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Otway Basin

Release Areas V17-2 and V17-3, offshore Victoria

Highlights

Bids close on Thursday 19 October 2017

  • Proven commercial gas province with ready access to an expanding infrastructure and growing southeast Australian energy market.
  • Close to the producing Minerva, Casino and Halladale–Speculant gas fields
  • Shallow water depths less than 80 m
  • Release areas partially covered by 3D seismic
  • Further guidance applies, refer to 2017 Special Notices

Release Areas V17-2 and V17-3 are located adjacent to the prospective Shipwreck Trough, in the offshore Otway Basin (Figure 1). They are near the producing Minerva, Casino and Halladale–Speculant fields, which provide gas for the southeastern Australian energy market. The greater Melbourne region currently represents Australia’s largest domestic gas market and is supported by a local petroleum refining industry. Release Area V17-2 lies on the Mussel Platform, in water less than 70 m deep, approximately 8 km south of Warrnambool. Release Area V17-3 is on the Prawn Platform in water less than 80 m deep, 8 km south of Port Campbell and adjacent to the gas pipelines to the Port Campbell onshore gas processing plant.

The Otway Basin is a northwest-trending passive margin rift basin that was formed during Gondwanan break-up and the Antarctic-Australian separation. Rift-related faulting resulted in the development of large, deep depocentres, including the Voluta and Shipwreck troughs in the offshore part of the basin. The Shipwreck Trough is a structural depression between the Mussel and Prawn platforms. Deposition throughout the Late Cretaceous was dominated by deltaic sedimentation of the Sherbrook Group (Figure 2), which hosts most of the offshore gas discoveries and is >5000 m thick in the trough. Two potential petroleum systems occur in the vicinity of the Release Areas, the proven Lower Cretaceous Austral 2 Petroleum System that is the source of the gas produced in the region, and the Upper Cretaceous Austral 3 Petroleum System with a potential Turonian oil-prone source rock.

The data coverage for the region is indicated in Figure 3 showing the Champion and Hercules 3D seismic survey overlapping parts of the V17-2 Release Area and the Shomberg-Minerva 3D survey partially covering V17-3. A detailed well log for Minerva 2A is shown in Figure 4, indicating the gas-bearing reservoir in the Upper Cretaceous Warre Formation of the Shipwreck Subgroup. A well correlation from Minerva 1 to the onshore wells in the Port Campbell Embayment is shown in Figure 5.