Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black
liquid mixture of mainly
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s, and is found in
geological formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
s. The name ''petroleum'' covers both naturally occurring unprocessed crude oil and
petroleum products that consist of refined crude oil. A
fossil fuel, petroleum is formed when large quantities of dead organisms, mostly
zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
and
algae, are buried underneath
sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
and subjected to both prolonged heat and pressure.
Petroleum is primarily recovered by
oil drilling
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may ...
. Drilling is carried out after studies of structural geology, sedimentary basin analysis, and reservoir characterisation. Recent developments in 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 petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and wate ...
and
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
.
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 by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...
, into innumerable products for direct use or use in manufacturing. Products include fuels such as
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organi ...
(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 engin ...
,
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
and
jet fuel among many others;
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...
and
lubricants; chemical
reagents used to make
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
s;
solvents,
textiles,
refrigerants
A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated d ...
,
paint,
synthetic rubber,
fertilizers
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
,
pesticides,
pharmaceuticals, and thousands of others. Petroleum is used in manufacturing a vast variety of materials essential for modern life,
and it is estimated that the world consumes about each day. Petroleum production can be extremely profitable and was critical to global economic development in the 20th century, with some countries, so called "
oil states
A petrostate or oil state is a nation whose economy is heavily dependent on the extraction and export of oil or natural gas. The presence alone of large oil and gas industries does not define a petrostate; countries like Norway, Canada, and the Uni ...
", gaining significant economic and international power because of their control of oil production.
Petroleum exploitation and use has had significant negative environmental and social consequences.
Extraction,
refining and
burning of petroleum fuels all release large quantities of
greenhouse gases, so petroleum is one of the
major contributors to climate change. Other
negative environmental effects include
oil spills, and air and water pollution. Some of these effects have direct and indirect health consequences for humans. Oil has also been a source of conflict leading to both
state-led-wars and other conflicts. Production of petroleum is speculated to reach
peak oil
Peak oil is the hypothetical point in time when the maximum rate of global oil production is reached, after which it is argued that production will begin an irreversible decline. It is related to the distinct concept of oil depletion; whil ...
before 2035 as global economies lower dependencies on petroleum as part of
climate change mitigation and a transition towards
renewable energy and
electrification
Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source.
The broad meaning of the term, such as in the history of technology, economic histor ...
.
Etymology
The word ''petroleum'' comes from Medieval Latin (literally 'rock oil'), which comes from Latin
petra 'rock' (from Greek ) and
oleum '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, first published in 1546. The book represents the first scientific attempt to categorize minerals, rocks and sediments since the publication of ...
'', published in 1546 by the German mineralogist
Georg Bauer
Georgius Agricola (; born Georg Pawer or Georg Bauer; 24 March 1494 – 21 November 1555) was a German Humanist scholar, mineralogist and metallurgist. Born in the small town of Glauchau, in the Electorate of Saxony of the Holy Roman Empire ...
, 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 from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils.
The name 'mineral oil' by itself is imprecise, ...
s produced by distillation from mined organic solids such as
cannel coal (and later
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
) 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. More than 4300 years ago,
bitumen was mentioned when the Sumerians used it to make boats. Tablet of the legend of the birth of
Sargon of Akkad, mentioned a basket which was closed by straw and bitumen. More than 4000 years ago, according to
Herodotus
Herodotus ( ; grc, , }; BC) was an ancient Greek historian and geographer
A geographer is a physical scientist, social scientist or humanist whose area of study is geography, the study of Earth's natural environment and human society ...
and
Diodorus Siculus,
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...
was used in the construction of the walls and towers of
Babylon; there were oil pits near Ardericca (near Babylon), and a pitch spring on
Zacynthus
Zakynthos (also spelled Zakinthos; el, Ζάκυνθος, Zákynthos ; it, Zacinto ) or Zante (, , ; el, Τζάντε, Tzánte ; from the Venetian form) is a Greek island in the Ionian Sea. It is the third largest of the Ionian Islands. Zak ...
.
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. Together with the Tigris, it is one of the two defining rivers of Mesopotamia ( ''the land between the rivers''). Originating in Turkey, the Eup ...
. Ancient
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
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'', 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 was often distilled by
Persian chemists, with clear descriptions given in Arabic handbooks such as those of
Muhammad ibn Zakarīya Rāzi
Abū Bakr al-Rāzī (full name: ar, أبو بکر محمد بن زکریاء الرازي, translit=Abū Bakr Muḥammad ibn Zakariyyāʾ al-Rāzī, label=none), () rather than ar, زکریاء, label=none (), as for example in , or in . In m ...
(Rhazes). The streets of
Baghdad
Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon. I ...
were paved with
tar
Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bi ...
, derived from petroleum that became accessible from natural fields in the region. In the 9th century,
oil fields were exploited in the area around modern
Baku,
Azerbaijan
Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan, , also sometimes officially called the Azerbaijan Republic is a transcontinental country located at the boundary of Eastern Europe and Western Asia. It is a part of t ...
. These fields were described by the
Arab geographer
Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age (variously dated between the 8th century and 16th century). Muslim scholars made advances to the map-maki ...
Abu al-Hasan 'Alī al-Mas'ūdī
Al-Mas'udi ( ar, أَبُو ٱلْحَسَن عَلِيّ ٱبْن ٱلْحُسَيْن ٱبْن عَلِيّ ٱلْمَسْعُودِيّ, '; –956) was an Arab historian, geographer and traveler. He is sometimes referred to as the "Herodotus ...
in the 10th century, and by
Marco Polo 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 products for military purposes. Through
Islamic Spain
Al-Andalus translit. ; an, al-Andalus; ast, al-Ándalus; eu, al-Andalus; ber, ⴰⵏⴷⴰⵍⵓⵙ, label= Berber, translit=Andalus; ca, al-Àndalus; gl, al-Andalus; oc, Al Andalús; pt, al-Ândalus; es, al-Ándalus () was the Mu ...
, distillation became available in
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context.
The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
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 and other
Iroquois
The Iroquois ( or ), officially the Haudenosaunee ( meaning "people of the longhouse"), are an Iroquoian-speaking confederacy of First Nations peoples in northeast North America/ Turtle Island. They were known during the colonial years to ...
in
Western Pennsylvania
Western Pennsylvania is a region in the U.S. state of Pennsylvania, covering the western third of the state. Pittsburgh is the region's principal city, with a metropolitan area population of about 2.4 million people, and serves as its economic ...
as early as 1415–1450. The French General
Louis-Joseph de Montcalm 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 Wells explai ...
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 Div ...
that, in 1795, had hundreds of hand-dug wells under production.
Pechelbronn
Merkwiller-Pechelbronn () is a commune in the Bas-Rhin department in Grand Est in north-eastern France.
It is notable as the original home of oil sands mining.
Oil sands were mined from 1745 in Merkwiller-Pechelbronn, initially under the direc ...
(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, Germany. It is situated at the confluence of the river Aller and its tributary Wietze, approx. 15 km west of Celle
Celle () is a town and capital of the district of ...
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 Young 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 o ...
colliery
Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from ...
at
Alfreton
Alfreton ( ) is a town and 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 2011 Census. The villages of Ir ...
,
Derbyshire
Derbyshire ( ) is a ceremonial county in the East Midlands, England. It includes much of the Peak District National Park, the southern end of the Pennine range of hills and part of the National Forest. It borders Greater Manchester to the nor ...
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 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, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to ...
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, Scotland, west of Livingston, Scotland, Livingston and adjacent to the M8 motorway (Scotland), M8 motorway. Nearby towns are Armadale, West Lothian, Armadale, Blackburn, ...
in
West Lothian 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
Jan Józef Ignacy Łukasiewicz (; 8 March 1822 – 7 January 1882) was a Polish pharmacist, engineer, businessman, inventor, and philanthropist. He was one of the most prominent philanthropists in the Kingdom of Galicia and Lodomeria, crown land o ...
. 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.
Early life
Edwin Drake was born in Greenville, New York on March 2 ...
'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 1858 in
Wietze
Wietze is a municipality in the district of Celle, in Lower Saxony, Germany. It is situated at the confluence of the river Aller and its tributary Wietze, approx. 15 km west of Celle
Celle () is a town and capital of the district of ...
, 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 in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...
in 1853, and another in nearby
Romania
Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...
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 Lesse ...
in Poland, with a larger one opened at
Ploiești
Ploiești ( , , ), formerly spelled Ploești, is a city and county seat in Prahova County, Romania. Part of the historical region of Muntenia, it is located north of Bucharest.
The area of Ploiești is around , and it borders the Blejoi commune ...
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, Canada, located along Former Provincial Highway 21 south of Oil City. The village, an enclave within Enniskillen Township, is the site of North America's first commercial oil well. It is home ...
(then
Canada West
The Province of Canada (or the United Province of Canada or the United Canadas) was a British colony in North America from 1841 to 1867. Its formation reflected recommendations made by John Lambton, 1st Earl of Durham, in the Report on the ...
).
[Oil Museum of Canada, Black Gold: Canada's Oil Heritage, Oil Springs: Boom & Bust](_blank)
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 i ...
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 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 or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, 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 company in
Azerbaijan
Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan, , also sometimes officially called the Azerbaijan Republic is a transcontinental country located at the boundary of Eastern Europe and Western Asia. It is a part of t ...
, 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 world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
, during which oil facilities were a major strategic asset and were
extensively bombed. The
German invasion of the Soviet Union
Operation Barbarossa (german: link=no, Unternehmen Barbarossa; ) was the invasion of the Soviet Union by Nazi Germany and many of its Axis allies, starting on Sunday, 22 June 1941, during the Second World War. The operation, code-named afte ...
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
Events January
* January 1 - The United Kingdom, the Republic of Ireland and Denmark 1973 enlargement of the European Communities, enter the European Economic Community, which later becomes the European Union.
* January 15 – Vietnam War: ...
, Saudi Arabia and other
Arab nations
The Arab world ( ar, اَلْعَالَمُ الْعَرَبِيُّ '), formally the Arab homeland ( '), also known as the Arab nation ( '), the Arabsphere, or the Arab states, refers to a vast group of countries, mainly located in Western As ...
imposed an
oil embargo An oil embargo is an economic situation wherein entities engage in an embargo to limit the transport of petroleum to or from an area, in order to exact some desired outcome. One commentator states, " oil embargo is not a common commercial practice; ...
against the United States, United Kingdom, Japan and other Western nations which supported
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
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 October 6 to 25, 1973 between Israel and a coalition of Arab states led by E ...
of October 1973. The embargo caused an
oil crisis. This was followed by the
1979 oil crisis, which was caused by a drop in
oil production
Petroleum is a fossil fuel that can be drawn from beneath the earth's surface. Reservoirs of petroleum was formed through the mixture of plants, algae, and sediments in shallow seas under high pressure. Petroleum is mostly recovered from oil dri ...
in the wake of the
Iranian Revolution
The Iranian Revolution ( fa, انقلاب ایران, Enqelâb-e Irân, ), also known as the Islamic Revolution ( fa, انقلاب اسلامی, Enqelâb-e Eslâmī), was a series of events that culminated in the overthrow of the Pahlavi dyna ...
and caused oil prices to more than double. The two oil price shocks had many short- and long-term effects on global politics and the global economy. In particular, they led to sustained reductions in demand as a result of substitution to other fuels (especially coal and nuclear) and improvements in energy efficiency, facilitated by government policies. High oil prices also induced investment in oil production by non-OPEC countries, including Prudhoe Bay in Alaska, the North Sea offshore fields of the United Kingdom and Norway, the Cantarell offshore field of Mexico, and oil sands in Canada.
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.
The top three oil producing countries are 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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
,
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
, and
Saudi Arabia
Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in Western Asia. It covers the bulk of the Arabian Peninsula, and has a land area of about , making it the fifth-largest country in Asia, the second-largest in the A ...
.
In 2018, due in part to developments in
hydraulic fracturing and
horizontal drilling
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal dir ...
, 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
Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in Western Asia. It covers the bulk of the Arabian Peninsula, and has a land area of about , making it the fifth-largest country in Asia, the second-largest in the A ...
,
United Arab Emirates
The United Arab Emirates (UAE; ar, اَلْإِمَارَات الْعَرَبِيَة الْمُتَحِدَة ), or simply the Emirates ( ar, الِْإمَارَات ), is a country in Western Asia ( The Middle East). It is located at t ...
,
Iraq
Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to the north, Iran to the east, the Persian Gulf and K ...
,
Qatar
Qatar (, ; ar, قطر, Qaṭar ; local vernacular pronunciation: ), officially the State of Qatar,) is a country in Western Asia. It occupies the Qatar Peninsula on the northeastern coast of the Arabian Peninsula in the Middle East; it ...
and
Kuwait
Kuwait (; ar, الكويت ', or ), officially the State of Kuwait ( ar, دولة الكويت '), is a country in Western Asia. It is situated in the northern edge of Eastern Arabia at the tip of the Persian Gulf, bordering Iraq to the nort ...
. A large portion of the world's total oil exists as unconventional sources, such as
bitumen in
Athabasca oil sands and
extra heavy oil
Heavy crude oil (or extra heavy crude oil) is highly-viscous oil that cannot easily flow from production wells under normal reservoir conditions.
It is referred to as "heavy" because its density or specific gravity is higher than that of light cr ...
in the
Orinoco 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, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
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 Ea ...
,
ethane
Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petroc ...
,
propane and
butane exist as gases, while
pentane 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 accumulation of hydrocarbons contained in porous or fractured rock formations.
Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...
the proportions of gas, liquid, and solid depend on subsurface conditions and on the
phase diagram of the petroleum mixture.
An
oil well produces predominantly crude oil, with some natural gas
dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of
solution
Solution may refer to:
* Solution (chemistry), a mixture where one substance is dissolved in another
* Solution (equation), in mathematics
** Numerical solution, in numerical analysis, approximate solutions within specified error bounds
* Soluti ...
and be recovered (or burned) as ''associated gas'' or ''solution gas''. A
gas well
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas m ...
produces predominantly
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
. 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.
It is a colorless liquid, odorless when pure, and with boiling points approximately . It is widely used as a cheap, relatively ...
, and
heptane
Heptane or ''n''-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 poin ...
in the
gaseous state
Gas is one of the four fundamental state of matter, states of matter (the others being solid, liquid, and plasma (physics), plasma).
A pure gas may be made up of individual atoms (e.g. a noble gas like neon), chemical element, elemental molec ...
. At surface conditions these will
condense
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...
out of the gas to form "
natural-gas condensate
Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields. Some gas species within the raw natur ...
", often shortened to ''condensate.'' Condensate resembles gasoline in appearance and is similar in composition to some
volatile light crude oil Light crude oil is liquid petroleum that has a low density and flows freely at room temperature. It has a low viscosity, low specific gravity and high API gravity due to the presence of a high proportion of light hydrocarbon fractions. It generally ...
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 accumulation of hydrocarbons contained in porous or fractured rock formations.
Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...
, ranging from as much as 97 percent by weight in the lighter oils to as little as 50 percent in the heavier oils and
bitumens.
The hydrocarbons in crude oil are mostly
alkanes,
cycloalkanes and various
aromatic hydrocarbon
Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...
s, while the other organic compounds contain
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
,
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
and
sulfur, and trace amounts of metals such as iron, nickel, copper and
vanadium. 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
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
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 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
Athabasca oil sands in Canada, where it is usually referred to as crude
bitumen. In Canada, bitumen is considered a sticky, black, tar-like form of crude oil which is so thick and heavy that it must be heated or diluted before it will flow. Venezuela also has large amounts of oil in the
Orinoco oil sands
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 language, Spanish name is ''Faja Petrolífera del Orinoco'' (Orinoco P ...
, although the hydrocarbons trapped in them are more fluid than in Canada and are usually called
extra heavy oil
Heavy crude oil (or extra heavy crude oil) is highly-viscous oil that cannot easily flow from production wells under normal reservoir conditions.
It is referred to as "heavy" because its density or specific gravity is higher than that of light cr ...
. 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
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
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
Primary energy (PE) is an energy form found in nature that has not been subjected to any human engineered conversion process. It is energy contained in raw fuels, and other forms of energy, including waste, received as input to a system. Prim ...
'' sources. Eight-four 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 refineries
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, lique ...
are increasingly having to process heavy oil and bitumen, and use more complex and expensive methods to produce the products required. Because heavier crude oils have too much carbon and not enough hydrogen, these processes generally involve removing carbon from or adding hydrogen to the molecules, and using
fluid catalytic cracking to convert the longer, more complex molecules in the oil to the shorter, simpler ones in the fuels.
Due to its high
energy density, easy transportability and
relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many
chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...
products, including
pharmaceutical
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field an ...
s,
solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
s,
fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
s,
pesticides, and plastics; the 16 percent not used for energy production is converted into these other materials. Petroleum is found in
porous
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure ...
rock formations
A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock formation'' can also refer to specific sedimen ...
in the upper
strata of some areas of the
Earth's crust. There is also petroleum in
oil sands (tar sands). Known
oil reserves
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...
are typically estimated at 190 km
3 (1.2
trillion
''Trillion'' is a number with two distinct definitions:
* 1,000,000,000,000, i.e. one million million, or (ten to the twelfth power), as defined on the short scale. This is now the meaning in both American and British English.
* 1,000,000,000,0 ...
(short scale) barrels
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, u ...
) without oil sands, or 595 km
3 (3.74 trillion barrels) with oil sands. Consumption is currently around per day, or 4.9 km
3 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 mainly a mixture of
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s, i.e. containing only carbon and hydrogen. The most common components are
alkanes (paraffins),
cycloalkanes (
naphthene
In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the monocyclic saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing ...
s), and
aromatic hydrocarbon
Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...
s. They generally have from 5 to 40 carbon atoms per molecule, although trace amounts of shorter or longer molecules may be present in the mixture.
The alkanes from
pentane (C
5H
12) to
octane (C
8H
18) are
refined into gasoline, the ones from
nonane
Nonane is a linear alkane hydrocarbon with the chemical formula C9H20. It is a colorless, flammable liquid, occurring primarily in the component of the petroleum distillate fraction commonly called kerosene, which is used as a heating, tractor, ...
(C
9H
20) to
hexadecane
Hexadecane (also called cetane) is an alkane hydrocarbon with the chemical formula C16H34. Hexadecane consists of a chain of 16 carbon atoms, with three hydrogen atoms bonded to the two end carbon atoms, and two hydrogens bonded to each of the ...
(C
16H
34) into
diesel fuel
Diesel fuel , also called diesel oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and ...
,
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
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, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to ...
is an alkane with approximately 25 carbon atoms, while
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...
has 35 and up, although these are usually
cracked
Cracked may refer to: Television
* ''Cracked'' (British TV series), a 2008 British comedy-drama television series that aired on STV
* ''Cracked'' (Canadian TV series), a 2013 Canadian crime drama series that aired on CBC
* "Cracked", a Season 8 ( ...
by modern refineries into more valuable products. The shortest molecules, those with four or fewer carbon atoms, are in a gaseous state at room temperature. They are the petroleum gases. Depending on demand and the cost of recovery, these gases are either
flared off, sold as
liquefied petroleum gas under pressure, or used to power the refinery's own burners. During the winter, butane (C
4H
10), 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 ''aromatic hydrocarbons'' are
unsaturated hydrocarbons
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
which have one or more planar six-carbon rings called
benzene ring
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atom ...
s, to which hydrogen atoms are attached with the formula C
nH
2n-6. They tend to burn with a sooty flame, and many have a sweet aroma. Some are
carcinogenic
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...
.
These different molecules are separated by
fractional distillation at an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbons. For example,
2,2,4-trimethylpentane
2,2,4-Trimethylpentane, also known as isooctane or iso-octane, is an organic compound with the formula (CH3)3CCH2CH(CH3)2. It is one of several isomers of octane (C8H18). This particular isomer is the standard 100 point on the octane rating scale ...
(isooctane), widely used in
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organi ...
, has a chemical formula of C
8H
18 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
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
, then separated in a
gas chromatograph
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, ...
, and finally determined with a suitable
detector
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
, such as a
flame ionization detector
A flame ionization detector (FID) is a scientific instrument that measures analytes in a gas stream. It is frequently used as a detector in gas chromatography. The measurement of ion per unit time make this a mass sensitive instrument. Standalo ...
or a
mass spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...
. Due to the large number of co-eluted hydrocarbons within oil, many cannot be resolved by traditional gas chromatography and typically appear as a hump in the chromatogram. This
Unresolved Complex Mixture (UCM) of hydrocarbons is particularly apparent when analysing weathered oils and extracts from tissues of organisms exposed to oil. Some of the components of oil will mix with water: the
water associated fraction The water associated fraction (WAF), sometimes termed the water-soluble fraction (W.S.F.), is the solution of low molecular mass hydrocarbons naturally released from petroleum hydrocarbon mixtures in contact with water. Although generally regarded ...
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
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
. 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
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words ''smoke'' and ''fog'' to refer to smoky fog due to its opacity, and odor. The word was then inten ...
.
Formation
Fossil petroleum
Petroleum is a
fossil fuel derived from ancient
fossilized
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
organic material
Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...
s, such as
zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
and
algae.
Vast amounts of these remains settled to sea or lake bottoms where they were covered in
stagnant water (water with no dissolved
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
) or
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...
s such as
mud and
silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel ...
faster than they could
decompose aerobically. Approximately 1
m below this sediment, water oxygen concentration was low, below 0.1 mg/L, and
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
Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...
, found in various
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
s around the world, and then with more heat into liquid and gaseous
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s via a process known as
catagenesis. Formation of petroleum occurs from hydrocarbon
pyrolysis
The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...
in a variety of mainly
endothermic
In thermochemistry, an endothermic process () is any thermodynamic process with an increase in the enthalpy (or internal energy ) of the system.Oxtoby, D. W; Gillis, H.P., Butler, L. J. (2015).''Principle of Modern Chemistry'', Brooks Cole. ...
reactions at high temperature or pressure, or both.
These phases are described in detail below.
Anaerobic decay
In the absence of plentiful oxygen,
''aerobic'' bacteria were prevented from decaying the organic matter after it was buried under a layer of sediment or water. However,
''anaerobic'' bacteria were able to reduce
sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
s and
nitrates among the matter to
H2S and
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
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolys ...
:
polysaccharides and
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
s were hydrolyzed to
simple sugars
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...
and
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
s respectively. These were further anaerobically
oxidized
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
at an accelerated rate by the
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s of the bacteria: e.g., amino acids went through
oxidative deamination to
imino acid
In organic chemistry, an imino acid is any molecule that contains both imine (>C=NH) and carboxyl (-C(=O)-OH) functional groups.
Imino acids are structurally related to amino acids, which have amino group instead of imine—a difference of si ...
s, which in turn reacted further to
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
and Keto acid, α-keto acids. Monosaccharides in turn ultimately decayed to Carbon dioxide, CO
2 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 Ea ...
. 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
Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...
. 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 Ea ...
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. Three types of kerogen exist: type I (algal), II (liptinic) and III (humic), which were formed mainly from
algae, 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, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
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 forms, from which the liquid can be extracted by drilling and pumping.
The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where hydrocarbons are broken down to oil and natural gas by a set of parallel reactions, and oil eventually breaks down to natural gas by another set of reactions. The latter set is regularly used in petrochemical plants and
oil refineries
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, lique ...
.
Petroleum has mostly been recovered by
oil drilling
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may ...
(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 petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and wate ...
and
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
. 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
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
. 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
Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...
. 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 by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...
, into numerous products for direct use or use in manufacturing, such as Gasoline, petrol (gasoline),
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 engin ...
and
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
to
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...
and chemical
reagents (ethylene, Propene, propylene, butene, acrylic acid, P-Xylene, para-xylene) used to make
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
s,
pesticides and
pharmaceuticals.
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.
Price
Trade
Crude oil is traded as a future on the Nymex exchange. Futures contracts are agreements in which buyers and sellers agree to purchase and deliver specific amounts of physical crude oil on a given date in the future. Each contract covers 1000 barrels and can be purchased up to nine years into the future.
Below are the contract specifications for crude oil:
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 fuels. 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 liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bi ...
* Asphalt
* Petroleum coke, used in speciality carbon products or as solid fuel
* Paraffin wax
* Aromatic petrochemicals to be used as precursors in other
chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...
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 m
3) 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 m
3/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 m
3/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 CO
2. Atmospheric CO
2 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#Concentrations in the geologic past, 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 liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bi ...
, 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 2018 road transport used 49% of petroleum, aviation 8%, and uses other than energy 17%. Electric vehicles are the main alternative for road transport and Aviation biofuel, biojet for aviation. Single-use plastics have a high carbon footprint and may pollute the sea, but as of 2022 the best alternatives are unclear.
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 and addressing climate change some commentators expect a realignment of international power away from petrostates.
Corruption
"Oil rents" have been described as connected with corruption in political literature. A 2011 study suggested that increases in oil rents increased corruption in countries with heavy government involvement in the production of oil. The study found that increases in oil rents "significantly deteriorates political rights". The researchers noted oil exploitation gave politicians "an incentive to extend civil liberties but reduce political rights in the presence of oil windfalls to evade redistribution and conflict".
Conflict
Petroleum production can be linked with conflict: whether through direct aggression, trade wars such as 2020 Russia–Saudi Arabia oil price war, the 2020 Russia–Saudi Arabia oil price war, or by indirectly funding aggressors, such as the Islamic State of Iraq and the Levant.
OPEC
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 lowering 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.
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
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal dir ...
and
hydraulic fracturing 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.
Drilled samples from the surface of Mars taken in 2015 by the Curiosity Rover, ''Curiosity'' rover's Mars Science Laboratory have found organic molecules of benzene and
propane in 3-billion-year-old rock samples in Gale Crater.
[
]
In fiction
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
* Unconventional (oil & gas) reservoir
Citations
Explanatory footnotes
General and cited 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 TrackerAPI – 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 OilBest Dubai Desert Safari Deals*
A Short History of Petroleum, Scientific American, 10 August 1878, p. 85
{{Authority control
Petroleum,
Causes of war
Chemical mixtures
Glassforming liquids and melts