Browse Basin

Location Map

Map showing the location of Bonaparte Basin in relation to Australia
© Geoscience Australia

Basin Details and Geological Overview

The Browse Basin is composed by the Leveque Shelf, Yampi Shelf, Barcoo Sub-basin, Caswell Sub-basin, Scott Plateau, Seringapatam Sub-basin.

The Late Carboniferous-Cainozoic Browse Basin is a large, offshore basin on the northwestern Australian poly-phased margin. The basin is a proven hydrocarbon province, with major undeveloped gas/condensate fields in the outer and central basin and minor oil discoveries on the basin's eastern margin. The identified reserves at the end of 2000 were 0.48 GL of oil, 94.3 GL of condensate and 858.96 BCM of gas.

The Browse Basin developed during six major tectonic phases: Late Carboniferous to Early Permian extension; Late Permian to Triassic thermal subsidence; Late Triassic to Early Jurassic inversion; Early to Middle Jurassic extension; Late Jurassic to Early Tertiary thermal subsidence; and Late Miocene inversion. Initial extension resulted in half-graben geometries and the formation of two distinct depocentres, the Caswell and Barcoo Sub-basins. These depocentres contain in excess of 15km sedimentary section and lie in 100 to 1500 metres water depth. The outer Browse Basin underlies the deep-water Scott Plateau (1500-4000 metres water depth).

The Carboniferous section is predominantly fluvio-deltaic and the Permian-Early Triassic section is marine. Middle-Late Triassic rocks include fluvial and shallow marine clastics and minor carbonates. Early-Middle Jurassic syn-rift sediments comprise deltaic and coastal-plain clastics and coal. Widespread erosion occurred in the Callovian and Upper Jurassic sandstones and shales onlap, drape and provide a thin regional seal across most pre-Callovian structures. Widespread transgression commenced in the Valanginian and peaked in the Turonian and resulted in the deposition of thick open marine claystones. The Turonian-Tertiary section records a major progradational clastic-to-carbonate cycle.

The Early Cretaceous claystones provide a thick regional seal and contain potential oil-prone source rocks. Potential source rocks also occur in the Late Jurassic, Middle-Early Jurassic, Triassic and syn-rift Palaeozoic sections. Reservoir facies are best developed within the fluvio-deltaic Middle-Early Jurassic section and submarine fans of Berriasian, Barremian, Campanian and Maastrichtian age.

 

Stratigraphy

Browse Basin Stratigraphic Column

Browse Basin Stratigraphic Column
© Geoscience Australia

The tectonostratigraphic framework study undertaken by Geoscience Australia during 1996-97 includes twenty-two sequences (BB1 to BB22), ranging in age from Carboniferous to late Tertiary. These sequences correlate to six tectonically-controlled basin phases and reflect the evolution of the basin from a Palaeozoic intra-cratonic rift basin to a passive margin basin following breakup in the Callovian.

Regional Cross-sections

Seismic line 119/5 across the
Caswell Sub-basin
© Geoscience Australia

GA seismic line 119/5 across the Caswell Sub-basin (tying North Scott Reef 1, Caswell 2 and Yampi 2) shows the stratal relationships and megasequence packaging of the basin fill. Seismic horizons are colour-coded to sequence boundaries shown on the Tectonostratigraphic Chart.

Petroleum Systems and Hydrocarbon Potential

Geochemical analysis (including biomarkers and isotopic data) of recovered oils, condensates and gases indicates that at least four hydrocarbon families are present in the Browse Basin (see Kennard et al. 2004).

  • An outer basin, relatively dry gas-prone system sourced from mixed terrestrial and marine organic matter within presumed Jurassic sediments (Scott Reef and Brecknock fields; condensate/gas ratio (CGR) around 10-20 BBL/MMSCF). The recent Argus gas discovery probably represents a northern extension of this system (CGR <20 BBL/MMSCF; Keall and Smith, 2004).
  • A central basin, wet gas/condensate-prone system, the source(s) of which has yet to be established (Brewster-Dinichthys-Gorgonichthys-Titanichthys Field and Adele-1; CGR about 60 BBL/MMSCF). The recent Crux gas discovery, interpreted to be sourced from mixed terrestrial and marine organic matter within Middle-Lower Jurassic Plover Formation source rocks in the Heywood Graben (Edwards et al., 2003), probably represents a northeastern extension of this system, but the gas is dryer (CGR 22-37 BBL/MMSCF; Kaoru et al., 2004).
  • An inner basin, oil (plus gas)-prone system sourced from predominantly marine algal and bacterial organic matter within Early Cretaceous sediments (Cornea and Gwydion fields, Caswell-2 oil accumulation and oil stains in Kalyptea-1).
  • An inner basin, high maturity dry gas-prone system (Macula-1) possibly sourced from Permian or Jurassic sediments.

Mature potential source rocks have been identified over much of the basin and are best developed within the Lower Permian, Jurassic and Lower Cretaceous sections. These source units underpin four major hypothetical petroleum systems identified in the basin (Blevin et al., 1998b):

Key references

Author(s) Year Title
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 Australian Petroleum Production & Exploration Association (APPEA) Journal, 44(1), 269-285.
Bint, A.N. 1988 Gas fields of the Browse Basin. IN: Purcell, P.G. and Purcell, R.R., (Editors), The North West Shelf, Australia: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1988, 413-417.
Blevin, J.E., Struckmeyer, H.I.M., Boreham, C.J., Cathro, D.L., Sayers, J. and Totterdell, J.M. 1997 Browse Basin high resolution study, interpretation report, North West Shelf, Australia AGSO Record 1997/38. 
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. 1998a Tectonostratigraphic framework and petroleum systems of the Browse Basin, North West Shelf. IN: Purcell, P.G. and Purcell, R.R. (Editors), The sedimentary basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1998, 369-395.
Blevin, J.E., Boreham, C.J., Summons, R.E., Struckmeyer, H.I.M. and Loutit, T.S. 1998b An effective Lower Cretaceous petroleum system on the North West Shelf: Evidence from the Browse Basin. IN: Purcell, P.G. and Purcell, R.R. (Editors), The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1998, 397-420.
Boreham, C.J., Roksandic, Z., Hope, J.M., Summons, R.E., Murray, A.P., Blevin, J.E. and Struckmeyer, H.I.M. 1997 Browse Basin organic geochemistry study, North West Shelf, Australia. Volume 1, interpretation report. AGSO Record 1997/57. 
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. IN: Ellis, G.K., Baillie, P.W. and Munson, T.J. (Editors), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19-20 June 2003. Northern Territory Geological Survey, Special Publication 1, 437-455.
Ellis, G.K., Baillie, P.W. and Munson, T.L. (Editors) 2004 Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19-20 June, 2003. Northern Territory Geological Survey, Special Publication 1. [CD Copies can be ordered from the Northern Territory Geological Survey, Geoscience Information, email: geoscience.info@nt.gov.au"].
Ingram, G.M., Eaton, S. and Regtien, J.M.M. 2000 Cornea case study: Lessons for the future. The APPEA Journal, 40(1), 56-65.
Kaoru, M., Kurata, Y., Christiansen, D. and Scott, J. 2004 The Crux gas-condensate discovery, Vulcan Sub-basin, Australia. IN: Ellis, G.K., Baillie, P.W. and Munson, T.J. (Editors), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19-20 June 2003. Northern Territory Geological Survey, Special Publication 1.
Keall, J. and Smith, P. 2004 The Argus 1 gas discovery, northern Browse Basin. IN: Ellis, G.K., Baillie, P.W. and Munson, T.J. (Editors), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19-20 June 2003. Northern Territory Geological Survey, Special Publication 1, 37-52.
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. (Editors), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, Northern Territory, 19-20 June 2003. Northern Territory Geological Survey, Special Publication 1, 411-435.
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.
Shuster, M.W., Eaton, S., Wakefield, L.L. and Kloosterman, H.J. 1998 Neogene tectonics, greater Timor Sea, offshore Australia: implications for trap risk. The APPEA Journal, 38 (1), 351-379.
Spry, T.B. and Ward, I. 1997 The Gwydion discovery: a new play fairway in the Browse Basin. The APPEA Journal, 37(1), 87-104.
Stein, A., Myers, K., Lewis, C., Cruse, T. and Winstanley, S. 1998 Basement control and geoscientific definition of the Cornea discovery, Browse Basin, Western Australia. IN: Purcell, P.G. and Purcell, R.R.(Editors), The sedimentary basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1998, 421-431.
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.(Editors), 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.
Willis, I. 1988 Results of exploration, Browse Basin, North West Shelf, Western Australia. IN: Purcell, P.G. and Purcell, R.R.(Editors), The North West Shelf, Australia: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, 1988, 259-272.

Topic contact: petroleum@ga.gov.au Last updated: May 31, 2012