petroleum (
L. petroleum, from
Greek:
petra (rock) +
Latin:
oleum (oil)
) or
crude oil is a naturally occurring,
flammable liquid consisting of a complex mixture of
hydrocarbons of various molecular weights and other liquid
organic compounds, that are found in
geologic formations beneath the
Earth's surface. A
fossil fuel, it is formed when large quantities of dead organisms, usually
zooplankton and
algae, are buried underneath sedimentary rock and undergo intense heat and pressure. Petroleum is recovered mostly through
oil drilling. This latter stage comes after the studies of structural geology (at the reservoir scale), sedimentary basin analysis, reservoir characterization (mainly in terms of porosity and permeable structures).
It is refined and separated, most easily by
boiling point, into a large number of consumer products, from petrol and
kerosene to
asphalt and chemical
reagents used to make plastics and
pharmaceuticals.
Petroleum is used in manufacturing a wide variety of materials,
and it is estimated that the world consumes about 88 million barrels each day. The use of fossil fuels such as petroleum can have a negative impact on Earth's biosphere, releasing pollutants and greenhouse gases into the air and damaging ecosystems through events such as
oil spills.
Etymology
The word
petroleum comes from Greek "petra" for rock and "elaion" for oil. The term was found (in the spelling "petraoleum") in 10th-century Old English sources.
It was used in the treatise
De Natura Fossilium, published in 1546 by the German mineralogist
Georg Bauer, also known as Georgius Agricola.
In the 19th century, the term
petroleum was frequently used to refer to mineral oils produced by distillation from mined organic solids such as
cannel coal (and later
oil shale), and refined oils produced from them; in the United Kingdom, storage (and later transport) of these oils were regulated by a series of Petroleum Acts, from the
Petroleum Act 1862 c. 66 onward.
[Composition
In its strictest sense, petroleum includes only crude oil, but in common usage it includes all liquid, gaseous, and solid (e.g.,
paraffin)
hydrocarbons. Under surface
pressure and temperature conditions, lighter hydrocarbons
methane,
ethane,
propane and
butane occur as gases, while
pentane and heavier ones are in the form of liquids or solids. However, in an underground
oil reservoir the proportions of gas, liquid, and solid depend on subsurface conditions and on the
phase diagram of the petroleum mixture.
An
oil well produces predominantly crude oil, with some natural gas
dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of
solution and be recovered (or burned) as
associated gas or
solution gas. A
gas well produces predominantly natural gas. However, because the underground temperature and pressure are higher than at the surface, the gas may contain heavier hydrocarbons such as
pentane,
hexane, and
heptane in the
gaseous state. At surface conditions these will
condense out of the gas to form
natural gas condensate, often shortened to
condensate. Condensate resembles petrol in appearance and is similar in composition to some
volatile light crude oils.
The proportion of light hydrocarbons in the petroleum mixture varies greatly among different
oil fields, ranging from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and
bitumens.
The hydrocarbons in crude oil are mostly
alkanes,
cycloalkanes and various
aromatic hydrocarbons while the other organic compounds contain
nitrogen,
oxygen and
sulfur, and trace amounts of metals such as iron, nickel, copper and
vanadium. The exact molecular composition varies widely from formation to formation but the proportion of
chemical elements vary over fairly narrow limits as follows:
Composition by weight
| Element | Percent range |
| Carbon | 83 to 87% |
| Hydrogen | 10 to 14% |
| Nitrogen | 0.1 to 2% |
| Oxygen | 0.05 to 1.5% |
| Sulfur | 0.05 to 6.0% |
| Metals | < 0.1% |
Four different types of hydrocarbon molecules appear in crude oil. The relative percentage of each varies from oil to oil, determining the properties of each oil.
Most of the world's oils are non-conventional.
Crude oil varies greatly in appearance depending on its composition. It is usually black or dark brown (although it may be yellowish, reddish, or even greenish). In the reservoir it is usually found in association with natural gas, which being lighter forms a gas cap over the petroleum, and
saline water which, being heavier than most forms of crude oil, generally sinks beneath it. Crude oil may also be found in semi-solid form mixed with sand and water, as in the
Athabasca oil sands in Canada, where it is usually referred to as crude
bitumen. In Canada, bitumen is considered a sticky, black, tar-like form of crude oil which is so thick and heavy that it must be heated or diluted before it will flow.
Venezuela also has large amounts of oil in the
Orinoco oil sands, although the hydrocarbons trapped in them are more fluid than in Canada and are usually called
extra heavy oil. These oil sands resources are called
unconventional oil to distinguish them from oil which can be extracted using traditional oil well methods. Between them, Canada and
Venezuela contain an estimated 3.6 trillion barrels (570
×109 m
3) of bitumen and extra-heavy oil, about twice the volume of the world's reserves of conventional oil.
Petroleum is used mostly, by volume, for producing
fuel oil and petrol, both important
"primary energy" sources.
84% by volume of the hydrocarbons present in petroleum is converted into energy-rich fuels (petroleum-based fuels), including petrol, diesel, jet, heating, and other fuel oils, and
liquefied petroleum gas.
The lighter grades of crude oil produce the best yields of these products, but as the world's reserves of light and medium oil are depleted,
oil refineries are increasingly having to process heavy oil and bitumen, and use more complex and expensive methods to produce the products required. Because heavier crude oils have too much carbon and not enough hydrogen, these processes generally involve removing carbon from or adding hydrogen to the molecules, and using
fluid catalytic cracking to convert the longer, more complex molecules in the oil to the shorter, simpler ones in the fuels.
Due to its high
energy density, easy transportability and
relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many
chemical products, including
pharmaceuticals,
solvents,
fertilizers,
pesticides, and plastics; the 16% not used for energy production is converted into these other materials. Petroleum is found in
porous rock formations in the upper
strata of some areas of the
Earth's
crust. There is also petroleum in
oil sands (tar sands). Known
oil reserves are typically estimated at around 190 km
3 (1.2
trillion (short scale) barrels) without oil sands,
or 595 km
3 (3.74 trillion barrels) with oil sands.
[16] Consumption is currently around 84 million barrels (13.4
×106 m
3) per day, or 4.9 km
3 per year. Which in turn yields a remaining oil supply of only about 120 years, if current demand remain static.
Chemistry
Petroleum is a mixture of a very large number of different
hydrocarbons; the most commonly found molecules are
alkanes (linear or branched),
cycloalkanes,
aromatic hydrocarbons, or more complicated chemicals like
asphaltenes. Each petroleum variety has a unique mix of
molecules, which define its physical and chemical properties, like color and
viscosity.
The
alkanes, also known as
paraffins, are
saturated hydrocarbons with straight or branched chains which contain only
carbon and
hydrogen and have the general formula C
nH
2n+2. They generally have from 5 to 40 carbon atoms per molecule, although trace amounts of shorter or longer molecules may be present in the mixture.
The alkanes from
pentane (C
5H
12) to
octane (C
8H
18) are
refined into petrol, the ones from
nonane (C
9H
20) to
hexadecane (C
16H
34) into
diesel fuel,
kerosene and
jet fuel). Alkanes with more than 16 carbon atoms can be refined into
fuel oil and
lubricating oil. At the heavier end of the range,
paraffin wax is an alkane with approximately 25 carbon atoms, while
asphalt has 35 and up, although these are usually
cracked by modern refineries into more valuable products. The shortest molecules, those with four or fewer carbon atoms, are in a gaseous state at room temperature. They are the petroleum gases. Depending on demand and the cost of recovery, these gases are either flared off, sold as liquified petroleum gas under pressure, or used to power the refinery's own burners. During the winter, Butane (C
4H
10), is blended into the petrol pool at high rates, because butane's high vapor pressure assists with cold starts. Liquified under pressure slightly above atmospheric, it is best known for powering cigarette lighters, but it is also a main fuel source for many developing countries. Propane can be liquified under modest pressure, and is consumed for just about every application relying on petroleum for energy, from cooking to heating to transportation.
The
cycloalkanes, also known as
naphthenes, are saturated hydrocarbons which have one or more carbon rings to which hydrogen atoms are attached according to the formula C
nH
2n. Cycloalkanes have similar properties to alkanes but have higher boiling points.
The
aromatic hydrocarbons are
unsaturated hydrocarbons which have one or more planar six-carbon rings called
benzene rings, to which hydrogen atoms are attached with the formula C
nH
n. They tend to burn with a sooty flame, and many have a sweet aroma. Some are
carcinogenic.
These different molecules are separated by
fractional distillation at an oil refinery to produce petrol, jet fuel, kerosene, and other hydrocarbons. For example,
2,2,4-Trimethylpentane (isooctane), widely used in petrol, has a chemical formula of C
8H
18 and it reacts with oxygen
exothermically:
[17]
- 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g) + 10.86 MJ/mol (of octane)
The amount of various molecules in an oil sample can be determined in laboratory. The molecules are typically extracted in a
solvent, then separated in a
gas chromatograph, and finally determined with a suitable
detector, such as a
flame ionization detector or a
mass spectrometer.
Due to the large number of co-eluted hydrocarbons within oil, many cannot be resolved by traditional gas chromatography and typically appear as a hump in the chromatogram. This
unresolved complex mixture (UCM) of hydrocarbons is particularly apparent when analysing weathered oils and extracts from tissues of organisms exposed to oil.
Incomplete combustion of petroleum or petrol results in production of toxic byproducts. Too little oxygen results in
carbon monoxide. Due to the high temperatures and high pressures involved, exhaust gases from petrol combustion in car engines usually include
nitrogen oxides which are responsible for creation of
photochemical smog.
Empirical equations for thermal properties
Heat of combustion
At a constant volume the heat of combustion of a petroleum product can be approximated as follows:
- Qv = 12,400 − 2,100d2.
where
Qv is measured in cal/gram and d is the specific gravity at
60 °F (16 °C).
Thermal conductivity
The thermal conductivity of petroleum based liquids can be modeled as follows:
![K = \frac{0.813}{d}[1-0.0203(t-32)]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_t--AE4DpRqZnc8VR2lfu7GnDh_xqBIGEMY22KdTVkcfrNa27qrBdVcrsrf92ES9uMIfHBJDGaz_Va5DaneE81CH4D16MxbqnBFzd5O7slTxBt07Qupmvw_SOpp8il2svuyz8wsqgdjhD-hHPmyb8ySQVPrnGCZ3odc5A=s0-d)
0.547
where K is measured in BTU
· hr
−1ft
−2 , t is measured in °F and d is the specific gravity at
60 °F (16 °C).
Specific heat
The specific heat of a petroleum oils can be modeled as follows:
![c = \frac{1}{\sqrt{d}} [0.388+0.00045t]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tmeNBCYqS6-uc9mJSjLUoYgQcevQb7jFasKERk-iM1gAUuNW-haaZ4DlmbhPG4GFrDrI6WDAdhcUbR07ze59rzuT7e7mHHSrMoziqA77g_N_I6hnz7cQDnb-vfchWqYc8M_skEMJznW8NGkw0gi2G9r3cvAslatBLmnLI=s0-d)
,
where c is measured in BTU/lbm-°F, t is the temperature in Fahrenheit and
d is the specific gravity at
60 °F (16 °C).
In units of kcal/(kg·°C), the formula is:
![\frac{1}{\sqrt{d}} [0.402+0.00081t]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sIdD90kRrRgkP6TKgjKcJFepMpmp3ZE2wi9JQeQZ19fBK8uezUWI7-vciZin3xriVNmRT_9Brf3op5YNmXpbVF9Oe1p2Jt0fnwZAnnb-iH5_9NnIO4PPOLjGy20Je3sMZP8roFDc92qyvuYc4C_-sjP2uvzeEtGrFJNG4=s0-d)
,
where the temperature
t is in Celsius and
d is the specific gravity at 15 °C.
Latent heat of vaporization
The latent heat of vaporization can be modeled under atmospheric conditions as follows:
![L = \frac{1}{d}[110.9 - 0.09t]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_ufgfnitfblSHDtslMILQrS0Ft5MnuTatqCgIgOraJt6J0PKT4GHv1MsquqLu465qzrvzfLmTCbCmZe4Yt68FhYxh-ZmF-bjii3EGP-eR32c_1HAUsDMlMOfiY0hldNYcts3u5ERGNQ0yJOpq1Ao_MXO2WKUHNI-kWVcU0=s0-d)
,
where L is measured in BTU/lbm, t is measured in °F and d is the specific gravity at
60 °F (16 °C).
In units of kcal/kg, the formula is:
![L = \frac{1}{d}[194.4 - 0.162t]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tl2D1DapT1sx0sEnNg85tpBUCxD7JZc8KWHlJ5-JjCz5g0u96oo61KffFpK-B43Lmot9-J7Qy0szG99xdVf-ynmHKSwPAXcu3bU2-V-ZevTMyS9xcb73ZzopqQtpE2C5F66-3xzaI0kqxpyxis9UOV__nm6lloz1lecEM=s0-d)
,
where the temperature
t is in Celsius and
d is the specific gravity at 15 °C.
[19]
Formation
Petroleum is a
fossil fuel derived from ancient
fossilized organic materials, such as
zooplankton and
algae.
Vast quantities of these remains settled to sea or lake bottoms, mixing with sediments and being buried under
anoxic conditions. As further layers settled to the sea or lake bed, intense heat and pressure built up in the lower regions. This process caused the organic matter to change, first into a waxy material known as
kerogen, which is found in various
oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons via a process known as
catagenesis. Formation of petroleum occurs from
hydrocarbon pyrolysis in a variety of mainly
endothermic reactions at high temperature and/or pressure.
There were certain warm nutrient-rich environments such as the
Gulf of Mexico and the ancient
Tethys Sea where the large amounts of organic material falling to the ocean floor exceeded the rate at which it could decompose. This resulted in large masses of organic material being buried under subsequent deposits such as shale formed from mud. This massive organic deposit later became heated and transformed under pressure into oil.
Geologists often refer to the temperature range in which oil forms as an "oil window"
—below the minimum temperature oil remains trapped in the form of kerogen, and above the maximum temperature the oil is converted to natural gas through the process of
thermal cracking. Sometimes, oil formed at extreme depths may migrate and become trapped at a much shallower level. The
Athabasca Oil Sands is one example of this.
Abiogenic origin hypothesis
A small number of geologists adhere to the
abiogenic petroleum origin hypothesis, maintaining that high molecular weight hydrocarbons of purely inorganic origin exist within Earth's interior and are the source for major petroleum deposits. The hypothesis was originally proposed by
Nikolai Kudryavtsev and
Vladimir Porfiriev in the 1950s, and more recently
Thomas Gold proposed a similar
deep hot biosphere idea. The thermodynamic synthesis routes necessary to carry abiogenic source material into subsurface oil are not established, observation of organic markers in kerogen and oil is not explained, and no oil deposits have been located by this hypothesis.
Reservoirs
Crude oil reservoirs
Three conditions must be present for oil reservoirs to form: a
source rock rich in hydrocarbon material buried deep enough for subterranean heat to cook it into oil; a
porous and
permeable reservoir rock for it to accumulate in; and a cap rock (seal) or other mechanism that prevents it from escaping to the surface. Within these reservoirs, fluids will typically organize themselves like a three-layer cake with a layer of water below the oil layer and a layer of gas above it, although the different layers vary in size between reservoirs. Because most hydrocarbons are less dense than rock or water, they often migrate upward through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as
reservoirs) by impermeable rocks above. However, the process is influenced by underground water flows, causing oil to migrate hundreds of kilometres horizontally or even short distances downward before becoming trapped in a reservoir. When hydrocarbons are concentrated in a trap, an
oil field forms, from which the liquid can be extracted by
drilling and
pumping.
The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where hydrocarbons are broken down to oil and natural gas by a set of parallel reactions, and oil eventually breaks down to natural gas by another set of reactions. The latter set is regularly used in
petrochemical plants and
oil refineries.
Wells are drilled into oil reservoirs to extract the crude oil. "Natural lift" production methods that rely on the natural reservoir pressure to force the oil to the surface are usually sufficient for a while after reservoirs are first tapped. In some reservoirs, such as in the Middle East, the natural pressure is sufficient over a long time. The natural pressure in many reservoirs, however, eventually dissipates. Then the oil must be pumped out using “artificial lift” created by mechanical pumps powered by gas or electricity. Over time, these "primary" methods become less effective and "secondary" production methods may be used. A common secondary method is “waterflood” or injection of water into the reservoir to increase pressure and force the oil to the drilled shaft or "wellbore." Eventually "tertiary" or "enhanced" oil recovery methods may be used to increase the oil's flow characteristics by injecting steam, carbon dioxide and other gases or chemicals into the reservoir. In the United States, primary production methods account for less than 40% of the oil produced on a daily basis, secondary methods account for about half, and tertiary recovery the remaining 10%. Extracting oil (or “bitumen”) from oil/tar sand and oil shale deposits requires mining the sand or shale and heating it in a vessel or retort, or using “in-situ” methods of injecting heated liquids into the deposit and then pumping out the oil-saturated liquid.
Unconventional oil reservoirs
Oil-eating bacteria
biodegrade oil that has escaped to the surface.
Oil sands are reservoirs of partially biodegraded oil still in the process of escaping and being biodegraded, but they contain so much migrating oil that, although most of it has escaped, vast amounts are still present—more than can be found in conventional oil reservoirs. The lighter fractions of the crude oil are destroyed first, resulting in reservoirs containing an extremely heavy form of crude oil, called crude bitumen in Canada, or extra-heavy crude oil in
Venezuela. These two countries have the world's largest deposits of oil sands.
On the other hand,
oil shales are source rocks that have not been exposed to heat or pressure long enough to convert their trapped hydrocarbons into crude oil. Technically speaking, oil shales are not always shales and do not contain oil, but are fined-grain sedimentary rocks containing an insoluble organic solid called
kerogen. The kerogen in the rock can be converted into crude oil using heat and pressure to simulate natural processes. The method has been known for centuries and was patented in 1694 under British Crown Patent No. 330 covering, "A way to extract and make great quantities of pitch, tar, and oil out of a sort of stone." Although oil shales are found in many countries, the United States has the world's largest deposits.
Classification
A sample of medium heavy crude oil
The
petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g.
West Texas Intermediate,
Brent, or
Oman), its
API gravity (an oil industry measure of density), and its sulfur content. Crude oil may be considered
light if it has low density or
heavy if it has high density; and it may be referred to as
sweet if it contains relatively little sulfur or
sour if it contains substantial amounts of sulfur.
The geographic location is important because it affects transportation costs to the refinery.
Light crude oil is more desirable than
heavy oil since it produces a higher yield of petrol, while
sweet oil commands a higher price than
sour oil because it has fewer environmental problems and requires less refining to meet sulfur standards imposed on fuels in consuming countries. Each crude oil has unique molecular characteristics which are understood by the use of
crude oil assay analysis in petroleum laboratories.
Barrels from an area in which the crude oil's molecular characteristics have been determined and the oil has been classified are used as pricing
references throughout the world. Some of the common reference crudes are:
- West Texas Intermediate (WTI), a very high-quality, sweet, light oil delivered at Cushing, Oklahoma for North American oil
- Brent Blend, comprising 15 oils from fields in the Brent and Ninian systems in the East Shetland Basin of the North Sea. The oil is landed at Sullom Voe terminal in Shetland. Oil production from Europe, Africa and Middle Eastern oil flowing West tends to be priced off this oil, which forms a benchmark
- Dubai-Oman, used as benchmark for Middle East sour crude oil flowing to the Asia-Pacific region
- Tapis (from Malaysia, used as a reference for light Far East oil)
- Minas (from Indonesia, used as a reference for heavy Far East oil)
- The OPEC Reference Basket, a weighted average of oil blends from various OPEC (The Organization of the Petroleum Exporting Countries) countries
- Midway Sunset Heavy, by which heavy oil in California is priced
There are declining amounts of these benchmark oils being produced each year, so other oils are more commonly what is actually delivered. While the reference price may be for West Texas Intermediate delivered at Cushing, the actual oil being traded may be a discounted Canadian heavy oil delivered at
Hardisty, Alberta, and for a Brent Blend delivered at Shetland, it may be a Russian Export Blend delivered at the port of
Primorsk.
Petroleum industry
The petroleum industry is involved in the global processes of
exploration,
extraction,
refining,
transporting (often with
oil tankers and
pipelines), and marketing petroleum products. The largest volume products of the industry are
fuel oil and petrol . Petroleum is also the raw material for many
chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics. The industry is usually divided into three major components:
upstream,
midstream and
downstream. Midstream operations are usually included in the downstream category.
Petroleum is vital to many industries, and is of importance to the maintenance of industrialized
civilization itself, and thus is critical concern to many nations. Oil accounts for a large percentage of the world's energy consumption, ranging from a low of 32% for Europe and Asia, up to a high of 53% for the Middle East. Other geographic regions' consumption patterns are as follows: South and Central America (44%), Africa (41%), and North America (40%). The world at large consumes 30 billion
barrels (4.8 km³) of oil per year, and the top oil consumers largely consist of developed nations. In fact, 24% of the oil consumed in 2004 went to the United States alone,
though by 2007 this had dropped to 21% of world oil consumed.
In the US, in the states of
Arizona, California, Hawaii,
Nevada,
Oregon and
Washington, the
Western States Petroleum Association (WSPA) represents companies responsible for producing, distributing, refining, transporting and marketing petroleum. This non-profit trade association was founded in 1907, and is the oldest petroleum trade association in the United States.
History
Petroleum, in one form or another, has been used since ancient times, and is now important across society, including in economy, politics and technology. The rise in importance was mostly due to the invention of the
internal combustion engine, the rise in
commercial aviation and the increasing use of plastic.
More than 4000 years ago, according to
Herodotus and
Diodorus Siculus,
asphalt was used in the construction of the walls and towers of
Babylon; there were oil pits near
Ardericca (near Babylon), and a pitch spring on
Zacynthus.
Great quantities of it were found on the banks of the river
Issus, one of the tributaries of the
Euphrates. Ancient
Persian tablets indicate the medicinal and lighting uses of petroleum in the upper levels of their society. By 347 AD, oil was produced from bamboo-drilled wells in China.
In the 1850s, the process to distill
kerosene from petroleum was invented by
Ignacy Łukasiewicz, providing a cheaper alternative to
whale oil. The demand for the petroleum as a fuel for lighting in North America and around the world quickly grew.
The world's first commercial oil well was drilled in
Poland in 1853. Oil exploration developed in many parts of the world with the Russian Empire, particularly the
Branobel company in
Azerbaijan (Asia's first modern borehole oil production began in 1848 at the Bibi-Heybat field near Baku), taking the lead in production by the end of the 19th century.
[verification needed]
Access to oil was and still is a major factor in several military conflicts of the twentieth century, including World War II, during which oil facilities were a major strategic asset and were
extensively bombed.
[35] Operation Barbarossa included the goal to capture the
Baku oilfields, as it would provide much needed oil-supplies for the German military which was suffering from blockades.
Oil exploration in North America during the early 20th century later led to the U.S. becoming the leading producer by the mid 1900s. As petroleum production in the U.S. peaked during the 1960s, however, the United States was surpassed by Saudi Arabia and Russia.
Today, about 90% of vehicular fuel needs are met by oil. Petroleum also makes up 40% of total energy consumption in the United States, but is responsible for only 1% of electricity generation. Petroleum's worth as a portable, dense energy source powering the vast majority of vehicles and as the base of many industrial chemicals makes it one of the world's most important
commodities. Viability of the oil commodity is controlled by several key parameters, number of vehicles in the world competing for fuel, quantity of oil exported to the world market (
Export Land Model),
Net Energy Gain (economically useful energy provided minus energy consumed), political stability of oil exporting nations and ability to defend oil supply lines.
The top three oil producing countries are
Saudi Arabia, Russia, and the United States.
About 80% of the world's readily accessible reserves are located in the Middle East, with 62.5% coming from the Arab 5:
Saudi Arabia,
UAE, Iraq,
Qatar and
Kuwait. A large portion of the world's total oil exists as unconventional sources, such as
bitumen in
Canada and
Venezuela and
oil shale. While significant volumes of oil are extracted from oil sands, particularly in Canada, logistical and technical hurdles remain, as oil extraction requires large amounts of heat and water, making its net energy content quite low relative to conventional crude oil. Thus, Canada's oil sands are not expected to provide more than a few million barrels per day in the foreseeable future.
Conventional crude oil production, those having Net Energy Gain above 10 stopped growing in 2005 at about 74 million barrels per day (11,800,000 m
3/d). The
International Energy Agency's (IEA) 2010 World Energy Outlook estimated that conventional crude oil production has peaked and is depleting at 6.8% per year.
US Joint Forces Command's Joint Operating Environment 2010 issued this warning to all US military commands "By 2012, surplus oil production capacity could entirely disappear, and as early as 2015, the shortfall in output could reach nearly 10 million barrels per day."
Price
After the collapse of the OPEC-administered pricing system in 1985, and a short lived experiment with netback pricing, oil-exporting countries adopted a market-linked pricing mechanism.
First adopted by
PEMEX in 1986, market-linked pricing was widely accepted, and by 1988 became and still is the main method for pricing crude oil in international trade.
The current reference, or pricing markers, are
Brent,
WTI, and
Dubai/Oman.
Uses
The chemical structure of petroleum is
heterogeneous, composed of
hydrocarbon chains of different lengths. Because of this, petroleum may be taken to
oil refineries and the hydrocarbon chemicals separated by
distillation and treated by other
chemical processes, to be used for a variety of purposes. See
Petroleum products.
Fuels
A poster used to promote
carpooling as a way to ration gasoline during World War II.
The most common
distillation fractions of petroleum are
fuels. Fuels include (by increasing boiling temperature range):
Other derivatives
Certain types of resultant hydrocarbons may be mixed with other non-hydrocarbons, to create other end products:
Agriculture
Since the 1940s, agricultural productivity has increased dramatically, due largely to the increased use of energy-intensive
mechanization,
fertilizers and
pesticides. Nearly all pesticides and many fertilizers are made from oil.
Petroleum by country
Consumption statistics
-
Global fossil carbon emissions, an indicator of consumption, for 1800–2007. Total is black, Oil is in blue.
-
EIA Primary Energy Outlook (retrieved on 2011-06)
-
daily oil consumption from 1980 to 2006
-
oil consumption by percentage of total per region from 1980 to 2006: red=USA, blue=Europe, yellow=Asia+Oceania
-
Consumption
According to the
CIA World Factbook estimate for 2010 the world consumes about 87 million barrels of oil each day.
Oil consumption per capita (darker colors represent more consumption).
This table orders the amount of petroleum consumed in 2008 in thousand
barrels (bbl) per day and in thousand cubic metres (m
3) per day:
| United States 1 | 19,497.95 | 3,099.9 | 314 | 22.6 | 3.59 |
| China | 7,831.00 | 1,245.0 | 1345 | 2.1 | 0.33 |
| Japan 2 | 4,784.85 | 760.7 | 127 | 13.7 | 2.18 |
| India 2 | 2,962.00 | 470.9 | 1198 | 0.9 | 0.14 |
| Russia 1 | 2,916.00 | 463.6 | 140 | 7.6 | 1.21 |
| Germany 2 | 2,569.28 | 408.5 | 82 | 11.4 | 1.81 |
| Brazil | 2,485.00 | 395.1 | 193 | 4.7 | 0.75 |
| Saudi Arabia (OPEC) | 2,376.00 | 377.8 | 25 | 33.7 | 5.36 |
| Canada | 2,261.36 | 359.5 | 33 | 24.6 | 3.91 |
| South Korea 2 | 2,174.91 | 345.8 | 48 | 16.4 | 2.61 |
| Mexico 1 | 2,128.46 | 338.4 | 109 | 7.1 | 1.13 |
| France 2 | 1,986.26 | 315.8 | 62 | 11.6 | 1.84 |
| Iran (OPEC) | 1,741.00 | 276.8 | 74 | 8.6 | 1.37 |
| United Kingdom 1 | 1,709.66 | 271.8 | 61 | 10.1 | 1.61 |
| Italy 2 | 1,639.01 | 260.6 | 60 | 10 | 1.6 |
Source:
US Energy Information Administration [bad link as of 2011-12-18]
Population Data:
1 peak production of oil already passed in this state
2 This country is not a major oil producer
Production
Graph of Top Oil Producing Countries 1960–2006, including Soviet Union
In petroleum industry parlance,
production refers to the quantity of crude extracted from reserves, not the literal creation of the product.
| 1 | Saudi Arabia (OPEC) | 10,665 | 10,234 | 10,782 | 9,760 | 11.8% |
| 2 | Russia 1 | 9,677 | 9,876 | 9,789 | 9,934 | 12.0% |
| 3 | United States 1 | 8,331 | 8,481 | 8,514 | 9,141 | 11.1% |
| 4 | Iran (OPEC) | 4,148 | 4,043 | 4,174 | 4,177 | 5.1% |
| 5 | China | 3,846 | 3,901 | 3,973 | 3,996 | 4.8% |
| 6 | Canada 2 | 3,288 | 3,358 | 3,350 | 3,294 | 4.0% |
| 7 | Mexico 1 | 3,707 | 3,501 | 3,185 | 3,001 | 3.6% |
| 8 | United Arab Emirates (OPEC) | 2,945 | 2,948 | 3,046 | 2,795 | 3.4% |
| 9 | Kuwait (OPEC) | 2,675 | 2,613 | 2,742 | 2,496 | 3.0% |
| 10 | Venezuela (OPEC) 1 | 2,803 | 2,667 | 2,643 | 2,471 | 3.0% |
| 11 | Norway 1 | 2,786 | 2,565 | 2,466 | 2,350 | 2.8% |
| 12 | Brazil | 2,166 | 2,279 | 2,401 | 2,577 | 3.1% |
| 13 | Iraq (OPEC) 3 | 2,008 | 2,094 | 2,385 | 2,400 | 2.9% |
| 14 | Algeria (OPEC) | 2,122 | 2,173 | 2,179 | 2,126 | 2.6% |
| 15 | Nigeria (OPEC) | 2,443 | 2,352 | 2,169 | 2,211 | 2.7% |
| 16 | Angola (OPEC) | 1,435 | 1,769 | 2,014 | 1,948 | 2.4% |
| 17 | Libya (OPEC) | 1,809 | 1,845 | 1,875 | 1,789 | 2.2% |
| 18 | United Kingdom | 1,689 | 1,690 | 1,584 | 1,422 | 1.7% |
| 19 | Kazakhstan | 1,388 | 1,445 | 1,429 | 1,540 | 1.9% |
| 20 | Qatar (OPEC) | 1,141 | 1,136 | 1,207 | 1,213 | 1.5% |
| 21 | Indonesia | 1,102 | 1,044 | 1,051 | 1,023 | 1.2% |
| 22 | India | 854 | 881 | 884 | 877 | 1.1% |
| 23 | Azerbaijan | 648 | 850 | 875 | 1,012 | 1.2% |
| 24 | Argentina | 802 | 791 | 792 | 794 | 1.0% |
| 25 | Oman | 743 | 714 | 761 | 816 | 1.0% |
| 26 | Malaysia | 729 | 703 | 727 | 693 | 0.8% |
| 27 | Egypt | 667 | 664 | 631 | 678 | 0.8% |
| 28 | Colombia | 544 | 543 | 601 | 686 | 0.8% |
| 29 | Australia | 552 | 595 | 586 | 588 | 0.7% |
| 30 | Ecuador (OPEC) | 536 | 512 | 505 | 485 | 0.6% |
| 31 | Sudan | 380 | 466 | 480 | 486 | 0.6% |
| 32 | Syria | 449 | 446 | 426 | 400 | 0.5% |
| 33 | Equatorial Guinea | 386 | 400 | 359 | 346 | 0.4% |
| 34 | Thailand | 334 | 349 | 361 | 339 | 0.4% |
| 35 | Vietnam | 362 | 352 | 314 | 346 | 0.4% |
| 36 | Yemen | 377 | 361 | 300 | 287 | 0.3% |
| 37 | Denmark | 344 | 314 | 289 | 262 | 0.3% |
| 38 | Gabon | 237 | 244 | 248 | 242 | 0.3% |
| 39 | South Africa | 204 | 199 | 195 | 192 | 0.2% |
| 40 | Turkmenistan | No data | 180 | 189 | 198 | 0.2% |
Source:
U.S. Energy Information Administration
1 Peak production of conventional oil already passed in this state
2 Although Canadian conventional oil production is declining, total oil production is increasing as oil sands production grows. If oil sands are included, it has the world's second largest oil reserves after Saudi Arabia.
3 Though still a member, Iraq has not been included in production figures since 1998
Export
In order of net exports in 2009 and 2006 in thousand
bbl/
d and thousand m³/d:
| 1 | Saudi Arabia (OPEC) | 7,322 | 1,164 | 8,651 | 1,376 |
| 2 | Russia 1 | 7,194 | 1,144 | 6,565 | 1,044 |
| 3 | Iran (OPEC) | 2,486 | 395 | 2,519 | 401 |
| 4 | United Arab Emirates (OPEC) | 2,303 | 366 | 2,515 | 400 |
| 5 | Norway 1 | 2,132 | 339 | 2,542 | 404 |
| 6 | Kuwait (OPEC) | 2,124 | 338 | 2,150 | 342 |
| 7 | Nigeria (OPEC) | 1,939 | 308 | 2,146 | 341 |
| 8 | Angola (OPEC) | 1,878 | 299 | 1,363 | 217 |
| 9 | Algeria (OPEC) 1 | 1,767 | 281 | 1,847 | 297 |
| 10 | Iraq (OPEC) | 1,764 | 280 | 1,438 | 229 |
| 11 | Venezuela (OPEC) 1 | 1,748 | 278 | 2,203 | 350 |
| 12 | Libya (OPEC) 1 | 1,525 | 242 | 1,525 | 242 |
| 13 | Kazakhstan | 1,299 | 207 | 1,114 | 177 |
| 14 | Canada 2 | 1,168 | 187 | 1,071 | 170 |
| 15 | Qatar (OPEC) | 1,066 | 169 | – | – |
| – | Mexico 1 | 1,039 | 165 | 1,676 | 266 |
Source:
US Energy Information Administration
1 peak production already passed in this state
2 Canadian statistics are complicated by the fact it is both an importer and exporter of crude oil, and refines large amounts of oil for the U.S. market. It is the leading source of U.S. imports of oil and products, averaging 2,500,000 bbl/d (400,000 m3/d) in August 2007.
Total world production/consumption (as of 2005) is approximately 84 million barrels per day (13,400,000 m
3/d).
Import
In order of net imports in 2009 and 2006 in thousand
bbl/
d and thousand m³/d:
| 1 | United States 1 | 9,631 | 1,531 | 12,220 | 1,943 |
| 2 | China 2 | 4,328 | 688 | 3,438 | 547 |
| 3 | Japan | 4,235 | 673 | 5,097 | 810 |
| 4 | Germany | 2,323 | 369 | 2,483 | 395 |
| 5 | India | 2,233 | 355 | 1,687 | 268 |
| 6 | South Korea | 2,139 | 340 | 2,150 | 342 |
| 7 | France | 1,749 | 278 | 1,893 | 301 |
| 8 | United Kingdom | 1,588 | 252 | – | – |
| 9 | Spain | 1,439 | 229 | 1,555 | 247 |
| 10 | Italy | 1,381 | 220 | 1,558 | 248 |
| 11 | Netherlands | 973 | 155 | 936 | 149 |
| 12 | Republic of China (Taiwan) | 944 | 150 | 942 | 150 |
| 13 | Singapore | 916 | 146 | 787 | 125 |
| 14 | Turkey | 650 | 103 | 576 | 92 |
| 15 | Belgium | 597 | 95 | 546 | 87 |
| – | Thailand | 538 | 86 | 606 | 96 |
Source:
US Energy Information Administration
1 peak production of oil already passed in this state[citation needed]
2 Major oil producer whose production is still increasing[citation needed]
Non-producing consumers
Countries whose oil production is 10% or less of their consumption.
| 1 | Japan | 5,578,000 | 886,831 |
| 2 | Germany | 2,677,000 | 425,609 |
| 3 | South Korea | 2,061,000 | 327,673 |
| 4 | France | 2,060,000 | 327,514 |
| 5 | Italy | 1,874,000 | 297,942 |
| 6 | Spain | 1,537,000 | 244,363 |
| 7 | Netherlands | 946,700 | 150,513 |
| 8 | Turkey | 575,011 | 91,663 |
Source:
CIA World Factbook[not in citation given]
Environmental effects
Diesel fuel spill on a road
Because petroleum is a naturally occurring substance, its presence in the environment need not be the result of human causes such as accidents and routine activities (
seismic exploration,
drilling, extraction, refining and combustion). Phenomena such as
seeps and
tar pits are examples of areas that petroleum naturally affects. Regardless of source, petroleum's effects when released into the environment are similar.
Global warming
When burned, petroleum releases carbon dioxide; a
greenhouse gas. Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO
2. Atmospheric CO
2 has risen steadily since the
industrial revolution to current levels of over 380ppmv, from the
180 – 300ppmv of the prior 800 thousand years, driving
global warming.
[47][48][49]
Oil extraction is simply the removal of oil from the reservoir (oil pool). Oil is often recovered as a water-in-oil emulsion, and
specialty chemicals called
demulsifiers are used to separate the oil from water. Oil extraction is costly and sometimes environmentally damaging, although
Dr. John Hunt of the
Woods Hole Oceanographic Institution pointed out in a 1981 paper that over 70% of the reserves in the world are associated with visible
macroseepages, and many oil fields are found due to natural
seeps. Offshore exploration and extraction of oil disturbs the surrounding marine environment.
Oil spills
Crude oil and refined fuel
spills from
tanker ship accidents have damaged natural
ecosystems in
Alaska, the
Gulf of Mexico, the
Galapagos Islands, France and many
other places.
The quantity of oil spilled during accidents has ranged from a few hundred tons to several hundred thousand tons (e.g.,
Deepwater Horizon Oil Spill,
Atlantic Empress,
Amoco Cadiz). Smaller spills have already proven to have a great impact on ecosystems, such as the
Exxon Valdez oil spill
Oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin
oil slick which can cover beaches with a thin coating of oil. This can kill sea birds, mammals, shellfish and other organisms it coats. Oil spills on land are more readily containable if a makeshift earth dam can be rapidly
bulldozed around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.
Control of oil spills is difficult, requires ad hoc methods, and often a large amount of manpower. The dropping of bombs and incendiary devices from aircraft on the
Torrey Canyon wreck produced poor results;
[51] modern techniques would include pumping the oil from the wreck, like in the
Prestige oil spill or the
Erika oil spill.
Though crude oil is predominantly composed of various hydrocarbons, certain nitrogen heterocylic compounds, such as
pyridine,
picoline, and
quinoline are reported as contaminants associated with crude oil, as well as facilities processing oil shale or coal, and have also been found at legacy wood treatment sites. These compounds have a very high water solubility, and thus tend to dissolve and move with water. Certain naturally occurring bacteria, such as
Micrococcus,
Arthrobacter, and
Rhodococcus and have been shown to degrade these contaminants.
Degradation of underground tanks located at gas stations may also occur, significantly affecting soil and groundwater. In these instances of the biological degradation of petroleum hydrocarbons, solutions such as bioremediation may be used.
[citation needed]
Tarballs
A tarball is a blob of
oil (not to be confused with
tar, which is typically derived from pine trees rather than petroleum) which has been weathered after floating in the ocean. Tarballs are an aquatic
pollutant in most environments, although they can occur naturally, for example, in the Santa Barbara Channel of California Their concentration and features have been used to assess the extent of
oil spills. Their composition can be used to identify their sources of origin,
and tarballs themselves may be dispersed over long distances by deep sea currents.
They are slowly decomposed by bacteria, including
Chromobacterium violaceum,
Cladosporium resinae,
Bacillus submarinus,
Micrococcus varians,
Pseudomonas aeruginosa,
Candida marina and
Saccharomyces estuari.
Whales
James S. Robbins has argued that the advent of petroleum-refined kerosene saved some species of great whales from
extinction by providing an inexpensive substitute for whale oil, thus eliminating the economic imperative for open-boat
whaling.
Alternatives to petroleum
In the United States in 2007 about 70% of petroleum was used for transportation (e.g. petrol, diesel, jet fuel), 24% by industry (e.g. production of plastics), 5% for residential and commercial uses, and 2% for electricity production.
Outside of the US, a higher proportion of petroleum tends to be used for electricity.
Alternatives to petroleum-based vehicle fuels
Alternative fuel vehicles refers to both:
Alternatives to using oil in industry
Biological feedstocks do exist for industrial uses such as
Bioplastic production.
Alternatives to burning petroleum for electricity
In oil producing countries with little refinery capacity, oil is sometimes burned to produce electricity.
Renewable energy technologies such as
solar power,
wind power,
micro hydro,
biomass and
biofuels might someday be used to replace some of these generators, but today the primary alternatives remain large scale
hydroelectricity,
nuclear and coal-fired generation.
Future of petroleum production
Consumption in the twentieth and twenty-first centuries has been abundantly pushed by automobile growth; the
1985–2003 oil glut even fuelled the sales of low economy vehicles in
OECD countries. In 2008, the economic crisis seems to have some impact on the sales of such vehicles; still, the 2008 oil consumption shows a small increase. The
BRIC countries might also kick in, as China briefly was the first automobile market in December 2009.
The immediate outlook still hints upwards. In the long term, uncertainties linger; the
OPEC believes that the
OECD countries will push low consumption policies at some point in the future; when that happens, it will definitely curb the oil sales, and both
OPEC and
EIA kept lowering their 2020 consumption estimates during the past 5 years.
Oil products are more and more in competition with alternative sources, mainly coal and natural gas, both cheaper sources.
US oil production and imports, 1920–2005.
Production will also face an increasingly complex situation; while OPEC countries still have large reserves at low production prices, newly found reservoirs often lead to higher prices; offshore giants such as
Tupi, Guara and
Tiber demand high investments and ever-increasing technological abilities. Subsalt reservoirs such as Tupi were unknown in the twentieth century, mainly because the industry was unable to probe them.
Enhanced Oil Recovery (EOR) techniques (example:
DaQing, China
) will continue to play a major role in increasing the world's recoverable oil.
Peak oil
Peak Oil is the scientific projection that future petroleum production (whether for individual oil wells, entire oil fields, whole countries, or worldwide production) will eventually peak and then decline at a similar rate to the rate of increase before the peak as these reserves are exhausted. The peak of oil discoveries was in 1965, and oil production per year has surpassed oil discoveries every year since 1980.
Hubbert applied his theory to accurately predict the peak of U.S. oil production at a date between 1966 and 1970. This prediction was based on data available at the time of his publication in 1956. In the same paper, Hubbert predicts world peak oil in "half a century" after his publication, which would be 2006.
It is difficult to predict the
oil peak in any given region, due to the lack of knowledge and/or transparency in accounting of global oil reserves.
The scientist and researchers from Oxford University argue that official figures are inflated because OPEC members over-reported reserves in the 1980s when competing for global market share.
Based on available production data, proponents have previously predicted the peak for the world to be in years 1989, 1995, or 1995–2000. Some of these predictions date from before the recession of the early 1980s, and the consequent reduction in global consumption, the effect of which was to delay the date of any peak by several years. Just as the 1971 U.S. peak in oil production was only clearly recognized after the fact, a peak in world production will be difficult to discern until production clearly drops off.
[original research?]
The
International Energy Agency (IEA) says production of conventional crude oil peaked in 2006.
Since virtually all economic sectors rely heavily on petroleum, peak oil could lead to a "partial or complete failure of markets."
Ruler can do anything, so Born to rule the Galaxy
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