TheInfoList

Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black
liquid A liquid is a nearly incompressible In fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics Mechanics (Ancient Greek, Greek: ) is the area of physics concerned with the motions of physical objects, ...

found in
geological formation A geological formation, or formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguish it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a ...
s beneath the surface. It is commonly refined into various types of
fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical con ...

s. Components of petroleum are separated using a technique called
fractional distillation Fractional distillation is the separation of a mixture In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matt ...
, i.e., separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a . It consists of naturally occurring
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
s of various molecular weights and may contain miscellaneous
organic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
s. The name ''petroleum'' covers both naturally occurring unprocessed crude oil and
petroleum product Petroleum products are materials derived from crude oil (petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible fluid In physics, a fluid is a ...
s that are made up of refined crude oil. A
fossil fuel A fossil fuel is a hydrocarbon In , a hydrocarbon is an consisting entirely of and . Hydrocarbons are examples of s. Hydrocarbons are generally colourless and hydrophobic with only weak odours. Because of their diverse molecular structure ...
, petroleum is formed when large quantities of dead organisms, mostly
zooplankton Zooplankton (; ) are heterotroph A heterotroph (; from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often ro ...

and
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic Photosynthesis is a process used by plants and other organisms to convert Conversion or convert may refer to: Arts, entertainment, and media * Co ...

, are buried underneath
sedimentary rock Sedimentary rocks are types of rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compoun ...

and subjected to both intense heat and pressure. Petroleum has mostly been recovered by
oil drilling , such as this one located south of Midland, Texas, is a common sight in West Texas West Texas is a loosely defined part of the U.S. state of Texas, generally encompassing the desert climate, arid and semi-arid climate, semiarid lands west of a ...
. Drilling is carried out after studies of structural geology, sedimentary basin analysis, and reservoir characterisation. Recent improvements to technologies have also led to exploitation of other unconventional reserves such as
oil sands Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional oil, unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of s ...
and
oil shale Oil shale is an organic-rich containing (a solid mixture of ) from which liquid s can be produced, called . Shale oil is a substitute for conventional crude oil; however, extracting shale oil is costlier than the production of conventional ...

. Once extracted, oil is refined and separated, most easily by
distillation Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, ...
, into numerous products for direct use or use in manufacturing, such as
gasoline Gasoline () or petrol () (see the #Etymology, etymology for naming differences and the use of the term ''gas'') is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignition engine, spark-ignite ...

(petrol),
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...
and
kerosene Kerosene, paraffin, or lamp oil is a combustible , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = G ...

to
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

and chemical
reagent A reagent is a substance or compound added to a system to cause a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter ...
s used to make
plastic Plastics are a wide range of syntheticA synthetic is an artificial material produced by organic chemistry, organic chemical synthesis. Synthetic may also refer to: In the sense of both "combination" and "artificial" * Synthetic chemical or s ...

s,
pesticide Pesticides are substances that are meant to control pests Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious d ...
s and
pharmaceuticals A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, therapy, treat, or preventive medicine, prevent disease. Drug therapy (pharmacotherapy) ...
. Petroleum is used in manufacturing a wide variety of materials, and it is estimated that the world consumes about each day. Petroleum production can be extremely profitable and was important for economic development in the 20th century, with some countries, so called " oil states", gaining significant economic and international power because of their control of oil production. Petroleum exploitation has significant negative environmental and social consequences. Most significantly, extraction,
refining {{Unreferenced, date=December 2009 Refining (also perhaps called by the mathematical term affining) is the process of purification of a (1) substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner ...
and
burning Combustion, or burning, is a high-temperature exothermic In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, radiation, and physical pro ...
of petroleum fuels all release large quantities of
greenhouse gas A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhou ...
es, so petroleum is one of the
major contributors to climate change Major is a military rank of commissioned officer status, with corresponding ranks existing in many military forces throughout the world. Background When used unhyphenated, in conjunction with no other indicators, major is one rank senior to ...
. Furthermore, parts of the petroleum industry actively suppressed science and policy that aimed to prevent the
climate crisis Climate crisis is a term describing global warming and climate change, and their consequences. The term has been used to describe the threat of global warming to the planet, and to urge aggressive climate change mitigation. For example, a Janu ...
. Other negative environmental effects include the environmental impacts of exploration and exploitation of petroleum reserves, such as
oil spill An oil spill is the release of a liquid petroleum Petroleum (), also known as crude oil and oil, is a #Latent heat of vaporization, naturally occurring, yellowish-black liquid found in geological formations beneath the Earth, Earth's surfac ...
s, and air and water pollution at the sites of utilization. All of these environmental impacts have direct health consequences for humans. Additionally, oil has also been a source of conflict leading to both and other kinds of conflicts (for example, oil revenue funded the
Islamic State , caption = , active = {{Collapsible list , title = 1999–present , 1 = 1999: Established under the name of Jama'at al-Tawhid wal-Jihad , 2 = October 2004: Joined al-Qaeda , 3 = 13 October 2006: Declaration of an Islamic ...
). Production of petroleum is expected to reach
peak oil''For Peak brand motor oil, see Peak (automotive products).'' Hubbert's upper-bound prediction for US crude oil production (1956) in red, and actual lower-48 states production through to 2014 in green Peak oil is the year when the maximum r ...
before 2035 as global economies reduce dependencies on petroleum as part of
climate change mitigation Climate change mitigation consists of actions to limit global warming Contemporary climate change includes both the global warming caused by humans, and its impacts on Earth's weather patterns. There have been , but the current cha ...
and a transition towards
renewable energy Renewable energy is energy that is collected from renewable resource File:Global Vegetation.jpg, Global vegetation A renewable resource, also known as a flow resource, is a natural resource which will replenish to replace the portion resou ...
and
electrification Electrification is the process of powering by electricity Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, mo ...

. This is expected to have significant economic impacts that stakeholders argue need to be anticipated by a
just transition Just transition is a framework developed by the trade union A trade union (or a labor union in American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of va ...
and addressing the
stranded assetStranded assets are "asset In financial accountancy, financial accounting, an asset is any resource owned or controlled by a business or an economic entity. It is anything (tangible or intangible) that can be used to produce positive economic value ...
s of the petroleum industry.

# Etymology

The word ''petroleum'' comes from Medieval Latin (literally 'rock oil'), which comes from Latin
petra The Positron-Electron Tandem Ring Accelerator (PETRA) is one of the particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to ...

'rock' (from Greek ) and
oleum Oleum (Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation wit ...

'oil' (from Greek ). The term was used in the treatise ''
De Natura Fossilium ''De Natura Fossilium'' is a scientific text written by Georg Bauer also known as Georgius Agricola Georgius Agricola (; born Georg Pawer or Georg Bauer; 24 March 1494 – 21 November 1555) was a German Humanist scholar, mineralogist Mi ...
'', published in 1546 by the German mineralogist Georg Bauer, also known as Georgius Agricola. In the 19th century, the term ''petroleum'' was often used to refer to
mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes Higher alkanes are alkanes having nine or more carbon atoms. Nonane is the lightest alkane to have a flash point above 25 °C, and is not classified as da ...
s produced by distillation from mined organic solids such as
cannel coal Cannel coal or candle coal is a type of bituminous coal Image:Coal bituminous.jpg, 275px, Bituminous coal Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen or asphalt. It is of higher quality th ...
(and later
oil shale Oil shale is an organic-rich containing (a solid mixture of ) from which liquid s can be produced, called . Shale oil is a substitute for conventional crude oil; however, extracting shale oil is costlier than the production of conventional ...

) 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 1863'' onwards.

# History

## Early

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 due to the invention of the
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do work (physics), mechanical work. It doe ...

, the rise in
commercial aviation Commercial aviation is the part of civil aviation that involves operating aircraft for remuneration or hire, as opposed to private aviation. Definition Commercial aviation is not a rigorously defined category. All Commercial Air Transport and Ae ...
, and the importance of petroleum to industrial organic chemistry, particularly the synthesis of plastics, fertilisers, solvents, adhesives and pesticides. More than 4000 years ago, according to
Herodotus Herodotus ( ; grc, Ἡρόδοτος, Hēródotos, ; BC) was an Classical Greece, ancient Greek writer, geographer, and historian born in the Greek city of Halicarnassus, part of the Achaemenid Empire, Persian Empire (now Bodrum, Turkey). He ...
and
Diodorus Siculus Diodorus Siculus, or Diodorus of Sicily ( grc-gre, Διόδωρος Σικελιώτης ;  1st century BC), was an ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern ...
,
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

was used in the construction of the walls and towers of
Babylon ''Bābili(m)'' * sux, 𒆍𒀭𒊏𒆠 * arc, 𐡁𐡁𐡋 ''Babil'' * grc-gre, Βαβυλών ''Babylṓn'' * he, בָּבֶל ''Bavel'' * peo, 𐎲𐎠𐎲𐎡𐎽𐎢 ''Bābiru'' * elx, 𒀸𒁀𒉿𒇷 ''Babili'' *Kassite The Kassites ...

; there were oil pits near Ardericca (near Babylon), and a pitch spring on
Zacynthus Zakynthos (also spelled Zakinthos; el, Ζάκυνθος, Zákynthos ; it, Zacinto ) or Zante (, , ; el, Τζάντε, Tzánte ; from the Venetian language, Venetian form) is a Greece, Greek island in the Ionian Sea. It is the third largest of ...
. Great quantities of it were found on the banks of the river Issus, one of the tributaries of the
Euphrates The Euphrates () is the longest and one of the most historically important rivers of Western Asia. Tigris–Euphrates river system, Together with the Tigris, it is one of the two defining rivers of Mesopotamia (the "Land Between the Rivers"). O ...
. Ancient
Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, Persian people, the majority ethnic group in Iran, not to be conflated with the Iranian peoples ** Persian language, an Iranian ...

tablets indicate the medicinal and lighting uses of petroleum in the upper levels of their society. The use of petroleum in ancient China dates back to more than 2000 years ago. The ''
I Ching The ''I Ching'' or ''Yi Jing'' (, ), usually translated as ''Book of Changes'' or ''Classic of Changes'', is an ancient Chinese divination Divination (from Latin ''divinare'', 'to foresee, to foretell, to predict, to prophesy') is the at ...
'', one of the earliest Chinese writings, cites that oil in its raw state, without refining, was first discovered, extracted, and used in China in the first century BCE. In addition, the Chinese were the first to record the use of petroleum as fuel as early as the fourth century BCE. By 347 CE, oil was produced from bamboo-drilled wells in China.
Crude oil Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...
was often distilled by Persian chemists, with clear descriptions given in Arabic handbooks such as those of
Muhammad ibn Zakarīya Rāzi Abū Bakr Muḥammad ibn Zakariyyāʾ al-Rāzī ( ar, أبو بكر محمد بن زكرياء الرازي, also known by his Persian name Rāzī and by his Latinization (literature), Latinized name Rhazes), 864 or 865 – 925 or 935 C ...
(Rhazes). The streets of
Baghdad Baghdad (; ar, بَغْدَاد ) is the capital of Iraq Iraq ( ar, الْعِرَاق, translit=al-ʿIrāq; ku, عێراق, translit=Êraq), officially the Republic of Iraq ( ar, جُمْهُورِيَّة ٱلْعِرَاق '; ku, ...

were paved with
tar Tar is a dark brown or black viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), ...

, derived from petroleum that became accessible from natural fields in the region. In the 9th century,
oil field A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons In organic chemistry, a hydrocarbon is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally ...

s were exploited in the area around modern
Baku Baku (, ; az, Bakı, ) is the Capital city, capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and of the Caucasus region. Baku is located below sea level, which makes it the List of capital cities by altitu ...

,
Azerbaijan Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan ( az, Azərbaycan Respublikası ), is a country in the Transcaucasia, Caucasus region of Eurasia. Located at the crossroads of Eastern Europe and Western Asia, it is boun ...

. These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by
Marco Polo Marco Polo (, , ; September 15, 1254January 8, 1324) was a merchant, explorer, and writer who travelled through Asia along the between 1271 and 1295. His travels are recorded in ' (also known as ''Book of the Marvels of the World '' and '' ...

in the 13th century, who described the output of those wells as hundreds of shiploads. Arab and Persian chemists also distilled crude oil in order to produce
flammable , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = German language, German , demonym = Germans, German , g ...
products for military purposes. Through , distillation became available in
Western Europe Western Europe is the western region of Europe Europe is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical r ...

by the 12th century. It has also been present in Romania since the 13th century, being recorded as păcură. Sophisticated oil pits, deep, were dug by the
Seneca People The Seneca () ( see, Onödowáʼga:, "Great Hill People") are a group of Indigenous Indigenous may refer to: *Indigenous peoples Indigenous peoples, also referred to as First people, Aboriginal people, Native people, or autochthonous people, ...
and other
Iroquois The Iroquois ( or ) or Haudenosaunee (; "People of the Longhouse") are an indigenous Indigenous may refer to: *Indigenous peoples Indigenous peoples, also referred to as First people, Aboriginal people, Native people, or autochthonous pe ...

in
Western Pennsylvania Western Pennsylvania is a region in the U.S. state of Pennsylvania Pennsylvania ( ) ( pdc, Pennsilfaani), officially the Commonwealth of Pennsylvania, is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic, Northeastern U ...
as early as 1415–1450. The French General
Louis-Joseph de Montcalm Louis-Joseph de Montcalm-Grozon, marquis de Montcalm de Saint-Veran (28 February 1712 – 14 September 1759) was a French French (french: français(e), link=no) may refer to: * Something of, from, or related to France France (), offi ...
encountered Seneca using petroleum for ceremonial fires and as a healing lotion during a visit to Fort Duquesne in 1750. Early British explorers to
Myanmar Myanmar, ); UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, John ...

documented a flourishing oil extraction industry based in
Yenangyaung Yenangyaung ( my, ရေနံချောင်း; literally "stream of oil") is a city in the Magway Region of central Myanmar, located on the Irrawaddy River and 363 miles from Yangon. Until 1974, it remained the capital city of both Minbu Divi ...

that, in 1795, had hundreds of hand-dug wells under production.
Pechelbronn Merkwiller-Pechelbronn () is a commune A commune is an intentional community of people sharing living spaces, interests, values, beliefs, and often property Property (''latin: Res Privata'') in the Abstract and concrete, abstract is wha ...
(Pitch fountain) is said to be the first European site where petroleum has been explored and used. The still active Erdpechquelle, a spring where petroleum appears mixed with water has been used since 1498, notably for medical purposes. Oil sands have been mined since the 18th century. In
Wietze Wietze is a municipality in the district of Celle, in Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state The Federal Republic of Germany, as a federal state, consists of sixtee ...
in lower Saxony, natural asphalt/bitumen has been explored since the 18th century. Both in Pechelbronn as in Wietze, the coal industry dominated the petroleum technologies.

## Modern

Chemist
James YoungJames Young may refer to: In business *James R. Young (UP) (1952–2014), president, CEO and Chairman of Union Pacific Railroad *James R. Young (North Carolina politician) (1853–1937), Insurance Commissioner of North Carolina *James Webb Young (1 ...
noticed a natural petroleum seepage in the
Riddings Riddings is a large village in Derbyshire, England. The appropriate ward of the Amber Valley Council is called Ironville and Riddings. The population of this ward as at the 2011 census was 5,821. It is located south of Alfreton near the hamlet of ...
colliery Coal mining is the process of from the ground. Coal is valued for its and since the 1880s has been widely used to generate electricity. and industries use coal as a fuel for extraction of iron from and for cement production. In the and ...
at
Alfreton Alfreton ( ) is a town and civil parishes in England, civil parish in the Amber Valley district of Derbyshire, England. The town was formerly a Norman Manor and later an Urban District. The population of the Alfreton parish was 7,971 at the 201 ...
,
Derbyshire Derbyshire (; or ) is a county in the East Midlands of England. It includes much of the Peak District, Peak District National Park, the southern end of the Pennines, Pennine range of hills, and part of the The National Forest (England), Nation ...

from which he distilled a light thin oil suitable for use as lamp oil, at the same time obtaining a more viscous oil suitable for lubricating machinery. In 1848, Young set up a small business refining the crude oil. Young eventually succeeded, by distilling
cannel coal Cannel coal or candle coal is a type of bituminous coal Image:Coal bituminous.jpg, 275px, Bituminous coal Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen or asphalt. It is of higher quality th ...
at a low heat, in creating a fluid resembling petroleum, which when treated in the same way as the seep oil gave similar products. Young found that by slow distillation he could obtain a number of useful liquids from it, one of which he named "paraffine oil" because at low temperatures it congealed into a substance resembling paraffin wax. The production of these oils and solid
paraffin wax Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible fluid In physics, ...

from coal formed the subject of his patent dated 17 October 1850. In 1850 Young & Meldrum and Edward William Binney entered into partnership under the title of E.W. Binney & Co. at
Bathgate Bathgate ( sco, Bathket or , gd, Both Chèit) is a town in West Lothian West Lothian ( sco, Wast Lowden; gd, Lodainn an Iar) is one of the 32 council areas of Scotland, and one of its historic counties. The county, which was historically ...

in
West Lothian West Lothian ( sco, Wast Lowden; gd, Lodainn an Iar) is one of the 32 council areas of Scotland, and was one of its shires of Scotland, historic counties. The county, which was known as Linlithgowshire, was bounded geographically by the River ...

and E. Meldrum & Co. at Glasgow; their works at Bathgate were completed in 1851 and became the first truly commercial oil-works in the world with the first modern oil refinery. The world's first oil refinery was built in 1856 by Ignacy Łukasiewicz. His achievements also included the discovery of how to distill kerosene from seep oil, the invention of the modern kerosene lamp (1853), the introduction of the first modern street lamp in Europe (1853), and the construction of the world's first modern oil well (1854). The demand for petroleum as a fuel for lighting in North America and around the world quickly grew.
Edwin Drake Edwin Laurentine Drake (March 29, 1819 – November 9, 1880), also known as Colonel Drake, was an American businessman and the first American to successfully drill for oil An oil is any nonpolar chemical substance A chemical substan ...

's 1859 well near Titusville, Pennsylvania, is popularly considered the first modern well. Already 1858 Georg Christian Konrad Hunäus had found a significant amount of petroleum while drilling for
lignite Lignite, often referred to as brown coal, is a soft, brown, combustible , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official langu ...

1858 in
Wietze Wietze is a municipality in the district of Celle, in Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state The Federal Republic of Germany, as a federal state, consists of sixtee ...
, Germany. Wietze later provided about 80% of the German consumption in the Wilhelminian Era. The production stopped in 1963, but Wietze has hosted a Petroleum Museum since 1970. Drake's well is probably singled out because it was drilled, not dug; because it used a steam engine; because there was a company associated with it; and because it touched off a major boom. However, there was considerable activity before Drake in various parts of the world in the mid-19th century. A group directed by Major Alexeyev of the Bakinskii Corps of Mining Engineers hand-drilled a well in the Baku region of Bibi-Heybat in 1846. There were engine-drilled wells in West Virginia in the same year as Drake's well. An early commercial well was hand dug in
Poland Poland, officially the Republic of Poland, is a country located in Central Europe. It is divided into 16 Voivodeships of Poland, administrative provinces, covering an area of , and has a largely Temperate climate, temperate seasonal cli ...

in 1853, and another in nearby
Romania Romania ( ; ro, România ) is a country at the crossroads of Central Central is an adjective usually referring to being in the center (disambiguation), center of some place or (mathematical) object. Central may also refer to: Directions ...

in 1857. At around the same time the world's first, small, oil refinery was opened at
Jasło Jasło is a county town in south-eastern Poland with 36,641 inhabitants, as of 31 December 2012. It is situated in the Subcarpathian Voivodeship (since 1999), and it was previously part of Krosno Voivodeship (1975–1998). It is located in Lesser ...

in Poland, with a larger one opened at
Ploiești Ploiești (, , ), formerly spelled Ploești, is a city A city is a large .Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. L ...
in Romania shortly after. Romania is the first country in the world to have had its annual crude oil output officially recorded in international statistics: 275 tonnes for 1857. The first commercial oil well in Canada became operational in 1858 at
Oil Springs, Ontario Oil Springs is a village in Lambton County, Ontario , Label_map = yes , image_map = Ontario in Canada 2.svg , map_alt = Map showing Ontario's location east/central of Canada. , coordinates ...
(then
Canada West The Province of Canada (or the United Province of Canada or the United Canadas) (french: link=no, Province du Canada) was a in North America from 1841 to 1867. Its formation reflected recommendations made by , in the following the . The , ...
).Oil Museum of Canada, Black Gold: Canada's Oil Heritage, Oil Springs: Boom & Bust
Businessman
James Miller Williams James Miller Williams (September 14, 1818 – November 25, 1890) was a Canadian-American businessman and politician. Williams is best known for establishing the first commercially successful oil well in 1858 and igniting the first oil boom in N ...
dug several wells between 1855 and 1858 before discovering a rich reserve of oil four metres below ground. Williams extracted 1.5 million litres of crude oil by 1860, refining much of it into kerosene lamp oil. Williams's well became commercially viable a year before Drake's Pennsylvania operation and could be argued to be the first commercial oil well in North America. The discovery at Oil Springs touched off an
oil boom An oil boom is a period of large inflow of income as a result of high global oil prices or large oil production The extraction of petroleum is the process by which usable petroleum Petroleum, also known as crude oil and oil, is a natura ...
which brought hundreds of speculators and workers to the area. Advances in drilling continued into 1862 when local driller Shaw reached a depth of 62 metres using the spring-pole drilling method. On January 16, 1862, after an explosion of
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

, Canada's first oil gusher came into production, shooting into the air at a recorded rate of per day. By the end of the 19th century the Russian Empire, particularly the
Branobel The Petroleum Production Company Nobel Brothers, Limited, or Branobel (short for братьев Нобель "brat'yev Nobel" — "Nobel Brothers" in Russian Russian refers to anything related to Russia, including: *Russians (русские, ''ru ...

company in
Azerbaijan Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan ( az, Azərbaycan Respublikası ), is a country in the Transcaucasia, Caucasus region of Eurasia. Located at the crossroads of Eastern Europe and Western Asia, it is boun ...

, had taken the lead in production.Akiner(2004), p. 5 Access to oil was and still is a major factor in several military conflicts of the twentieth century, including
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a global war A world war is "a war War is an intense armed conflict between states State may refer to: Arts, entertainment, and media Literatur ...
, during which oil facilities were a major strategic asset and were extensively bombed. The 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 US's becoming the leading producer by mid-century. As petroleum production in the US peaked during the 1960s, however, the United States was surpassed by Saudi Arabia and the Soviet Union. In 1973, Saudi Arabia and other Arab nations imposed an
oil embargoAn oil embargo is an economic situation wherein entities engage in an embargo to limit the transport of petroleum Petroleum (), also known as crude oil and oil, is a #Latent heat of vaporization, naturally occurring, yellowish-black liquid foun ...
against the United States, United Kingdom, Japan and other Western nations which supported
Israel Israel (; he, יִשְׂרָאֵל, translit=Yīsrāʾēl; ar, إِسْرَائِيل, translit=ʾIsrāʾīl), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a ...

in the
Yom Kippur War The Yom Kippur War, also known as the Ramadan War, the October War, the 1973 Arab–Israeli War or the Fourth Arab–Israeli War, was an armed conflict fought from 6 to 25 October 1973 between Israel Israel (; he, יִשְׂרָאֵ ...
of October 1973. The embargo caused an oil crisis with many short- and long-term effects on global politics and the global economy. Today, about 90 percent of vehicular fuel needs are met by oil. Petroleum also makes up 40 percent of total energy consumption in the United States, but is responsible for only 1 percent 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 In economics, a commodity is an economic goods, good, usually a resource, that has full or substantial fungibility: that is, the Market (economics), market treats instances of the good as equivalent or nearly so with no regard to who Production ...
. The top three oil producing countries are
Russia Russia ( rus, link=no, Россия, Rossiya, ), or the Russian Federation, is a country spanning Eastern Europe Eastern Europe is the eastern region of . There is no consistent definition of the precise area it covers, partly because th ...

,
Saudi Arabia (''Shahada'') , national_anthem = "National Anthem of Saudi Arabia, " "National Anthem of Saudi Arabia" , image_map = Saudi Arabia (orthographic projection).svg , capital = Riyadh , coordinates ...

and the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. In 2018, due in part to developments in
hydraulic fracturing Hydraulic fracturing, also called fracking, hydrofracking, and hydrofracturing, is a well stimulation technique involving the fracturing of bedrock Formation (geology), formations by a pressurized liquid. The process involves the high-pressur ...
and horizontal drilling, the United States became the world's largest producer. About 80 percent of the world's readily accessible reserves are located in the Middle East, with 62.5 percent coming from the Arab 5:
Saudi Arabia (''Shahada'') , national_anthem = "National Anthem of Saudi Arabia, " "National Anthem of Saudi Arabia" , image_map = Saudi Arabia (orthographic projection).svg , capital = Riyadh , coordinates ...

,
United Arab Emirates The United Arab Emirates (UAE; ar, الإمارات العربية المتحدة ) or the Emirates ( ar, الإمارات ), is a country in Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion A subregio ...

,
Iraq Iraq ( ar, الْعِرَاق, translit=al-ʿIrāq; ku, عێراق, translit=Êraq), officially the Republic of Iraq ( ar, جُمْهُورِيَّة ٱلْعِرَاق '; ku, کۆماری عێراق, translit=Komarî Êraq), is a country i ...

,
Qatar Qatar (, , or ; ar, قطر, Qaṭar ; local vernacular pronunciation: ), officially the State of Qatar,) is a country in Western Asia. It occupies the small Qatar Peninsula on the northeastern coast of the Arabian Peninsula, and shares it ...

and
Kuwait Kuwait (; ar, الكويت ', or ), officially the State of Kuwait ( ar, دولة الكويت '), is a country in Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion A subregion is a part of a larger regi ...

. A large portion of the world's total oil exists as unconventional sources, such as
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

in and extra heavy oil in the
Orinoco Belt The Orinoco Belt is a territory in the southern strip of the eastern Orinoco River Basin in Venezuela which overlies the world's largest deposits of petroleum. Its local Spanish name is ''Faja Petrolífera del Orinoco'' (Orinoco Petroleum Belt). ...
. 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.

# Composition

Petroleum includes not only crude oil, but all liquid, gaseous and solid
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
s. Under surface pressure and temperature conditions, lighter hydrocarbons
methane Methane (, ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth ...
,
ethane Ethane ( or ) is an Organic compound, organic chemical compound with chemical formula . At Standard conditions for temperature and pressure, standard temperature and pressure, ethane is a colorless, odourless gas. Like many hydrocarbons, ethane ...
,
propane Propane () is a three-carbon Carbon (from la, carbo "coal") is a chemical element with the Symbol (chemistry), symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—making four electrons available to form covalen ...

and
butane Butane () or ''n''-butane is an alkane with the formula C4H10. Butane is a gas at room temperature and atmospheric pressure. Butane is a highly flammable, colorless, easily liquefy, liquefied gas that quickly vaporizes at room temperature. The n ...

exist as gases, while
pentane Pentane is an organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ion ...

and heavier hydrocarbons are in the form of liquids or solids. However, in an underground
oil reservoir A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbon In organic chemistry, a hydrocarbon is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any che ...
the proportions of gas, liquid, and solid depend on subsurface conditions and on the
phase diagram A phase diagram in physical chemistry Physical chemistry is the study of macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical ins ...

of the petroleum mixture. An
oil well An oil well is a boring Boring may refer to: *Something that causes boredom Engineering and science * Boring (earth), drilling a hole, tunnel, or well in the earth ** Tunnel boring machine, a machine used in boring tunnels * Boring (manufactu ...

produces predominantly crude oil, with some natural gas in it. Because the pressure is lower at the surface than underground, some of the gas will come out of
solution Solution may refer to: * Solution (chemistry) Image:SaltInWaterSolutionLiquid.jpg, upMaking a saline water solution by dissolving Salt, table salt (sodium chloride, NaCl) in water. The salt is the solute and the water the solvent. In chemistry ...
and be recovered (or burned) as ''associated gas'' or ''solution gas''. A gas well produces predominantly
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

. However, because the underground temperature is higher than at the surface, the gas may contain heavier hydrocarbons such as pentane,
hexane Hexane () is an organic compound, a straight-chain alkane with six carbon atoms and has the molecular formula C6H14. Hexane is a significant constituent of gasoline. It is a colorless liquid, odorless when pure, and with boiling points approxim ...

, and
heptane Heptane or ''n''-heptane is the straight-chain alkane In , an alkane, or paraffin (a historical that also has ), is an . In other words, an alkane consists of and atoms arranged in a structure in which all the s are . Alkanes have the g ...

in the
gaseous state Gas is one of the four fundamental states of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space ...
. At surface conditions these will
condense Condensation is the change of the state of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space ...

out of the gas to form "
natural-gas condensate Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon In organic chemistry, a hydrocarbon is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are gen ...
", often shortened to ''condensate.'' Condensate resembles gasoline in appearance and is similar in composition to some volatile
light crude oilLight crude oil is liquid petroleum Petroleum (), also known as crude oil and oil, is a #Latent heat of vaporization, naturally occurring, yellowish-black liquid found in geological formations beneath the Earth, Earth's surface. It is commonly r ...
s. The proportion of light hydrocarbons in the petroleum mixture varies greatly among different
oil fields A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbon In organic chemistry, a hydrocarbon is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any che ...
, ranging from as much as 97 percent by weight in the lighter oils to as little as 50 percent in the heavier oils and
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

s. The hydrocarbons in crude oil are mostly
alkane In , an alkane, or paraffin (a historical that also has ), is an . In other words, an alkane consists of and atoms arranged in a structure in which all the s are . Alkanes have the general chemical formula C''n''H2''n''+2. The alkanes rang ...
s,
cycloalkane In organic chemistry Organic chemistry is a branch of that studies the structure, properties and reactions of s, which contain in .Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Stu ...

s and various
aromatic hydrocarbon Aromatic compounds are those chemical compounds (most commonly organic compound, organic) that contain one or more ring (chemistry), rings with pi electrons delocalized all the way around them. In contrast to compounds that exhibit aromaticity, al ...
s, while the other organic compounds contain
nitrogen Nitrogen is the chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

,
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

and
sulfur Sulfur (in nontechnical British English: sulphur) is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: th ...

, and trace amounts of metals such as iron, nickel, copper and
vanadium Vanadium is a chemical element with the Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

. Many oil reservoirs contain live bacteria. The exact molecular composition of crude oil varies widely from formation to formation but the proportion of
chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo du ...
s varies over fairly narrow limits as follows: 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. 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 Saline water (more commonly known as salt water) is water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere an ...
which, being heavier than most forms of crude oil, generally sinks beneath it. Crude oil may also be found in a semi-solid form mixed with sand and water, as in the in Canada, where it is usually referred to as crude
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

. 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 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 refining into fuel oil and gasoline, both important ''"primary energy"'' sources. 84 percent by volume of the hydrocarbons present in petroleum is converted into energy-rich fuels (petroleum-based fuels), including gasoline, 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 refinery, 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 oil reserves, 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,
pesticide Pesticides are substances that are meant to control pests Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious d ...
s, and plastics; the 16 percent not used for energy production is converted into these other materials. Petroleum is found in porosity, porous rock formations in the upper stratum, strata of some areas of the Earth's crust. There is also petroleum in tar sands, oil sands (tar sands). Known oil reserves are typically estimated at around 190 km3 (1.2 1000000000000 (number), trillion long and short scales, (short scale) barrel (unit), barrels) without oil sands, or 595 km3 (3.74 trillion barrels) with oil sands. Consumption is currently around per day, or 4.9 km3 per year, yielding a remaining oil supply of only about 120 years, if current demand remains static. More recent studies, however, put the number at around 50 years.

# Chemistry

Petroleum is a mixture of a very large number of different
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
s; the most commonly found molecules are
alkane In , an alkane, or paraffin (a historical that also has ), is an . In other words, an alkane consists of and atoms arranged in a structure in which all the s are . Alkanes have the general chemical formula C''n''H2''n''+2. The alkanes rang ...
s (paraffins),
cycloalkane In organic chemistry Organic chemistry is a branch of that studies the structure, properties and reactions of s, which contain in .Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Stu ...

s (naphthenes),
aromatic hydrocarbon Aromatic compounds are those chemical compounds (most commonly organic compound, organic) that contain one or more ring (chemistry), rings with pi electrons delocalized all the way around them. In contrast to compounds that exhibit aromaticity, al ...
s, 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 and unsaturated compounds, saturated hydrocarbons with straight or branched chains which contain only carbon and hydrogen and have the general formula CnH2n+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 Pentane is an organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ion ...

(C5H12) to octane (C8H18) are oil refinery, refined into gasoline, the ones from nonane (C9H20) to hexadecane (C16H34) into diesel fuel,
kerosene Kerosene, paraffin, or lamp oil is a combustible , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = G ...

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 Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid A liquid is a nearly incompressible fluid In physics, ...

is an alkane with approximately 25 carbon atoms, while
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

has 35 and up, although these are usually Fluid catalytic cracking, 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 flare stack, flared off, sold as liquefied petroleum gas under pressure, or used to power the refinery's own burners. During the winter, butane (C4H10), is blended into the gasoline pool at high rates, because its high vapour 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 CnH2n. Cycloalkanes have similar properties to alkanes but have higher boiling points. The ''aromatic hydrocarbons'' are degree of unsaturation, unsaturated hydrocarbons which have one or more planar six-carbon rings called benzene rings, to which hydrogen atoms are attached with the formula CnH2n-6. 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 Fractional distillation is the separation of a mixture In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matt ...
at an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbons. For example, 2,2,4-Trimethylpentane, 2,2,4-trimethylpentane (isooctane), widely used in
gasoline Gasoline () or petrol () (see the #Etymology, etymology for naming differences and the use of the term ''gas'') is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignition engine, spark-ignite ...

, has a chemical formula of C8H18 and it reacts with oxygen exothermically: :2 (''l'') + 25 (''g'') → 16 (''g'') + 18 (''g'') (ΔH = −5.51 MJ/mol of octane) The number of various molecules in an oil sample can be determined by laboratory analysis. 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, Unresolved Complex Mixture (UCM) of hydrocarbons is particularly apparent when analysing weathered oils and extracts from tissues of organisms exposed to oil. Some of the components of oil will mix with water: the water associated fraction of the oil. Incomplete combustion of petroleum or gasoline results in production of toxic byproducts. Too little oxygen during combustion results in the formation of carbon monoxide. Due to the high temperatures and high pressures involved, exhaust gases from gasoline 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: :$Q_v = 12400 - 2100d^2$, where $Q_v$ is measured in calories per gram and $d$ is the specific gravity at .

## Thermal conductivity

The thermal conductivity of petroleum based liquids can be modeled as follows: :$K = \frac\left[1-0.0003\left(t-32\right)\right]$ where $K$ is measured in BTU°F−1hr−1ft−1 , $t$ is measured in °F and $API$ is degrees API gravity.

## Specific heat

The specific heat of petroleum oils can be modeled as follows: :$c = \frac \left[0.388+0.00046t\right]$, where $c$ is measured in BTU/(lb °F), $t$ is the temperature in Fahrenheit and $d$ is the specific gravity at . In units of kcal/(kg·°C), the formula is: :$c = \frac \left[0.4024+0.00081t\right]$, 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: :$L = \frac\left[110.9 - 0.09t\right]$, where $L$ is measured in BTU/lb, $t$ is measured in °F and $d$ is the specific gravity at . In units of kcal/kg, the formula is: :$L = \frac\left[194.4 - 0.162t\right]$, where the temperature $t$ is in Celsius and $d$ is the specific gravity at 15 °C.

# Formation

## Fossil petroleum

Petroleum is a
fossil fuel A fossil fuel is a hydrocarbon In , a hydrocarbon is an consisting entirely of and . Hydrocarbons are examples of s. Hydrocarbons are generally colourless and hydrophobic with only weak odours. Because of their diverse molecular structure ...
derived from ancient fossilized organic materials, such as
zooplankton Zooplankton (; ) are heterotroph A heterotroph (; from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often ro ...

and
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic Photosynthesis is a process used by plants and other organisms to convert Conversion or convert may refer to: Arts, entertainment, and media * Co ...

. Vast amounts of these remains settled to sea or lake bottoms where they were covered in Water stagnation, stagnant water (water with no dissolved
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

) or sediments such as mud and silt faster than they could Decomposition#Anaerobic vs Aerobic, decompose aerobically. Approximately 1 Metre, m below this sediment, water oxygen concentration was low, below 0.1 mg/l, and Anoxic waters, anoxic conditions existed. Temperatures also remained constant. 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, found in various
oil shale Oil shale is an organic-rich containing (a solid mixture of ) from which liquid s can be produced, called . Shale oil is a substitute for conventional crude oil; however, extracting shale oil is costlier than the production of conventional ...

s around the world, and then with more heat into liquid and gaseous
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
s via a process known as Catagenesis (geology), catagenesis. Formation of petroleum occurs from hydrocarbon pyrolysis in a variety of mainly Endothermic process, endothermic reactions at high temperature or pressure, or both. These phases are described in detail below. ;Anaerobic decay: In the absence of plentiful oxygen, Aerobic organism, ''aerobic'' bacteria were prevented from decaying the organic matter after it was buried under a layer of sediment or water. However, Anaerobic organism, ''anaerobic'' bacteria were able to reduce sulfates and nitrates among the matter to Hydrogen sulfide, H2S and Nitrogen, N2 respectively by using the matter as a source for other reactants. Due to such anaerobic bacteria, at first this matter began to break apart mostly via hydrolysis: polysaccharides and proteins were hydrolyzed to Monosaccharide, simple sugars and amino acids respectively. These were further anaerobically Redox, oxidized at an accelerated rate by the enzymes of the bacteria: e.g., amino acids went through oxidative deamination to imino acids, which in turn reacted further to ammonia and Keto acid, α-keto acids. Monosaccharides in turn ultimately decayed to Carbon dioxide, CO2 and
methane Methane (, ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth ...
. The anaerobic decay products of amino acids, monosaccharides, phenols and aldehydes combined to fulvic acids. Fats and waxes were not extensively hydrolyzed under these mild conditions. ;Kerogen formation: Some phenolic compounds produced from previous reactions worked as bactericides and the actinomycetales order of bacteria also produced antibiotic compounds (e.g., streptomycin). Thus the action of anaerobic bacteria ceased at about 10 m below the water or sediment. The mixture at this depth contained fulvic acids, unreacted and partially reacted fats and waxes, slightly modified lignin, resins and other hydrocarbons. As more layers of organic matter settled to the sea or lake bed, intense heat and pressure built up in the lower regions. As a consequence, compounds of this mixture began to combine in poorly understood ways to kerogen. Combination happened in a similar fashion as phenol and formaldehyde molecules react to Urea-formaldehyde, urea-formaldehyde resins, but kerogen formation occurred in a more complex manner due to a bigger variety of reactants. The total process of kerogen formation from the beginning of anaerobic decay is called diagenesis, a word that means a transformation of materials by dissolution and recombination of their constituents. ;Transformation of kerogen into fossil fuels: Kerogen formation continued to the depth of about 1 Kilometre, km from the Earth's surface where temperatures may reach around 50 Celsius, °C. Kerogen formation represents a halfway point between organic matter and fossil fuels: kerogen can be exposed to oxygen, oxidize and thus be lost, or it could be buried deeper inside the Crust (geology), Earth's crust and be subjected to conditions which allow it to slowly transform into fossil fuels like petroleum. The latter happened through catagenesis in which the reactions were mostly Radical (chemistry), radical Rearrangement reaction, rearrangements of kerogen. These reactions took thousands to millions of years and no external reactants were involved. Due to radical nature of these reactions, kerogen reacted towards two classes of products: those with low H/C ratio (anthracene or products similar to it) and those with high H/C ratio (
methane Methane (, ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth ...
or products similar to it); i.e., carbon-rich or hydrogen-rich products. Because catagenesis was closed off from external reactants, the resulting composition of the fuel mixture was dependent on the composition of the kerogen via reaction stoichiometry. 3 main types of kerogen exist: type I (algal), II (liptinic) and III (humic), which were formed mainly from
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic Photosynthesis is a process used by plants and other organisms to convert Conversion or convert may refer to: Arts, entertainment, and media * Co ...

, plankton and woody plants (this term includes trees, shrubs and lianas) respectively. Catagenesis was Pyrolysis, pyrolytic despite the fact that it happened at relatively low temperatures (when compared to commercial pyrolysis plants) of 60 to several hundred °C. Pyrolysis was possible because of the long reaction times involved. Heat for catagenesis came from the decomposition of Radioactive decay, radioactive materials of the crust, especially Potassium-40, 40K, Thorium-232, 232Th, Uranium-235, 235U and Uranium-238, 238U. The heat varied with geothermal gradient and was typically 10-30 °C per km of depth from the Earth's surface. Unusual magma intrusions, however, could have created greater localized heating. ;Oil window (temperature range) 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. 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 are one example of this.

## Abiogenic petroleum

An alternative mechanism to the one described above was proposed by Russian scientists in the mid-1850s, the hypothesis of abiogenic petroleum origin (petroleum formed by inorganic means), but this is contradicted by geological and Geochemistry, geochemical evidence. Abiogenic sources of oil have been found, but never in commercially profitable amounts. "The controversy isn't over whether abiogenic oil reserves exist," said Larry Nation of the American Association of Petroleum Geologists. "The controversy is over how much they contribute to Earth's overall reserves and how much time and effort geologists should devote to seeking them out."

# Reservoirs

Three conditions must be present for oil reservoirs to form: * a source rock rich in
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
material buried deeply enough for subterranean heat to cook it into oil, * a porous and permeability (fluid), permeable reservoir rock where it can accumulate, * a caprock (seal) or other mechanism to prevent the oil 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 oil reservoir, 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 A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons In organic chemistry, a hydrocarbon is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally ...

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 refinery, oil refineries. Petroleum has mostly been recovered by
oil drilling , such as this one located south of Midland, Texas, is a common sight in West Texas West Texas is a loosely defined part of the U.S. state of Texas, generally encompassing the desert climate, arid and semi-arid climate, semiarid lands west of a ...
(natural petroleum springs are rare). Drilling is carried out after studies of structural geology (at the reservoir scale), sedimentary basin analysis, and reservoir characterisation (mainly in terms of the porosity and Permeability (earth sciences), permeability of geologic reservoir structures). Recent improvements to technologies have also led to exploitation of other unconventional reserves such as
oil sands Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional oil, unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of s ...
and
oil shale Oil shale is an organic-rich containing (a solid mixture of ) from which liquid s can be produced, called . Shale oil is a substitute for conventional crude oil; however, extracting shale oil is costlier than the production of conventional ...

. 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 most reservoirs, however, eventually dissipates. Then the oil must be extracted using "artificial lift" means. Over time, these "primary" methods become less effective and "secondary" production methods may be used. A common secondary method is Water injection (oil production), "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 percent of the oil produced on a daily basis, secondary methods account for about half, and tertiary recovery the remaining 10 percent. 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 the liquid back out saturated with oil.

## Unconventional oil reservoirs

Oil-eating bacteria biodegradation, 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

The petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g., West Texas Intermediate, Brent oilfield, Brent, or DME Oman Crude Oil Futures Contract, Oman), its API gravity (an oil industry measure of density), and its sulfur content. Crude oil may be considered ''Light crude oil, light'' if it has low density, ''Heavy crude oil, heavy'' if it has high density, or ''medium'' if it has a density between that of ''light'' and ''heavy''. Additionally, it may be referred to as ''sweet crude oil, sweet'' if it contains relatively little sulfur or ''sour crude oil, 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 gasoline, 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 revealed by the use of Crude oil assay analysis in petroleum laboratories. barrel (unit), 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 Benchmark (crude oil), 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 Crude, Brent Blend, consisting of 15 oils from fields in the Brent oilfield, Brent and Ninian Central Platform, 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 (crude oil), benchmark * Dubai Crude, Dubai-Oman, used as benchmark for Middle East sour crude oil flowing to the Asia-Pacific region * Tapis crude, 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 Oil Field, Midway Sunset Heavy, by which heavy oil in California is priced * Western Canadian Select the benchmark crude oil for emerging heavy, high TAN (acidic) crudes. 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—Western Canadian Select—delivered at Hardisty, Alberta, Hardisty, Alberta, and for a Brent Blend delivered at Shetland, it may be a discounted Russian Export Blend delivered at the port of Primorsk, Leningrad Oblast, Primorsk. Once extracted, oil is refined and separated, most easily by
distillation Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, ...
, into numerous products for direct use or use in manufacturing, such as
gasoline Gasoline () or petrol () (see the #Etymology, etymology for naming differences and the use of the term ''gas'') is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignition engine, spark-ignite ...

(petrol),
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...
and
kerosene Kerosene, paraffin, or lamp oil is a combustible , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = G ...

to
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

and chemical
reagent A reagent is a substance or compound added to a system to cause a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter ...
s (ethylene, Propene, propylene, butene, acrylic acid, P-Xylene, para-xylene) used to make
plastic Plastics are a wide range of syntheticA synthetic is an artificial material produced by organic chemistry, organic chemical synthesis. Synthetic may also refer to: In the sense of both "combination" and "artificial" * Synthetic chemical or s ...

s,
pesticide Pesticides are substances that are meant to control pests Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious d ...
s and
pharmaceuticals A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, therapy, treat, or preventive medicine, prevent disease. Drug therapy (pharmacotherapy) ...
.

# Industry

## Transport

In the 1950s, shipping costs made up 33 percent of the price of oil transported from the Persian Gulf to the United States, but due to the development of supertankers in the 1970s, the cost of shipping dropped to only 5 percent of the price of Persian oil in the US. Due to the increase of the value of the crude oil during the last 30 years, the share of the shipping cost on the final cost of the delivered commodity was less than 3% in 2010.

# Uses

The chemical structure of petroleum is Heterogeneity, heterogeneous, composed of hydrocarbon chains of different lengths. Because of this, petroleum may be taken to oil refinery, oil refineries and the hydrocarbon chemicals separated by distillation and treated by other chemical processes, to be used for a variety of purposes. The total cost per plant is about 9 billion dollars.

## Fuels

The most common Fractional distillation, distillation fractions of petroleum are
fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical con ...

s. Fuels include (by increasing boiling temperature range): Petroleum classification according to chemical composition.

## Other derivatives

Certain types of resultant hydrocarbons may be mixed with other non-hydrocarbons, to create other end products: * Alkenes (olefins), which can be manufactured into plastics or other compounds * Lubricants (produces light machine oils, motor oils, and Grease (lubricant), greases, adding viscosity stabilizers as required) * Wax, used in the packaging of frozen foods, among others * Sulfur or sulfuric acid. These are useful industrial materials. Sulfuric acid is usually prepared as the acid precursor oleum, a byproduct of Hydrodesulfurization, sulfur removal from fuels. * Bulk
tar Tar is a dark brown or black viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), ...

* Asphalt * Petroleum coke, used in speciality carbon products or as solid fuel * Paraffin wax * Aromatic petrochemicals to be used as precursors in other chemical production

# Use by country

## Consumption statistics

File:Global Carbon Emissions.svg, Global fossil carbon emissions, an indicator of consumption, from 1800. File:World energy consumption.svg, Rate of world energy usage per year from 1970.BP
Statistical Review of World Energy
, Workbook (xlsx), London, 2012
File:Oil consumption per day by region from 1980 to 2006.svg, Daily oil consumption from 1980 to 2006. File:Oil consumption per day by region from 1980 to 2006 solid3.svg, Oil consumption by percentage of total per region from 1980 to 2006: . File:World oil consumption 1980 to 2007 by region.svg, Oil consumption 1980 to 2007 by region.

## Consumption

According to the US Energy Information Administration (EIA) estimate for 2017, the world consumes 98.8 million barrels of oil each day. This table orders the amount of petroleum consumed in 2011 in thousand Barrel (unit), barrels (1000 bbl) per day and in thousand cubic metres (1000 m3) per day: Source
US Energy Information Administration
Population Data: 1 Peak oil, peak production of oil already passed in this state 2 This country is not a major oil producer

## Production

In petroleum industry parlance, ''production'' refers to the quantity of crude extracted from reserves, not the literal creation of the product.

## Exportation

In order of net exports in 2011, 2009 and 2006 in thousand Barrel (unit), bbl/Day, d and thousand m3/d: Source
US Energy Information Administration
1 Peak oil, 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 in August 2007. Total world production/consumption (as of 2005) is approximately .

## Importation

In order of net imports in 2011, 2009 and 2006 in thousand Barrel (unit), bbl/Day, d and thousand m3/d: Source
US Energy Information Administration

## Non-producing consumers

Countries whose oil production is 10% or less of their consumption. Source

# Environmental effects

## Climate change

, about a quarter of annual global greenhouse gas emissions is the carbon dioxide from burning petroleum (plus methane leaks from the industry). Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO2. Atmospheric CO2 has risen over the last 150 years to current levels of over 415 Parts-per notation, ppmv, from the Carbon dioxide in Earth's atmosphere#Past concentration, 180–300 ppmv of the prior 800 thousand years. The rise in Arctic temperature has reduced the minimum Arctic ice pack to , a loss of almost half since satellite measurements started in 1979. Ocean acidification is the increase in the acidity of the Earth's oceans caused by the uptake of carbon dioxide () from the Earth's atmosphere, atmosphere. This increase in acidity inhibits all marine life—having a greater impact on smaller organisms as well as shelled organisms (see scallops).

## Extraction

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 often environmentally damaging. Offshore exploration and extraction of oil disturb the surrounding marine environment.

## Oil spills

Crude oil and refined fuel Oil spill, spills from tanker (ship), tanker ship accidents have damaged natural ecosystems and human livelihoods in Alaska, the Gulf of Mexico, the Galápagos Islands, France and many List of oil spills, 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, SS Atlantic Empress, Amoco Cadiz). Smaller spills have already proven to have a great impact on ecosystems, such as the Exxon Valdez oil spill, ''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 wreck produced poor results; modern techniques would include pumping the oil from the wreck, like in the Prestige oil spill, ''Prestige'' oil spill or the MV Erika, ''Erika'' oil spill. Though crude oil is predominantly composed of various hydrocarbons, certain nitrogen heterocyclic 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 creosote, 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'' have been shown to degrade these contaminants. 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 (seismology, seismic exploration, Boring (earth), drilling, extraction, refining and combustion). Phenomena such as petroleum seep, seeps and tar pits are examples of areas that petroleum affects without man's involvement.

## Tarballs

A tarball is a blob of crude oil (not to be confused with
tar Tar is a dark brown or black viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), ...

, which is a man-made product derived from pine trees or refined from 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 or in the Gulf of Mexico off Texas. 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, but others say that fossil fuels increased whaling with most whales being killed in the 20th century.

# Alternatives

In the United States in 2007 about 70 percent of petroleum was used for transportation (e.g. gasoline, diesel, jet fuel), 24 percent by industry (e.g. production of plastics), 5 percent for residential and commercial uses, and 2 percent for electricity production. Outside of the US, a higher proportion of petroleum tends to be used for electricity.

## Vehicle fuels

Petroleum-based vehicle fuels can be replaced by either alternative fuels, or other methods of propulsion such as Electric motor, electric or Nuclear power, nuclear. Alternative fuel vehicles refers to both: * Vehicles that use alternative fuels used in standard or modified
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do work (physics), mechanical work. It doe ...

s such as natural gas vehicles, neat ethanol vehicles, flexible-fuel vehicles, biodiesel-powered vehicles, propane autogas, and Hydrogen internal combustion engine vehicle, hydrogen vehicles. * Vehicles with advanced propulsion systems that reduce or substitute petroleum use such as battery electric vehicles, plug-in hybrid electric vehicles, hybrid electric vehicles, and hydrogen vehicle, hydrogen fuel cell vehicles.

## Industrial oils

Biological feedstocks do exist for industrial uses such as Bioplastic production.

## Electricity

In oil producing countries with little refinery capacity, oil is sometimes burned to produce electricity.

# International relations

Control of petroleum production has been a significant driver of international relations during much of the 20th and 21st centuries. Organizations like OPEC have played an outsized role in international politics. Some historians and commentators have called this the "Age of Oil" With the rise of
renewable energy Renewable energy is energy that is collected from renewable resource File:Global Vegetation.jpg, Global vegetation A renewable resource, also known as a flow resource, is a natural resource which will replenish to replace the portion resou ...
and addressing climate change some commentators expect a realignment of international power away from petrostates.

## Conflict

Petroleum production is tightly linked with conflict: whether through direct aggression such as the U.S. invasion of Iraq, trade wars such as 2020 Russia–Saudi Arabia oil price war, the 2020 Russia–Saudi Arabia oil price war, or by fueling conflict in regions such as funding Islamic State of Iraq and the Levant in the Syrian civil war.

# Future production

Consumption function, Consumption in the twentieth and twenty-first centuries has been abundantly pushed by automobile sector growth. The 1980s oil glut, 1985–2003 oil glut even fueled the sales of low fuel economy vehicles in OECD countries. The 2008 economic crisis seems to have had some impact on the sales of such vehicles; still, in 2008 oil consumption showed a small increase. In 2016 Goldman Sachs predicted lower demand for oil due to emerging economies concerns, especially China. The BRICS (Brasil, Russia, India, China, South Africa) countries might also kick in, as China briefly had the largest automobile market in December 2009. 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 oil sales, and both OPEC and the Energy Information Administration (EIA) kept lowering their 2020 consumption estimates during the past five years. A detailed review of International Energy Agency oil projections have revealed that revisions of world oil production, price and investments have been motivated by a combination of demand and supply factors. All together, Non-OPEC conventional projections have been fairly stable the last 15 years, while downward revisions were mainly allocated to OPEC. Recent upward revisions are primarily a result of US tight oil. 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 oil field, Tupi, Guara and Tiber oilfield, 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 Field, DaQing, China) will continue to play a major role in increasing the world's recoverable oil. The expected availability of petroleum resources has always been around 35 years or even less since the start of the modern exploration. The oil constant, an insider pun in the German industry, refers to that effect. A growing number of divestment campaigns from major funds pushed by newer generations who question the sustainability of petroleum may hinder the financing of future oil prospection and production.

## Peak oil

Peak oil is a term applied to the 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. However, this does not mean that potential oil production has surpassed oil demand. 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. 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. The peak is also a moving target as it is now measured as "liquids", which includes synthetic fuels, instead of just conventional oil. In 2020, according to BP#Climate policy, BP's Energy Outlook 2020, peak oil had been reached, due to the changing energy landscape coupled with the Financial market impact of the COVID-19 pandemic#Oil prices, economic toll of the COVID-19 pandemic. While there has been much focus historically on peak oil supply, focus is increasingly shifting to peak demand as more countries seek to transition to renewable energy. The GeGaLo index of geopolitical gains and losses assesses how the geopolitical position of 156 countries may change if the world fully transitions to renewable energy resources. Former oil exporters are expected to lose power, while the positions of former oil importers and countries rich in renewable energy resources is expected to strengthen.

## Unconventional oil

Unconventional oil is petroleum produced or extracted using techniques other than the conventional methods. The calculus for peak oil has changed with the introduction of unconventional production methods. In particular, the combination of horizontal drilling and
hydraulic fracturing Hydraulic fracturing, also called fracking, hydrofracking, and hydrofracturing, is a well stimulation technique involving the fracturing of bedrock Formation (geology), formations by a pressurized liquid. The process involves the high-pressur ...
has resulted in a significant increase in production from previously uneconomic plays. Analysts expected that \$150 billion would be spent on further developing North American tight oil fields in 2015. The large increase in tight oil production is one of the reasons behind the price drop in late 2014. Certain rock strata contain hydrocarbons but have low permeability and are not thick from a vertical perspective. Conventional vertical wells would be unable to economically retrieve these hydrocarbons. Horizontal drilling, extending horizontally through the strata, permits the well to access a much greater volume of the strata. Hydraulic fracturing creates greater permeability and increases hydrocarbon flow to the wellbore.

# Hydrocarbons on other worlds

On Saturn (planet), Saturn's largest moon, Titan (moon), Titan, lakes of liquid hydrocarbons comprising methane, ethane, propane and other constituents, occur naturally. Data collected by the space probe ''Cassini–Huygens'' yield an estimate that the visible lakes and seas of Titan contain about 300 times the volume of Earth's proven oil reserves.

# See also

* Barrel of oil equivalent * Filling station * Gas oil ratio * List of oil exploration and production companies * List of oil fields * Manure-derived synthetic crude oil * Oil burden * Petroleum geology * Petroleum politics * Petrocurrency * Thermal depolymerization * Total petroleum hydrocarbon * Waste oil

# References

* * translated 1955 * * * * * * * Mirbabayev M.F.(2017).Brief history of the first drilled oil well;and the people involved.-"Oil-Industry History"(US),vol.18,#1, p. 25-34.

# Further reading

* Antonia Juhasz, Juhasz, Antonia, "The End of OIL?: The COVID-19 pandemic, pandemic has battered an already struggling oil industry. Whether it survives is up to us", ''Sierra Magazine'', vol. 105, no. 5 (September / October 2020), pp. 36–40, 51. *

# External links

Global Fossil Infrastructure Tracker

API – the trade association of the US oil industry.
(American Petroleum Institute)
U.S. Energy Information Administration
*

* [https://www.jodidata.org/ Joint Organisations Data Initiative , Oil and Gas Data Transparency]
U.S. National Library of Medicine: Hazardous Substances Databank – Crude Oil
*
A Short History of Petroleum
, Scientific American, 10 August 1878, p. 85 {{Authority control Petroleum, Chemical mixtures Glassforming liquids and melts Causes of war