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Maher Megallaa and Jim Driscoll*
GeoScience Victoria
*Acreage Release Coordinator
The Acreage
At the 2007 APPEA Conference in Adelaide, three offshore areas were jointly released by the Commonwealth of Australia and the State of Victoria. These were V07-1, V07-2 and V07-3, the locations of which are shown in the inner back cover of this supplement and on Figure 1.
The released areas are located in the north-eastern offshore Gippsland Basin and are approximately 200 km from significant population and industry centres in the east Gippsland region. There is sizable petroleum infrastructure onshore, including the plants at Longford, Lang Lang and Orbost, which process the produced hydrocarbons from offshore fields. The areas are close to three major pipeline networks which can distribute the processed gas to the Victorian, New South Wales, South Australian and Tasmanian markets.
Bids Close
The closing date for applications is Thursday, 18th October 2007, at 4PM (EST).
The closing date for applications is Thursday, 17th April 2008, at 4PM (EST).
Applications
Submission of bids is governed by the Commonwealth Petroleum (Submerged Lands) Act 1967. Gazetted notice, conditions for the submission of applications and the criteria for both bid assessment and the selection of the successful bidder, can be viewed on the DPI’s website: http://www.dpi.vic.gov.au/minpet/acreagerelease, or on the Commonwealth’s (DITR) website: http://industry.gov.au/petexp.
Enquiries about applications for the 2007 Victorian acreage release can be directed to:
Jim Driscoll at DPI
Tel: +61 3 9658 4535 Fax: +61 3 9658 4555
Email: jim.driscoll@dpi.vic.gov.au
or to Richard Sams at ITR
Tel: +61 2 6213 6792 Fax: +61 2 6213 7955
Email: richard.sams@industry.gov.au
Description Of Areas
• Area V07-1 lies on the continental shelf and
consists of 23 graticular and part blocks
(1,240 km2) and is bounded to the north
by the State’s 3 Mile Zone. Water depths
in the block gradually increase in a south-
easterly direction from 20 m to 200 m.
• Area V07-2 lies on the continental shelf and
consists of 21 graticular blocks (1,420 km2),
within which water depths increase gradually
from 120 m to a maximum of approximately
200 m along its southern boundary.
• Area V07-3 consists of 32 graticular blocks
(2,160 km2) and is located on the upper
continental slope. Water depths within V07-3
increase rapidly from approximately 200 m to
almost 1,000 m in the middle of the block;
and 2,000 m in the south-east and south-west
corners of the block, along the northern flank
of the Bass Canyon.
Data Availability
Copies of basic seismic data (e.g. field tapes, UKOOA data, SEGY tapes etc,); well data (e.g. WCR, wireline logs) and open file reports pertaining to the released areas can be ordered from the Energy Geoscience Group, GeoScience Victoria (GSV); contact Terry Smith [Tel: +61 3 9658 4544; email: terry.smith@dpi.vic.gov.au].
The Energy Geoscience Group has produced VIMP Report 92, which addresses the petroleum geology and the prospectivity of the released areas [next article on Opportunities in Offshore Gippslan's Northeast]. This report can be obtained from the DPI website at http://www.dpi.vic.gov.au/minpet/acreagerelease.
Exploration Review
The gazetted acreage covers the easternmost parts of the Gippsland Basin and includes parts of the Northern Platform, the Northern Terrace and the Central Deep. The acreage has only been explored sporadically, with only one well, Northright-1, drilled in any of the blocks (V07-1). Well control is provided by several wells drilled to the west of blocks V07-2 and V07-3 and to the south and west of V07-1 (Fig. 1).
A regional aeromagnetic survey was carried out in 1999 by AGSO (now Geoscience Australia) and covers all of the released areas and surrounds. These aeromagnetic data have assisted in refining the deep-seated basin architecture of the region.
The Northern Platform is located to the north of the Lake Wellington Fault System and comprises
Late Palaeozoic basement rocks that are overlain by a thin Tertiary sedimentary veneer. Located immediately to the south, the Northern Terrace is essentially a tilted Early Cretaceous half-graben which is bounded by the Lake Wellington (north) and the Rosedale (south) fault systems, and contains a thick, thermally mature section of Strzelecki Group sediments. It is possible that source rocks within the Strzelecki Group have sourced the dry gas reservoirs within the Sole field. The Strzelecki Group, on the Northern Terrace, is overlain by a moderately thick, although thermally immature section of Tertiary Latrobe Group sediments, which are the regional reservoir rocks. The Central Deep, the focus of Latrobe Group deposition in the Gippsland Basin, occurs to the south of the Northern Terrace, across the Rosedale Fault System. The Central Deep contains the source rocks which have charged the majority of the oil and gas accumulations within the basin.
Area V07-1 straddles both the Northern Platform and Northern Terrace; V07-2 is principally located over the Northern Platform, whereas Area
V07-3 extends from the Northern Platform to the Central Deep and hence has the greatest variety of plays.
Seismic coverage consists principally of older regional seismic lines (e.g. Esso 1969, Shell 1970-1992, and BMR 1987); seismic density decreases eastwards, ranging from detailed over V07-1 to regional over V07-3 (Fig. 1).
Some of V07-1 is covered by more modern seismic data, including 223 line km of 2D data acquired by Bass Strait Oil. In addition, there are several 3D surveys located immediately south and south-east of the block.
Both V07-2 and V07-3 are covered with vintage 2D seismic data, which become progressively sparser in the southern portion of V07-3. The far south-western portion of V07-3 is overlapped by the 1999 regional deepwater GDW-99 survey, which was acquired by Seismic Australia for DPI.
The critical exploration uncertainties in these blocks relate to the charge and trapping mechanisms and hence a combination of seismic acquisition, AVO analysis and migration modelling may provide the necessary tools to understand the potential of these areas.
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