Energy Resources

Fossil Fuels

Supervisor: PhD. Bùi Trọng VinhBy: Kiều Nhật Nam

Contents

I. Introduction

II. Oil and Natural Gas

III. Coal

IV. Oil shale

V. Tar sand

Introduction

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 )

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

Oil and Natural Gas

Oil and Natural Gas1/ Formation of Oil and Natural Gas Deposits

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.

Oil and Natural GasThe 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.

2/ Supply and Demand for Oil and Natural Gas

* Oil:

Oil and Natural Gas

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.

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.

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.

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

Oil and Natural Gas

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

3/ Future ProspectsOil and Natural Gas

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.

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.

4/ Enhanced Oil Recovery

Oil and Natural Gas

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

Oil and Natural GasOn 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.

Oil and Natural Gas

Oil and Natural GasHowever, 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.

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.

Oil and Natural Gas

Oil and Natural GasSome 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.

Oil and Natural GasStill 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.

6/ Oil spills:

Oil and Natural Gas

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.

Oil and Natural GasIn 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.

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.

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).

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

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.

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.

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.

Oil and Natural Gas

1. Formation of Coal Deposits

2. Coal Reserves and Resources

3. Limitations on Coal Use

4. Environmental Impacts of Coal Use

Coal

1/ Formation of Coal Deposits:

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)

Coal

2/ Coal Reserves and Resources

Coal

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.

3/ Limitations on Coal Use

Coal

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.

CoalCoal 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.

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.

CoalPilot 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.

Coal

CoalLike 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

4/ Environmental Impacts of Coal Use

*Gases

Coal

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).)

CoalThe 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%

3%

15%

5%

7%

10%

Carbon

Sulfur

Nitrogen

Hydrogen

Oxygen

Ash

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.

Coal

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.

*Ash

Coal

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.

CoalThere 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.

CoalBetween 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.

*Coal-mining hazardCoal 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.

Coal

CoalAn 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

• Centralia photography

Coal

CoalAcid 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.

CoalBecause 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.

Oil shaleOil 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.

Oil shaleFor 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

Oil shaleMining 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.

Tar sandWHAT 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.

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.

71%

12%

17%

Global oil sand reserves

Canada Russia Other countries

Tar sand

Mining BitumenThere 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.)

Tar sandOpen-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.

Tar sandIn 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.

Tar sandEnviromental 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.

• 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…

Source