer to Guidance Notes
Release Areas W13-1, W13-2 and W13-3 are located within the Caswell Sub-basin, the northernmost depocentre of the
Browse Basin, which contains up to 15 km of Paleozoic to Cenozoic sediments. The Caswell Sub-basin hosts significant
discoveries of gas, condensate and, to a lesser extent, oil. Many of the fields are in advanced stages of development.
Numerous petroleum systems have been proven within the Caswell Sub-basin, with migration pathways extending east
across the Prudhoe Terrace and Yampi Shelf, west to the Buffon-Scott Reef-Brecknock Anticlinal Trend and north to the
Poseidon and Argus structures. Proven structural and stratigraphic plays include Upper Jurassic to Lower Cretaceous
drape over erosional basement highs on the Yampi Shelf, Jurassic horsts/tilted fault blocks and associated drape
anticlines, and Cretaceous submarine canyon fill, basin floor fans and ‘ponded’ turbidite stratigraphic traps. Organic-rich
rocks with fair to moderate oil potential occur within the Plover Formation, lower and upper Vulcan formations and
Echuca Shoals Formation. Gas-prone, high-quality coals and pro-delta shales occur within the Plover Formation. Four
separate developments are underway: the Prelude Floating Liquefied Natural Gas (FLNG) Development, the Ichthys
Project, the Browse Liquefied Natural Gas (LNG) Development (encompassing the Torosa, Brecknock and Calliance
fields) and the Crux Liquids Project
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Figure 2 Structural elements of the Caswell Sub-basin showing petroleum fields and discoveries, the location of the
regional cross-section and the 2013 Release Areas
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Figure 3 Stratigraphy and hydrocarbon discoveries of the Caswell and Barcoo sub-basins, Prudhoe Terrace, and Yampi
and Leveque shelves based on the Browse Basin Biozonation and Stratigraphy Chart (Nicoll et al, 2009). Geologic Time
Scale after Gradstein et al (202012). Seismic horizons used to define BB sequences (AGSO Browse Basin Project
Team, 1997) and AGSO regional seismic horizons (AGSO, 2001) shown
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Figure 4 Part of AGSO seismic line 119/04 across the Caswell Sub-basin (AGSO, 2001). Location of the line is shown in
Figure 2. Regional seismic horizons are shown in Figure 3
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PETROLEUM SYSTEMS ELEMENTS
Caswell Sub-basin
Sources
 Lower–Middle Jurassic fluvio-deltaic Plover Formation (oil- and gas-prone)
 Callovian–Valanginian marine, lower and upper Vulcan Formation
(oil-prone)
 Valanginian–Aptian marine Echuca Shoals Formation (oil-prone)
 Aptian–Cenomanian shallow marine, lower and upper Jamieson Formation (oil-prone, immature–
marginally mature)
Reservoirs
Multiple stratigraphic levels within:
 Jurassic fluvio-deltaic Plover Formation
 Cretaceous upper Vulcan Formation, Echuca Shoals Formation, lower and upper Jamieson Formation
(shallow marine sandstones, submarine fans and ‘ponded’ turbidites)
Seals
Regional Seals
 Upper Jurassic–Lower Cretaceous marine Vulcan Formation
 Lower Cretaceous marine Echuca Shoals Formation
Intraformational Seals
 Lower–Middle Jurassic fluvio-deltaic Plover Formation
Traps
 Upper Jurassic to Lower Cretaceous drape over erosional basement highs on the Yampi Shelf
 Jurassic horsts/tilted fault blocks and associated drapes
 Cretaceous submarine canyon fill, basin floor fans and ‘ponded’ turbidite stratigraphic traps
INFRASTRUCTURE AND MARKETS
Multiple construction activities are currently being undertaken proximal to the Release Areas, including the Prelude
FLNG and the Ichthys FPSO and pipeline.
CRITICAL RISKS
Proven petroleum systems and migration pathways have been established in the region of the Release Areas. Therefore,
continued success relies on the identification of additional valid traps with access to charge from effective source rocks
that have been robust enough to withstand later structural spill. Reservoir quality is also an issue, particularly within the
Plover Formation, which also may contain gases with high CO2 content.
DATA SETS
For the Wells Data Listing go to
http://www.petroleum-acreage.gov.au/2013/support/geo.html
For the Seismic Surveys Listing go to
http://www.ga.gov.au/energy/projects/acreage-release-and-promotion/2013.html#data-packages
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GEOSCIENCE AUSTRALIA PRODUCTS
Regional Geology and Seismic
 Browse Basin High Resolution Seismic Study - North West Shelf, Australia - Interpretation Report, 1997. Australian
Geological Survey Organisation Record 1997/38. GEOCAT 23689
 Browse Basin Well Composites, 2005. GEOCAT 61819
 Basement and Crustal Structure of the Bonaparte - Browse Basins (2003) GEOCAT 41976
 Interpreted Horizons and Faults for Seismic Surveys 119 and 130 – Digital Horizon and Fault Data in ASCII Format,
2001. GEOCAT 35244 and 35248 respectively.
 Line Drawings of AGSO – Geoscience Australia’s Regional Seismic Profiles, Offshore Northern and Northwestern
Australia, Australian Geological Survey Organisation Record 2001/36. GEOCAT 36353.
Stratigraphy

Browse Basin Biozonation and Biostratigraphy Chart No. 32, 2009. GEOCAT 65649
Petroleum Systems and Accumulations
 Hydrocarbon Migration and Seepage in the Timor Sea and Browse Basin North West Shelf Australia: An Integrated
SAR, Geological and Geochemical Study, Australian Geological Survey Organisation Record 2001/11.
GEOCAT 35246
 Browse Basin Organic Geochemistry Study, North West Shelf, Australia, 1997. Australian Geological Survey
Organisation Record 1997/57. GEOCAT 24474
 Subsidence and thermal history modelling: new insights into hydrocarbon expulsion from multiple petroleum systems
in the Browse Basin, 2003. GEOCAT 42156
 Geoscience Australia Survey 267, Post Survey Report: Testing Natural Hydrocarbon Seepage Detection Tools on the
Yampi Shelf, Northwestern Australia, Geoscience Australia Record 2005/15. GEOCAT 61717
 Characterisation of Natural Gases from West Australian Basins, 2000. GEOCAT 33569
 Hydrocarbon Generation and Expulsion from Early Cretaceous Source Rocks in the Browse Basin, North West Shelf,
Australia: A Small Angle Neutron Scattering and Pyrolysis Study, Geoscience Australia Record 2007/04. GEOCAT
64144
 Source Rock Time Slice Maps: Offshore Northwest Australia, 2004. GEOCAT 61179
 Oils of Western Australia II: Regional Petroleum Geochemistry and Correlation of Crude Oils and Condensates from
Western Australia and Papua New Guinea, 2005. Geoscience Australia and GeoMark Research. GEOCAT 37512
Contact Geoscience Australia’s Sales Centre for more information or to order these reports or products, phone
61 (0)2 6249 9966, email sales@ga.gov.au
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KEY REFERENCES
AGSO, 2001—Line Drawings of AGSO – Geoscience Australia’s Regional Seismic Profiles, Offshore Northern and
Northwestern Australia. Australian Geological Survey Organisation Record 2001/36.
AGSO BROWSE BASIN PROJECT TEAM, 1997—Browse Basin High Resolution Study, Interpretation Report, North
West Shelf, Australia. Australian Geological Survey Organisation Record 1997/38.
BENSON, J.M., BREALEY, S.J., LUXTON, C.W., WALSHE, P.F. AND TUPPER, N.P., 2004—Late Cretaceous ponded
turbidite systems: a new stratigraphic play fairway in the Browse Basin. The APPEA Journal, 44(1), 269–285.
BLEVIN, J.E., BOREHAM, C.J., SUMMONS, R.E., STRUCKMEYER, H.I.M. AND LOUTIT, T.S., 1998—An effective
Lower Cretaceous petroleum system on the North West Shelf: evidence from the Browse Basin. In: Purcell, P.G. and
Purcell, R.R. (eds), The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of
Australia Symposium, Perth, 1998, 397–420.
BLEVIN, J.E., STRUCKMEYER, H.I.M., CATHRO, D.L., TOTTERDELL, J.M., BOREHAM, C.J., ROMINE, K.K., LOUTIT,
T.S. AND SAYERS, J., 1998—Tectonostratigraphic framework and petroleum systems of the Browse Basin, North West
Shelf. In: Purcell, P.G. and Purcell, R.R. (eds), The Sedimentary Basins of Western Australia 2: Proceedings of the
Petroleum Exploration Society of Australia Symposium, Perth, 1998, 369–395.
BRINCAT, M. P., LISK, M., KENNARD, J. M., BAILEY, W. R. AND EADINGTON, P. J., 2004—Evaluating the oil
potential of the Caswell Sub-basin; insights from fluid inclusion studies. Special Publication - Northern Territory
Geological Survey,437–455
FUJIMOTO, M., YOSHIDA, T. AND LONG, A., 2010—Improved seismic inversion and reservoir description of Ichthys
gas-condensate field, Browse Basin, Western Australia. The APPEA Journal 50(1).
KENNARD, J.M., DEIGHTON, I., RYAN, D., EDWARDS, D.S. AND BOREHAM, C.J., 2004—Subsidence and thermal
history modelling: new insights into hydrocarbon expulsion from multiple petroleum systems in the Browse Basin. In:
Ellis, G.K., Baillie, P.W. and Munson, T.J. (eds), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea
Symposium, Darwin, 19–20 June 2003. Northern Territory Geological Survey, Special Publication 1, 411–435.
KROH, F. AND WILLIAMSON, P. E. 2006—Preliminary AVO results from the Caswell Sub-basin NW Australia. Preview
124, 16–18.
LONGLEY, I.M., BUESSENSCHUETT, C., CLYDSDALE, L., CUBITT, C.J., DAVIS, R.C., JOHNSON, M.K., MARSHALL,
N.M., MURRAY, A.P., SOMERVILLE, R., SPRY, T.B. AND THOMPSON, N.B., 2002—The North West Shelf of Australia
– a Woodside perspective. In: Keep, M. and Moss, S.J. (eds), The Sedimentary Basins of Western Australia 3:
Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2002, 27–88.
POWER M. R., 2008—Miocene carbonate reef complexes in the Browse Basin and the implication for drilling operations.
The APPEA Journal 48(1), 115–132.
RADLINSKI, A.P., KENNARD, J.M., EDWARDS, D.S., HINDE, A.L. AND DAVENPORT, R., 2004—Hydrocarbon
generation and expulsion from Early Cretaceous source rocks in the Browse Basin, North West Shelf, Australia: a Small
Angle Neutron Scattering study. The APPEA Journal, 44(1), 151–180.
STRUCKMEYER, H.I.M., BLEVIN, J.E., SAYERS, J., TOTTERDELL, J.M., BAXTER, K. AND CATHRO, D.L., 1998—
Structural evolution of the Browse Basin, North West Shelf: new concepts from deep-seismic data. In: Purcell, P.G. and
Purcell, R.R. (eds), The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of
Australia Symposium, Perth, 1998, 345–367.
SYMONDS, P.A., COLLINS, C.D.N. AND BRADSHAW, J., 1994—Deep structure of the Browse Basin: implications for
basin development and petroleum exploration. In: Purcell, P.G. and Purcell, R.R. (editors), The Sedimentary Basins of
Western Australia: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1994, 315–331.
VOLK, H., BRINCAT, M. P., GEORGE, S. C., KENNARD, J. M., EDWARDS, D. S., BOREHAM, C. J., AHMED, M. AND
LISK, M. 2005—Clues to fill histories of gas fields in the Caswell Sub-basin; evidence from the distribution and
geochemistry of palaeo-oils. The APPEA Journal 45, 679.
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WILLIS, I., 1988—Results of exploration, Browse Basin, North West Shelf, Western Australia. In: Purcell, P.G. and
Purcell, R.R. (eds), The North West Shelf, Australia: Proceedings of the Petroleum Exploration Society of Australia
Symposium, Perth, 1988, 259–272.
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