“It’s clear that drilling the Bight is not a sensible proposition,” said Peter Owen, the South Australian director of the Wilderness Society, who was due in the Federal Court in March in an action against the approval of Equinor’s Stromlo-1 well by the federal regulator, National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA).
Today’s announcement that the company would abandon its controversial project as “not commercially competitive” compared with other exploration opportunities makes it the fourth major oil company to decide the huge challenges of the project were just too great to make any project viable.
When you consider the scale of the task involved, combined with oil market jitters on the back of an 11 per cent drop in oil exports by global leader Saudi Arabia last year, it is not hard to see why.
Drilling slap-bang in the middle of the Bight – 476 kilometres west of Port Lincoln and 400 kilometres
southwest of Ceduna – Stromlo-1
well would have taken a familiar operational path.
That begins with a Mobile Offshore Drilling Unit, held
in place by eight massive thruster propellers controlled by gyroscopes reacting
to GPS signals and data from transponders placed on the seabed.
guide the drill string through 2240 meters of water to the seabed where it
slopes away from the continental shelf.
In the case of Stromlo-1, that would still have been
less than halfway to its target – with drilling using progressively narrower and
narrower casings destined to travel a further 2700 meters beneath the seabed.
That’s challenging even by the gargantuan scale of
To put it in perspective, BP’s ill-fated Deepwater Horizon well in its Macondo
Prospect in the Gulf of Mexico was just 66 kilometres off the coast of
Louisiana, at a water depth of only 1500 metres.
“They are extremely
difficult drilling conditions both in terms of depth and of the environment,” says Sheik Rahman, a professor in Petroleum
Engineering at UNSW in Sydney who, after graduating from Strathclyde
University, cut his teeth in the industry during the heyday of North Sea
“It was always going
to be tough.”
The irony is that Equinor, then known as Statoil, has
already been part of a consortium with BP that in October 2016 dumped plans to
drill in the Bight. The reason? Better prospects elsewhere given the
engineering challenges and vocal opposition, the same as Equinor’s conclusions.
If anything good has come out of these rolling
explorations and withdrawals it is the unprecedented knowledge we have gained of the
complex and unique ecosystems of the region through the Great Australian Bight
Research Program, which ran from 2013 to 2017.
The four-year, $20 million social, environmental and
economic study brought together multi-disciplinary research teams comprising
more than 100 scientists and technical staff and was a collaborative program
involving BP (Equinor’s previous partner in
oil exploration in the region), the CSIRO, the South Australian Research and
Development Institute (SARDI), the University of Adelaide,
In the words of the report it generated, the research
program “transformed the deep ecosystems of the Great
Australian Bight from one of Australia’s least studied environments to one of the most
well-known” and formed the
knowledge base on which Equinor relied for its environmental protection plan.
It found that more than 85 per cent of known species
in the region are found nowhere else in the world.
The Bight provides critical habitats and migration
pathways for iconic species and apex predators such as Australian sea lions,
white sharks and pygmy blue whales. It contains Australia’s largest and most valuable stocks of fish in the open
sea, especially Australian sardine and southern bluefin tuna, as well as
important coastal fisheries.
But the study also noted that the Bight could be one
of the world’s most high-potential areas for oil and gas, if one of the most
under-explored regions in the world. Equinor’s latest decision should meet it
stays that way, says Owen.
“Opening up a new high-risk frontier oil field when we
are hurtling towards catastrophic climate change is madness. We are now calling
on the Australian Government to listen to the people and permanently protect
the unique waters of the Great Australian Bight from drilling for good,” he
Ironically, the dubious economic value of the venture
has always been one of the arguments it has used against drilling. That, set
against the risk of environmental devastation from oil and gas drilling makes a
permanent ban on operations in a region a no-brainer.
At the forefront of concerns has always been an oil
spill, which could do untold damage not just to the Bight but but across
From an engineering perspective, the critical
infrastructure safeguarding against that is construction of the wellhead – the structure stabilising the steel-lined top hole of
the well, which goes down some 100 metres and is sealed into place with cement.
This is topped by a blowout preventer (BOP) – a 400-tonne mechanical valve through which the drill
pipe passes and seals the bore if necessary.
The failure of just a similar concrete casing and BOP
was the central cause of the Deepwater Horizon disaster that resulted in an
explosion and oil spill that killed 11 crew members and took 87 days to get
But Equinor has always said that the risk of a major
oil spill for Stromlo-1 is extremely low.
“Major oil spills are
extremely rare,” it noted
in its environmental plan. “In approximately 59,000 offshore wells drilled around
the world since 1980, there have been two major oil spill incidents – the Macondo spill in the Gulf of Mexico in 2010 and
the Montara spill in the Timor Sea in 2009.
“Our experience in
drilling in deep offshore waters and in very rough seas, coupled with several
additional safety barriers including sound well design and the use of
technology will enable us to drill the well safely.”
Professor Rahman, who took part in the enquiry into
the causes of the Montana spill, offers a cautionary note.
technology of oil exploration is very advanced, very sophisticated,” he says. “But because we are human beings, there is always the
chance for mistakes to be made.”
Opponents have also been wary of statistics. They say
one spill, no matter how unlikely, would be so unimaginably catastrophic as to
make the risk unacceptable.
“The Bight carries
massive risks because it is so remote, so rough, so deep and right in the
middle of the Great Australian Bight Marine Park,” says Owen. “Deepwater Horizon, by comparison, was in the middle of
one of the most established industrial precincts on the planet and it still
took them three months to shut that down.”
No one is disputing a spill would be a disaster of
Equinor’s own modelling
showed the potential to affect a vast area from Albany in Western Australia to
Port Macquarie in NSW, although it is at pains to qualify this as not
representative of the area a single spill would affect but the combination of
100 different extremely unlikely worst-case scenarios.
Nevertheless a “worst credible case
discharge” scenario of between
4.3 million barrels and 7.9 million could deliver more than 10 grams of oil per
square metre on some of Australia’s most famous
beaches, and devastate South Australian fisheries and tourism putting at least
9000 jobs at risk, quite apart from the impact on wildlife.
With little physical infrastructure nearby to respond
to any oil spill, perhaps the gravest risk is posed by the remote geographic
location itself. Should the BOP fail, the next weapon in the arsenal would be a
capping stack – a 100-tonne device
that is mounted over a leaking wellhead. The nearest available is in Singapore
and would take up to 15 days to arrive in the Bight. If that doesn’t work, the next step would be to drill a relief well,
but a second rig would take up to 88 days to arrive from the North West Shelf – one day longer than the time it took to get Deepwater
Horizon under control.
While an oil spill is the nightmare scenario, many
scientists are concerned about smaller impacts from drilling even if nothing
goes wrong, with noise a major culprit. And a lot of that damage would be done
through the geophysical surveys that take place long before drilling even
The surveys capture images of the geology up to 10
kilometres below the seabed. Surveys with the biggest impact on wildlife are
carried out using air guns which generate sound in the frequency range of 10 to
“So it’s a big impulse,” says Associate Professor Robert McCauley of Curtin
University, who has studied the effect of this noise through experiments with
plankton, scallops, lobster, squid, fish, sea turtles and humpback whales.
“To generate that
impulse they use a metal tube filled with high pressure air equivalent to 2000
scuba type pressures – instantly released into the water. The air rushes out
and that outrush of air produces a positive impulse.”
A typical grid might be made up of 40 air gun tubes,
five to 10 meters below the surface over 20 square metres. These operate along
a line firing a pulse every 10 to 20 seconds – or even down to five or six seconds in some instances.
“They’ll just go bang, bang, bang, and they’ll do that for an entire seismic survey line, which
could be upwards of 50 or 60 kilometres,” says McCauley.
But it is not the sound itself that is of such
concern, but the way it is generated. The outgoing air from the gun produces a
positive impulse as the air comes out. But in addition to the downward energy,
there is also a reflection off the sea surface. The soundwaves from that bounce
downwards, travelling just a few milliseconds after the primary pulse as a
“So you get a massive
positive increase, and then a massive drop to a negative pressure – and this is where the damage accrues, because it
produces a jerk to a small animal,” says McCauley.
“If you imagine a
bubble being hit. If you just got hit by the positive pressure, the bubble
would compress and most bubbles – and tissues can compress quite well. But then if you
then get hit by a negative pressure, they can quite literally explode.
“And similar things
happen with body tissues, they get hammered. They get driven one way and then
rapidly driven the other way.”
If the one-two punch impulses don’t kill small animals such as squid, lobster and fish
outright, they can destroy their sensory systems, which increases mortality in
the longer term.
And while larger animals, such as whales, may be
unaffected by the impulses themselves there are less direct and longer-term
effects that could make their mark.
“We did experiments
with plankton and got some startling results that looked like the smaller
plankton were killed out to a kilometre from a single airgun,” says McCauley.
“This has been quite
contentious, but I’ll stand by it. And
we’re hoping to do some
more of that work in the next month. And that’s a worrying thing because if you don’t have plankton, you don’t have anything else.”
With such negatives stacked against it, the risk of a
catastrophic oil spill, and the huge investment required to search for oil in
such difficult conditions in a market where pressure on the price of oil
appears to be on a downward trend, some have wondered why Equinor is bothering
at all and doesn’t follow other
companies, such as its former partner BP, to the exits, especially in the face
of such widespread opposition.
“Recent polling shows
that the majority of Australians and over 70 per cent of South Australians
oppose drilling in the Bight,” says
“There are fossil fuel precincts already in the country, such as the North West Shelf. So why would you be pushing to expand the industry into a pristine marine wilderness?”
For now, it seems, we have an answer.
Bill Condie has been a journalist for more than 30 years, working as a writer and editor in Europe, Asia and Australia for newspapers including The Guardian, The Observer and The Times. He is a former publisher of Cosmos magazine.
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