Question One
Q. What are the oil sands?
A: The oil sands are very different from conventional oil and natural gas deposits. In
conventional deposits, oil and gas are trapped in porous rocks. Drilling into the
porous rock releases the oil and gas which then can be pumped to the surface. Or, in
some cases, no pumping is necessary where conventional fields are under pressure
and oil and gas can be collected at the surface.
Unlike conventional oil, the oil sands are a mixture of bitumen, sand, water and clay.
If you were to look at oil sands under a microscope you would see that each grain of
sand is surrounded by a thin envelope of water. This water also contains extremely
fine particles of clay and other trace materials. The bitumen, a particularly thick and
tar-like hydrocarbon, surrounds the sand and water. The major challenge in
developing oil sands is separating the bitumen from the sand, water and clay. Once
separated, bitumen can then be upgraded into a high-quality oil called "synthetic
crude," but not until all the sand, water, clay and carbon have been removed.
Question Two
Q: Where are the oil sands located?
A: Oil sands and oil shale deposits are found all over the world. In fact, there are 16
major oil sands deposits that have been found by geologists world-wide. The two
largest are the Athabasca Oil Sands in northern Alberta and the Orinoco River
deposit in Venezuela. The Athabasca Oil Sands is just one of several deposits found
in Canada. There is a major oil sands deposit on Melville Island in the Canadian
Arctic and three other smaller deposits in northern Alberta: the Peace River,
Wabasca and Cold Lake deposits. In total, the Athabasca Oil Sands alone cover an
area of more than 42,000 square kilometres!
No two oil sands deposits are exactly alike and each presents its own specific challenges
in separating the oil from sand and other materials. Problems include climatic conditions,
remote locations, environmental concerns, and the costs of producing oil.
Question Three
Q: How much oil does Alberta's oil sands contain?
A: The four major oil sands deposits in Alberta contain more than 1.7 trillion barrels
of bitumen. Using current technology this could potentially be turned into over 1
trillion barrels of synthetic crude oil, although much of the bitumen probably cannot
be recovered at a reasonable cost (with current technology only 300 billion barrels
are recoverable). The Athabasca Oil Sands is the largest of these oil sands deposits.
It contains over one trillion barrels of bitumen on its own, although only about 300
billion barrels of bitumen can be recovered using current methods of mining. There
are other large oil sands deposits in Canada as well, most notably a large deposit on
Melville Island in the Canadian Arctic. It is Canada's next largest oil sands deposit
after the Athabasca Oil Sands. It has the potential to produce about 500 million
barrels of crude oil.
By comparison, Alberta's conventional oil reserves are currently estimated at about
4.5 billion barrels of oil. Put another way, the Athabasca Oil Sands contain more oil
than all the known reserves in Saudi Arabia. Clearly Alberta's oil sands hold the key
to the long term production of oil and oil products in Alberta, and as time goes by
more and more of Canada's oil needs will have to be met by Alberta's oil sands
deposits.
Question Four
Q: Where does oil come from?
A: The oil in the Athabasca Oil Sands was almost certainly formed somewhere else.
The oil then migrated into a vast sand reservoir. This sand, that was once part of a
huge river delta and the shores of an ocean, acted like a giant sponge soaking up the
oil and holding it in place. There would be no oil sands if it were not for the fortunate
combination of a sand reservoir and migrating oil.
There is considerable debate among scientists about how exactly oil is formed. We
do know that oil, like other hydrocarbons such as natural gas, coal and peat, was
originally organic. This means that it slowly formed over millions of years from plant
and animal matter. Most scientists believe that oil is formed when plants and animals
died and sank to the bottom of ancient seas. They were gradually covered by
sediments which hardened into rock. Beneath the rock, organic material slowly
decomposed under conditions of heat and pressure. Some believe that heat,
pressure, time and a lack of oxygen alone are enough to produce oil from organic
material. Other scientists believe bacteria, chemical reactions and even the natural
radioactivity of the earth may also play a role in creating this very specific form of
hydrocarbon.
Question Five
Q: What is bitumen?
A: Bitumen has been described as hydrogen-deficient oil. In order to be used,
bitumen needs to be upgraded by either removing most of the carbon, a process
known as "coking," or adding hydrogen, a process known as "hydrogenation" or
"hydrocracking." This has to be done because bitumen contains extremely large
hydrocarbon molecules. The natural gas you burn in your furnace or stove consists of
one or two carbon atoms surrounded by 4 to 6 hydrogen atoms. These natural gases
are known as methane and ethane.
The gasoline you use in your car is mostly octane: a chain of 8 carbon atoms
surrounded by 18 hydrogen atoms. Diesel oil can consist of a chain of 20 to 30
carbon atoms and up to 62 hydrogen atoms.
The longer the carbon chain the higher the temperature at which it boils, the harder
it is to get it to burn, and the thicker or more "viscous" the oil. Bitumen is often
composed of molecules containing as many as 2000 carbon atoms! As a result it is
almost impossible to get it to burn, it will not boil, and it is extremely thick and tarry.
It is often described as similar to cold molasses in consistency. In its natural state it
cannot be refined into useful products such as diesel oil or gasoline or natural gas.
To do this the long chain molecules have to be split into smaller pieces by taking
carbon out and adding hydrogen to the resulting synthetic oil.
Question Six
Q: How do you get bitumen out of the oil sands?
A: The amount of bitumen in Alberta's oil sands varies from deposit to deposit and
even within deposits. Overall the Athabasca Oil Sands average about 10% bitumen
by volume, but in some places the bitumen content can be as high as 18% or as low
as 1%. This means that even with the richest oil sands more than 80% of the
material mined has to be removed somehow.
The basic method used to separate bitumen from the water, sand and clay that make
up the rest of the oil sands, is a process called hot water extraction. This process
involves mixing oil sands with hot water, steam and caustic soda that help to
separate bitumen from the sand. Most of the bitumen rises to the top of the hot
water as froth that can be collected for further processing. Huge centrifuges, that
work much like cream separators, and inclined plate separators take the froth and
separate it again into water and bitumen. Other secondary processes further clean
and separate the bitumen, sand and water. When extraction is complete about 98%
of the bitumen is removed from the original oil sands material. The cleaned sand can
be used to help reclaim land at the mine site. Much of the water is recycled or sent
to tailings ponds. The water in these tailings ponds includes clay and other
suspended materials which slowly precipitate out.
Question Seven
Q: What products are made from oil from oil sands?
A: The bitumen collected from the oil sands is upgraded in Fort McMurray to produce
a number of raw materials. For example, sulphur is removed from the bitumen
before it is turned into synthetic crude oil. Some of this sulphur is processed in plants
located at Fort Saskatchewan, Alberta into fertilizers for agricultural use. Sulphur is
also used in the production of some steel. Some people also believe that trace
metals found in the bitumen can be collected and sold for manufacture into
consumer products. The main product made from bitumen, however, is synthetic
crude oil. This oil is real, but it is called "synthetic" crude because the molecular
structure has been changed - it has been altered from its naturally occurring state.
Synthetic crude oil is shipped by pipeline to refineries in Edmonton and Fort
Saskatchewan in Alberta and further east to refineries in Sarnia, Ontario and other
centres. In these refineries it is turned into many consumer goods and further raw
materials. Because most of the sulphur has already been removed, synthetic crude is
a high grade oil. It is often used to produce aviation fuel because it burns very
cleanly. It can also be used to make gasoline, diesel fuel, lubricating oils and other
such products. However, oil is not just used for heating houses and running cars.
There are literally tens of thousands of products that are made in whole, or in part,
from oil and oil by-products. There are very few items in a modern Canadian
household that are not connected in some way to the petrochemical industry. If it is
made from plastic or synthetic rubber, or if it is painted or dyed, it contains
petroleum by-products. Most solvents and detergents are also petrochemicals. Any
food you eat that was grown using fertilizers, and many of the clothes you wear, if
they are not made from cotton or linen or leather, are also dependent on the
petrochemical industry.
Question Eight
Q: Who discovered the oil sands?
A: Oil and gas in underground deposits have to be discovered using methods like
seismic exploration and drilling. Oil sands deposits are usually more obvious. A
sizable part of the Athabasca Oil Sands, for example, lie right at the surface, and
they have been known for as long as there have been people in the area. The first
written reference to Alberta's oil sands may date as far back as 1719 when a
Chipewyan trader named Wa-pu-su or Captain Swan, brought a sample of "pitch," an
old term for tar or asphalt, to York Factory, a Hudson's Bay Company post on
Hudson Bay. In 1778, the North West Company trader, Peter Pond also made clear
reference to the Athabasca Oil Sands, as did Sir Alexander Mackenzie in the 1790s.
Mackenzie indicated that Aboriginal people used the tarry bitumen to gum the seams
of their canoes.
In the 1870s and 1880s a number of scientists, including John Macoun and Robert
Bell of the Geological Survey of Canada, surveyed the Athabasca Oil Sands and
attempted to assess their potential for development. It was these early surveys that
really alerted Canadians to the potential value of this natural resource.
The first commercially successful oil sands plant was in 1967 when Great Canadian
Oil Sands first produced synthetic crude oil. "G.C.O.S." was the forerunner of Suncor
Energy, Oil Sands.
Question Nine
Q: How are the oil sands mined and what is done after mining is complete?
A: To understand how mining works it is necessary to know the geology of the Fort
McMurray area. Portions of the oil sands are found on the surface, especially in the
valley of the Athabasca River where the river has worn away surface rock and gravel.
Most of the oil sands, however, are buried under sand, gravel, and rock, called
overburden, and in some places up to 16 metres of muskeg or swamp. The amount
of overburden varies, but generally it increases the further you get away from the
Athabasca and Clearwater River valleys. The oil sands themselves lie in a band, often
50 metres deep, below the overburden and above a layer of limestone bedrock.
Companies have to remove the muskeg and overburden to expose the layer of oil
sands. Then draglines, trucks, shovels and other heavy equipment remove the oil
sands and take it away to the extraction and upgrading plants for processing. This is
called open pit mining. Eventually, as mining operations move into new areas, earlier
parts of the old mine have to be reclaimed. Reclamation is intended to return the
mined area to a natural state which can be producible. Oil sands companies are
continually doing research on how to reclaim land and how to retain a varied
landscape with mixed forests, grasslands, wetlands and lakes. It would be easier to
simply create one type of landscape, but this would not allow different plants and
animal species to reestablish themselves on reclaimed land.
Reclamation is a big job. Since 1979, Syncrude alone has replanted about 1,500,000
trees on about 2,300 hectares of land. In one interesting project, Syncrude has
reintroduced wood bison to the Fort McMurray area, more than a century after the
last bison disappeared from this part of Alberta.
New technology: Mine ore is pumped into crushers or sizing plants, processed
through horizontal slow-speed breakers to separate lumps of 2 inches or more.
Warm water is added to form the mixture that is then pumped (hydro-transported)
to the extraction plant. Partial separation actually starts in the pipe as the oil travels
long distances to the separation vessels.
Question Ten
Q: When do you use "in-situ" production and when does it make more sense
to mine oil sands?
A: Using current technology and at today's oil prices, only about 10-20% of the
Athabasca Oil Sands can be mined. Mining only makes economic and engineering
sense when the overburden is less than about 75 metres thick. Ideally, companies
look for areas with less overburden since removing overburden and then reclaiming
the land adds considerably to the cost of mining oil sands. As a result development
of the remaining 80-90% of the Athabasca Oil Sands and all of the Cold Lake, Peace
River and Wabasca deposits depends on something called "in-situ," meaning in-place
production. There are many different techniques which have been developed for "in
situ" production, but all of them really depend on using energy to produce energy. In
order to begin to separate the bitumen from the sand, and then to make the bitumen
liquid enough to pump, oil sands deposits have to be heated in some way. Although
many methods of in-situ production have been suggested, the two techniques that
have been proven to work on a commercial scale are fireflooding and various
methods of steam injection.
The simplest form of steam injection involves drilling two parallel wells. One well is
used to get high pressure steam into the oil sands. Like fireflooding, this begins the
separation of the bitumen from the sand and lowers the viscosity of the bitumen
enough that it can be collected from a second well. This method has a recovery rate
of about 30% of the bitumen in the formation.
Recently, however, a variation on this technique has been developed which greatly
improves recovery and lowers the cost of production. This method of in-situ
production is called Steam Assisted Gravity Drainage, or SAGD. It involves drilling
two horizontal wells one above the other. The top well is used to introduce steam
into the oil sands. As the bitumen thins and separates, gravity causes it to collect in
the second parallel well where it can be pumped to the surface for further
processing. SAGD significantly improves bitumen recovery rates and therefore lowers
costs of production. In time it may prove the most successful of the in-situ
production methods developed to date.