Coasts and Oceans Theme Report
Australia State of the Environment Report 2001 (Theme Report)
Australian State of the Environment Committee, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06751 5
Offshore petroleum production has significant economic and strategic importance for Australia, with some 85% of our petroleum demands being met from offshore wells in Bass Strait, the Timor Sea and the North West Shelf.
Exploration drilling for petroleum in Australian waters has been largely focused on the Twofold Shelf (in Bass Strait) and the North West Shelf. In the North West Shelf area, petroleum exploration and production occurs over an area of great conservation value. An application has been made (in late 2000) for an exploration permit for an area west of Carnarvon, Western Australia, which takes in the northern waters of the Shark Bay World Heritage Area.
Environmental approvals for petroleum industry activities in Commonwealth waters are governed by the provisions of the Petroleum (Submerged Lands) Act 1967 and the Environment Protection and Biodiversity Conservation Act 1999. Petroleum operations in coastal waters are the responsibility of individual State and Territory governments.
The petroleum industry in Australia is recognised as having a good environmental record and is strictly regulated regarding environmental protection. As a result, the risks to the offshore environment from petroleum operations are low. However, while the risk of a major incident occurring is low, there could be a potentially very significant effect if such an incident did occur.
Oil companies have drilled over 550 exploration wells in the past 10 years and with a similar trend for development wells (Figure 28).
Figure 28: Exploration wells drilled, 1989-1999.
Source: Commonwealth of Australia (2001)
A review of the environmental impacts of petroleum exploration in offshore Commonwealth waters, together with the implications of the EPBC Act has recently been completed for the Department of Industry, Science and Resources (DISR 2001b). The following discussion reflects some of the compilation of research relevant to SoE reporting.
An independent scientific review of research into the environmental implications of offshore petroleum exploration was conducted by Swan et al. (1994). The review found that the offshore exploration and production industry in Australia not only met statutory requirements, but had ' set an excellent example in taking all possible steps to safeguard the marine environment'. More recent research has been funded by individual petroleum companies and by the Australian Petroleum Production and Exploration Association (APPEA) with a view to further improving the industry's environmental management and continuing to reduce impacts and risks associated with industry activities.
Following the Swan review, APPEA facilitated a scientific assessment of environmental issues and identified several specific areas where knowledge of environmental impacts could be improved. These included:
- the fate and effects of oil and dispersants on mangroves in Australia: protection, clean-up and rehabilitation,
- dispersion and fates of produced formation water constituents, and
- investigation of the environmental effects of offshore seismic survey activities (McCauley et al 2000).
The petroleum industry has a commitment to support scientific research that furthers an understanding of the impacts of industry activities on the environment. In addition to APPEA generated initiatives, company sponsored research projects are regularly supported. Two recent projects include:
- the ecotoxicology of non-water based drilling fluid (Tsvetnenko 1999), and
- the ecotoxicology of some light Australian crudes.
In addition to these studies, a number of companies have investigated the size, chemical composition and longevity of seafloor drill cutting piles resulting from drilling activities.
The Australian Petroleum Production and Exploration Association (APPEA) has prepared its own Code of Environmental Practice (APPEA 1996). The Code outlines an environmental management framework, a management system, and a comprehensive set of environmental guidelines for the petroleum industry. Environmental guidelines for offshore petroleum activities address seismic surveys, drilling operations and development and production operations. This Code is currently being revised to reflect advances in technology, new information, and the requirements under the new EPBC Act 1999.
The effects of seismic surveys continue to be investigated by independent researchers and industry because of the concern that sound waves produced by air guns could cause mortality or sublethal injury to marine organisms, or might modify the feeding or mating activity of marine mammals, fish and other organisms. The greatest risk from seismic surveys to marine animals appears to be during breeding or spawning periods. Studies have shown that noise associated with air guns can influence the behaviour of some species of mammals, fishes and squid. Further, damage to hearing organs have been reported for some species of fishes, while mortality has been reported for planktonic organisms, usually at very close range to the source of noise.
The general response to seismic surveys of migrating Humpback Whales off the north-west coast of Australia is to take avoidance action. Humpback Whale pods, consisting of cows and calves, have shown avoidance responses at a range of 7 to 12 kilometres from a large seismic source.
The Western Australian Department of Minerals and Energy has developed guidelines to minimise the effects of seismic surveys on Humpback Whales. Environment Australia, with input from the Australian Petroleum Production and Exploration Association, is currently finalising guidelines (linked to the EPBC Act) to minimise the effects of seismic surveys on Humpback, Southern Right and Blue Whales.