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Vulcan Sub-basin

Release areas AC16-1 and AC16-2 Vulcan Sub-basin, Bonaparte Basin, Territory of Ashmore and Cartier Islands

Highlights

Bids close 8 December 2016

  • Proven oil-producing province; development planned for nearby Cash/Maple gas accumulation
  • Water depths of 110–210 m
  • Potential for structural and stratigraphic Triassic–Jurassic, Cretaceous and Paleogene plays
  • Special Notices apply, refer to Guidance Notes

Release Areas AC16-1 and AC16-2 are located in the Vulcan Sub-basin, western Bonaparte Basin in the Timor Sea (Figure 1), approximately 255 km offshore and 600 km from Darwin. Both Release Areas cover two graticular blocks (170 km2 each) in water depths up to 210 m. The Release Areas are located on the flank of the Paqualin Graben extending onto the Jabiru Terrace, and are adjacent to a number of discoveries including the Oliver oil and gas accumulation and the Pengana gas accumulation.

The Vulcan Sub-basin is a northeast-oriented Mesozoic extensional depocentre that contains Permian–Holocene sediments (Figure 2). The sub-basin comprises a complex series of horsts, graben and marginal terraces. It is a proven hydrocarbon province which includes several producing oil fields of the Montara project, as well as several other oil fields (Jabiru, Cassini and Challis) and sub-economic accumulations. Development options for the Cash/Maple gas and oil accumulation and further production of the Puffin oil accumulation are currently being considered. The Release Areas are located on the flank of the Paqualin Graben extending onto the Jabiru Terrace, and are adjacent to a number of discoveries including the Oliver oil and gas accumulation and the Pengana gas accumulation.

The Swan and Paqualin graben form the major source kitchens in the Vulcan Sub-basin, containing mature oil- and gas-prone source rocks in the lower Vulcan Formation, Montara Formation and underlying Plover Formation (Figure 2).

Upper Jurassic and Upper Cretaceous submarine fan sandstones are proven exploration targets within the sub-basin. Hydrocarbons at Oliver and Pengana are reservoired in the Plover and Nome formations, respectively. The Jabiru oil field produced from the Jurassic Montara Formation. The Cash/Maple accumulation is hosted in the Challis, Plover and Montara formations. In addition, numerous wells in the immediate vicinity of the Release Areas record oil and gas shows in the Challis (Tancred 1), Plover (Audacious 1, Augustus 1, Octavius 2), Lower Vulcan (Tancred 1), Upper Vulcan (Capricious 1, Katandra 1A, Octavius 1) and the Johnson (Snowmass 1) formations (Figure 1). Structural traps containing Triassic to Jurassic sandstone reservoirs are sealed by Lower Cretaceous claystones (Figure 3). These traps are commonly either horsts (some complexly faulted), or tilted fault blocks.

Data coverage for the Vulcan Sub-basin is extensive (Figure 4), with 2D and 3D seismic data available and numerous wells drilled. Release Area AC16-1 is intersected by the Lantana 1 well.






Figures

Figure 1

Structural elements of the Vulcan Sub-basin in the vicinity of the 2016 Release Areas, showing showing petroleum fields, key wells, and the 2015 and 2016 Release Areas


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Figure 2

Stratigraphy, basin phases and hydrocarbon shows in the Vulcan Sub-basin based on the Bonaparte Basin Biozonation and Stratigraphy Chart (Kelman et al, 2014). Geologic Time Scale after Gradstein et al (2012)


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Figure 3

Play types in the vicinity of the Release Areas in the Vulcan Sub-basin, Bonaparte Basin


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Figure 4

Seismic and well data in the vicinity of the Release Areas in the Vulcan Sub-basin, Bonaparte Basin


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