Central Caswell Sub-basin
Bids close 21 April 2016
- Adjacent to the Ichthys and Prelude/Concerto gas developments
- Proximal to Burnside, Crown/Proteus and Lasseter gas accumulations
- Release Area W15-4 includes the Caswell oil accumulation and Marabou gas discovery
- Close to Ichthys Gas Pipeline to Bladin Point, Darwin (currently under construction)
- Shallow to deep water depths, 100–450 m
- Quality reservoirs and seals, multiple potential oil- and gas-prone source rocks and active petroleum systems
- Special Notices apply, refer to Guidance Notes
Release Areas W15-3 and W15-4 are located within the central Caswell Sub-basin, southwest of the Ichthys, Prelude and Concerto gas accumulations (Figure 1). Release Area W15-3 consists of six graticular blocks, approximately 25 km east of the Burnside gas accumulation, in shallow water depths (100–130 m). Release Area W15-4 is a larger area consisting of 34 graticular blocks, in water depths of 100 to 450 m. It is adjacent to the Burnside gas accumulation and incorporates the Caswell oil accumulation and Marabou gas discovery. The Release Areas lie between 160 to 300 km from the northwest coast of Western Australia where multiple construction activities are in progress. These include Prelude FLNG, the Ichthys LNG Project and gas pipeline and Browse FLNG.
Numerous petroleum systems have been proven within the Caswell Sub-basin. Organic-rich rocks with fair to moderate oil potential occur within the Plover, Vulcan and Echuca Shoals formations. Gas-prone, high-quality coals and pro-delta shales occur within the Plover Formation (Figure 2). Proven combined structural and stratigraphic plays include Jurassic horsts/tilted fault blocks and associated drape anticlines (Figure 3), and Cretaceous submarine canyon fill and basin floor fans. Figure 4 shows the existing data coverage of the region, with few wells and numerous 3D seismic surveys throughout Release Area W15-4, whereas Release Area W15-3 only has 2D seismic data.
Petroleum systems elements
Infrastructure and markets
There are four gas developments at various stages of implementation in the Browse Basin, including a gas pipeline to Bladin Point, Darwin and two FLNG vessels. The Ichthys gas pipeline is currently under construction and will come within 50 km of the Release Areas. First gas from the Ichthys accumulation is planned to come online by 2017. Prelude FLNG, servicing the Prelude and Concerto accumulations, is expected to produce LNG in 2016 and Browse FLNG is planned to commercialise the Torosa, Brecknock and Calliance gas accumulations with an FID targeted for late 2015.
Proven petroleum systems and migration pathways have been established within Release Area W15-4. Poor reservoir development and low porosities were found in the oil-bearing Campanian sediments of the Caswell 1 and 2 wells; though fair to excellent reservoir characteristics were exhibited in the same unit of the nearby Walkley 1 well, which is water-wet. Reservoir and charge were proven at Marabou 1 with good quality Campanian gas-bearing sandstones. However, the poor quality stratigraphic seal led to this well being plugged and abandoned. Continued success in the region thus relies on the identification of additional valid well sealed traps in areas of good reservoir quality, with access to charge from effective source rocks.
Wells Data and Seismic Survey listings for the central Caswell Sub-basin are available on the Supporting Information page.
Geoscience Australia products
Regional geology and seismic
- Browse Basin High Resolution Seismic Study – North West Shelf, Australia – Interpretation Report. Australian Geological Survey Organisation Record 1997/38 by Blevin et al. 1997.
- Browse Basin Well Composites. Dataset by Ryan et al. 2005.
- Basement and Crustal Structure of the Bonaparte - Browse Basins. Conference abstract by Goncharov et al. 2003.
- Interpreted Horizons and Faults for Seismic Survey 119. Browse Basin. Data package by Kennard et al. 2001.
- Interpreted Horizons and Faults for Seismic Survey 130. Browse Basin. Data package by Kennard et al. 2001.
- Line Drawings of AGSO – Geoscience Australia’s Regional Seismic Profiles, Offshore Northern and Northwestern Australia. Geoscience Australia Record 2001/36 by Colwell and Kennard 2001.
- Browse Basin Biozonation and Biostratigraphy Chart 32. Chart by Kelman et al. 2014.
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. Geoscience Australia Record 2001/11 by O’Brien et al 2000.
- Browse Basin, Australian Petroleum Accumulations Report 7, 2nd Edition. Publication by Le Poidevin et al. 2014.
- Browse Basin Organic Geochemistry Study, North West Shelf, Australia. Australian Geological Survey Organisation Record 1997/57 by Boreham et al. 1998.
- Subsidence and Thermal History Modelling: New Insights into Hydrocarbon Expulsion from Multiple Petroleum Systems in the Browse Basin. Conference abstract by Kennard et al. 2003.
- Geoscience Australia Survey 267, Post Survey Report: Testing Natural Hydrocarbon Seepage Detection Tools on the Yampi Shelf, Northwestern Australia. Geoscience Australia Record 2005/15 by Jones et al. 2005.
- Characterisation of Natural Gases from West Australian Basins. Publication by Boreham et al. 2012.
- 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 by Radlinski et al. 2006.
- Source Rock Time Slice Maps: Offshore Northwest Australia, 2004. Dataset by West et al. 2004.
- The Oils of Western Australia II. Publication by Edwards and Zumberge 2005.
Search for these and other Geoscience Australia reports and products at www.ga.gov.au/search
Contact Geoscience Australia’s Sales Centre for more information: phone +61 (0)2 6249 9966, email firstname.lastname@example.org
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.
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.
FUJIMOTO, M., YOSHIDA, T. AND LONG, A., 2010—Improved seismic inversion and reservoir description of the Ichthys gas-condensate field, Browse Basin, Western Australia. The APPEA Journal, 50(1) Presentation.
KELMAN, A.P., KENNARD, J.M., NICOLL, R.S., LAURIE, J.R., EDWARDS, D.S., KHIDER, K. AND LE POIDEVIN, S., 2014—Browse Basin Biozonation and Stratigraphy 2014 Chart 32. Geoscience Australia Biozonation and Stratigraphy Chart Series (http://www.ga.gov.au/corporate_data/76687/Chart_32_Browse_Basin_2014.pdf).
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.
LAWRENCE, S.H.F., THOMPSON, M., RANKIN, A.P.C., ALEXANDER, J.C., BISHOP, D.J. AND BOTERHOVEN, B., 2014—A new structural analysis of the Browse Basin, Australian North West Margin. The APPEA Journal 54, 1–10.
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), 2002, The Sedimentary Basins of Western Australia 3: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2002, 27–88.
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.
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.
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