Petroleum#Transformation of kerogen into fossil fuels

File:Fractional distillation apparatus.jpg

The word petroleum comes from Medieval Latin {{wikt-lang|la|petroleum}} (literally 'rock oil'), which comes from Latin petra 'rock' (from Greek {{transliteration|grc|pétra}} {{wikt-lang|grc|πέτρα}}) and oleum 'oil' (from Greek {{transliteration|grc|élaion}} {{wikt-lang|grc|ἔλαιον}}).[https://www.ahdictionary.com/word/search.html?q=petroleum "petroleum"] {{Webarchive|url=https://web.archive.org/web/20200516164428/https://www.ahdictionary.com/word/search.html?q=petroleum |date=May 16, 2020 }}, in the American Heritage Dictionary[http://www.thefreedictionary.com/petroleum Petroleum], Medieval Latin: literally, rock oil = Latin petr(a) rock (< Greek pétra) + oleum oil, The Free Dictionary.com. {{Webarchive|url=https://web.archive.org/web/20170110024856/http://www.thefreedictionary.com/petroleum|date=January 10, 2017}}

The origin of the term stems from monasteries in southern Italy where it was in use by the end of the first millennium as an alternative for the older term "naphtha".van Dijk, J.P. (2022); Unravelling the Maze of Scientific Writing Through the Ages: On the Origins of the Terms Hydrocarbon, Petroleum, Natural Gas, and Methane. Amazon Publishers, 166 pp. PaperBack Edition B0BKRZRKHW. {{ISBN|979-8-3539-8917-2|invalid1=yes}} After that, the term was used in numerous manuscripts and books, such as in the treatise De Natura Fossilium, published in 1546 by the German mineralogist Georg Bauer, also known as Georgius Agricola.{{cite book |author-link=Georg Bauer |author=Bauer, Georg |date=1955 |translator=Bandy, Mark Chance |translator2=Bandy, Jean A. |title=De Natura Fossilium |location=Mineola, NY |publisher=Dover |orig-date=1546}} After the advent of the oil industry, during the second half of the 19th century, the term became commonly known for the liquid form of hydrocarbons.

{{Main|History of the petroleum industry}}

File:Edwindrake.jpg drilled the world's first successful oil well at what is now known as Drake Well in Cherrytree Township, Pennsylvania]]

File:Gusher Okemah OK 1922.jpg in 1922]]

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. A tablet of the legend of the birth of Sargon of Akkad mentions a basket which was closed by straw and bitumen. More than 4000 years ago, according to Herodotus and Diodorus Siculus, asphalt was used in the construction of the walls and towers of Babylon; there were oil pits near Ardericca and Babylon, and a pitch spring on Zakynthos.{{EB1911|wstitle=Petroleum |volume=21 |page=316 |first=Boverton |last=Redwood |inline=1}} Great quantities of it were found on the banks of the river Issus, one of the tributaries of the Euphrates. Ancient Persian tablets indicate the medicinal and lighting uses of petroleum in the upper levels of their society.

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.{{Cite book |last=Zhiguo |first=Gao |title=Environmental regulation of oil and gas |date=1998 |publisher=Kluwer Law International |isbn=978-90-411-0726-8 |location=London |page=8 |oclc=39313498}}{{Cite book |last=Deng |first=Yinke |url=https://archive.org/details/ancientchinesein0000deng |title=Ancient Chinese Inventions |publisher=Cambridge University Press |year=2011 |isbn=978-0-521-18692-6 |page=[https://archive.org/details/ancientchinesein0000deng/page/40 40] |url-access=registration}}{{Cite book |last=Burke |first=Michael |title=Nanotechnology: The Business |publisher=Taylor & Francis |year=2008 |isbn=978-1-4200-5399-9 |page=3}} By 347 CE, oil was produced from bamboo-drilled wells in China.{{Cite web |last=Totten |first=George E. |title=ASTM International – Standards Worldwide |url=http://www.astm.org/COMMIT/D02/to1899_index.html |url-status=live |archive-url=https://web.archive.org/web/20170706232229/https://www.astm.org/COMMIT/D02/to1899_index.html |archive-date=July 6, 2017 |access-date=March 18, 2018 |website=astm.org}}{{Cite book |last=Dalvi |first=Samir |title=Fundamentals of Oil & Gas Industry for Beginners |publisher=Notion Press |year=2015 |isbn=978-93-5206-419-9}}

In the 7th century, petroleum was among the essential ingredients for Greek fire, an incendiary projectile weapon that was used by Byzantine Greeks against Arab ships, which were then attacking Constantinople.{{Cite encyclopedia |title=Greek fire {{!}} Byzantine, Naval Warfare, Incendiary {{!}} Britannica |url=https://www.britannica.com/technology/Greek-fire |access-date=October 1, 2023 |encyclopedia=Encyclopædia Britannica |language=en}} Crude oil was also distilled by Persian chemists, with clear descriptions given in Arabic handbooks such as those of Abu Bakr al-Razi (Rhazes).{{Cite book |last=Forbes |first=Robert James |url=https://books.google.com/books?id=eckUAAAAIAAJ&pg=PA149 |title=Studies in Early Petroleum History |date=1958 |publisher=Brill Publishers |page=149 |access-date=April 3, 2019 |archive-url=https://web.archive.org/web/20200315165347/https://books.google.com/books?id=eckUAAAAIAAJ&pg=PA149 |archive-date=March 15, 2020 |url-status=live}} The streets of Baghdad were paved with tar, 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. These fields were described by the Persian geographer Abu Bakr al-Razi in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads.{{Cite book |last=Salim Al-Hassani |title=A shared legacy: Islamic science East and West |publisher=Edicions Universitat Barcelona |year=2008 |isbn=978-84-475-3285-8 |editor-last=Emilia Calvo Labarta |pages=57–82 [63] |chapter=1000 Years of Missing Industrial History |author-link=Salim Al-Hassani |editor-last2=Mercè Comes Maymo |editor-last3=Roser Puig Aguilar |editor-last4=Mònica Rius Pinies}} Arab and Persian chemists also distilled crude oil to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century.{{Cite encyclopedia |title=petroleum |encyclopedia=Encyclopædia Britannica |url=http://www.britannica.com/EBchecked/topic/454269/petroleum |access-date=June 30, 2008 |archive-url=https://web.archive.org/web/20150429155229/http://www.britannica.com/EBchecked/topic/454269/petroleum |archive-date=April 29, 2015 |last2=Gordon I. Atwater |author1=Joseph P. Riva Jr. |url-status=live}} It has also been present in Romania since the 13th century, being recorded as păcură.Istoria Romaniei, Vol II, p. 300, 1960

Sophisticated oil pits, {{convert|15|to|20|ft|m|order=flip|round=0.5}} deep, were dug by the Seneca people and other Iroquois in Western Pennsylvania 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.{{Cite book |last1=Keoke |first1=Emory Dean |title=American Indian Contributions to the World: 15,000 Years of Inventions and Innovations |last2=Porterfield |first2=Kay Marie |publisher=Facts on File |year=2003 |isbn=978-0-8160-5367-4 |page=199}}

Early British explorers to Myanmar documented a flourishing oil extraction industry based in Yenangyaung that, in 1795, had hundreds of hand-dug wells under production.{{Cite book |last=Longmuir |first=Marilyn V. |title=Oil in Burma: the extraction of "earth-oil" to 1914 |date=2001 |publisher=White Lotus Press |isbn=978-974-7534-60-3 |location=Bangkok |page=329 |oclc=48517638}}

Merkwiller-Pechelbronn 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.

File:West Lothian shale bing, Scotland.JPG near Broxburn, three of a total of 19 in West Lothian, Scotland]]

File:Ride with hitler.jpg poster promoting carpooling as a way to ration vital gasoline during the war]]

There was activity 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.{{Cite journal |last=Matveichuk |first=Alexander A |date=2004 |title=Intersection of Oil Parallels: Historical Essays |journal=Russian Oil and Gas Institute}} There were engine-drilled wells in West Virginia in 1859, the same year as Drake's well.{{Cite book |last1=McKain |first1=David L. |title=Where It All Began: The Story of the People and Places Where the Oil Industry Began – West Virginia and South-eastern Ohio |last2=Bernard |first2=L. Allen |publisher=D.L. McKain |year=1994 |location=Parkersburg, WV |asin=B0006P93DY}} An early commercial well was hand dug in Poland in 1853, and another in nearby Romania in 1857. At around the same time the world's first, small, oil refinery was opened at Jasło in Poland (then Austria), with a larger one opened at Ploiești in Romania shortly after. Romania (then being a vassal of the Ottoman Empire) is the first country in the world to have had its annual crude oil output officially recorded in international statistics: 275 tonnes for 1857.{{Cite web |title=The History Of Romanian Oil Industry |url=http://www.rri.ro/arh-art.shtml?lang=1&sec=9&art=3596 |archive-url=https://web.archive.org/web/20090603102058/http://www.rri.ro/arh-art.shtml?lang=1&sec=9&art=3596 |archive-date=June 3, 2009 |website=rri.ro}}{{Cite web |last=Thomas Eakins |title=Scenes from Modern Life: World Events: 1844–1856 |url=https://www.pbs.org/eakins/we_1844.htm |url-status=live |archive-url=https://web.archive.org/web/20170705142847/https://www.pbs.org/eakins/we_1844.htm |archive-date=July 5, 2017 |website=pbs.org}}

In 1858, Georg Christian Konrad Hunäus found a significant amount of petroleum while drilling for lignite in Wietze, Germany. Wietze later provided about 80% of German consumption in the Wilhelmine Era.{{Cite news |last=Lucius |first=Robert von |date=June 23, 2009 |title=Deutsche Erdölförderung: Klein-Texas in der Lüneburger Heide |language=de |work=FAZ.NET |url=https://www.faz.net/1.812092 |url-status=live |access-date=March 18, 2018 |archive-url=https://web.archive.org/web/20170126111737/https://www.faz.net/aktuell/wirtschaft/deutsche-erdoelfoerderung-klein-texas-in-der-lueneburger-heide-1812092.html |archive-date=January 26, 2017 |issn=0174-4909}} The production stopped in 1963, but Wietze has hosted a Petroleum Museum since 1970.{{Cite web |title=Deutsches Erdölmuseum Wietze |url=http://www.erdoelmuseum.de/ |url-status=live |archive-url=https://web.archive.org/web/20171014171832/http://www.erdoelmuseum.de/ |archive-date=October 14, 2017 |access-date=March 18, 2018 |website=www.erdoelmuseum.de}}

Oil sands have been mined since the 18th century.{{Cite news |date=February 23, 1880 |title=The oil wells of Alsace; a discovery made more than a century ago. What a Pennsylvania operator saw abroad, primitive methods of obtaining oil, the process similar to that used in coal mining |work=The New York Times |url=https://timesmachine.nytimes.com/timesmachine/1880/02/23/98888884.pdf |url-status=live |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20191218003110/https://timesmachine.nytimes.com/timesmachine/1880/02/23/98888884.pdf |archive-date=December 18, 2019}} In Wietze in lower Saxony, natural asphalt/bitumen has been explored since the 18th century.{{Cite book |title=Erdöl in Wietze |date=1994 |publisher=Geiger |isbn=978-3-89264-910-6 |edition=1. Aufl |location=Horb am Neckar |oclc=75489983}} Both in Pechelbronn as in Wietze, the coal industry dominated the petroleum technologies.{{Cite book |last1=Karlsch |first1=Rainer |title=Faktor Öl: die Mineralölwirtschaft in Deutschland 1859–1974 |last2=Stokes |first2=Raymond G. |date=2003 |publisher=C.H. Beck |others=Stokes, Raymond G. |isbn=978-3-406-50276-7 |location=Munich |oclc=52134361}}

Chemist James Young in 1847 noticed a natural petroleum seepage in the coal mine at riddings Alfreton, Derbyshire 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 crude oil.

Young eventually succeeded, by distilling cannel coal at 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 several useful liquids from it, one of which he named "paraffine oil" because at low temperatures it congealed into a substance resembling paraffin wax.{{Cite book |last=Russell |first=Loris S. |title=A Heritage of Light: Lamps and Lighting in the Early Canadian Home |publisher=University of Toronto Press |year=2003 |isbn=978-0-8020-3765-7}}

The production of these oils and solid paraffin wax from coal formed the subject of his patent dated October 17, 1850. In 1850, Young & Meldrum and Edward William Binney entered into partnership under the title of E.W. Binney & Co. at Bathgate 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.{{Cite web |last=By |first=Undiscovered Scotland |title=James Young: Biography on Undiscovered Scotland |url=http://www.undiscoveredscotland.co.uk/usbiography/y/jamesyoung.html |url-status=live |archive-url=https://web.archive.org/web/20170629094925/https://www.undiscoveredscotland.co.uk/usbiography/y/jamesyoung.html |archive-date=June 29, 2017 |access-date=March 18, 2018 |website=www.undiscoveredscotland.co.uk}}

{{Clarify|date=December 2023|reason=the preceding statement seems to say the first modern refinery was completed in 1851; the subsequent statement says the first refinery was built in 1856: the distinction between these two types could be detailed for better comprehension}}

The world's first oil refinery was built in 1856 by Ignacy Łukasiewicz in Austria.{{Cite book |last=Frank, Alison Fleig |title=Oil Empire: Visions of Prosperity in Austrian Galicia (Harvard Historical Studies) |publisher=Harvard University Press |year=2005 |isbn=978-0-674-01887-7}} 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 "mine" (1854).{{Cite web |date=May 19, 2007 |title=Skansen Przemysłu Naftowego w Bóbrce / Museum of Oil Industry at Bobrka |url=http://www.geo.uw.edu.pl/BOBRKA/DATY/daty.htm |archive-url=https://web.archive.org/web/20070519031720/http://www.geo.uw.edu.pl/BOBRKA/DATY/daty.htm |archive-date=May 19, 2007 |access-date=March 18, 2018}} at Bóbrka, near Krosno (still operational as of 2020).

The demand for petroleum as a fuel for lighting in North America and around the world quickly grew.{{Cite book |last=Maugeri |first=Leonardo |url=https://archive.org/details/ageofoilmytholog0000maug/page/3 |title=The age of oil: the mythology, history, and future of the world's most controversial resource |date=2005 |publisher=Lyons Press |isbn=978-1-59921-118-3 |edition=1st Lyons Press |location=Guilford, CN |page=[https://archive.org/details/ageofoilmytholog0000maug/page/3 3] |oclc=212226551 |url-access=registration}}

The first oil well in the Americas was drilled in 1859 by Edwin Drake at what is now called the Drake Well in Cherrytree Township, Pennsylvania. There also was a company associated with it, and it sparked a major oil drilling boom.{{Cite book |last=Vassiliou |first=Marius S. |title=Historical dictionary of the petroleum industry, 2nd Edition |date=2018 |publisher=Rowman and Littlefield |isbn=978-1-5381-1159-8 |location=Lanham, MD |page=621 |oclc=315479839}}

The first commercial oil well in Canada became operational in 1858 at Oil Springs, Ontario (then Canada West).[http://www.lclmg.org/lclmg/Museums/OilMuseumofCanada/BlackGold2/OilHeritage/OilSprings/tabid/208/Default.aspx Oil Museum of Canada, Black Gold: Canada's Oil Heritage, Oil Springs: Boom & Bust] {{webarchive|url=https://web.archive.org/web/20130729191500/http://www.lclmg.org/lclmg/Museums/OilMuseumofCanada/BlackGold2/OilHeritage/OilSprings/tabid/208/Default.aspx |date=July 29, 2013 }} Businessman James Miller Williams dug several wells between 1855 and 1858 before discovering a rich reserve of oil four metres below ground.Turnbull Elford, Jean. "Canada West's Last Frontier". Lambton County Historical Society, 1982, p. 110{{Specify|reason=Unlear citation style.|date=December 2018}} 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.{{Cite web |title=Oil Museum of Canada, Black Gold: Canada's Oil Heritage |url=http://www.lclmg.org/lclmg/Museums/OilMuseumofCanada/BlackGold2/OilHeritage/OilSprings/tabid/208/Default.aspx |archive-url=https://web.archive.org/web/20130729191500/http://www.lclmg.org/lclmg/Museums/OilMuseumofCanada/BlackGold2/OilHeritage/OilSprings/tabid/208/Default.aspx |archive-date=July 29, 2013 |website=lclmg.org}} 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.{{Cite book |last=May |first=Gary |title=Hard oiler!: the story of Canadiansʼ quest for oil at home and abroad |date=1998 |publisher=Dundurn Press |isbn=978-1-55002-316-9 |location=Toronto |page=43 |oclc=278980961}} On January 16, 1862, after an explosion of natural gas, Canada's first oil gusher came into production, shooting into the air at a recorded rate of {{convert|3000|oilbbl|m3|order=flip}} per day.{{Cite book |last=Ford |first=R.W. A |title=History of the Chemical Industry in Lambton County |year=1988 |page=5}} By the end of the 19th century the Russian Empire, particularly the Branobel company in Azerbaijan, had taken the lead in production.{{cite book |editor1=Akiner, Shirin |editor2=Aldis, Anne |title=The Caspian: Politics, Energy and Security |publisher=Routledge |year=2004 |location=New York |isbn=978-0-7007-0501-6|page=5}}

Access to oil was and still is a major factor in several military conflicts of the 20th century, including World War II, during which oil facilities were a major strategic asset and were extensively bombed.{{Cite web |last=Baldwin |first=Hanson |title=Oil Strategy in World War II |url=http://www.oil150.com/essays/article?article_id=91 |url-status=live |archive-url=https://web.archive.org/web/20090815114446/http://www.oil150.com/essays/2007/08/oil-strategy-in-world-war-ii |archive-date=August 15, 2009 |website=oil150.com |publisher=American Petroleum Institute Quarterly – Centennial Issue |pages=10–11}} The German invasion of the Soviet Union 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.{{Cite web |last=Alakbarov |first=Farid |title=10.2 An Overview – Baku: City that Oil Built |url=http://azer.com/aiweb/categories/magazine/ai102_folder/102_articles/102_overview_alakbarov.html |archive-url=https://web.archive.org/web/20101213083150/http://azer.com/aiweb/categories/magazine/ai102_folder/102_articles/102_overview_alakbarov.html |archive-date=December 13, 2010 |access-date=March 18, 2018 |website=azer.com}}

Oil exploration in North America during the early 20th century later led to the U.S. becoming the leading producer by mid-century. As petroleum production in the U.S. peaked during the 1960s, the United States was surpassed by Saudi Arabia and the Soviet Union in total output.{{Cite news |last=Times |first=Christopher S. Wren Special to The New York |date=November 13, 1974 |title=Soviet Moves Ahead of U.S. in oil output. |language=en-US |work=The New York Times |url=https://www.nytimes.com/1974/11/13/archives/soviet-moves-ahead-of-us-in-oil-output-minister-sees-mondale.html |url-status=live |access-date=April 4, 2020 |archive-url=https://web.archive.org/web/20200531155823/https://www.nytimes.com/1974/11/13/archives/soviet-moves-ahead-of-us-in-oil-output-minister-sees-mondale.html |archive-date=May 31, 2020 |issn=0362-4331}}{{Cite news |date=July 12, 2018 |title=US expected to surpass Saudi Arabia, Russia as world's top oil producer |work=Christian Science Monitor |url=https://www.csmonitor.com/Business/2018/0712/US-expected-to-surpass-Saudi-Arabia-Russia-as-world-s-top-oil-producer |url-status=live |access-date=April 5, 2020 |archive-url=https://web.archive.org/web/20200516034628/https://www.csmonitor.com/Business/2018/0712/US-expected-to-surpass-Saudi-Arabia-Russia-as-world-s-top-oil-producer |archive-date=May 16, 2020 |issn=0882-7729}}{{Cite book |url=https://books.google.com/books?id=zKEe6yC-IQcC&q=Annual+Energy+Review+1987&pg=PA252 |title=Annual Energy Review |date=1990 |publisher=The Administration |page=252 |language=en |access-date=November 18, 2020 |archive-url=https://web.archive.org/web/20211122221351/https://books.google.com/books?id=zKEe6yC-IQcC&q=Annual+Energy+Review+1987&pg=PA252 |archive-date=November 22, 2021 |url-status=live}}

In 1973, Saudi Arabia and other Arab nations imposed an oil embargo against the United States, United Kingdom, Japan and other Western nations which supported Israel in the Yom Kippur War of October 1973.{{Cite news |date=November 23, 1973 |title=The Arab Oil Threat |work=The New York Times |url=https://www.nytimes.com/1973/11/23/archives/the-arab-oil-threat.html |url-status=live |access-date=July 22, 2019 |archive-url=https://web.archive.org/web/20190722073135/https://www.nytimes.com/1973/11/23/archives/the-arab-oil-threat.html |archive-date=July 22, 2019}} The embargo caused an oil crisis. This was followed by the 1979 oil crisis, which was caused by a drop in oil production in the wake of the Iranian Revolution 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.{{Cite news |date=April 18, 2006 |title=The price of oil – in context |work=CBC News |url=http://www.cbc.ca/news/background/oil/ |url-status=live |archive-url=https://web.archive.org/web/20070609145246/http://www.cbc.ca/news/background/oil/ |archive-date=June 9, 2007}} 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.{{Cite web |last=World Bank |title=Commodity Markets Outlook: The Impact of the War in Ukraine on Commodity Markets, April 2022. |url=https://openknowledge.worldbank.org/bitstream/handle/10986/37223/CMO-April-2022.pdf}} 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.{{Cite web |title=Commodity Markets: Evolution, Challenges, and Policies |url=https://www.worldbank.org/en/research/publication/commodity-markets |access-date=May 13, 2022 |website=World Bank |language=en}}

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 one percent of electricity generation.{{Cite web |title=EIA – Electricity Data |url=https://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_1 |url-status=live |archive-url=https://web.archive.org/web/20170710095902/https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_1 |archive-date=July 10, 2017 |access-date=April 18, 2017 |website=www.eia.gov}} 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 as of 2018 are the United States, Russia, and Saudi Arabia.{{Cite web |title=The United States is now the largest global crude oil producer |url=https://www.eia.gov/todayinenergy/detail.php?id=37053 |url-status=live |archive-url=https://web.archive.org/web/20181003230307/https://www.eia.gov/todayinenergy/detail.php?id=37053 |archive-date=October 3, 2018 |access-date=October 6, 2018 |website=www.eia.gov |publisher=Today in Energy – U.S. Energy Information Administration (EIA)}} In 2018, due in part to developments in hydraulic fracturing and horizontal drilling, the United States became the world's largest producer.{{Cite web |title=US soon to leapfrog Saudis, Russia as top oil producer |url=https://www.abqjournal.com/1195285/us-soon-to-leapfrog-saudis-russia-as-top-oil-producer.html |url-status=live |archive-url=https://web.archive.org/web/20181006075340/https://www.abqjournal.com/1195285/us-soon-to-leapfrog-saudis-russia-as-top-oil-producer.html |archive-date=October 6, 2018 |access-date=October 6, 2018 |website=www.abqjournal.com |publisher=The Associated Press}}

About 80 percent of the world's readily accessible reserves are located in the Middle East, with 62.5 percent coming from the Arab five: Saudi Arabia, United Arab Emirates, Iraq, Qatar, and Kuwait. A large portion of the world's total oil exists as unconventional sources, such as bitumen in Athabasca oil sands and extra heavy oil 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.{{Cite news |date=October 18, 2017 |title=Canada's oil sands survive, but can't thrive in a $50 oil world |language=en |work=Reuters |url=https://www.reuters.com/article/us-canada-oilsands-economics-analysis-idUSKBN1CN0FD |url-status=live |access-date=April 5, 2020 |archive-url=https://web.archive.org/web/20200518005508/https://www.reuters.com/article/us-canada-oilsands-economics-analysis-idUSKBN1CN0FD |archive-date=May 18, 2020}}{{Cite web |title=Crude Oil Forecast {{!}} Canadian Association of Petroleum Producers |url=https://www.capp.ca/resources/crude-oil-forecast/ |url-status=live |archive-url=https://web.archive.org/web/20200515020045/https://www.capp.ca/resources/crude-oil-forecast/ |archive-date=May 15, 2020 |access-date=April 5, 2020 |website=CAPP |language=en-US}}{{Cite web |title=IHS Markit: Canadian oil sands production to be ~1M barrels higher by 2030 but with lower annual growth; boosted by deterioration in Venezuela |url=https://www.greencarcongress.com/2019/06/20190606-oilsands.html |url-status=live |archive-url=https://web.archive.org/web/20200531155825/https://www.greencarcongress.com/2019/06/20190606-oilsands.html |archive-date=May 31, 2020 |access-date=April 5, 2020 |website=Green Car Congress}}

Petroleum consists of a variety of liquid, gaseous, and solid components. Lighter hydrocarbons are the gases methane, ethane, propane and butane. Otherwise, the bulk of the liquid and solids are largely heavier organic compounds, often hydrocarbons (C and H only). The proportion of light hydrocarbons in the petroleum mixture varies among oil fields.{{Cite book |last=Norman |first=J. Hyne |title=Nontechnical guide to petroleum geology, exploration, drilling, and production |date=2001 |publisher=Penn Well Corp |isbn=978-0-87814-823-3 |edition=2nd |location=Tulsa, OK |pages=1–4 |oclc=49853640}}

An oil well produces predominantly crude oil. Because the pressure is lower at the surface than underground, some of the gas will come out of solution and be recovered (or burned) as associated gas or solution gas. A gas well produces predominantly natural gas. However, because the underground temperature is higher than at the surface, the gas may contain heavier hydrocarbons such as pentane, hexane, and heptane ("natural-gas condensate", often shortened to condensate.) Condensate resembles gasoline in appearance and is similar in composition to some volatile light crude oils.{{Cite book |last=Speight |first=James G. |url=https://books.google.com/books?id=uG-KDwAAQBAJ&q=Condensate+resembles+gasoline&pg=PA13 |title=Heavy Oil Recovery and Upgrading |publisher=Elsevier |year=2019 |isbn=978-0-12-813025-4 |page=13 |language=en |access-date=November 18, 2020 |archive-url=https://web.archive.org/web/20211122221156/https://books.google.com/books?id=uG-KDwAAQBAJ&q=Condensate+resembles+gasoline&pg=PA13 |archive-date=November 22, 2021 |url-status=live}}{{Cite book |last=Hilyard |first=Joseph |url=https://books.google.com/books?id=F91w410iRLsC&q=Condensate+resembles+gasoline+in+appearance+and+is+similar+in+composition+to+some+volatile+light+crude+oils.&pg=PA31 |title=The Oil & Gas Industry: A Nontechnical Guide |date=2012 |publisher=PennWell Books |isbn=978-1-59370-254-0 |page=31 |language=en}}

The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hydrocarbons, while the other organic compounds contain nitrogen, oxygen, and sulfur, and traces of metals such as iron, nickel, copper and vanadium. Many oil reservoirs contain live bacteria.{{Cite book |last1=Ollivier |first1=Bernard |title=Petroleum Microbiology |last2=Magot |first2=Michel |date=2005 |publisher=American Society of Microbiology |isbn=978-1-55581-758-9 |location=Washington, DC |doi=10.1128/9781555817589}} The exact molecular composition of crude oil varies widely from formation to formation but the proportion of chemical elements varies over fairly narrow limits as follows:{{Cite book |last=Speight |first=J. G. |title=The chemistry and technology of petroleum |date=1999 |publisher=Marcel Dekker |isbn=978-0-8247-0217-5 |edition=3rd ed., rev. and expanded |location=New York |pages=215–216, 543 |oclc=44958948}}

Four different types of hydrocarbon appear in crude oil. The relative percentage of each varies from oil to oil, determining the properties of each oil.

File:Total World Oil Reserves Conventional Unconventional.png

File:Isooctane-3D-balls.png, a hydrocarbon with the octane number of 100. Black spheres are carbon and white spheres are hydrogen atoms.]]

The alkanes from pentane (C₅H₁₂) to octane (C₈H₁₈) are refined into gasoline, the ones from nonane (C₉H₂₀) to hexadecane (C₁₆H₃₄) into diesel fuel, kerosene and jet fuel. Alkanes with more than 16 carbon atoms can be refined into fuel oil and lubricating oil. At the heavier end of the range, paraffin wax is an alkane with approximately 25 carbon atoms, while asphalt has 35 and up, although these are usually cracked in modern refineries into more valuable products. The lightest fraction, the so-called petroleum gases are subjected to diverse processing depending on cost. These gases are either flared off, sold as liquefied petroleum gas, or used to power the refinery's own burners. During the winter, butane (C₄H₁₀), is blended into the gasoline pool at high rates, because its high vapour pressure assists with cold starts.

The aromatic hydrocarbons are unsaturated hydrocarbons that have one or more benzene rings. They tend to burn with a sooty flame, and many have a sweet aroma. Some are carcinogenic.

These different components are separated by fractional distillation at an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbon fractions.

The components in an oil sample can be determined by gas chromatography and mass spectrometry.[http://www.norden.org/pub/ebook/2003-516.pdf Use of ozone depleting substances in laboratories] {{webarchive|url=https://web.archive.org/web/20080227052412/http://www.norden.org/pub/ebook/2003-516.pdf |date=February 27, 2008 }}. TemaNord 2003:516. Due to the large number of co-eluted hydrocarbons within oil, many cannot be resolved by traditional gas chromatography. This unresolved complex mixture (UCM) of hydrocarbons is particularly apparent when analysing weathered oils and extracts from tissues of organisms exposed to 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.{{Cite web |year=2007 |title=Oil Sands – Glossary |url=http://www.energy.gov.ab.ca/OilSands/1106.asp |archive-url=https://web.archive.org/web/20071101112113/http://www.energy.gov.ab.ca/OilSands/1106.asp |archive-date=November 1, 2007 |access-date=October 2, 2008 |website=Mines and Minerals Act |publisher=Government of Alberta}} Venezuela also has large amounts of oil in the Orinoco oil sands, although the hydrocarbons trapped in them are more fluid than in Canada and are usually called extra heavy oil. These oil sands resources are called unconventional oil to distinguish them from oil which can be extracted using traditional oil well methods. Between them, Canada and Venezuela contain an estimated {{convert|3.6|Toilbbl}} of bitumen and extra-heavy oil, about twice the volume of the world's reserves of conventional oil.{{Cite web |year=2008 |title=Oil Sands in Canada and Venezuela |url=http://oilsands.infomine.com/countries/ |archive-url=https://web.archive.org/web/20081219113841/http://oilsands.infomine.com/countries/ |archive-date=December 19, 2008 |access-date=October 2, 2008 |publisher=Infomine Inc.}}

File:Treibs&Chlorophyll.png compound (left) extracted from petroleum by Alfred E. Treibs, father of organic geochemistry. Treibs noted the close structural similarity of this molecule and chlorophyll a (right).{{Cite journal |last=Treibs, A.E. |year=1936 |title=Chlorophyll- und Häminderivate in organischen Mineralstoffen |journal=Angew. Chem. |volume=49 |issue=38 |pages=682–686 |bibcode=1936AngCh..49..682T |doi=10.1002/ange.19360493803|issn = 0044-8249}}{{Cite journal |last=Kvenvolden, K.A. |year=2006 |title=Organic geochemistry – A retrospective of its first 70 years |url=https://zenodo.org/record/1000677 |url-status=live |journal=Org. Geochem. |volume=37 |issue=1 |pages=1–11 |bibcode=2006OrGeo..37....1K |doi=10.1016/j.orggeochem.2005.09.001 |s2cid=95305299 |archive-url=https://web.archive.org/web/20190607232519/https://zenodo.org/record/1000677 |archive-date=June 7, 2019 |access-date=July 1, 2019}}]]

Petroleum is a fossil fuel derived from fossilized organic materials, such as zooplankton and algae.{{Cite journal |last=Kvenvolden |first=Keith A. |year=2006 |title=Organic geochemistry – A retrospective of its first 70 years |url=https://zenodo.org/record/1000677 |url-status=live |journal=Organic Geochemistry |volume=37 |issue=1 |pages=1–11 |bibcode=2006OrGeo..37....1K |doi=10.1016/j.orggeochem.2005.09.001 |s2cid=95305299 |archive-url=https://web.archive.org/web/20190607232519/https://zenodo.org/record/1000677 |archive-date=June 7, 2019 |access-date=July 1, 2019}}{{Cite book |last=Schobert |first=Harold H. |title=Chemistry of fossil fuels and biofuels |publisher=Cambridge University Press |year=2013 |isbn=978-0-521-11400-4 |location=Cambridge |pages=103–130 |oclc=795763460}} Vast amounts of these remains settled to sea or lake bottoms where they were covered in stagnant water (water with no dissolved oxygen) or sediments such as mud and silt 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 into the sea or lake bed, intense heat and pressure built up in the lower regions. This process caused the organic matter to change, first into a waxy material known as kerogen, found in various oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons via a process known as catagenesis. Formation of petroleum occurs from hydrocarbon pyrolysis in a variety of mainly endothermic reactions at high temperatures or pressures, or both. These phases are described in detail below.

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 sulfates 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: polysaccharides and proteins were hydrolyzed to simple sugars and amino acids respectively. These were further anaerobically oxidized at an accelerated rate by the enzymes of the bacteria: e.g., amino acids went through oxidative deamination to amino acids, which in turn reacted further to ammonia and α-keto acids. Monosaccharides in turn ultimately decayed to CO₂ and methane. The anaerobic decay products of amino acids, monosaccharides, phenols and aldehydes combined into fulvic acids. Fats and waxes were not extensively hydrolyzed under these mild conditions.

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 into the sea or lake bed, intense heat and pressure built up in the lower regions.{{Cite report |url=http://www.osti.gov/servlets/purl/10169154-cT5xip/ |title=Chemical reaction model for oil and gas generation from type 1 and type 2 kerogen |last1=Braun |first1=R.L. |last2=Burnham |first2=A.K. |date=June 1993 |publisher=Lawrence Livermore National Laboratory |doi=10.2172/10169154 |access-date=March 18, 2018 |archive-url=https://web.archive.org/web/20200517104249/https://www.osti.gov/biblio/10169154-cT5xip/ |archive-date=May 17, 2020 |url-status=live}} As a consequence, compounds of this mixture began to combine in poorly understood ways to kerogen. Combination happened in a similar fashion as phenol and formaldehyde molecules react to urea-formaldehyde 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.

Kerogen formation continued to a depth of about 1 km from the Earth's surface where temperatures may reach around 50 °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 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 rearrangements of kerogen. These reactions took thousands to millions of years and no external reactants were involved. Due to the 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 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 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 materials of the crust, especially ⁴⁰K, ²³²Th, ²³⁵U and 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.

Geologists often refer to the temperature range in which oil forms as an "oil window".{{Cite web |last=Malyshev |first=Dmitry |date=December 13, 2013 |title=Origin of oil |url=http://large.stanford.edu/courses/2013/ph240/malyshev2/ |url-status=live |archive-url=https://web.archive.org/web/20210921125720/http://large.stanford.edu/courses/2013/ph240/malyshev2/ |archive-date=September 21, 2021 |access-date=September 21, 2021 |website=large.stanford.edu |language=English}}{{Cite book |url=https://books.google.com/books?id=xwLHnC9qMsgC&pg=PA104 |title=Polar Prospects:A minerals treaty for Antarctica |publisher=United States, Office of Technology Assessment |year=1989 |isbn=978-1-4289-2232-7 |page=104 |access-date=May 12, 2020 |archive-url=https://web.archive.org/web/20200729203620/https://books.google.com/books?id=xwLHnC9qMsgC&pg=PA104 |archive-date=July 29, 2020 |url-status=live}} 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.

{{Main|Abiogenic petroleum origin}}

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 geochemical evidence.{{Cite journal |last=Glasby |first=Geoffrey P |date=2006 |title=Abiogenic origin of hydrocarbons: an historical overview |url=http://static.scribd.com/docs/j79lhbgbjbqrb.pdf |journal=Resource Geology |volume=56 |issue=1 |pages=85–98 |doi=10.1111/j.1751-3928.2006.tb00271.x |bibcode=2006ReGeo..56...83G |s2cid=17968123 |archive-url=https://wayback.archive-it.org/all/20080226224750/http://static.scribd.com/docs/j79lhbgbjbqrb.pdf |archive-date=February 26, 2008 |access-date=January 29, 2008}} 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."{{Cite journal |date=October 11, 2005 |title=The Mysterious Origin and Supply of Oil |url=http://www.livescience.com/9404-mysterious-origin-supply-oil.html |url-status=live |journal=Live Science |archive-url=https://web.archive.org/web/20160127095201/http://www.livescience.com/9404-mysterious-origin-supply-oil.html |archive-date=January 27, 2016}}

{{main|Petroleum reservoir}}

{{More citations needed section|date=October 2016}}

File:Structural Trap (Anticlinal).svg trap consists of a reservoir rock (yellow) where oil (red) can accumulate, and a caprock (green) that prevents it from egressing.]]

Three conditions must be present for oil reservoirs to form:

• A source rock rich in hydrocarbon material buried deeply enough for subterranean heat to cook it into oil,
• A porous and 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 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.

Petroleum has mostly been recovered by oil drilling (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 of geologic reservoir structures).{{Cite journal |vauthors=Guerriero V, etal |year=2012 |title=A permeability model for naturally fractured carbonate reservoirs |journal=Marine and Petroleum Geology |volume=40 |pages=115–134 |doi=10.1016/j.marpetgeo.2012.11.002}}{{Cite journal |vauthors=Guerriero V, etal |year=2011 |title=Improved statistical multi-scale analysis of fractures in carbonate reservoir analogues |journal=Tectonophysics |volume=504 |issue=1 |pages=14–24 |bibcode=2011Tectp.504...14G |doi=10.1016/j.tecto.2011.01.003}} 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 "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.

{{See also|Unconventional oil|Oil sands|Oil shale reserves|Unconventional (oil and gas) reservoir}}

Oil-eating bacteria biodegrade oil that has escaped to the surface. Oil sands are reservoirs of partially biodegraded oil still in the process of escaping and being biodegraded, but they contain so much migrating oil that, although most of it has escaped, vast amounts are still present—more than can be found in conventional oil reservoirs. The lighter fractions of the crude oil are destroyed first, resulting in reservoirs containing an extremely heavy form of crude oil, called crude bitumen in Canada, or extra-heavy crude oil in Venezuela. These two countries have the world's largest deposits of oil sands.{{Cite web |date=June 19, 2020 |title=Tar sands |url=https://www.strausscenter.org/energy-and-security-project/tar-sands/ |access-date=June 26, 2022 |publisher=The Strauss Center.}}

On the other hand, oil shales are source rocks that have not been exposed to heat or pressure long enough to convert their trapped hydrocarbons into crude oil. Technically speaking, oil shales are not always shales and do not contain oil, but are fined-grain sedimentary rocks containing an insoluble organic solid called kerogen. The kerogen in the rock can be converted into crude oil using heat and pressure to simulate natural processes. The method has been known for centuries and was patented in 1694 under British Crown Patent No. 330 covering, "A way to extract and make great quantities of pitch, tar, and oil out of a sort of stone." Although oil shales are found in many countries, the United States has the world's largest deposits.{{Cite news |last=Lambertson |first=Giles |date=February 16, 2008 |title=Oil Shale: Ready to Unlock the Rock |publisher=Construction Equipment Guide |url=http://www.cegltd.com/story.asp?story=10092 |url-status=live |access-date=May 21, 2008 |archive-url=https://web.archive.org/web/20170711112037/http://www.constructionequipmentguide.com/redirect/10092?story=10092 |archive-date=July 11, 2017}}

{{globalize|date=January 2024}}

{{See also|Benchmark (crude oil)}}

File:Crudes.PNG with their sulfur content (horizontal) and API gravity (vertical) and relative production quantity.{{citation needed|date=March 2020|reason=Brent shown as sweeter than WTI, yet most sources claim the opposite. That and other claims in image probably need checking and sourcing. Example: http://www.petroleum.co.uk/benchmarks}}]]

The petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g., West Texas Intermediate, Brent, or Oman), its API gravity (an oil industry measure of density), and its sulfur content. Crude oil may be considered light if it has low density, heavy if it has high density, or medium if it has a density between that of light and heavy.{{Cite web |date=2009 |title=Glossary |url=http://www.capp.ca/library/glossary/Pages/default.aspx#l |archive-url=https://web.archive.org/web/20090827031218/http://www.capp.ca/library/glossary/Pages/default.aspx#l |archive-date=August 27, 2009 |access-date=November 29, 2020 |publisher=Canadian Association of Petroleum Producers}} Additionally, it may be referred to as sweet if it contains relatively little sulfur or sour if it contains substantial amounts of sulfur.{{Cite web |title=Heavy Sour Crude Oil, A Challenge For Refiners |url=http://www.commodity-trading-today.com/sour-crude-oil.html |archive-url=https://web.archive.org/web/20081121001856/http://www.commodity-trading-today.com/sour-crude-oil.html |archive-date=November 21, 2008 |access-date=November 29, 2020}}

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.{{Cite journal |last=Rhodes |first=Christopher J. |year=2008 |title=The Oil Question: Nature and Prognosis |journal=Science Progress |volume=91 |issue=4 |pages=317–375 |doi=10.3184/003685008X395201 |pmc=10367496 |pmid=19192735 |s2cid=31407897}}

Barrels from an area in which the crude oil's molecular characteristics have been determined and the oil has been classified are used as pricing references throughout the world. Some of the common reference crudes are:{{cite web |language=en |access-date=16 December 2024 |website=Fuel Logic |title=How US Gas Prices Affect the Overall Economy |date=September 12, 2024 |url=https://www.fuellogic.net/how-us-gas-prices-affect-the-overall-economy/}}

• West Texas Intermediate (WTI), a very high-quality, sweet, light oil delivered at Cushing, Oklahoma for North American oil
• Brent Blend, consisting of 15 oils from fields in the Brent and Ninian systems in the East Shetland Basin of the North Sea. The oil landed at Sullom Voe terminal in Shetland. Oil production from Europe, Africa and Middle Eastern oil flowing West tends to be priced off this oil, which forms a benchmark
• Dubai-Oman, used as a benchmark for the Middle East sour crude oil flowing to the Asia-Pacific region
• Tapis (from Malaysia, used as a reference for light Far East oil)
• Minas (from Indonesia, used as a reference for heavy Far East oil)
• The OPEC Reference Basket, a weighted average of oil blends from various OPEC (Organization of the Petroleum Exporting Countries) countries
• Midway Sunset Heavy, by which heavy oil in California is priced{{Cite web |date=May 1, 2007 |title=Chevron Crude Oil Marketing – North America Posted Pricing – California |url=http://crudemarketing.chevron.com/posted_pricing_daily_california.asp |url-status=live |archive-url=https://web.archive.org/web/20100607035625/http://crudemarketing.chevron.com/posted_pricing_daily_california.asp |archive-date=June 7, 2010 |access-date=August 29, 2010 |publisher=Crudemarketing.chevron.com}}{{Failed verification|date=March 2018}}
• Western Canadian Select the benchmark crude oil for emerging heavy, high TAN (acidic) crudes.{{Cite report |url=http://www.nrcan.gc.ca/sites/www.nrcan.gc.ca.energy/files/pdf/eneene/sources/crubru/revrev/pdf/revrev-09-eng.pdf |title=Canadian Crude Oil, Natural Gas and Petroleum Products: Review of 2009 & Outlook to 2030 |last=Natural Resources Canada |date=May 2011 |publisher=Government of Canada |location=Ottawa |page=9 |isbn=978-1-100-16436-6 |archive-url=https://web.archive.org/web/20131003093310/http://www.nrcan.gc.ca/sites/www.nrcan.gc.ca.energy/files/pdf/eneene/sources/crubru/revrev/pdf/revrev-09-eng.pdf |archive-date=October 3, 2013}}

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, and for a Brent Blend delivered at Shetland, it may be a discounted Russian Export Blend delivered at the port of Primorsk.{{Cite web |year=2006 |title=Light Sweet Crude Oil |url=http://www.nymex.com/lsco_fut_descri.aspx |archive-url=https://web.archive.org/web/20080314074204/http://www.nymex.com/lsco_fut_descri.aspx |archive-date=March 14, 2008 |access-date=April 21, 2008 |website=About the Exchange |publisher=New York Mercantile Exchange (NYMEX)}}

Once extracted, oil is refined and separated, most easily by distillation, into numerous products for direct use or use in manufacturing, such as gasoline (petrol), diesel and kerosene to asphalt and chemical reagents (ethylene, propylene, butene, acrylic acid, para-xylene{{Cite journal |last1=Li |first1=Guixian |last2=Wu |first2=Chao |last3=Ji |first3=Dong |last4=Dong |first4=Peng |last5=Zhang |first5=Yongfu |last6=Yang |first6=Yong |date=April 1, 2020 |title=Acidity and catalyst performance of two shape-selective HZSM-5 catalysts for alkylation of toluene with methanol |journal=Reaction Kinetics, Mechanisms and Catalysis |language=en |volume=129 |issue=2 |pages=963–974 |doi=10.1007/s11144-020-01732-9 |issn=1878-5204 |s2cid=213601465}}) used to make plastics, pesticides and pharmaceuticals.{{Cite web |title=Organic Hydrocarbons: Compounds made from carbon and hydrogen |url=http://cactus.dixie.edu/smblack/chem1010/lecture_notes/2B.htm |archive-url=https://web.archive.org/web/20110719184614/http://cactus.dixie.edu/smblack/chem1010/lecture_notes/2B.htm |archive-date=July 19, 2011}}

In terms of volume, most petroleum is converted into fuels for combustion engines. In terms of value, petroleum underpins the petrochemical industry, which includes many high value products such as pharmaceuticals and plastics.

Petroleum is used mostly, by volume, for refining into fuel oil and gasoline, both important primary energy sources. 84% by volume of the hydrocarbons present in petroleum is converted into fuels, including gasoline, diesel, jet, heating, and other fuel oils, and liquefied petroleum gas.{{Cite web |title=Crude oil is made into different fuels |url=http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html#Howused |url-status=live |archive-url=https://web.archive.org/web/20090823080443/http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html |archive-date=August 23, 2009 |access-date=August 29, 2010 |publisher=Eia.doe.gov}}

Due to its high energy density, easy transportability and relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics; the 16 percent not used for energy production is converted into these other materials. Petroleum is found in porous rock formations in the upper strata of some areas of the Earth's crust. There is also petroleum in oil sands (tar sands). Known oil reserves are typically estimated at 190 km³ (1.2 trillion (short scale) barrels) without oil sands,{{Cite web |title=EIA reserves estimates |url=http://www.eia.doe.gov/emeu/international/reserves.html |archive-url=https://web.archive.org/web/20100830033649/http://www.eia.doe.gov/emeu/international/reserves.html |archive-date=August 30, 2010 |access-date=August 29, 2010 |publisher=Eia.doe.gov}} or 595 km³ (3.74 trillion barrels) with oil sands.{{Cite web |date=November 14, 2006 |title=CERA report on total world oil |url=http://www.cera.com/aspx/cda/public1/news/pressReleases/pressReleaseDetails.aspx?CID=8444 |archive-url=https://web.archive.org/web/20101125004643/http://www.cera.com/aspx/cda/public1/news/pressReleases/pressReleaseDetails.aspx?CID=8444 |archive-date=November 25, 2010 |access-date=August 29, 2010 |publisher=Cera.com}} Consumption is currently around {{convert|84|Moilbbl}} per day, or 4.9 km³ per year, yielding a remaining oil supply of only about 120 years, if current demand remains static.{{Cite web |title=Peak oil: Does it really matter? |url=https://www.oilandgasmiddleeast.com/article-8400-peak-oil-does-it-really-matter |url-status=live |archive-url=https://web.archive.org/web/20200406204626/https://www.oilandgasmiddleeast.com/article-8400-peak-oil-does-it-really-matter |archive-date=April 6, 2020 |access-date=April 6, 2020 |website=Oil & Gas Middle East |date=February 3, 2011 |language=en}} More recent studies, however, put the number at around 50 years.{{Cite web |title=Energy Alternatives and the Future of Oil and Gas in the Gulf |url=http://studies.aljazeera.net/en/dossiers/2015/03/201533183514675179.html |url-status=live |archive-url=https://web.archive.org/web/20200406204625/https://studies.aljazeera.net/en/dossiers/2015/03/201533183514675179.html |archive-date=April 6, 2020 |access-date=April 6, 2020 |website=Al Jazeera Center for Studies |language=en}}{{Cite news |date=July 14, 2014 |title=How long will world's oil reserves last? 53 years, says BP |work=Christian Science Monitor |url=https://www.csmonitor.com/Environment/Energy-Voices/2014/0714/How-long-will-world-s-oil-reserves-last-53-years-says-BP |url-status=live |access-date=April 6, 2020 |archive-url=https://web.archive.org/web/20200406204616/https://www.csmonitor.com/Environment/Energy-Voices/2014/0714/How-long-will-world-s-oil-reserves-last-53-years-says-BP |archive-date=April 6, 2020 |issn=0882-7729}}

Closely related to fuels for combustion engines are Lubricants, greases, and viscosity stabilizers. All are derived from petroleum.

{{Further|Petroleum product| Petrochemical}}

File:Alkene General Formula V.1.svg]]

Many pharmaceuticals are derived from petroleum, albeit via multistep processes.{{Citation needed|date=February 2024}} Modern medicine depends on petroleum as a source of building blocks, reagents, and solvents.{{cite journal |pmid=21778473 |date=2011 |last1=Hess |first1=J. |last2=Bednarz |first2=D. |last3=Bae |first3=J. |last4=Pierce |first4=J. |title=Petroleum and health care: Evaluating and managing health care's vulnerability to petroleum supply shifts |journal=American Journal of Public Health |volume=101 |issue=9 |pages=1568–1579 |doi=10.2105/AJPH.2011.300233 |pmc=3154246 }} Similarly, virtually all pesticides - insecticides, herbicides, etc. - are derived from petroleum. Pesticides have profoundly affected life expectancies by controlling disease vectors and by increasing yields of crops. Like pharmaceuticals, pesticides are in essence petrochemicals. Almost all plastics and synthetic polymers are derived from petroleum, which is the source of monomers. Alkenes (olefins) are one important class of these precursor molecules.

File:Bitumen.jpg, commonly referred to as Asphalt]]

• Wax, used in the packaging of frozen foods, among others, Paraffin wax, derived from petroleum oil.{{Cite journal |last1=Ferris |first1=S. W. |last2=Cowles |first2=H. C. |last3=Henderson |first3=L. M. |date=November 1, 1929 |title=Composition of Paraffin Wax |url=https://pubs.acs.org/doi/abs/10.1021/ie50239a029 |journal=Industrial & Engineering Chemistry |language=en |volume=21 |issue=11 |pages=1090–1092 |doi=10.1021/ie50239a029 |issn=0019-7866}}
• Sulfur and its derivative sulfuric acid. Hydrogen sulfide is a product of sulfur removal from petroleum fraction. It is oxidized to elemental sulfur and then to sulfuric acid.
• Bulk tar and Asphalt
• Petroleum coke, used in speciality carbon products or as solid fuel

{{Excerpt|oil industry}}

{{excerpt|Petroleum transport}}

In the 1950s, shipping costs made up 33 percent of the price of oil transported from the Persian Gulf to the United States,{{Cite news |date=July 14, 2012 |title=A liquid market: Thanks to LNG, spare gas can now be sold the world over |newspaper=The Economist |url=http://www.economist.com/node/21558456 |url-status=live |access-date=January 6, 2013 |archive-url=https://web.archive.org/web/20140614054033/http://www.economist.com/node/21558456 |archive-date=June 14, 2014}} 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 in the value of 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.

{{Excerpt|oil prices}}

File:Crude oil prices since 1861.png

Crude oil is traded as a future on both the NYMEX and ICE exchanges.{{Cite web |title=Brent Crude Futures |url=https://www.ice.com/products/219/Brent-Crude-Futures |access-date=2024-02-22 |website=www.ice.com}} 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. A contract covers any multiple of 1000 barrels and can be purchased up to nine years into the future.{{Cite web |title=Historical Crude Oil Intraday Data (CLA) |url=https://portaracqg.com/futures/int/cla |access-date=August 30, 2022 |website=PortaraCQG |language=en-US}}

File:Global Carbon Emissions.svg|Global fossil carbon emissions, an indicator of consumption, from 1800. {{legend-line|black solid 3px|Total}}{{legend-line|blue solid 3px|Oil}}

File:World energy consumption.svg|Rate of world energy usage per year from 1970.BP: [http://www.bp.com/sectiongenericarticle800.do?categoryId=9037130&contentId=7068669 Statistical Review of World Energy] {{webarchive|url=https://web.archive.org/web/20130516003736/http://www.bp.com/sectiongenericarticle800.do?categoryId=9037130&contentId=7068669 |date=May 16, 2013 }}, 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: {{legend|red|US}}{{legend|blue|Europe}}{{legend|#D1D117|Asia and Oceania}}.

File:World oil consumption 1980 to 2007 by region.svg|Oil consumption 1980 to 2007 by region.

According to the US Energy Information Administration (EIA) estimate for 2021, the world consumes 97.26 million barrels of oil each day.{{Cite web |title=Oil and petroleum products explained |url=https://www.eia.gov/energyexplained/oil-and-petroleum-products/use-of-oil.php#:~:text=In%202019%2C%20U.S.%20petroleum%20consumption,million%20b%2Fd%20of%20biofuels.&text=The%20transportation%20sector%20accounts%20for%20the%20largest%20share%20of%20U.S.%20petroleum%20consumption. |url-status=live |archive-url=https://web.archive.org/web/20241225153357/https://www.eia.gov/energyexplained/oil-and-petroleum-products/use-of-oil.php |archive-date=December 25, 2024 |access-date=December 27, 2024 |publisher=U.S. Energy Information Administration}}

[[File:OilConsumptionpercapita.png|thumb|upright=3.4|Oil consumption per capita (darker colors represent more consumption, gray represents no data) (source: see file description).

]]

This table orders the amount of petroleum consumed in 2011 in thousand barrels (1,000 bbl) per day and in thousand cubic metres (1,000 m³) per day:U.S. Energy Information Administration. [http://www.eia.doe.gov/emeu/international/RecentPetroleumConsumptionBarrelsperDay.xls Excel file] {{webarchive|url=https://web.archive.org/web/20081006235221/http://www.eia.doe.gov/emeu/international/RecentPetroleumConsumptionBarrelsperDay.xls |date=October 6, 2008 }} from [http://tonto.eia.doe.gov/dnav/pet/pet_pri_wco_k_w.htm this] {{webarchive|url=https://web.archive.org/web/20081110134954/http://tonto.eia.doe.gov/dnav/pet/pet_pri_wco_k_w.htm |date=November 10, 2008 }} web page. Table Posted: March 1, 2010From DSW-Datareport 2008 ("Deutsche Stiftung Weltbevölkerung")

Source: US Energy Information Administration{{cite web |url=http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=5&pid=5&aid=2 |title=Data |publisher=U.S. Energy Information Administration |access-date=January 13, 2025}}

Population Data:{{Cite web |title=IBGE |url=http://www.ibge.gov.br/paisesat/main.php |url-status=live |archive-url=https://web.archive.org/web/20100904063203/http://www.ibge.gov.br/paisesat/main.php |archive-date=September 4, 2010 |access-date=August 29, 2010}}

¹ peak production of oil already passed in this state

² This country is not a major oil producer

{{For|oil production by country|List of countries by oil production}}

{{For|oil reserves by country|List of countries by proven oil reserves}}

{{Image frame

| caption=Top oil-producing countries{{Cite web |title=Crude oil including lease condensate production (Mb/d) |url=https://www.eia.gov/international/data/world/petroleum-and-other-liquids/annual-petroleum-and-other-liquids-production?pd=5&p=00000000000000000000000000000000002&u=0&f=A&v=mapbubble&a=-&i=none&vo=value&t=C&g=00000000000000000000000000000000000000000000000001&l=249-ruvvvvvfvtvnvv1vrvvvvfvvvvvvfvvvou20evvvvvvvvvvvvvvs&s=63072000000&e=1514764800000&ev=false& |url-status=live |archive-url=https://web.archive.org/web/20200514060445/https://www.eia.gov/international/data/world/petroleum-and-other-liquids/annual-petroleum-and-other-liquids-production?pd=5&p=00000000000000000000000000000000002&u=0&f=A&v=mapbubble&a=-&i=none&vo=value&t=C&g=00000000000000000000000000000000000000000000000001&l=249-ruvvvvvfvtvnvv1vrvvvvfvvvvvvfvvvou20evvvvvvvvvvvvvvs&s=63072000000&e=1514764800000&ev=false& |archive-date=May 14, 2020 |access-date=April 14, 2020 |publisher=U.S. Energy Information Administration}}

| align=center

| content ={{Graph:Chart

| width=400

| height=150

| xAxisTitle=Year

| yAxisTitle=Crude Oil (Mbbl/d)

| yAxisMin = 0

| yAxisMax = 12000

| legend=

| y1Title=Canada

| y2Title=China

| y3Title=Iran

| y4Title=Russia

| y5Title=Saudi Arabia

| y6Title=United States

| type=line

| x=1973,1974,1975,1976,1977,1978,1979,1980,1981,1982,1983,1984,1985,1986,1987,1988,1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018

| y1=1798,1551,1430,1314,1321,1316,1500,1435.202186,1284.728767,1271.150685,1356.230137,1437.622951,1471.052055,1474.219178,1534.928767,1616.23224,1560.09589,1552.999671,1547.980644,1605.225025,1679.0784,1746.194521,1805.271233,1836.674863,1922.394521,1981.084932,1906.635616,1976.893443,2029.172603,2170.6,2305.726027,2398.420765,2368.877597,2525.397101,2628.124781,2579.308861,2579.479849,2740.756164,2900.646575,3137.838798,3325.128767,3613.224658,3677.126027,3679.046448,3976.665753,4343.361644

| y2=1090,1315,1490,1670,1874,2082,2122,2113.852459,2012.438356,2045,2119.60274,2295.669399,2505.164384,2620.287671,2690,2730.319672,2756.791781,2773.999159,2835.00043,2844.663106,2889.801184,2939.287671,2990.049315,3131.338798,3200.342466,3198.178082,3194.994521,3248.762295,3300.004,3389.652055,3408.871233,3485.314208,3608.621918,3672.735068,3735.971233,3790.181967,3795.95863,4078.360274,4052.055616,4074.074317,4163.816712,4208.254795,4277.693151,3983.480874,3821.230137,3772.876712

|

y3=5861,6021.6,5350.1,5882.9,5662.8,5241.7,3168,1661.967213,1379.956164,2213.838356,2439.756164,2174.31694,2250.474183,2034.986301,2298.057534,2240.030055,2809.873973,3087.998989,3311.999723,3429.098361,3539.864232,3618.054795,3643.219178,3685.710383,3664.178082,3633.767123,3557.164384,3696.3,3723.70137,3444.30137,3742.794973,4001.434426,4138.575342,4027.808219,3911.890411,4050.273224,4037.038348,4080.418951,4054,3386.849727,3113.29863,3239.068493,3293.189041,4151.166667,4468.69589,4254.827397

|

y4=,,,,,,,,,,,,,,,,,,,7631.937156,6730.008721,6135.084932,5995.221918,5849.874317,5920.084932,5853.882192,6078.983562,6479.202,6917,7408.173,8132.198795,8804.70765,9043.082192,9247.205479,9437.063449,9356.783607,9495.364932,9694.114466,9773.517808,9921.60929,10053.84384,10107.08767,10252.85479,10551.49727,10580.19178,10758.66027

|

y5=7596,8480,7075,8577,9245,8301,9532,9900.15847,9814.947945,6482.991781,5085.89589,4663.202186,3387.821918,4870.016438,4264.991781,5085.95082,5064.156164,6410.003595,8114.995863,8332.19425,8198.232877,8119.873973,8231.232877,8218.117486,8362.175342,8388.90411,7833.391781,8403.79918,8031.09589,7634.39589,8775,9100.819672,9550.136986,9152.328767,8721.506849,9261.25097,8250.112447,8900,9458.356164,9832.322404,9693.150685,9735.342466,10168.24658,10460.71038,10133.75342,10425.13699

|

y6=9207.953,8774.205,8374.737,8131.639,8244.562,8707.441,8551.534,8596.625757,8571.572515,8648.534345,8687.668397,8878.950702,8971.377997,8680.14249,8348.978025,8139.688511,7613.07671,7355.307356,7416.545101,7171.124525,6846.664918,6661.627397,6559.589041,6464.557377,6451.435616,6251.909589,5881.460274,5821.601095,5801.402738,5744.076712,5649.238356,5440.915301,5183.712329,5085.865786,5073.898375,4999.669254,5356.695871,5484.267945,5666.619277,6518.316888,7492.879452,8786.865679,9438.734255,8839.297746,9351.830356,10990.46488

}} }}

File:Oil producing countries map.png from 2006 to 2012}}]]

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

{{See also|Fossil fuel exporters|OPEC}}

File:2014 Petroleum Countries Export Treemap.png

In order of net exports in 2011, 2009 and 2006 in thousand bbl/d and thousand m³/d:

Source: US Energy Information Administration{{cite web |url=http://www.eia.gov/countries/index.cfm?topL=exp |title=International |publisher=US Energy Information Administration |access-date=14 January 2025}}

¹ peak production already passed in this state

² Canadian statistics are complicated by the fact it is both an importer and exporter of crude oil, and refines large amounts of oil for the U.S. market. It is the leading source of U.S. imports of oil and products, averaging {{convert|2500000|oilbbl/d|abbr=on}} in August 2007.{{Cite web |title=U.S. Imports by Country of Origin |url=https://www.eia.gov/dnav/pet/pet_move_impcus_a2_nus_ep00_im0_mbblpd_m.htm |url-status=live |archive-url=https://web.archive.org/web/20180103234600/https://www.eia.gov/dnav/pet/pet_move_impcus_a2_nus_ep00_im0_mbblpd_m.htm |archive-date=January 3, 2018 |access-date=February 21, 2018 |publisher=U.S. Energy Information Administration}}

Total world production/consumption (as of 2005) is approximately {{convert|84|Moilbbl/d|m3/d}}.

In order of net imports in 2011, 2009 and 2006 in thousand bbl/d and thousand m³/d:

Source: US Energy Information Administration{{cite web |url=http://www.eia.gov/countries/index.cfm?topL=imp |title=International |publisher=U.S. Energy Information Administration |access-date=22 January 2025}}

{{smalldiv|1=

¹ peak production of oil expected in 2020"[http://www.eia.gov/forecasts/aeo/er/early_production.cfm AEO2014 Early Release Overview] {{webarchive|url=https://web.archive.org/web/20131220215802/http://www.eia.gov/forecasts/aeo/er/early_production.cfm |date=December 20, 2013 }}" [http://www.eia.gov/forecasts/aeo/er/pdf/0383er(2014).pdf Early report] {{webarchive|url=https://web.archive.org/web/20131220211420/http://www.eia.gov/forecasts/aeo/er/pdf/0383er(2014).pdf |date=December 20, 2013 }} US Energy Information Administration, December 2013. Accessed: December 2013. Quote:"Domestic production of crude oil .. increases sharply .. is expected to level off and then slowly decline after 2020"

}}

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

Source: CIA World Factbook{{Failed verification|date=July 2010|reason=maybe factbook changed? suggest clarify this table by using a factbook snapshot of a specific year}}

{{Main|Environmental impact of the petroleum industry}}

File:Dieselrainbow.jpg

File:Carbonate system of seawater.svg

{{As of|2018}}, about a quarter of annual global greenhouse gas emissions is the carbon dioxide from burning petroleum (plus methane leaks from the industry).{{Cite journal |last1=Ritchie |first1=Hannah |last2=Roser |first2=Max |last3=Rosado |first3=Pablo |date=May 11, 2020 |title={{CO2}} emissions by fuel |url=https://ourworldindata.org/emissions-by-fuel |url-status=live |journal=Our World in Data |archive-url=https://web.archive.org/web/20201103122924/https://ourworldindata.org/emissions-by-fuel |archive-date=November 3, 2020 |access-date=January 22, 2021}}{{Cite web |title=Methane Tracker 2020 – Analysis |url=https://www.iea.org/reports/methane-tracker-2020 |url-status=live |archive-url=https://web.archive.org/web/20210119102518/https://www.iea.org/reports/methane-tracker-2020 |archive-date=January 19, 2021 |access-date=January 22, 2021 |website=IEA |date=March 30, 2020 |language=en-GB}}{{efn|12.4 gigatonnes petroleum (and about 1 Gt CO₂ eq from methane)/50 gigatonnes total.}} Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO₂.{{Cite journal |last1=Marland |first1=Gregg |last2=Houghton |first2=R. A. |last3=Gillett |first3=Nathan P. |last4=Conway |first4=Thomas J. |last5=Ciais |first5=Philippe |last6=Buitenhuis |first6=Erik T. |last7=Field |first7=Christopher B. |last8=Raupach |first8=Michael R. |last9=Quéré |first9=Corinne Le |date=November 20, 2007 |title=Contributions to accelerating atmospheric {{CO2}} growth from economic activity, carbon intensity, and efficiency of natural sinks |journal=Proceedings of the National Academy of Sciences |volume=104 |issue=47 |pages=18866–18870 |bibcode=2007PNAS..10418866C |doi=10.1073/pnas.0702737104 |issn=0027-8424 |pmc=2141868 |pmid=17962418 |doi-access=free}}{{Cite journal |last1=Zheng |first1=Bo |last2=Zaehle |first2=Sönke |last3=Wright |first3=Rebecca |last4=Wiltshire |first4=Andrew J. |last5=Walker |first5=Anthony P. |last6=Viovy |first6=Nicolas |last7=Werf |first7=Guido R. van der |last8=Laan-Luijkx |first8=Ingrid T. van der |last9=Tubiello |first9=Francesco N. |date=December 5, 2018 |title=Global Carbon Budget 2018 |journal=Earth System Science Data |language=en |volume=10 |issue=4 |pages=2141–2194 |bibcode=2018ESSD...10.2141L |doi=10.5194/essd-10-2141-2018 |issn=1866-3508 |doi-access=free|hdl=21.11116/0000-0002-518C-5 |hdl-access=free }} Atmospheric CO₂ has risen over the last 150 years to current levels of over 415 ppmv,{{Cite web |last=US Department of Commerce |first=NOAA |title=Global Monitoring Laboratory – Carbon Cycle Greenhouse Gases |url=https://www.esrl.noaa.gov/gmd/ccgg/trends/ |url-status=live |archive-url=https://web.archive.org/web/20070316011636/https://www.esrl.noaa.gov/gmd/ccgg/trends/ |archive-date=March 16, 2007 |access-date=May 24, 2020 |website=www.esrl.noaa.gov |language=EN-US}} from the 180–300 ppmv of the prior 800 thousand years.[http://maps.grida.no/go/graphic/historical-trends-in-carbon-dioxide-concentrations-and-temperature-on-a-geological-and-recent-time-scale Historical trends in carbon dioxide concentrations and temperature, on a geological and recent time scale] {{webarchive|url=https://web.archive.org/web/20110724175732/http://maps.grida.no/go/graphic/historical-trends-in-carbon-dioxide-concentrations-and-temperature-on-a-geological-and-recent-time-scale |date=July 24, 2011 }}. (June 2007). In UNEP/GRID-Arendal Maps and Graphics Library. Retrieved 19:14, February 19, 2011.[http://news.bbc.co.uk/1/hi/sci/tech/5314592.stm Deep ice tells long climate story] {{webarchive|url=https://web.archive.org/web/20070830193909/http://news.bbc.co.uk/1/hi/sci/tech/5314592.stm |date=August 30, 2007 }}. Retrieved 19:14, February 19, 2011.{{Cite journal |last=Mitchell, John F.B. |year=1989 |title=The "Greenhouse" Effect and Climate Change |url=http://www.webpages.uidaho.edu/envs501/downloads/Mitchell |journal=Reviews of Geophysics |volume=27 |issue=1 |pages=115–139 |bibcode=1989RvGeo..27..115M |citeseerx=10.1.1.459.471 |doi=10.1029/RG027i001p00115 |archive-url=http://archive.wikiwix.com/cache/20080904222649/http://www.webpages.uidaho.edu/envs501/downloads/Mitchell |archive-date=September 4, 2008}} The rise in Arctic temperature has reduced the minimum Arctic ice pack to {{convert|4320000|km2|abbr=on|}}, a loss of almost half since satellite measurements started in 1979.{{Cite web |last=Change |first=NASA Global Climate |title=Arctic Sea Ice Minimum |url=https://climate.nasa.gov/vital-signs/arctic-sea-ice |url-status=live |archive-url=https://web.archive.org/web/20200524202942/https://climate.nasa.gov/vital-signs/arctic-sea-ice/ |archive-date=May 24, 2020 |access-date=May 24, 2020 |website=Climate Change: Vital Signs of the Planet}}

Ocean acidification is the increase in the acidity of the Earth's oceans caused by the uptake of carbon dioxide ({{CO2}}) from the atmosphere.The saturation state of calcium carbonate decreases with the uptake of carbon dioxide in the ocean.{{Cite journal |last1=Sommer |first1=Ulrich |last2=Paul |first2=Carolin |last3=Moustaka-Gouni |first3=Maria |date=May 20, 2015 |title=Warming and Ocean Acidification Effects on Phytoplankton—From Species Shifts to Size Shifts within Species in a Mesocosm Experiment |journal=PLOS ONE |language=en |volume=10 |issue=5 |pages=e0125239 |bibcode=2015PLoSO..1025239S |doi=10.1371/journal.pone.0125239 |issn=1932-6203 |pmc=4439082 |pmid=25993440 |doi-access=free}} This increase in acidity inhibits all marine life—having a greater effect on smaller organisms as well as shelled organisms (see scallops).{{Cite news |date=February 26, 2014 |title=Acidic ocean deadly for Vancouver Island scallop industry |work=cbc.ca |url=http://www.cbc.ca/news/canada/british-columbia/acidic-ocean-deadly-for-vancouver-island-scallop-industry-1.2551662 |url-status=live |archive-url=https://web.archive.org/web/20140427195837/http://www.cbc.ca/news/canada/british-columbia/acidic-ocean-deadly-for-vancouver-island-scallop-industry-1.2551662 |archive-date=April 27, 2014}}

Oil extraction is simply the removal of oil from the reservoir (oil pool). There are many methods on extracting the oil from the reservoirs for example; mechanical shaking,{{Cite journal |last1=Schwab |first1=A. P. |last2=Su |first2=J. |last3=Wetzel |first3=S. |last4=Pekarek |first4=S. |last5=Banks |first5=M. K. |date=June 1, 1999 |title=Extraction of Petroleum Hydrocarbons from Soil by Mechanical Shaking |url=https://pubs.acs.org/doi/10.1021/es9809758 |journal=Environmental Science & Technology |language=en |volume=33 |issue=11 |pages=1940–1945 |bibcode=1999EnST...33.1940S |doi=10.1021/es9809758 |issn=0013-936X}} water-in-oil emulsion, and specialty chemicals called demulsifiers that separate the oil from water. Oil extraction is costly and often environmentally damaging. Offshore exploration and extraction of oil disturb the surrounding marine environment.[http://www.offshore-environment.com/discharges.html Waste discharges during the offshore oil and gas activity] {{webarchive|url=https://web.archive.org/web/20090926140659/http://www.offshore-environment.com/discharges.html |date=September 26, 2009 }} by Stanislave Patin, tr. Elena Cascio

{{Further|Oil spill|List of oil spills}}

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| caption1 = Kelp after an oil spill.

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| caption2 = Oil slick from the Montara oil spill in the Timor Sea, September 2009.

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| caption3 = Volunteers cleaning up the aftermath of the Prestige oil spill.

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Crude oil and refined fuel spills from tanker ship accidents have damaged natural ecosystems and human livelihoods in Alaska, the Gulf of Mexico, the Galápagos Islands, France and many other places.

The quantity of oil spilled during accidents has ranged from a few hundred tons to several hundred thousand tons (e.g., Deepwater Horizon oil spill, SS Atlantic Empress, Amoco Cadiz). Smaller spills have already proven to have a great impact on ecosystems, such as the Exxon Valdez oil spill.

Oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin oil slick which can cover beaches with a thin coating of oil. This can kill sea birds, mammals, shellfish, and other organisms it coats. Oil spills on land are more readily containable if a makeshift earth dam can be rapidly bulldozed around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.

Control of oil spills is difficult, requires ad hoc methods, and often a large amount of manpower. The dropping of bombs and incendiary devices from aircraft on the {{SS|Torrey Canyon}} wreck produced poor results;Torrey Canyon bombing by the Navy and RAF modern techniques would include pumping the oil from the wreck, like in the Prestige oil spill or the Erika oil spill.{{Cite web |title=Pumping of the Erika cargo |url=http://www.total.com/en/group/news/special_report_erika/erika_measures_total/erika_pumping_cargo_11379.htm |url-status=live |archive-url=https://web.archive.org/web/20081119225756/http://www.total.com/en/group/news/special_report_erika/erika_measures_total/erika_pumping_cargo_11379.htm |archive-date=November 19, 2008 |access-date=August 29, 2010 |publisher=Total.com}}

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 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.{{Cite journal |last1=Sims |first1=Gerald K. |last2=O'Loughlin |first2=Edward J. |last3=Crawford |first3=Ronald L. |year=1989 |title=Degradation of pyridines in the environment |journal=Critical Reviews in Environmental Control |volume=19 |issue=4 |pages=309–340 |doi=10.1080/10643388909388372|bibcode=1989CRvEC..19..309S }}

Because petroleum is a naturally occurring substance, its presence in the environment does not need to be the result of human causes such as accidents and routine activities (seismic exploration, drilling, extraction, refining and combustion). Phenomena such as seeps{{Cite web |title=Seeps Home Page |url=http://seeps.wr.usgs.gov/ |archive-url=https://web.archive.org/web/20080820012319/http://seeps.wr.usgs.gov/ |archive-date=August 20, 2008 |access-date=May 17, 2010}} Natural Oil and Gas Seeps in California and tar pits are examples of areas that petroleum affects without man's involvement.

A tarball is a blob of crude oil (not to be confused with tar, which is a human-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{{Cite journal |last1=Itah A.Y. |last2=Essien J.P. |date=Oct 2005 |title=Growth Profile and Hydrocarbonoclastic Potential of Microorganisms Isolated from Tarballs in the Bight of Bonny, Nigeria |journal=World Journal of Microbiology and Biotechnology |volume=21 |issue=6–7 |pages=1317–1322 |doi=10.1007/s11274-004-6694-z |s2cid=84888286}}{{Cite journal |last1=Hostettler |first1=Frances D. |last2=Rosenbauer |first2=Robert J. |last3=Lorenson |first3=Thomas D. |last4=Dougherty |first4=Jennifer |year=2004 |title=Geochemical characterization of tarballs on beaches along the California coast. Part I – Shallow seepage impacting the Santa Barbara Channel Islands, Santa Cruz, Santa Rosa and San Miguel |journal=Organic Geochemistry |volume=35 |issue=6 |pages=725–746 |bibcode=2004OrGeo..35..725H |doi=10.1016/j.orggeochem.2004.01.022}} or in the Gulf of Mexico off Texas.{{Cite magazine |last=Drew Jubera |date=August 1987 |title=Texas Primer: The Tar Ball |url=http://www.texasmonthly.com/story/texas-primer-tar-ball |url-status=live |magazine=Texas Monthly |archive-url=https://web.archive.org/web/20150707102758/http://www.texasmonthly.com/story/texas-primer-tar-ball |archive-date=July 7, 2015 |access-date=October 20, 2014}} 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,{{Cite journal |last1=Knap Anthony H |last2=Burns Kathryn A |last3=Dawson Rodger |last4=Ehrhardt Manfred |last5=Palmork Karsten H |date=December 1984 |title=Dissolved/dispersed hydrocarbons, tarballs and the surface microlayer: Experiences from an IOC/UNEP Workshop in Bermuda |journal=Marine Pollution Bulletin |volume=17 |issue=7 |pages=313–319 |doi=10.1016/0025-326X(86)90217-1}}{{cite journal |last1=Wang |first1=Zhendi |last2=Fingas |first2=Merv |last3=Landriault |first3=Michael |last4=Sigouin |first4=Lise |last5=Castle |first5=Bill |last6=Hostetter |first6=David |last7=Zhang |first7=Dachung |last8=Spencer |first8=Brad |date=July 1998 |title=Identification and Linkage of Tarballs from the Coasts of Vancouver Island and Northern California Using GC/MS and Isotopic Techniques |journal=Journal of High Resolution Chromatography |volume=21 |issue=7 |pages=383–395 |doi=10.1002/(SICI)1521-4168(19980701)21:7<383::AID-JHRC383>3.0.CO;2-3}} 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.

File:Natural whale oil bottle.jpg]]

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,{{usurped|1=[https://web.archive.org/web/20120315153109/http://newscotland1398.ca/99/gesner-whales.html How Capitalism Saved the Whales]}} by James S. Robbins, The Freeman, August 1992. but others say that fossil fuels increased whaling with most whales being killed in the 20th century.{{Cite journal |last=York |first=Richard |date=January 1, 2017 |title=Why Petroleum Did Not Save the Whales |journal=Socius |language=en |volume=3 |page=2378023117739217 |doi=10.1177/2378023117739217 |issn=2378-0231 |s2cid=115153877 |quote=Ironically, even though fossil fuels provided substitutes for the main uses of whale oil, the rise of fossil fuel use in the nineteenth century served to increase the intensity of whaling. |doi-access=free}}

In 2018 road transport used 49% of petroleum, aviation 8%, and uses other than energy 17%.{{Cite web |title=World oil final consumption by sector, 2018 – Charts – Data & Statistics |url=https://www.iea.org/data-and-statistics/charts/world-oil-final-consumption-by-sector-2018 |access-date=April 3, 2022 |website=IEA |language=en-GB}} Electric vehicles are the main alternative for road transport and biojet for aviation.{{Cite web |title=Reaching Zero with Renewables: Biojet Fuels |url=https://www.irena.org/publications/2021/Jul/Reaching-Zero-with-Renewables-Biojet-Fuels |access-date=April 3, 2022 |website=/publications/2021/Jul/Reaching-Zero-with-Renewables-Biojet-Fuels |date=July 22, 2021 |language=en}}{{Cite web |title=ReFuelEU Aviation initiative: Sustainable aviation fuels and the fit for 55 package {{!}} Think Tank {{!}} European Parliament |url=https://www.europarl.europa.eu/thinktank/en/document/EPRS_BRI(2022)698900 |access-date=April 3, 2022 |website=www.europarl.europa.eu |language=en}}{{Cite web |date=October 11, 2021 |title=Aviation emissions: 'We can't wait for hydrogen or electric' |url=https://www.energymonitor.ai/sectors/transport/aviation-emissions-we-cant-wait-for-hydrogen-or-electric |access-date=April 3, 2022 |website=Energy Monitor |language=en-US}} Single-use plastics have a high carbon footprint and may pollute the sea, but as of 2022 the best alternatives are unclear.{{Cite web |title=This is how to ensure sustainable alternatives to plastic |url=https://www.weforum.org/agenda/2022/03/are-we-replacing-plastic-with-more-energy-intensive-alternatives/ |access-date=April 3, 2022 |website=World Economic Forum |language=en}}

{{See also|2022 boycott of Russia and Belarus}}

Control of petroleum production has been a significant driver of international relations during much of the 20th and 21st centuries.{{Cite news |date=September 17, 2020 |title=Is it the end of the oil age? |newspaper=The Economist |url=https://www.economist.com/leaders/2020/09/17/is-it-the-end-of-the-oil-age |url-status=live |access-date=December 31, 2020 |archive-url=https://web.archive.org/web/20201231201354/https://www.economist.com/leaders/2020/09/17/is-it-the-end-of-the-oil-age |archive-date=December 31, 2020 |issn=0013-0613}} 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.{{citation needed|date=August 2024}}

"Oil rents" have been described as connected with corruption in political literature.{{Cite web |title=Oil, gas, and mining |url=https://www.u4.no/topics/oil-gas-and-mining/basics |access-date=May 9, 2022 |website=U4 Anti-Corruption Resource Centre}} 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 investigators say that 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".{{Cite journal |last1=Arezki |first1=Rabah |last2=Brückner |first2=Markus |date=October 1, 2011 |title=Oil rents, corruption, and state stability: Evidence from panel data regressions |url=https://www.sciencedirect.com/science/article/pii/S0014292111000316 |journal=European Economic Review |language=en |volume=55 |issue=7 |pages=955–963 |doi=10.1016/j.euroecorev.2011.03.004 |issn=0014-2921}}

{{Main|oil war|Petro-aggression}}

Petroleum production has been linked with conflict for many years, leading to thousands of deaths.{{Cite journal |last=Lujala |first=Päivi |date=2009 |title=Deadly Combat over Natural Resources: Gems, Petroleum, Drugs, and the Severity of Armed Civil Conflict |journal=The Journal of Conflict Resolution |volume=53 |issue=1 |pages=50–71 |doi=10.1177/0022002708327644 |issn=0022-0027 |jstor=27638653 |s2cid=155043015}} Petroleum deposits are in hardly any countries around the world; mainly in Russia and some parts of the middle east.{{Cite web |title=International – U.S. Energy Information Administration (EIA) |url=https://www.eia.gov/international/data/world#/?pa=00000000000000000000000000000000002&c=ruvvvvvfvtvnvv1vrvvvvfvvvvvvfvvvou20evvvvvvvvvvvvuvo&ct=0&tl_id=5-A&vs=INTL.57-1-AFG-TBPD.A&vo=0&v=H&start=2014&end=2016 |access-date=February 16, 2023 |website=www.eia.gov}}{{Cite book |last=Alnasrawi |first=Abbas |title=The economy of Iraq: oil, wars, destruction of development and prospects, 1950–2010 |date=1994 |publisher=Greenwood Press |isbn=0-313-29186-1 |location=Westport, Conn. |oclc=28965749}} Conflicts may start when countries refuse to cut oil production in which other countries respond to such actions by increasing their production causing a trade war as experienced during the 2020 Russia–Saudi Arabia oil price war.{{Cite journal |last1=Ma |first1=Richie Ruchuan |last2=Xiong |first2=Tao |last3=Bao |first3=Yukun |date=October 1, 2021 |title=The Russia-Saudi Arabia oil price war during the COVID-19 pandemic |journal=Energy Economics |language=en |volume=102 |page=105517 |doi=10.1016/j.eneco.2021.105517 |issn=0140-9883 |pmc=8652835 |pmid=34898736|bibcode=2021EneEc.10205517M }} Other conflicts start due to countries wanting petroleum resources or other reasons on oil resource territory experienced in the Iran–Iraq War.{{Cite web |title=Iran-Iraq War {{!}} Causes, Summary, Casualties, & Facts {{!}} Britannica |url=https://www.britannica.com/event/Iran-Iraq-War |access-date=February 16, 2023 |website=www.britannica.com |language=en}}

{{Excerpt|OPEC}}

{{Update section|date=February 2021}}

File:World oil production.webp

Consumption in the twentieth and twenty-first centuries has been abundantly pushed by automobile sector growth. The 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.{{Cite news |last=Hume |first=Neil |date=March 8, 2016 |title=Goldman Sachs says commodity rally is unlikely to last |work=Financial Times |url=https://www.ft.com/content/e178653e-e517-11e5-bc31-138df2ae9ee6 |url-status=live |access-date=March 8, 2016 |archive-url=https://web.archive.org/web/20180429093259/https://www.ft.com/content/e178653e-e517-11e5-bc31-138df2ae9ee6 |archive-date=April 29, 2018 |issn=0307-1766}} The BRICS (Brasil, Russia, India, China, South Africa) countries might also kick in, as China briefly had the largest automobile market in December 2009.{{Cite news |last=Chris Hogg |date=February 10, 2009 |title=China's car industry overtakes US |work=BBC News |url=http://news.bbc.co.uk/2/hi/business/7879372.stm |url-status=live |archive-url=https://web.archive.org/web/20111019234900/http://news.bbc.co.uk/2/hi/business/7879372.stm |archive-date=October 19, 2011}} 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.{{Cite web |last=OPEC Secretariat |year=2008 |title=World Oil Outlook 2008 |url=http://www.opec.org/library/World%20Oil%20Outlook/pdf/WOO2008.pdf |archive-url=https://web.archive.org/web/20090407091227/http://www.opec.org/library/World%20Oil%20Outlook/pdf/WOO2008.pdf |archive-date=April 7, 2009}} 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.{{Cite journal |last1=Wachtmeister |first1=Henrik |last2=Henke |first2=Petter |last3=Höök |first3=Mikael |date=2018 |title=Oil projections in retrospect: Revisions, accuracy and current uncertainty |journal=Applied Energy |volume=220 |pages=138–153 |doi=10.1016/j.apenergy.2018.03.013 |doi-access=free|bibcode=2018ApEn..220..138W }} All together, Non-OPEC conventional projections have been fairly stable the last 15 years, while downward revisions were mainly allocated to OPEC. 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, Guara and Tiber demand high investments and ever-increasing technological abilities. Subsalt reservoirs such as Tupi were unknown in the twentieth century, mainly because the industry was unable to probe them. Enhanced Oil Recovery (EOR) techniques (example: DaQing, China{{Cite web |last=Ni Weiling |date=October 16, 2006 |title=Daqing Oilfield rejuvenated by virtue of technology |url=http://en.ce.cn/Insight/200610/16/t20061016_8980162.shtml |url-status=live |archive-url=https://web.archive.org/web/20111212081616/http://en.ce.cn/Insight/200610/16/t20061016_8980162.shtml |archive-date=December 12, 2011 |website=Economic Daily}}) 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.Samuel Schubert, Peter Slominski UTB, 2010: Die Energiepolitik der EU Johannes Pollak, 235 Seiten, p. 20

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.{{Cite web |date=January 27, 2021 |title=Rating agency S&P warns 13 oil and gas companies they risk downgrades as renewables pick up steam |url=http://www.theguardian.com/business/2021/jan/27/rating-agency-sp-warns-13-oil-and-gas-companies-they-risk-downgrades-as-renewables-pick-up-steam |url-status=live |archive-url=https://web.archive.org/web/20210127175822/https://www.theguardian.com/business/2021/jan/27/rating-agency-sp-warns-13-oil-and-gas-companies-they-risk-downgrades-as-renewables-pick-up-steam |archive-date=January 27, 2021 |access-date=January 27, 2021 |website=The Guardian |language=en}}

{{Main|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.{{Citation needed|date=May 2022}}{{cite book |last=Islam |first=M. R. |chapter=New Methods of Petroleum Sludge Disposal and Utilization |date=1995 |title=Asphaltenes |pages=219–235 |location=Boston |publisher=Springer US |doi=10.1007/978-1-4757-9293-5_8 |isbn=978-1-4757-9295-9}} The peak of oil discoveries was in 1965, and oil production per year has surpassed oil discoveries every year since 1980.{{Cite web |last=Campbell CJ |date=December 2000 |title=Peak Oil Presentation at the Technical University of Clausthal |url=http://energycrisis.org/de/lecture.html |url-status=live |archive-url=https://web.archive.org/web/20070705152332/http://energycrisis.org/de/lecture.html |archive-date=July 5, 2007}}

It is difficult to predict the oil peak in any given region, due to the lack of knowledge and/or transparency in the accounting of global oil reserves.{{Cite web |date=March 31, 2004 |title=New study raises doubts about Saudi oil reserves |url=http://www.iags.org/n0331043.htm |url-status=live |archive-url=https://web.archive.org/web/20100529211546/http://www.iags.org/n0331043.htm |archive-date=May 29, 2010 |access-date=August 29, 2010 |publisher=Iags.org}} Based on available production data, proponents have previously predicted the peak for the world to be in the 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.[http://www.oildecline.com/ Peak Oil Info and Strategies] {{webarchive|url=https://web.archive.org/web/20120617184210/http://www.oildecline.com/ |date=June 17, 2012 }} "The only uncertainty about peak oil is the time scale, which is difficult to predict accurately."

In 2020, according to BP's Energy Outlook 2020, peak oil had been reached, due to the changing energy landscape coupled with the economic toll of the COVID-19 pandemic.

While there has been much focus historically on peak oil supply, the 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.{{Cite journal|last1=Overland|first1=Indra|last2=Bazilian|first2=Morgan|last3=Ilimbek Uulu|first3=Talgat|last4=Vakulchuk|first4=Roman|last5=Westphal|first5=Kirsten|date=2019|title=The GeGaLo index: Geopolitical gains and losses after energy transition|journal=Energy Strategy Reviews|language=en|volume=26|page=100406|doi=10.1016/j.esr.2019.100406|doi-access=free|bibcode=2019EneSR..2600406O |hdl=11250/2634876|hdl-access=free}}

{{Update section|date=May 2022}}

Unconventional oil is petroleum produced or extracted using techniques other than the conventional methods. The calculus for peak oil has changed with the introduction of unconventional production methods. In particular, the combination of horizontal drilling and hydraulic fracturing has resulted in a significant increase in production from previously uneconomic plays.{{Citation | date = May 28, 2015 | title = U.S. Crude Oil Production Forecast – Analysis of Crude Types | publisher = U.S. Energy Information Administration | place = Washington, DC | url = http://www.eia.gov/analysis/petroleum/crudetypes/pdf/crudetypes.pdf | access-date = September 13, 2018 | quote = U.S. oil production has grown rapidly in recent years. U.S. Energy Information Administration (EIA) data, which reflect combined production of crude oil and lease condensate, show a rise from 5.6 million barrels per day (bbl/d) in 2011 to 7.5 million bbl/d in 2013, and a record 1.2 million bbl/d increase to 8.7 million bbl/d in 2014. Increasing production of light crude oil in low-permeability or tight resource formations in regions like the Bakken, Permian Basin, and Eagle Ford (often referred to as light tight oil) account for nearly all the net growth in U.S. crude oil production.
EIA's latest Short-Term Energy Outlook, issued in May 2015, reflects continued production growth in 2015 and 2016, albeit at a slower pace than in 2013 and 2014, with U.S. crude oil production in 2016 forecast to reach 9.2 million bbl/d. Beyond 2016, the Annual Energy Outlook 2015 (AEO2015) projects further production growth, although its pace and duration remains highly uncertain. | archive-date = November 22, 2019 | archive-url = https://web.archive.org/web/20191122192224/https://www.eia.gov/analysis/petroleum/crudetypes/pdf/crudetypes.pdf | url-status = live }} 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.

On Saturn's largest 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.{{cite web|url=http://www.space.com/scienceastronomy/080213-titan-oil.html |title=Titan Has More Oil Than Earth |date=February 13, 2008 |website=Space.com |access-date=February 13, 2008}}{{cite web|url=https://www.newscientist.com/article/dn24754-astrophile-titan-lake-has-more-liquid-fuel-than-earth/ |title=Astrophile: Titan lake has more liquid fuel than Earth |date=December 13, 2013 |work=New Scientist |first=Katia |last=Moskvitch |access-date=December 14, 2013}} Drilled samples from the surface of Mars taken in 2015 by the Curiosity rover's Mars Science Laboratory have found organic molecules of benzene and propane in 3-billion-year-old rock samples in Gale Crater.{{cite news |url=https://www.nytimes.com/2018/06/07/science/mars-nasa-life.html |title=Life on Mars? Rover's Latest Discovery Puts It 'On the Table' |first=Kenneth |last=Chang |date= June 7, 2018 |work=The New York Times |quote=The identification of organic molecules in rocks on the red planet does not necessarily point to life there, past or present, but does indicate that some of the building blocks were present. }}

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{{Portal|Energy}}

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{{Commons|Petroleum}}

{{NIE Poster|Petroleum}}

• [http://ggon.org/fossil-tracker/ Global Fossil Infrastructure Tracker]
• [http://www.api.org/ API – the trade association of the US oil industry.] (American Petroleum Institute)
• [http://www.eia.doe.gov/oil_gas/petroleum/info_glance/petroleum.html U.S. Energy Information Administration]
• [http://www.eia.doe.gov/emeu/international/contents.html U.S. Department of Energy EIA – World supply and consumption]
• [https://www.jodidata.org/ Joint Organisations Data Initiative | Oil and Gas Data Transparency]
• [http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+@rel+Crude+oil U.S. National Library of Medicine: Hazardous Substances Databank – Crude Oil]
• {{Cite AmCyc|wstitle=Petroleum|short=x}}
• "[https://books.google.com/books?id=p4o9AQAAIAAJ A Short History of Petroleum]", Scientific American, August 10, 1878, p. 85

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