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 AUSTRALIA
Australasia
Most of Australia’s shores are unproductive but
Australia has two key producing regions, the Bass Strait (between the
mainland and Tasmania) and the North West Shelf (between the mainland
and Timor).
 Limited
onshore oil and gas are also produced from remote basins in the centre
and east of the country. Licensing is by individual states - for
example, the department of Minerals and Energy in Western
Australia.
Onshore production is mostly inland from the North West
Shelf and from the central Cooper/Eromanga basins. Some minor onshore
production occurs in the Perth basin on the southwest where there are
small oil and some larger gas fields. Onshore oil forms only a small
percentage of Australian output.
 Offshore the oldest producing area is the Gippsland Basin
in the Bass Strait southeast of Melbourne but this area is in decline.
The NW Shelf in Western Australia is the focus of most of Australia’s
activity. A number of other areas have some potential but output of both
oil and gas will never match levels achieved from Gippsland and the NW
Shelf.
The Gippsland Basin: The Gippsland basin in the
Bass Strait, began producing oil and gas in October 1969, and has
produced over 60% of Australia’s oil and around 40% of its gas. The
first offshore well, Barracouta No. 1, drilled by Esso and BHP in 1965
was an oil and gas discovery. It was brought onstream in March 1969,
developed, like most of the fields in the area, with a conventional
steel platform producing oil and gas to Longford on the coast by
pipeline.
Marlin also came onstream in 1969 and Halibut in 1970.
Australia’s largest oil field, Kingfish, was discovered in 1966 and the
Kingfish A and B platforms began producing in 1971. Since then 13
further oil and gas fields have been developed and a number of small,
undeveloped discoveries remain.
Esso and BHP Billiton operate all the large fields.
Although the basin is well explored, the operators started a large
combined E & P drilling programme using a rig capable of drilling wells
from either existing platforms or in new locations. In particular, the
joint venture is trying to commercialise small accumulations near
existing infrastructure and extend the productive life of platforms and
pipelines. Such small finds will be brought into production quickly.
The NW Shelf: The Northwest Shelf of Australia is
primarily a gas province but it does contain significant oil-bearing
regions. It lies offshore of the town of Carnarvon in the south to
Darwin in the north and includes the Bonaparte, Browse, Offshore
Canning, Roebuck and Carnarvon basins.
The Mesozoic contains several source-rock intervals,
mostly below the oil-generating window explaining the many
gas-condensate finds. The southern part of the Carnarvon basin
(including the Exmouth Plateau) and the Bonaparte basin in the north are
the key areas. Deep-water exploration in Australia has mainly occurred
in the outer shelf of the Carnarvon Basin although gas finds have been
made in the Browse Basin.
The Carnarvon basin: Oil has been produced from
the Carnarvon basin since 1964 (on Barrow island) but the first offshore
discovery was made in June 1971 when the giant North Rankin gas field
was discovered close to the shelf edge.
Gas has been produced since 1984 from the North Rankin
conventional steel platform. Gas and condensate is piped to shore near
Dampier where the some of the gas is tied to a grid serving the coastal
belt. The Goodwyn gas/condensate field, also discovered in
1971, was added in 1995 and other discoveries are planned for
development. Since 1989 large volumes of gas have been converted to LNG
for export, mostly to Japan.
Offshore oil production began in 1986 from the Harriet
field, close to Barrow Island, discovered by Occidental in 1983. Over 30
modest oil and oil and gas accumulations have been developed in the
neighbourhood. The largest, Wanaea, which perhaps contained 200 mm Bbls
of recoverable oil, came onstream in 1995.
Over one third of the fields have been developed since
2000, nearly all with small single leg platforms and, more recently,
with floating facilities. Small discoveries continue to be made. The Monet Field,
discovered in 2004, 3.5 km NE of the Simpson Bravo Platform, produces
only at 2,000 Bbls per day, but has robust economics due to the existing
infrastructure and rapid development. Gas and gas liquids development activity is increasing
and new gas/condensate fields are being sought in deep waters.
The Bonaparte Basin: The Bonaparte basin straddles
the border between Western Australia, Northern Territory and, to the
north, Timor Leste. Initially a number of gas fields were discovered in
the region including Petrel in 1970, Tern in 1971 and Sunrise and
Troubadour in 1974 but none have yet been developed due to their remote
location. There are a large number of undeveloped oil, oil & gas, and
gas discoveries.
A number of fields have achieved commercial production.
The Jabiru field was discovered in 1983 and was the first development
brought onstream in 1986 using an FPSO (converted from a tanker) plus
shuttle tanker moored in 119m of water. The Challis oilfield nearby in
106m of water was discovered in 1984 and production began in 1989 from
this and the Cassini field also with a permanently moored FPSO. Oil is
produced from subsea wells in all these fields.
The Skua field (1991) and the Elang/Kakatua/Kakatua North
fields (1998) produced from subsea wells into an FPSO but were abandoned
in 1997 and 2007 respectively. The Buffalo field (also abandoned), came
onstream in 1999 and produced into an FPSO from an unmanned wellhead
platform. Before 2007 the deepest developments in Australia were
Laminaria and Corallina, discovered in 1994 and 1995 respectively.
Subsea wellheads are linked to a permanently moored common FPSO
facility. Production commenced in 1999 with the FPSO moored at 385m
water depth. The Puffin field, discovered back in 1972, came onstream in
2007 and several further small developments are planned, all with FPSOs.
Close to the border with Timor Leste in the Northern
Territory where the Bonaparte basin underlies the Timor Sea, Woodside is
hoping to develop its Greater Sunrise gas fields (discovered in 1974)
which could begin production in 2011. Along with the estimated 250 Bcm
of natural gas there may be 320 mm barrels of liquids. The project has
been pushed back due to uncertainty over how best to develop the field
and disputes over the location of the border between Australia and Timor
Leste. However, this seems to have been resolved with a pact that will
see Timor Leste gain access to half of Sunrise’s future revenues (up
from 20%) in return for setting aside negotiations on a permanent
maritime boundary for 50 years.
The Timor Gap Zone of Co-operation (ZOC) was signed in
1989 by Indonesia (transferred to Timor Leste) and Australia, covering a
part of the Timor Sea that takes in the ConocoPhillips operated Bayu
Undan gas field in a 90% to 10% deal in favour of Timor Leste. Timor
Leste wished to redefine the border halfway between the two countries
whilst Australia argued for the edge of the continental shelf. Many
potential fields lie in the overlapping area that may be developed with
subsea technology.
The Browse Basin: Lying between the Bonaparte and
Carnarvon basins is the offshore Browse basin. Although no production
has been realised from this area as yet, substantial gas and condensate
resources are present on the deepwater shelf. The undeveloped Scott Reef
gas field was discovered in 1971 followed by the Brecknock and Brewster
gas fields in 1979 and 1980 respectively. A number of other gas
discoveries have also been made and a small oil discovery, Gwydion, in
1995.
Other offshore Australia: A number of other
offshore basins have undeveloped gas discoveries whose development is
imminent. One oil discovery, Cliff Head, in the Perth basin came
onstream in 2005. Otherwise deepwater basins to the south of Australia
could contain oil reservoirs, albeit of high risk, but little
exploration has been carried out.
Exploration of the Bass basin, an intra-cratonic rift
between Tasmania and Victoria, began in 1965. A number of wells have
been drilled but only the Yolla Gas field, discovered in 1985 and
located approximately 120 kms from the coast of Tasmania and 150 kms
from the coast of Victoria, has commercial hydrocarbons.
Several gas discoveries have been made in the Otway
basin, west of the Bass basin. The Otway Gas Project, run by Woodside
Energy, involves the development of the Geographe and the Thylacine gas
fields, located 70 kms south of Port Campbell, Victoria in a water depth
of around 100 m and jointly containing around 30 Bcm of gas.
The Perth basin has some onshore gas and minor oil
production but had no offshore production. However, ROC Oil developed
the Cliff Head oil field discovered at the end of 2001, 11 kms offshore
in 16 m of water. First oil in 2005 came from an un-manned production
platform connected to onshore processing facilities. It is believed to
hold between 30 and 50 mm Bbls of recoverable oil and produces at
maximum rates of between 15,000-20,000 Bbls per day.
The rest of offshore Australia has few drilling targets
although the deep waters to the south are under review. Although some
sporadic drilling has been carried out over the northern offshore shelf,
including the Gulf of Carpenteria and the Arafura Sea, there is no
production. On the east coast the shelf dips beyond the Great Barrier
Reef into the Coral Sea whilst to the south, offshore of Brisbane and
Sydney, it dips steeply into the Tasman Sea.
The Indian Ocean abuts the coastline from Mount Gambier
on the Victoria/South Australia border along the Great Australian Bight,
around the Darling Ranges to Perth. The largely unexplored Bight basin
off South and Western Australia may have deep water potential in its
Jurassic to Cretaceous sedimentary section.
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