This document summarizes various fossil fuels and their formation. It discusses oil and natural gas deposits, how they are formed, and supply and demand issues. Specifically, it notes that while over 1 trillion barrels of oil have been consumed, estimated remaining reserves are only about 1.2 trillion barrels. For natural gas, global demand is expected to increase significantly as nations adopt cleaner fuels. The document also briefly outlines coal, oil shale, tar sands, and potential alternate natural gas sources like methane hydrates.

1. Energy Resources
Fossil Fuels
Supervisor: PhD. Bùi Trọng Vinh
By: Kiều Nhật Nam

2. Contents
I. Introduction
II. Oil and Natural Gas
III. Coal
IV. Oil shale
V. Tar sand

3. Introduction

4. Introduction
The fossil fuels are those energy sources that formed from the remains of
once-living organisms. When we burn them, we are using that stored energy
( Energy is stored in the chemical bonds of the organic compounds of living
organisms )

5. Oil and Natural Gas
1. Formation of Oil and Natural Gas Deposits
2. Supply and Demand for Oil and Natural Gas
3. Future Prospects
4. Enhanced Oil Recovery
5. Alternate Natural Gas Sources
6. Oil Spill

6. Oil and Natural Gas
1/ Formation of Oil and Natural Gas Deposits

7. Oil and Natural Gas
Commercially, the most valuable deposits are those in which a large quantity of oil and/or gas has been
concentrated and confined (trapped) by impermeable rocks in geologic structures. The reservoir rocks in
which the oil or gas has accumulated should be relatively porous if a large quantity of petroleum is to be
found in a small volume of rock and should also be relatively permeable so that the oil or gas flows out readily
once a well is drilled into the reservoir. If the reservoir rocks are not naturally very permeable, it may be
possible to fracture them artificially with explosives or with water or gas under high pressure to increase the
rate at which oil or gas flows through them.

8. Oil and Natural Gas
The amount of time required for oil and gas to form is not known precisely. Since virtually no
petroleum is found in rocks younger than 1 to 2 million years old, geologists infer that the
process is comparatively slow. Even if it took only a few tens of thousands of years (a
geologically short period), the world’s oil and gas is being used up far faster than significant
new supplies could be produced. Therefore, oil and natural gas are among the
nonrenewable energy sources. We have an essentially finite supply with which to work.

9. Oil and Natural Gas
2/ Supply and Demand for Oil and Natural Gas
* Oil:
Oil is commonly discussed in units of
barrels (1 barrel = 5.42 gallons ~ 20.52
liter). Worldwide, over one trillion
barrels of oil have been consumed,
according to estimates by the U.S.
Geological Survey. The estimated
remaining reserves are about 1.2
trillion barrels. That does not sound too
ominous until one realizes that close to
half of the consumption has occurred
in the last quarter-century or so. Also,
global demand continues to increase
as more countries advance
technologically.

10. Oil and Natural Gas
Oil supply and demand are
very unevenly distributed
around the world. Some
low population, low-technology,
oil-rich
countries (Libya, for
example) maybe
producing fifty or a
hundred times as much oil
as they themselves
consume.
At the other extreme are
countries like Japan,
highly industrialized and
energy-hungry, with no
petroleum reserves at all.

11. Oil and Natural Gas
Both U.S. and world oil supplies could be nearly exhausted within decades ,
especially considering the probable acceleration of world energy demands. On
occasion, explorationists do find the rare, very large concentrations of petroleum
Yet even these make only a modest difference in the long-term picture. The
Prudhoe Bay oil field, for instance, represented reserves of only about 13 billion
barrels, a great deal for a single region, but less than two years’ worth of U.S.
consumption.

12. Oil and Natural Gas
Concern about dependence on imported oil led to the establishment of the
Strategic Petroleum Reserve in 1977, but the amount of oil in the SPR
stayed at about 550 million barrels from 1980 to 2000, while the number of
days’ worth of imports that it represents has declined from a high of 115 in
1985 to 50 in 2002. Only renewed addition of imported oil, to raise SPR
stocks to about 697 million barrels in 2007, reversed the decline in the
number of days of imports held in the SPR, but that figure was still only 58
in 2008. Such facts increase pressure to develop new domestic oil sources

13. Natural Gas:
Global demand for natural gas is
expected to expand significantly as
more nations adopt environmentally
cleaner fuels to meet future
economic growth and prioritize
alternatives to minimize the impact
of increasing oil – based energy
costs. The environmental benefits of
natural gas are clear. Natural gas
emits 43% fewer carbon emissions
than coal, and 30% fewer emissions
than oil, for each unit of energy
delivered. Many of the most rapidly
growing gas markets are in emerging
economies in Asia, particularly India
and China, the Middle East and
South America, economies which
battle the balance between air quality
and living standards on a daily basis.
Oil and Natural Gas

14. Oil and Natural Gas
3/ Future Prospects
Some such areas are now being explored, but with limited success. Other, more promising areas may be
protected or environmentally sensitive. The costs of exploration have gone up, drilling for oil or gas in 2006
cost an average of $324 per foot. The average oil or natural gas well drilled was over 6400 feet deep (it was
about 3600 feet in 1949); even with increasingly sophisticated methods of exploration to target areas most
likely to yield economic hydrocarbon deposits. Costs for drilling offshore are substantially higher than for
land-based drilling. Yield from producing wells is also declining, from a peak average of 18.6 barrels of oil
per well per day in 1972 to 10.2 barrels in 2007.

15. Oil and Natural Gas
Despite a quadrupling in oil prices between 1970 and 1980 (after adjustment for
inflation), U.S. proven reserves continued to decline. They are declining still,
despite oil prices recently at record levels. This is further evidence that higher
prices do not automatically lead to proportionate, or even appreciable, increases in
fuel supplies. Also, many major oil companies have been branching out into other
energy sources beyond oil and natural gas, suggesting an expectation of a shift
away from petroleum in the future.

16. Oil and Natural Gas
4/ Enhanced Oil Recovery
A few techniques are being developed to increase petroleum production from known deposits.
An oil well initially yields its oil with minimal pumping, or even “gushes” on its own, because the
oil and any associated gas are under pressure from overlying rocks, or perhaps because the
oil is confined like water in an artesian system. Recovery using no techniques beyond pumping
is primary recovery. When flow falls off, water may be pumped into the reservoir, filling empty
pores and buoying up more oil to the well (secondary recovery). Primary and secondary
recovery together extract an average of one-third of the oil in a given trap

17. Oil and Natural Gas
On average, then, two-thirds of the oil in each deposit has historically been left in the ground.
Thus, additional enhanced recovery methods have attracted much interest.
Enhanced recovery comprises a variety of methods beyond conventional secondary
recovery. Permeability of rocks may be increased by deliberate fracturing, using explosives
or even water under very high pressure. Carbon dioxide gas under pressure can be used to
force out more oil. Hot water or steam may be pumped underground to warm thick, viscous
oils so that they flow more easily and can be extracted more completely.
There have also been experiments using detergents or other substances to break up the oil.

18. Oil and Natural Gas

19. Oil and Natural Gas
However, be kept in mind that enhanced recovery may involve increases in
problems such as ground subsidence or groundwater pollution that arise also with
conventional recovery methods. Even conventional drilling uses large volumes of
drilling mud to cool and lubricate the drill bits. The drilling muds may become
contaminated with oil and must be handled carefully to avoid polluting surface or
ground water. When water is more extensively used in fracturing rock or warming
the oil, the potential for pollution is correspondingly greater.

20. Oil and Natural Gas
5/ Alternate Natural Gas Sources:
During coal formation, quantities of methane-rich gas are also produced. Most coal deposits contain
significant amounts of coal-bed methane . Historically, this methane has been treated as a hazardous
nuisance, potentially explosive, and its incidental release during coal mining has contributed to rising
methane concentrations in the atmosphere. However, an estimated 100 trillion cubic feet of methane that
would be economically recoverable with current technology exists in-place in U.S. coal beds. If it could
be extracted for use rather than wasted, it could contribute significantly to U.S. gas reserves.

21. Oil and Natural Gas
Some evidence suggests that additional natural gas reserves exist at very great depths in the earth. Thousands
of meters below the surface, conditions are sufficiently hot that any oil would have been broken down to
natural gas. This natural gas, under the tremendous pressures exerted by the overlying rock, may be dissolved
in the water filling the pore spaces in the rock, much as carbon dioxide is dissolved in a bottle of soda.
Pumping this water to the surface is like taking off the bottle cap: The pressure is released, and the gas
bubbles out. Enormous quantities of natural gas might exist in such geopressurized zones ; recent estimates
of the amount of potentially recoverable gas in this form range from 150 to 2000 trillion cubic feet.

22. Oil and Natural Gas
Still more recently, the significance of methane hydrates has been increasingly discussed.
Gas (usually methane) hydrates are crystalline solids of gas and water molecules. These
hydrates have been found to be abundant in arctic regions and in marine sediments. The U.S.
Geological Survey has estimated that the amount of carbon found in gas hydrates may be
twice that in all known fossil fuels on earth, and a 2008 study suggested a probable 85 trillion
cubic feet of (yet-undiscovered) methane in gas hydrates of Alaska’s North Slope alone.
Methane in methane hydrate thus represents a huge potential natural gas resource. Just how
to tap methane hydrates safely for their energy is not yet clear.

23. Oil and Natural Gas
6/ Oil spills:
Most oils and all natural gases are less dense than water, so they tend to rise as well as to migrate laterally
through the water-filled pores of permeable rocks. Unless stopped by impermeable rocks, oil and gas may
keep rising right up to the earth’s surface. At many known oil and gas seeps, these substances escape into the
air or the oceans or flow out onto the ground. These natural seeps, which are one of nature’s own pollution
sources, are not very efficient sources of hydrocarbons for fuel if compared with present drilling and extraction
processes.

24. Oil and Natural Gas
In fact, it is estimated that oil rising up through permeable rocks escapes into the
ocean at the rate of 600,000 tons per year, though many natural seeps seal
themselves as leakage decreases remaining pressure. Tankers that flush out their
holds at sea continually add to the oil pollution of the oceans and, collectively, are a
significant source of such pollution. The oil spills about which most people have
been concerned, however, are the large, sudden, catastrophic spills that occur in
two principal ways: from accidents during drilling of offshore oil wells and from
wrecks of oil tankers at sea.

25. Oil and Natural Gas
Oil spills represent the largest negative impacts from the extraction and
transportation of petroleum, although as a source of water pollution, they are
less significant volumetrically than petroleum pollution from careless disposal of
used oil, amounting to only about 5% of petroleum released into the
environment. And although we tend to hear only about the occasional massive,
disastrous spill, there are many more that go unreported in the media: The U.S.
Coast Guard reports about 10,000 spills in and around U.S. waters each year,
totaling 15 to 25 million gallons of oil annually.

26. Oil and Natural Gas
Exxon Valdez oil spill:
The Exxon Valdez oil spill occurred in Prince William Sound, Alaska, on
March 24, 1989, when Exxon Valdez, an oil tanker bound for Long Beach,
California, struck Prince William Sound's Bligh Reef . More than 10 million
gallons of oil escaped, eventually to spread over more than 900 square miles
of water. The various cleanup efforts cost Exxon an estimated $2.5 billion
(the worst oil spill yet in U.S. waters).

27. Oil and Natural Gas
• Skimmers recovered relatively little of the oil, as is typical: Three weeks after the
accident, only about 5% of the oil had been recovered. Chemical dispersants were
not very successful (perhaps because their use was delayed by concerns over their
impact on the environment), nor were attempts to burn the spill. Four days after the
accident, the oil had emulsified by interaction with the water into a thick, mousse-like
substance, difficult to handle, too thick to skim, impossible to break up or burn
effectively

28. Oil and Natural Gas
• Oil that had washed up on shore had coated many miles of beaches and rocky coast
Thousands of birds and marine mammals died or were sickened by the oil. The
annual herring season in Valdez was cancelled, and salmon hatcheries were
threatened. When other methods failed, it seemed that only slow degradation over
time would get rid of the oil. Given the size of the spill and the cold Alaskan
temperatures, prospects seemed grim; microorganisms that might assist in the
breakdown grow and multiply slowly in the cold. It appeared highly likely that the
spill would be very persistent.

29. Oil and Natural Gas
• So, in a $10-million experiment, Exxon scientists sprayed miles of beaches in
the Sound with a fertilizer solution designed to stimulate the growth of
naturally occurring microorganisms that are known to “eat” oil, thereby
contributing to its decomposition. Within two weeks, treated beaches were
markedly cleaner than untreated ones. Five months later, the treated beaches
still showed higher levels of those microorganisms than did untreated beaches.
This type of treatment isn’t universally successful. The fertilizer solution runs
off rocky shores, so this treatment won’t work on rocky stretches of the oil
contaminated coast; nor is it as effective once the oil has seeped deep into
beach sands. But microorganisms may indeed be the future treatment of
choice.

30. Oil and Natural Gas
• In 2006, a study done by the National Marine Fisheries Service in
Juneau found that about 9.6 kilometres of shoreline around Prince
William Sound was still affected by the spill, with 101.6 tonnes of
oil remaining in the area. Exxon Mobil denied any concerns over
any remaining oil, stating that they anticipated a remaining fraction
that they assert will not cause any long-term ecological impacts,
according to the conclusions of the studies they had done: "We've
done 350 peer-reviewed studies of Prince William Sound, and those
studies conclude that Prince William Sound has recovered, it's
healthy and it's thriving. However, in 2007 a NOAA study
concluded that this contamination can produce chronic low-level
exposure, discourage subsistence where the contamination is heavy,
and decrease the "wilderness character" of the area.

31. Coal
1. Formation of Coal Deposits
2. Coal Reserves and Resources
3. Limitations on Coal Use
4. Environmental Impacts of Coal Use

32. Coal
1/ Formation of Coal Deposits:

33. Coal
The first combustible product formed under suitable conditions is peat. Further burial, with
more heat, pressure, and time, gradually dehydrates the organic matter and transforms the
spongy peat into soft brown coal (lignite) and then to the harder coals (bituminous/anthracite)

34. Coal
2/ Coal Reserves and Resources
The estimated world reserve of coal is about
one trillion tons; total resources are estimated
at over 10 trillion tons. The United States is
particularly well supplied with coal, possessing
about 25% of the world’s reserves, over 270
billion tons of recoverable coal. Total U.S. coal
resources may approach ten times that
amount, and most of that coal is yet unused
and unmined. At present, coal provides
between 20 and 25% of the energy used in the
United States. While the United States has
consumed probably half of its total petroleum
resources, it has used up only a few percent of
its coal. Even if only the reserves are counted,
the U.S. coal supply could satisfy U.S. energy
needs for more than 200 years at current
levels of energy use, if coal could be used for
all purposes.

35. Coal
3/ Limitations on Coal Use
A primary limitation of coal use is that solid coal is simply not as versatile a substance as petroleum
or natural gas. A major shortcoming is that it cannot be used directly in most forms of modern
transportation. Coal is also a dirty and inconvenient fuel for home heating, which is why it was
abandoned in favor of oil or natural gas. Therefore, given present technology, coal simply cannot be
adopted as a substitute for oil in all applications.

36. Coal
Coal can be converted to liquid or gaseous hydrocarbon fuels by causing the coal to react
with steam or with hydrogen gas at high temperatures. The conversion processes are called
gasification (when the product is gaseous) and liquefaction (when the product is liquid fuel).
Both processes are intended to transform coal into a cleaner burning, more versatile fuel,
thus expanding its range of possible applications.

37. Coal
Commercial coal gasification has existed on some scale for 150 years. Current gasification processes
yield a gas that is a mixture of carbon monoxide and hydrogen with a little methane. The heat derived
from burning this mix is only 15 to 30% of what can be obtained from burning an equivalent volume of
natural gas. Because the low heat value makes it uneconomic to transport this gas over long distances, it
is typically burned only where produced. Technology exists to produce high-quality gas from coal,
equivalent in heat content to natural gas, but it is presently uneconomical when compared to natural gas.

38. Coal
Pilot projects are also underway to study in situ underground coal gasification, through which coal
would be gasified in place and the gas extracted directly. The expected environmental benefits of not
actually mining the coal include reduced land disturbance, water use, air pollution, and solid waste
produced at the surface. Potential drawbacks include possible groundwater pollution and surface
subsidence over gasified coal beds. Underground gasification may provide a means of using coals that
are too thin to mine economically or that would require excessive land disruption to extract. However,
in the near future, simple extraction of coal-bed methane is likely to yield economical gas more readily.

39. Coal

40. Coal
Like gasification, the practice of generating liquid fuel from coal has a longer history than
many people realize. The Germans used it to produce gasoline from their then-abundant
coal during World War II; South Africa has a liquefaction plant in operation now, producing
gasoline and fuel oil. Even so, their liquid fuel products have not historically been
economically competitive with conventional petroleum. The higher gasoline prices rise, of
course, the more economically viable coal liquefaction becomes. The most obvious
advantage is that it would allow us to use our plentiful coal resources to meet a need now
satisfied by petroleum, much of it imported

41. Coal
4/ Environmental Impacts of Coal Use
*Gases
A major problem posed by coal is the pollution associated with its mining and use. Like all fossil fuels,
coal produces carbon dioxide (CO2) when burned. In fact, it produces significantly more carbon dioxide
per unit energy released than oil or natural gas. (It is the burning of the carbon component—making
CO2— that is the energy-producing reaction when coal is burned; when hydrocarbons are burned, the
reactions produce partly CO2, partly H2O as their principal by-products, the proportions varying with
the ratio of carbon to hydrogen in the particular hydrocarbon(s).)

42. Coal
The additional pollutant
that is of special concern
with coal is sulfur. The
sulfur content of coal can
be more than 3%, some in
the form of the iron sulfide
mineral pyrite (FeS2),
some bound in the
organic matter of the coal
itself. When the sulfur is
burned along with the
coal, sulfur gases, notably
sulfur dioxide (SO2), are
produced. These gases
are poisonous and are
extremely irritating to eyes
and lungs.
60%
7%
5%
15%
3%
10%
Carbon
Sulfur
Nitrogen
Hydrogen
Oxygen
Ash

43. Coal
The gases also react with water in the atmosphere to produce sulfuric acid, a very strong acid.
This acid then falls to earth as acid rainfall. Acid rain falling into streams and lakes can kill fish
and other aquatic life. It can acidify soil, stunting plant growth. It can dissolve rock; in areas
where acid rainfall is a severe problem, buildings and monuments are visibly corroding away
because of the acid. The geology of acid rain is explored further in chapter 18.
Another toxic substance of growing concern with increasing coal use is mercury. A
common trace element in coal, mercury is also a very volatile (easily-vaporized) metal,
so it can be released with the waste gases.

44. Coal
*Ash
Coal use also produces a great deal of solid
waste. The ash residue left after coal is
burned typically ranges from 5 to 20% of
the original volume. The ash, which
consists mostly of noncombustible silicate
minerals, also contains toxic metals. If
exposed at the surface, the fine ash, with its
proportionately high surface area, may
weather very rapidly, and the toxic metals
such as selenium and uranium can be
leached from it, thus posing a water-pollution
threat. Uncontrolled erosion of
the ash could likewise cause sediment
pollution. The magnitude of this waste-disposal
problem should not be
underestimated.

45. Coal
There is no obvious safe place to dump all that waste. Some is used to make
concrete, and it has been suggested that the ash could actually serve as a useful
source of some of the rarer metals concentrated in it. At present, however, much of
the ash from coal combustion is deposited in landfills.

46. Coal
Between combustion and disposal, the ash may be stored wet, in containment ponds. These,
too, can pose a hazard: In December 2008, a containment pond along the Emory River in
Tennessee failed, releasing an estimated 5.4 million cubic meters of saturated ash from the
Kingston Fossil Plant into the river . The surge of sludge buried nearly half a square mile of
land, damaged many homes, and released such pollutants as arsenic, chromium, and lead into
the water. It was originally estimated, optimistically, that cleanup might take 4 to 6 weeks. It
now appears that the process will take years, and projections of total cleanup costs range up
to $1 billion.

47. Coal
*Coal-mining hazard
Coal mining poses further problems. Underground mining of coal is notoriously
dangerous, as well as expensive. Mines can collapse; miners may contract black lung
disease from breathing the dust; there is always danger of explosion from pockets of
natural gas that occur in many coal seams. A tragic coal-mine fire in Utah in December
1984 and a methane explosion in a Chinese coal mine in 2004 that killed over 100 people
were reminders of the seriousness of the hazards. Recent evidence further suggests that
coal miners are exposed to increased cancer risks from breathing the radioactive gas
radon, which is produced by natural decay of uranium in rocks surrounding the coal seam.

48. Coal
An underground fire that may have
been started by a trash fire in an
adjacent dump has been burning
under Centralia, Pennsylvania, since
1962; over 1000 residents have
been relocated, at a cost of more
than $40 million, and collapse and
toxic fumes threaten the handful of
remaining residents resisting
evacuation. And while Centralia’s
fire may be among the most famous,
it is by no means the only such fire,
and they are a problem in other
nations as well. China relies heavily
on coal for its energy; uncontrolled
coal-mine fires there have cost over
$100 million in lost coal, the carbon-dioxide
emissions from them are
estimated to account for several
percent of global CO2 emissions

49. Coal
• Centralia photography

50. Coal
Acid Mine Drainage (AMD)
Acid mine drainage - refers to the outflow of
acidic water from metal mines or coal mines.
AMD occurs naturally within some environments
as part of the rock weathering process but is
exacerbated by large-scale earth disturbances
characteristic of mining and other large
construction activities, usually within rocks
containing an abundance of sulfide minerals.
Areas where the earth has been disturbed (e.g.
construction sites, subdivisions,and transportation
corridors) may create acid rock drainage. In many
localities, the liquid that drains from coal stocks,
coal handling facilities, coal washeries, and coal
waste tips can be highly acidic, and in such cases
it is treated as acid rock drainage.
The same type of chemical reactions and
processes may occur through the disturbance of
acid sulfate soils formed under coastal or
estuarine conditions after the last major sea level
rise, and constitutes a similar environmental
hazard.

51. Coal
Because plants grow poorly in very acid conditions, this acid slows revegetation
of the area by stunting plant growth or even preventing it altogether. The acid
runoff can also pollute area ground and surface waters, killing aquatic plants
and animals in lakes and streams and contaminating the water supply. Very
acidic water also can be particularly effective at leaching or dissolving some
toxic elements from soils, further contributing to water pollution.

52. Oil shale
Oil shale, also known as kerogen shale, is an organic-rich fine-grained sedimentary rock containing
kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons called shale
oil (not to be confused with tight oil—crude oil occurring naturally in shales) can be produced. Shale
oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly
than the production of conventional crude oil both financially and in terms of its environmental impact.
Deposits of oil shale occur around the world, including major deposits in the United States. Estimates
of global deposits range from 4.8 to 5 trillion barrels of oil in place.

53. Oil shale
For a number of reasons, the United States is not yet using this apparently vast resource to any
significant extent, and it may not be able to do so in the near future .One reason for this is that
much of the kerogen is so widely dispersed through the oil shale that huge volumes of rock must be
processed to obtain moderate amounts of shale oil. Even the richest oil shale yields only about
three barrels of shale oil per ton of rock processed. The cost is not presently competitive with that
of conventional petroleum, except when oil prices are extremely high. The cost of producing a
barrel of oil at a surface retorting complex in the United States (comprising a mine, retorting plant,
upgrading plant, supporting utilities, and spent shale reclamation), would range between US$70–95

54. Oil shale
Mining oil shale involves a number of environmental impacts, more pronounced in surface mining than in
underground mining. These include acid drainage induced by the sudden rapid exposure and subsequent
oxidation of formerly buried materials, the introduction of metals including mercury into surface-water and
groundwater, increased erosion, sulfur-gas emissions, and air pollution caused by the production of particles
during processing, transport, and support activities. In 2002, about 97% of air pollution, 86% of total waste and
23% of water pollution in Estonia came from the power industry, which uses oil shale as the main resource for its
power production. Oil-shale extraction can damage the biological and recreational value of land and the
ecosystem in the mining area. Combustion and thermal processing generate waste material. In addition, the
atmospheric emissions from oil shale processing and combustion include carbon dioxide, a greenhouse gas.
Environmentalists oppose production and usage of oil shale, as it creates even more greenhouse gases than
conventional fossil fuels.

55. Tar sand
WHAT ARE THE TAR-SANDS ?
Tar sands , also known as oil sands , are sedimentary rocks containing a very thick, semisolid,
tar like petroleum called bitumen. The heavy petroleum in tar sands is believed to be formed
in the same way and from the same materials as lighter oils. Tar-sand deposits may represent
very immature petroleum deposits, in which the breakdown of large molecules has not
progressed to the production of the lighter liquid and gaseoushydrocarbons. Alternatively, the
lighter compounds may have migrated away, leaving this dense material behind. Either way,
the bitumen is too thick to flow out of the rock.

56. Tar sand
TAR SAND RESERVES
Natural bitumen deposits
are reported in many
countries, but in particular
are found in extremely large
quantities in Canada. Other
large reserves are located
in Russia. The estimated
worldwide deposits of oil
are more than 2 trillion
barrels, and 70.8%, are in
Canada.
Global oil sand reserves
Canada Russia Other countries
71%
12%
17%

57. Tar sand
Mining Bitumen
There are two different methods of producing oil from the oil sands: open-pit mining ( for
Bitumen that is close to the surface is mined ) and in situ ( for Bitumen that occurs deep
within the ground is produced in situ using specialized extraction techniques.)

58. Tar sand
Open-pit mining is similar to many coal mining operations – large shovels scoop the oil sand into
trucks that then take it to crushers where the large clumps of earth are broken down. This mixture is
then thinned out with water and transported to a plant, where the bitumen is separated from the
other components and upgraded to create synthetic oil. This technique is sometimes
misrepresented as the only method of mining oil sands. Just 20 per cent of the oil sands are
recoverable through open-pit mining.

59. Tar sand
In Situ Drilling 80 per cent of oil sands reserves (which underly approximately 97 per cent of
the oil sands surface area) are recoverable through in situ technology, with limited surface
disturbance.Advances in technology, such as directional drilling, enable in situ operations to
drill multiple wells (sometimes more than 20) from a single location, further reducing the
surface disturbance. The majority of in situ operations use steam-assisted gravity drainage
(SAGD). This method involves pumping steam underground through a horizontal well to
liquefy the bitumen that is then pumped to the surface through a second well.

60. Tar sand
Enviromental impacts: The scale of operations is large and growing, as is
the scale of corresponding environmental impacts, including land disturbance by
mining; accumulation of oily tailings that leave oil slicks on tailings ponds, which
can endanger migrating birds; and the fact that processing tar sand releases
two to three times as much in CO2 emissions as extracting conventional oil via
wells. Those environmental impacts cause serious concern, but the resource is
too large and too valuable to ignore.

61. Source
• Environmental Geology - Carla W Montgomery
• American Association of Petroleum Geologists
• Canadian Association of Petroleum Producers
• U.S Enegry Information Administration
• The Geological Society
• National Geographic
• Pembina Institute
• Etc…