Barrow Sub-basin

Release Area W16-23, Barrow Sub-basin, Northern Carnarvon Basin, Western Australia

Highlights

Bids close 23 March 2017

  • Within one of Australia’s premier offshore producing basins
  • Proximal to Barrow Island facilities
  • Shallow water depths, 20–100 m
  • Oil-prone Upper Jurassic and gas-prone Triassic to Middle Jurassic source rocks
  • Proven multi-level structural and stratigraphic plays in Triassic, Jurassic and Lower Cretaceous strata
  • Further guidance available, please refer to 2016 Special Notices

Release Area W16-23 is in the central Barrow Basin, 6 km west of Barrow Island and 50 km north of Onslow, in shallow water (20–100 m) (Figure 1). The Release Area is in the vicinity of several oil and gas accumulations, including the Barrow Island and Woollybutt oil accumulations and the Maitland and East Spar gas accumulations. Three wells have been drilled within the Release Area: in the south are Leaf 1 and Bay 1, which both have gas shows, and in the north is Robot 1A, which encountered minor oil.

The Barrow Sub-basin contains a Mesozoic to Cenozoic sedimentary succession, with a maximum thickness of 20 km. The region offers proven petroleum systems of Upper Triassic, Middle–Upper Jurassic and Lower Cretaceous age (Figure 2). Oil and gas accumulations exist within this sub-basin, offering a range of play types to be targeted. Gas is sourced from Triassic to Middle Jurassic fluvio-deltaic rocks of the Mungaroo and Brigadier formations, Murat Siltstone, and Athol and Legendre formations. Oil is sourced from the Upper Jurassic Dingo Claystone. Structural plays include tilted fault blocks and rollovers, anticlines and drapes, and horsts. Stratigraphic plays include pinch-outs, unconformity traps and transgressive sandstone packages at the base of the Locker Shale (Figure 3).

Figure 4 shows the existing data coverage in the vicinity of the Release Area in the Barrow Sub-basin. There is good seismic coverage, with 2D seismic averaging a line spacing of less than 2 km and the West Barrow and Kathleen 3D seismic surveys covering parts of the Release Area. The region contains existing infrastructure that would facilitate further development.






Figures

Figure 1

Structural elements of the Barrow Sub-basin in the vicinity of the 2016 Release Area, showing petroleum fields, key wells, and the 2016 Release Area


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Figure 2

 

Stratigraphy and hydrocarbon shows in the Barrow Sub-basin, based on the Northern Carnarvon Basin Biozonation and Stratigraphy Chart (Kelman et al, 2013). Geologic Time Scale after Gradstein et al (2012)


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Figure 3

Selected play types in the vicinity of the Release Area in the Barrow Sub-basin: a) Paleogene (Maitland Sandstone) stratigraphic play (adapted from Apache Energy, 2009); b) Lower Cretaceous (Birdrong Sandstone) structural/stratigraphic play (adapted from Santos Limited, 2009) ; c) Lower Cretaceous (Barrow Group) rotated slump block and stratigraphic channel plays (adapted from Tap Oil Limited, 2005); d) Upper Jurassic (Dingo Claystone, Dupuy Formation) and Lower Cretaceous (Barrow Group) structural/stratigraphic play (adapted from Australian Occidental Pty Ltd, 1983); e) Lower Cretaceous (Leaf Sands) basin-floor fan complex stratigraphic play with a component of structural closure (adapted from Apache Energy, 2005). See Figure 1 for well locations


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Figure 4

Seismic and well data in the vicinity of the Release Area in the Barrow Sub-basin, Northern Carnarvon Basin


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