Energy News Bulletin
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Tuesday, 15 November 2011
WOODSIDE Petroleum is confident of managing the risk to fisheries, marine fauna and flora under the greatest threat from development of the upstream component of its $A30 billion Browse LNG project.
In its environmental impact statement, Woodside said the development of the Torosa, Brecknock and Calliance fields did not represent a significant threat to any listed or migratory species and management response measures were in place in the event an unplanned incident like a spill occurred.
Woodside said 50-90 wells would be drilled over the project life.
They will be connected to manifolds (four at Torosa, two at Calliance and one at Brecknock), which will be connected in turn through flowlines to their respective infield platforms.
The platforms will be connected to the central processing facility, which will comprise up to four platforms located on the continental shelf in 80-120m of water.
Gas and condensate will be processed at the facility before it is sent by about 310km of pipeline to the LNG plant at James Price Point.
The upstream facilities will tap the 13.3 trillion cubic feet of gas and 360 million barrels of condensate believed to be present in the three fields.
While most of the expected impacts are classed as low risk, Woodside noted
local fisheries faced a medium risk through exclusion zones around platforms and drill rigs, though the total area is expected to be small.
Woodside also carried out tests to determine the impact of light from the Torosa platform on marine turtles and concluded maximum light levels reaching Sandy Islet would appear to be no more than a small lit object, which Woodside said would not influence nesting behaviour of adult turtles.
However, the company said it had started a long-term monitoring program of turtles on the island to identify impacts from the development.
Noise produced during the construction of the project, vessel movements and operational activities were also assessed and while most were found to be of low risk to cetaceans, uncertainty over the noise from the subsea choke valves in the channel between the north and south reefs at Scott reef led Woodside to conclude it presented a medium risk to cetaceans until more data became available.
Woodside said besides carrying out measurements of the noise, it would also investigate insulation methods to reduce the noise produced by fluids through the chokes.
Other risks brought up by the report included the high possibility vessels and rigs might bring in invasive species – though Woodside said its comprehensive management plan made the likelihood low – and changes in water quality due to elevated suspended sediment from pipeline trenching works.
The study also examined the reasons behind the Browse joint venture’s decision to drop development alternatives.
Woodside said the Browse to Darwin option was dropped in 2007 due to the higher cost of running a long pipeline, while an option to build a liquefaction facility in the shallow water of the southern lagoon of Scott reef was deemed to be environmentally unacceptable.
Floating LNG was also dropped due to the need for multiple facilities to efficiently recover gas from the fields.
Woodside acknowledged the option to pipe gas to the Burrup peninsula, widely considered to be the most viable alternative to developing Browse LNG at James Price Point, did not pose unmanageable environmental issues though it raised the possibility that issues related to the cumulative impacts on the Burrup peninsula might present challenges for the option.
The EIS represents 17 years of research that has shed new light on Western Australia’s northern offshore ecosystems.
“Browse represents a major opportunity for Australia to meet the world’s growing demand for cleaner forms of energy,” Woodside Browse senior vice president Michael Hession said.
“It is likely to be a major part of Woodside’s growth as an energy supplier.
“We are also working closely with traditional owners to make sure that Kimberley indigenous people can realise the economic and social development opportunities from this project.”
Browse LNG is expected to generate up to $50 billion for the Australian economy and create up to 8000 jobs, 6000 onshore and 2000 offshore, during construction.
The 12 million tonnes per annum LNG project is expected to be approved next year, with first production in 2017