Australia's marine environment is special in many ways - it covers an
enormous area, over one and a half times larger than Australia's land
surface; it extends from the tropics to Antarctica. It includes extensive
submarine environments including sea grass beds and unique coral reef
systems which support an array of marine creatures from whales, dugongs,
dolphins and seals to thousands of species of fish, shellfish, and a
myriad of microscopic organisms. According to the Federal Environment
Department (State of the Marine Environment Report 1995) our marine
environment is in very good condition.
The petroleum industry shares the community's concern for the protection
of the marine environment. Conserving biological diversity and maintaining
ecological processes and systems are among the core objectives of
ecologically sustainable development which have been endorsed by the
petroleum industry. The responsible development of petroleum resources
from offshore areas is consistent with achieving these objectives.
Petroleum resources are not easy to find, nor are they often located in
convenient places for oil or gas to be extracted, processed and sent to be
used by the community.
Most of Australia's petroleum production comes from offshore wells.
Exploring for oil and gas under the sea bed, and the production activities
which follow a successful exploration program, all involve some risks and
potential impacts on the marine environment. Clearly identifying these
risks and impacts and developing detailed management plans to avoid,
prevent or minimise them is a vital and integral part of planning these
exploration and production activities.
An independent review by eminent scientists of the environmental
impacts of offshore oil and gas exploration and production concluded that
the Australian offshore petroleum industry has had no significant effects
on the marine and coastal environment in over twenty-five years of
operation. The industry is committed to maintaining this record and
ensuring that the marine environment in which it operates is well managed
and able to be enjoyed by future generations, long after the petroleum
industry has completed its work.
Petroleum, like other mineral resources under the ground, is owned by the
Crown, that is Governments own them on behalf of the community.
Governments allow companies to explore and produce oil and gas under
strict conditions and in return receive all the information collected
about the resources and a large share of the pre-tax profits. Currently
well over half of the pre-tax profit) from the sale of the petroleum is
returned to the government via taxation.
State and Territory Governments are responsible for managing and
regulating most activities, including petroleum exploration and production
within 3 nautical miles (5.6km) of their coasts.
The Federal Government is responsible for the area from 3 -200 nautical
miles off the coast (out to the extent of our Exclusive Economic Zone -
defined by the United Nations Convention on the Law of the Sea). Similar
legislation is implemented by all Australian governments to regulate
activities associated with petroleum exploration and production. The key
law for offshore activities is the Petroleum (Submerged Lands) Act 1967,
but there are many other Acts that can affect industry operations
includingthe Endangered Species Act 1992, Environment Protection (Impact
of Proposals) Act1974 , Sea Installations Act 1987, Whale Protection Act
1980, Protection of the Sea (Prevention of Pollution from Ships) Act 1983
and variousState/Territory and Commonwealth Environment Protection Acts.
The Industry's Code of Environmental Practice lists almost 80 main Acts
that potentially affect environmental management planning.
These laws are aimed at protecting one or more aspects of the marine
environment, including cultural and historic values, as well as
biodiversity and air and water quality. Controls are placed on all aspects
of offshore operations, and licences defining limits are required for
various discharges. Strict limits are imposed on discharges to the air and
The industry recognises that various risks and consequences are associated
with petroleum exploration and production activities. These are carefully
identified and minimised as activities may take place in, or near,
environmentally important areas. Environmental impact assessments are
undertaken to identify areas of environmental concern and provide the
basis for the development and implementation of an environmental
management strategy. Baseline studies are usually conducted to accurately
describe the environment before any work commences. Direct and indirect
environmental effects are monitored.
Direct effects are those which may affect the ecology of a
particular site or area and whose source is easily identified, while
indirect impacts are those which do not affect a localised area (Table 1).
The risk and consequence of oil spills is of greatest environmental
concern however, dredging, the physical effects of equipment and ship
movement including anchoring, drilling, routine discharges including
kitchen wastes, noise, artificial lights, and air emissions are all
matters that are carefully considered. Table 1: Management of Direct and
Indirect Environmental Impacts
Direct Potential Impact or Risk
Indirect Potential Impact or Risk
The risk of an oil spill is directly related to: a) frequency of
b) physical and mechanical condition of a ship and its equipment;
c) performance of crews.
Oil spill risk is minimised through achieving appropriate
standards and adequate training.
Impacts of an oil spill may be severe on sensitive organisms
In the event of an oil spill, sophisticated oil spill contingency
plans aim to prevent, contain and minimise impacts.
Open ocean impacts likely to be less than coastal impacts.
Dredging navigation channels, if necessary, may disturb and modify
the sea floor. Dredge spoil is dumped under permit in locations of
Noise, lights and physical presence of ships may affect the
movement of sensitive species. Effects are of short duration and
impacts are likely to be minimal.
Air based energy sources in seismic arrays generate sounds and
may have potential impacts on organisms within range. To avoid
adverse impacts, surveys are adapted or scheduled to avoid
seasonal migrations or key breeding locations.
Avoidance behaviour by some species may affect feeding. Impacts
are likely to be of short duration
Drilling rig placement
Physical placement of drilling rig may cause localised damage,
depending on the nature of the sea floor, however the area, if
affected, is very small.
Localised physical damage may be observed.
Minimised by avoiding seabed structures of environmental or
When drill cuttings are discharged overboard impacts are limited
to the immediate area surrounding the drill site. Drilling fluids
are comprised of clays, and include metals such as barium, and a
range of additives depending on the type of rock being drilled.
Harmful constituents are generally recycled or removed before
discharge to the ocean.
Monitoring of drilling impacts reveals only minor adverse impact
beyond the immediate discharge zone.
Suspended sediment in the water column may reduce the amount of
light reaching the sea floor. This may reduce plant growth until
the particulate material settles. Effects of short duration.
Localised effects may be impact on the food chain. Such effects
can be minimised by reducing levels of toxic components, and/or
removing or recycling fluids before discharge. Generally, no toxic
oil-based drilling fluids are used in Australia, hence discharges
of these substances to the marine environment are very rare.
Drilling is undertaken for a relatively short period of an oil
filed operation, eg. 3 months to 3-4 years.
Ocean environments facilitate the rapid dispersion, resulting in
minimal seabed impact.
In very sensitive environments, waste from drilling operations may
be collected and stored onboard for disposal on land.
Habitat disturbance can be minimised through careful placement.
A site is chosen after an environmental impact assessment has been
Platforms often attract marine life and can act as artificial
reefs. They often become important resting points for seabirds and
Produced formation water (PFW)
Hydrocarbon traces in PFW may have localised impacts. Although
PFW is of low toxicity, it is often warmer than the ocean when
discharged and may cause possible local effects when organisms
make inadvertent contact.
Cumulative and/or sublethal impacts may occur from long exposure
to low levels of particular hydrocarbons. PFW may have a salt
content greater or less than sea water causing localised transient
salinity levels which are unlikely to affect nearby organisms.Low
regulatory limits for hydrocarbons and rapid dispersion ensures
that impacts are within metres of discharge. APPEA is funding a 2
year research project to assess and improve current management
practices for PFW discharge.
Reinjection of water or gas down wells is sometimes used to
increase the amount of oil recovered.
Reinjection of gas decreases the volume of gas that might be
otherwise flared (reducing emissions of greenhouse gases).
Reinjection of gas or water is costly but where possible, is often
a more environmentally sound option than discharge to the
Increased nutrient content in the water column.
May increase population numbers of some organisms.Quantities are
small and treated before discharge. Dispersion rapidly dilutes any
Greenhouse gas emissions
Contributes to global greenhouse concentrations. Exploration and
production activities contribute less than 3% of Australia's total
greenhouse gas emissions. Minimised through careful management of
sources, including power generating equipment, flaring and
fugitive fuel emissions. APPEA member companies participate in
voluntary cooperative action to minimise avoidable greenhouse gas
May have toxic and/or smothering effects for some species on
contact. Most offshore platforms are considerable distances from
A range of safety features such as automatic shut-down valves
ensures that the risk of a significant oil spill is extremely
Possible impacts on the food chain, as a result of contamination
or loss of food sources. However effects are transient.
Hydrocarbons are organic compounds and are readily decomposed or
used as food sources by some microorganisms.
Most Australian crude oils are light and evaporate readily (adding
to the volume of atmospheric greenhouse concentrations), and
greatly reduce the likelihood of impacts on sensitive coastal or
marine organisms. The proximity to sensitive species is dependent
on the type of oil, currents, and wind. Oil spill risk cannot be
eliminated but may be reduced to very low levels. The Australian
industry has an excellent record of minimal spills and virtually
no impacts over 25 years. APPEA is funding a 3 year research
project on the impacts of oils spills on key mangrove species, to
recommend improved procedures to protect and enhance recovery of
affected mangroves. (NB the few instances of oil spills on
mangroves are associated with port and onshore processing rather
than exploration and production activities.)
Exploration and production activities result in the release or emission of
several greenhouse gases, notably carbon dioxide and methane. Small
quantities of other gases such as the hydrocarbons propane and butane, and
other products of fuel combustion are also released. The industry
recognises the need to carefully manage and reduce the levels of
emissions, and is participating in the Federal Government's Greenhouse
Challenge program to voluntarily address the issue of emissions.
Greenhouse gases are those gases suspected of contributing to global
warming in the lower atmosphere
The primary greenhouse gas emitted by human activities in Australia is
carbon dioxide from energy use, including transport and industrial
processes, land use change and forestry and energy production. The main
sources of methane emissions in Australia are coal mining, agriculture,
decomposing wastes and energy production.
(CO 2 )
CO 2 is the dominant greenhouse gas in Australia and effectively
accounts for about 75% of all greenhouse gas emissions.
(CH 4 )
CH 4 is a very effective greenhouse gas with a high global
warming potential (GWP), and although present at much lower levels
than CO 2 may have significant impact because of this higher GWP.
The main source of CH 4 is from agriculture (mainly
(NO x )
Nitrogen oxides consist of nitrogen oxide (NO) and nitrogen
dioxide (NO 2 ). NO x is a small component of greenhouse emissions
(N 2 O)
N 2 O is a gas produced both naturally and by combustion of
fuels. The majority of N 2 O (80%) is produced from agriculture.
They mostly come from burning fuel (cars and power
Volatile organic compounds
Volatile organic compounds are hydrocarbons (excluding methane)
which are capable of forming oxidants (particularly ozone) by
reactions with nitrogen oxides in the presence of sunlight. Major
sources of VOC's are vehicles, solvents and process industry
CO is generated as a result of incomplete combustion(eg poorly
maintained wood heaters and cars), and reacts preferentially with
naturally occurring hydroxyl radicals in the lower atmosphere.
This has the effect of increasing the lifetime of VOC's and so
enhances the formation of photochemical smog (largely
(H 2 S)
H 2 S is a toxic gas occurring naturally during decomposition.
Natural gas is normally treated to remove this H 2 S to form
sulphur or it can be burned. H 2 S forms SO 2 during the
combustion process or photochemically when released to the
(SO 2 )
SO 2 results in dry acid deposition and in the formation of acid
rain thereby increasing the acidity of soils. This is a major
problem in the Northern hemisphere, but is not a significant
pollutant in Australia except in a few instances.
Atmospheric releases from oil and gas production activities are attracting
increasing interest from both industry operators and regulatory
authorities. Concerns focus on the contribution from industry sources to
Growth in Australia's emissions in the past few years has principally been
because of growth in the economy and population growth which have been
higher in Australia than the rest of the developed countries. Australia's
greenhouse gas emissions are about 1.5% of the annual global total, and
the underlying rate of growth of emissions annually is little more than
one per cent.
An inventory of greenhouse gas emissions from flaring, venting and fuel
consumption in the Australian exploration and production industry reveals
that approximately 50% of emissions are sourced from fuel consumed in the
machinery and equipment used to produce petroleum.
Oil and gas explorers and producers are actively identifying where, and
how much, greenhouse gas emissions are produced in their operations.
Efforts are being made across the industry to reduce these emissions
through measures that are technically and economically possible. Natural
gas is one of the cleanest fuels to use to produce heat and electricity
and its use is growing in Australia, replacing other energy sources. This
growth in gas use means that emission from gas explorers and producers are
likely to increase. The net effect for Australia is positive, as switching
to natural gas means less emissions overall.
Decommissioning of offshore production facilities has recently become a
topical issue. As a producing field reaches the end of its operational
life, several options are available for the removal and disposal of
redundant facilities. The extent to which offshore petroleum facilities
must be removed is determined by the responsible Government authority on
case by case basis. Although the responsibility for decommissioning lies
with the operators, government departments have a role in ensuring the
acceptability of any removal program. Under the guidelines developed by
the International Maritime Organisation (IMO) there are specific
requirements depending on the water depth, weight of structure and date of
construction. Various options are recognised for the removal and disposal
process: Complete removal requires that no debris remain above the mudline
at the platform site and the sea bed is returned to its natural state.
Partial removal is restricted to structures on which the entire base may
be left in place. The requirement under the IMO guidelines is to remove
all components of the structure to a minimum depth of 55 metres below the
surface to ensure safe navigation in the waters above.
In situ toppling is only feasible in deep water, where it does not pose a
hazard for navigation and fishing. Hazardous material and equipment which
can be reused is transported onshore. The platform is toppled using
explosives, or by underwater cutting of the supports.
Alternative uses : several alternatives for decommissioning exist
Artificial reefs : the facility may be placed as artificial reefs in
selected areas. Artificial reefs benefit the local ecology by creating
additional habitats, which will support marine organisms which
previously may not have been able to live there. Artificial reefs can
be formed through placement of toppled and partially removed
structures. A 'Rigs to reefs' program operates in the Gulf of Mexico,
where some 100 platforms have been converted to artificial reefs.
Marine research centres : this is an alternative where the facility
remains in place, and is used by universities and research
institutions for on site studies of the marine environment.
The guidelines issued by the IMO, combined with the Geneva Convention of
1958, the Law of the Sea of 1982 and the London Convention of 1972 provide
the major guidance when addressing decommissioning issues. The industry
believes that decommissioning options must have regard for a wide range of
relevant safety issues, environmental and cost considerations and the
interests of other users of the ocean. Each decommissioning case therefore
must be considered and decided on its own merits.
It is neither sensible nor practical to rule out offshore disposal of
installations until environmental impact and safety assessments have been
conducted for the range of options available to individual proposals. In
some instances the safest and most environmentally acceptable alternative
may be offshore disposal, with decisions being based on objective and
scientific evidence, and assessed on a case-by-case basis.
The petroleum industry's safety record of handling oil and its products in
Australia is excellent and has been maintained throughout the past two
decades, with increasing volumes being produced and transported in
Australian waters. Oil spills from offshore production have been
insignificant, and while there have been some spills arising from shipping
accidents, none have had lasting adverse effects on the marine
environment. In over 25 years of operation in Commonwealth waters, the
petroleum industry has produced nearly 4 billion barrels of oil and only
900 barrels of oil have been spilt (or about 0.00002%).
Statistics show that historically the petroleum industry is directly
responsible for a very small proportion of marine oil spills however, the
industry does not take the risk or consequences of spills lightly. There
are strict regulations and management arrangements governing all aspects
of exploration and production activities through to the delivery of
refined petroleum products. In addition to the introduction of more
rigorous inspections, standards, practices and safeguards on all
installations and tanker fleets, the industry has established one of the
best equipped marine oil spill response and training centres in the world.
If an oil spill does occur off Australia's coastline, the oil industry, in
association with government agencies, is well prepared to minimise
possible impacts on the environment.
A Marine and Estuarine Protected Area (MEPA) is a defined area identified
as environmentally significant and is designated by legislation for
protection. There are many objectives for which MEPA's may be established,
for example, protection of specific endangered species, breeding grounds
for migratory species or for the sustainable use of resources. The
industry supports the establishment of MEPA's for clearly defined
objectives that have been determined on scientific evidence. Protected
areas must be actively managed to be effective and achieve the objectives
for which they were established. A range of activities, such as oil and
gas exploration and production, fishing and tourism, may be permitted in
some of the protected areas subject to strict conditions that ensure the
management objectives of the MEPA can be achieved. This approach, often
called multiple use, represents an important pathway to ecologically
sustainable development. The petroleum industry is well aware of its
responsibility to protect and preserve the environment in which it
operates, wherever this may be - inside or outside a marine protected
area. The industry works closely with environmental agencies to ensure
that all interests are accommodated and protected.
The offshore continental shelf has the greatest potential for future
discoveries of oil and gas. Continuing access to the offshore region for
petroleum exploration and production is essential to maintain Australia's
energy reserves. Energy supply and the petroleum industry are critical to
the future performance of Australia's economy. The industry has
significant expertise, and an excellent record, in operating in the marine
environment and believes its activities are compatible with the objectives
of marine conservation and management, permitting economic development
that is sustainable in its environmental impacts.