The Department of Mines, Industry Regulation and Safety (DMIRS) continues to promote the petroleum potential of Western Australia’s vast sedimentary basins using a specific area release system. On 16 May 2017, DMIRS gazetted a total of five onshore release areas in the central and southern Canning Basin (Fig.1). Release area size ranges from 5324 km2 to 6667 km2. This gazettal was timed to coincide with the 2017 APPEA Conference in Pert, reports Richard Bruce, DMIRS exploration geologist Petroleum Division.
Interest in the Canning Basin has revived significantly in recent years with new oil plays discovered at Ungani 1 and Ungani Far West 1. Canning Basin oil may be trucked to ports in the north of the State for shipment to refineries in southeast Asia or trucked to the Kwinana oil refinery in the south of the State.
The northern three Release Areas, L17-1 to -3, are contiguous and collectively cover 17,664 km2 (Fig. 2). These areas are accessible from Broome via the Great Northern Highway and extend from the southeastern Broome Platform eastward, across the northwestern Crossland Platform and the central Barbwire Terrace, and into the Gregory Sub-Basin. These are among the best explored regions of the Canning Basin, where 15 wells have recorded hydrocarbon shows, including Looma 1, Acacia 2, Mirbelia 1 and 2 and Sally May 1.
Release Areas L17-1 to -3 are considered prospective for both subsalt (Ordovician) and suprasalt (Devonian) plays. A new Devonian play has been proposed for the Barbwire Terrace, where a series of en echelon wrench-related anticlines have been interpreted from seismic data.
The southern two Release Areas, L17-4 and L17-5, collectively cover 12,905 km2 and are regarded as frontier acreage, with much less on-ground exploration than the northern three Release Areas (Fig. 3). However, couldn’t there be room for a large discovery? Salt diapirism may provide traps in areas of the basin that lack major block faulting.
‘The best remaining frontier prospects lie … in older basins with a high preservation potential such as intracratonic basins with evaporite seals.’
Duncan S Macgregor, BP, 1996
Release Areas L17-4 and L17-5 are contiguous and lie just south of the three northern Release Areas. These two Release Areas are accessible via the Kidson Track, the Kiwirrkurra Road and the Canning Stock Route and extend across the northern flank of the Kidson Sub-basin eastward, over the southwestern flank of the Crossland Platform. The closest well to the southern Release Areas is Gibb-Maitland 1, drilled during December 2012. Peripheral margins of the Kidson Sub-basin are generally considered prospective for conventional salt-related plays (including sub-salt Ordovician) that have hardly been tested.
This information includes prospectivity of release areas, a Canning Basin summary, available data listings, new bid assessment guidelines, land access and environment considerations, schedule of fees and information regarding how to make a valid application for an exploration permit. More detail on the prospectivity of the Release Areas has been described by the Geological Survey of Western Australia.
The most current release information is available on the Department’s website at: www.dmp.wa.gov.au/acreage_release
Work program bids for the release areas close at 4pm Australian Western Standard Time on Thursday 1 February 2018 and applications can only be made online.