OFFSHORE PETROLEUM EXPLORATION
ACREAGE RELEASE  AUSTRALIA 2014
Release Areas AC14-2, AC14-3 and AC14-4,
northern Caswell Sub-basin, Browse Basin,
Western Australia
Highlights
Bids close 2 October 2014
Figure 1

Adjacent to the Skua, Swift/Swallow and
Montara oil developments

Proximal to the Ichthys, Prelude/Concerto and
Crux gas developments

Shallow to deep water depths, 50–300 m

Thick Jurassic–Lower Cretaceous mature
source rocks

Tilted Permo-Triassic and Jurassic fault
blocks, and fluvio-deltaic to marine fan sands
with Cretaceous seal

Special Notices apply, refer to Guidance Notes
Location of the 2014 Release Areas in the
Northern Caswell Sub-basin, Browse Basin
Release Areas AC14-2, AC14-3 and AC14-4 are located in the southern Vulcan and northeastern Caswell sub-basins,
and the Ashmore Platform, some 230 to 280 km from the northeast coast of Western Australia. Release Area AC14-2 is
located in the northeastern part of the Caswell Sub-basin and extends into the southern part of the Vulcan Sub-basin.
Release Area AC14-3 is located in the northern Caswell Sub-basin and extends onto the Ashmore Platform, while
AC14-4 is located in the northern Caswell Sub-basin. All Release Areas are within the Territory of Ashmore and
Cartier Islands.
A diverse range of undrilled structures may be prospective in the Release Areas. The dominant fault style in the region
are tilted horst blocks where the dominant reservoirs are the Upper Triassic Nome Formation, the Jurassic Plover and
Montara formations, the Upper Jurassic–Lower Cretaceous Vulcan and Echuca Shoals formations and, in some
locations, the Upper Cretaceous Puffin Formation. In the southern Vulcan Sub-basin, the Montara field is producing
hydrocarbons via a Floating Production Storage and Offloading (FPSO) facility, while the Skua and Swift/Swallow oil
accumulations are currently in the development phase. In the northern Browse Basin, the Ichthys FPSO Project, and the
Prelude and Concerto gas accumulations are under development, and production is being planned for the Crux gas and
liquids project.
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Offshore Petroleum Exploration Acreage Release
DISCLAIMER: This document has been developed as a guide only. Explorers should not rely solely on this information when making commercial decisions.
Image courtesy of BHP Billiton Petroleum Pty Ltd.
1
Figure 2
Structural elements of the Northern Caswell region showing petroleum fields and discoveries, the location of
the regional seismic section and the 2014 Release Areas. Release Areas shown by outline only are
discussed elsewhere
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Figure 3
Stratigraphy and hydrocarbon discoveries of the Vulcan and Caswell sub-basins based on the Bonaparte Basin and Browse Basin Biozonation and Stratigraphy Charts 33
and 32 (Nicoll et al, 2009) respectively. Geologic Time Scale after Gradstein et al (2012). Regional seismic horizons after AGSO (1997, 2001)
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Offshore Petroleum Exploration Acreage Release
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Figure 4
Seismic line 119/09 across the Northern Caswell Sub-basin. Interpretation after AGSO (2001). Location of the seismic line is shown in Figure 2. Regional seismic horizons
are shown in Figure 3
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Offshore Petroleum Exploration Acreage Release
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Figure 5
Seismic and well data in the vicinity of the Release Areas in the Northern Caswell Sub-basin, Browse Basin.
Release Areas shown by outline only are discussed elsewhere
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Offshore Petroleum Exploration Acreage Release
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Petroleum systems elements
Northern Caswell Sub-basin
Sources


Lower–Middle Jurassic fluvio-deltaic Plover Formation (oil- and gas-prone)
Callovian–Valanginian marine Vulcan and Montara formations (oil-prone), major sediment
thickening occurs towards Northern Caswell Release Areas
Reservoirs






Upper Triassic deltaic Nome Formation
Lower–Middle Jurassic fluvio-deltaic Plover Formation
Middle–Upper Jurassic marine Montara (Ichthys) Formation
Upper Jurassic–Lower Cretaceous marine upper Vulcan Formation (Brewster Member)
Lower Cretaceous Echuca Shoals Formation (shallow marine sandstones and submarine fans)
Upper Cretaceous Puffin Formation (submarine fan sandstones)
Seals
Regional Seals


Upper Jurassic–Lower Cretaceous marine Vulcan Formation
Lower Cretaceous marine Echuca Shoals and Jamieson formations (claystone seal 500–600 m
thick across the sub-basin)
Intra-formational seals
Traps


Lower–Middle Jurassic fluvio-deltaic Plover Formation
Upper Cretaceous Puffin Formation and Paleocene Johnson Formation


Jurassic horsts/tilted fault blocks and associated drapes
Cretaceous submarine canyon fill, basin floor fans and ‘ponded’ turbidite stratigraphic traps
Infrastructure and markets
In the southern Vulcan Sub-basin, Bonaparte Basin, the Montara (AC/L7) oil field is in production via a Floating
Production Storage and Offloading (FPSO) facility, with the Skua (AC/P34) and Swift/Swallow (AC/P34) accumulations
under development. Also under development are the Ichthys (WA-50-L) FPSO Project, the Prelude (WA-44-L) FLNG
Project (encompassing the Prelude and Concerto accumulations) in the northern Browse Basin, with production being
planned for the Crux (AC/RL9) gas and liquids project.
Critical risks
Suitable migration pathways from adjacent or underlying mature source rocks have been a limitation for some of the
wells in adjacent parts of the region. Many faults have limited leakage potential due to high integrity traps, leading to a
high probability of gas flushing in younger sequences. Trap integrity is a risk due to reactivation of late Miocene–Pliocene
faults extending to the seafloor. Fault traps with limited seal integrity are prone to leakage of gas, but have greater
potential to retain an oil charge.
Data sets
For the Wells Data Listing go to
http://www.petroleum-acreage.gov.au/2014/support/geo.html
For the Seismic Surveys Listing go to
http://www.ga.gov.au/energy/projects/acreage-release-and-promotion/2014.html#data-packages
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Offshore Petroleum Exploration Acreage Release
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Geoscience Australia products
Regional geology and seismic

Browse Basin High Resolution Seismic Study – North West Shelf, Australia – Interpretation Report, 1997.
GEOCAT 23689

Browse Basin Well Composites, 2005. GEOCAT 61819

Vulcan Sub-basin Composite Well Log, 2011. GEOCAT 25307

Vulcan Sub-basin, Offshore WA, 1989 (P556). GEOCAT 60009

Basement and Crustal Structure of the Bonaparte - Browse Basins, 2003. GEOCAT 41976

Interpreted Horizons and Faults for Seismic Surveys 119 and 130. Browse Basin, 2001. GEOCAT 35244 and
GEOCAT 35248 respectively.

Line Drawings of AGSO – Geoscience Australia’s Regional Seismic Profiles, Offshore Northern and Northwestern
Australia, 2001. GEOCAT 36353
Stratigraphy

Browse Basin Biozonation and Biostratigraphy Chart 32, 2014. GEOCAT 76687

Bonaparte Basin Biozonation and Biostratigraphy Chart 34, 2014. GEOCAT 76687
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, 2001. GEOCAT 35246

Bonaparte Basin, Northern Territory (NT), Western Australia (WA), Territory of Ashmore and Cartier Islands
Adjacent Area (AC), Joint Petroleum Development Area (JPDA), Australian Petroleum Accumulations Report 5, 2nd
Edition, 2004. GEOCAT 60865

The Petroleum Systems of the Bonaparte Basin. 2004. GEOCAT 61365

Light Hydrocarbon Geochemistry of the Vulcan Sub-basin, Timor Sea: Rig Seismic Survey 97: Project 121.19, 1992.
GEOCAT 14570

Source Rock Distributions and Petroleum Fluid Bulk Compositional Predictions on the Vulcan Sub-basin, Offshore
Western Australia, 2009. GEOCAT 69210

Characterisation of Natural Gases from West Australian Basins, 2012. GEOCAT 33569

Ashmore-Cartier Prospectivity Package: An Analysis of the Petroleum Prospectivity of Vacant Areas Overlying the
Ashmore Platform, Vulcan Sub-basin, Jabiru Terrace and Northern Browse Basin, 1991. GEOCAT 14475

Browse Basin Organic Geochemistry Study, North West Shelf, Australia, 1997. GEOCAT 24474

Subsidence and Thermal History Modelling: New Insights into Hydrocarbon Expulsion from Multiple Petroleum
Systems in the Browse Basin, 2003. GEOCAT 42156

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

The Oils of Western Australia II, 2005. 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, 174pp.
AGSO BROWSE BASIN PROJECT TEAM, 1997—Browse Basin High Resolution Study, Interpretation Report,
North West Shelf, Australia. Australian Geological Survey Organisation Record, 1997/38.
BAN, S. AND PITT, G., 2006—The Ichthys giant gas-condensate field. 2006 AAPG International Conference and
Exhibition, 5–8 November, Perth, Australia, Abstract.
BAXTER, K., COOPER, G.T., O'BRIEN, G.W., HILL, K.C. AND STURROCK, S., 1997—Flexural isostatic modelling as a
constraint on basin evolution, the development of sediment systems and palaeo-heat flow: application to the Vulcan
Sub-basin Timor Sea. The APPEA Journal, 37(1), 136–153.
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
R.R. (eds), 1998, The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of
Australia Symposium, Perth, WA, 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 R.R. (eds), 1998, The Sedimentary Basins of Western Australia 2: Proceedings of the
Petroleum Exploration Society of Australia Symposium, Perth, WA, 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.
CHEN, G., HILL, K.C. AND HOFFMAN, N., 2002—3D structural analysis of hydrocarbon migration in the Vulcan
Sub-basin, Timor Sea. In: Keep, M. and Moss, S.J. (eds), 2002, The Sedimentary Basins of Western Australia 3,
Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2002, 377–388.
DAWSON, D., GRICE, K., ALEXANDER, R. AND EDWARDS, D., 2007—The effect of source and maturity on the stable
isotopic compositions of individual hydrocarbons in sediments and crude oils from the Vulcan Sub-basin, Timor Sea,
northern Australia. Organic Geochemistry, 38, 1015–1038.
EDWARDS, D.S., PRESTON, J.C., KENNARD, J.M., BOREHAM, C.J., VAN AARSSEN, B.G.K., SUMMONS, R.E. AND
ZUMBERGE, J.E., 2004—Geochemical characteristics of hydrocarbons from the Vulcan Sub-basin, western Bonaparte
Basin, Australia. 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, 169–
201.
EDWARDS, H., CROSBY, J., DAVID, N., LOADER, C. AND WESTLAKE, S., 2005—Australian Megasurveys – the key
to new discoveries in maturing areas. The APPEA Journal, 45(1), 407–419
FUJII, T., O’BRIEN, G.W., TINGATE, P AND CHEN, G., 2004—Using 2D and 3D basin modelling to investigate controls
on hydrocarbon migration and accumulation in the Vulcan Sub-basin, Timor Sea, northwestern Australia. The APPEA
Journal, 44(1), 93–122.
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) Presentation.
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.
KIVIOR, T., KALDI, J.G. AND LANG, S.C., 2002—Seal potential in Cretaceous and Late Jurassic rocks of the Vulcan
Sub-basin, North West Shelf, Australia. The APPEA Journal, 42(1), 203–224.
LIU, K., FENTON, S., BASTOW, T., VAN AARSSEN, B. AND EADINGTON, P., 2005—Geochemical evidence of
multiple hydrocarbon charges and long distance oil migration in the Vulcan Sub-basin, Timor Sea. The APPEA Journal,
45(1), 493–509.
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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. (eds), The Sedimentary Basins of Western Australia III:
Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2002, 27–88.
MILDREN, S.D., HILLIS, R.R., KIVIOR, T. AND KALDI, J.G., 2004—Integrated seal assessment and geologic risk with
application to the Skua Field, Timor Sea, Australia. In: Ellis, G.K., Baillie, P.W. and Munson, T.J. (eds), Timor Sea
Petroleum Geoscience, Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19–20 June 2003,
Northern Territory Geological Survey, Special Publication 1, 275–294.
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
R.R. (eds), 1998, The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of
Australia Symposium, Perth, WA, 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 R.R. (eds), The Sedimentary Basins of Western
Australia: Proceedings of 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(1), 679.
WANG Z.X., ZHU G.H., PANG L.A. AND TANG W.L., 2012—An oil and gas resource assessment of the Bonaparte
Basin, northwest shelf of Australia. Bulletin of Canadian Petroleum Geology, 60(3), 218-226.
WILLIS, I., 1988—Results of exploration, Browse Basin, North West Shelf, Western Australia. In: Purcell, P.G. and R.R.
(eds), The North West Shelf, Australia: Proceedings of Petroleum Exploration Society of Australia Symposium, Perth,
1988, 259–272.
WOODS, E.P., 1992—Vulcan Sub-basin fault styles; implications for hydrocarbon migration and entrapment. The APEA
Journal, 32, 138–158.
YASSIR, N. AND OTTO, C.J., 1997—Hydrodynamics and fault seal assessment in the Vulcan Sub-basin, Timor Sea.
The APPEA Journal, 37(1), 380–389.
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