Petroleum

• 1. Introduction

  ›

  Petroleum sits underground as a yellowish-black liquid, a chemical mixture made mostly of hydrocarbons, hidden inside geological formations. The world burns through it at a staggering pace. By a 2021 estimate, the planet consumes 97.26 million barrels of oil every single day. About 90 percent of vehicular fuel needs are met by oil. It also forms the base of thousands of petrochemicals, from plastics and pharmaceuticals to pesticides and synthetic rubber.

  Yet this substance took millions of years to make. It formed from the anaerobic decay of buried prehistoric organisms, particularly plankton and algae. Roughly 70 percent of the world's oil deposits formed during the Mesozoic, 20 percent in the Cenozoic, and only 10 percent in the Paleozoic.

  How did a sticky residue once used to caulk boats become one of the world's most important commodities? Who first drilled for it on purpose, and where? Why does its name mean rock oil? And what happens to a world that has built itself on a non-renewable resource that may peak before 2035? The answers run from ancient Babylon to the lakes of Saturn's largest moon.

• 2. Rock Oil

  ›

  The word petroleum comes from Medieval Latin meaning literally rock oil, built from the Latin for rock, which traces to the Greek petra, and the Latin for oil, which traces to the Greek elaion. The term took root in monasteries in southern Italy, where it was in use by the end of the first millennium as an alternative for the older word naphtha.

  Georg Bauer, a German mineralogist, used the term in his treatise De Natura Fossilium, published in 1546. After the oil industry arose during the second half of the 19th century, petroleum became the common name for the liquid form of hydrocarbons. The substance behind the name had already been in human hands for thousands of years under other labels.

• 3. Ancient Uses

  ›

  More than 4,300 years ago, the Sumerians used bitumen to make boats. A tablet recounting the legend of the birth of Sargon of Akkad mentions a basket sealed with straw and bitumen. More than 4,000 years ago, according to Herodotus and Diodorus Siculus, asphalt went into the walls and towers of Babylon, where there were oil pits near Ardericca and a pitch spring on Zakynthos. In Babylon, petroleum served road construction, ship caulking, and medicine.

  The I Ching, one of the earliest Chinese writings, records that oil in its raw state was first discovered, extracted, and used in China in the 1st century BCE. The Chinese were the first to record petroleum used as fuel, as early as the 4th century BCE. By 347 CE, oil was produced from bamboo-drilled wells in China.

  In the 7th century, petroleum became an essential ingredient of Greek fire, an incendiary projectile weapon the Byzantine Greeks used against Arab ships attacking Constantinople. Persian chemists distilled crude oil, with clear descriptions in Arabic handbooks such as those of Abu Bakr al-Razi. In the 9th century, oil fields were worked around modern Baku, Azerbaijan. Marco Polo described those wells in the 13th century, putting their output at hundreds of shiploads.

• 4. The First Wells

  ›

  In 1846, a group of Russian Imperial engineers led by Major Alexeyev of the Bakinskii Corps of Mining Engineers accidentally struck oil while hand-drilling with a primitive percussion rig in Bibi-Heybat, near Baku. They were not even searching for oil. In 1853, Ignacy Lukasiewicz, who had discovered how to distill kerosene from seep crude and invented the modern kerosene lamp, hand-dug the first intentional well for commercial oil extraction in Bobrka, Poland. That well is still operational.

  Romania, then a vassal of the Ottoman Empire, became the first country to have its annual crude output officially recorded in international statistics, at 275 tonnes for 1857. In 1858, Georg Christian Konrad Hunaus found a significant amount of petroleum while drilling for lignite in Wietze, Germany. Wietze later supplied about 80 percent of German consumption in the Wilhelmine Era, and production ran until 1963.

  The first oil well in the Americas was drilled in 1859 by Edwin Drake at what is now the Drake Well in Cherrytree Township, Pennsylvania, sparking an oil boom. In Canada, James Miller Williams dug several wells between 1855 and 1858 before striking a rich reserve four metres below ground. Williams extracted 1.5 million litres of crude by 1860. On the 16th of January 1862, after a natural gas explosion, Canada's first oil gusher came in, shooting into the air at a recorded 3000 barrels per day.

• 5. Born From Decay

  ›

  Vast amounts of zooplankton and algae once settled to sea or lake bottoms, covered by stagnant water or sediment faster than they could decompose aerobically. Roughly one metre below the sediment, oxygen fell below 0.1 milligrams per litre and anoxic conditions set in. Anaerobic bacteria broke the matter apart, reducing sulfates and nitrates while polysaccharides and proteins hydrolyzed into simple sugars and amino acids.

  Phenolic compounds and antibiotics, including streptomycin from the Actinomycetales order, halted the bacteria at about 10 metres down. The surviving mixture of fulvic acids, fats, waxes, and modified lignin combined into a waxy material called kerogen. This whole transformation, from the start of anaerobic decay, is called diagenesis.

  Kerogen formation continued to about one kilometre below the surface, where temperatures may reach around 50 degrees Celsius. There, through a process called catagenesis, radical rearrangements turned kerogen into liquid and gaseous hydrocarbons over thousands to millions of years. The heat came from decaying radioactive materials in the crust, including potassium-40, thorium-232, and uranium-235 and 238. Geologists call the temperature band where oil forms the oil window. Above its ceiling, oil converts to natural gas through thermal cracking.

• 6. What Oil Is Made Of

  ›

  Carbon makes up 83 to 85 percent of crude oil by weight, hydrogen 10 to 14 percent, with smaller fractions of nitrogen, oxygen, and sulfur, plus traces of metals like iron, nickel, copper, and vanadium. Many oil reservoirs even contain live bacteria. Four hydrocarbon types appear in crude, averaging roughly 30 percent alkanes, 49 percent naphthenes, 15 percent aromatics, and 6 percent asphaltics.

  The lighter hydrocarbons are gases like methane, ethane, propane, and butane. Alkanes from pentane to octane refine into gasoline, while those from nonane to hexadecane become diesel, kerosene, and jet fuel. Paraffin wax is an alkane with about 25 carbon atoms, while asphalt runs to 35 and up. In winter, butane gets blended into the gasoline pool because its high vapour pressure helps with cold starts.

  Crude oil is usually black or dark brown, though it may run yellowish, reddish, or even greenish. In the reservoir it sits with a gas cap above it and saline water below. Three conditions must align to form a reservoir: a source rock cooked deep enough to make oil, a porous reservoir rock to hold it, and a caprock to seal it in. Canada's Athabasca oil sands hold crude bitumen so thick it must be heated or diluted before it will flow.

• 7. The Modern Order

  ›

  Access to oil shaped the military conflicts of the 20th century. The German invasion of the Soviet Union during World War II included the goal of capturing the Baku oilfields, since they would supply a military hampered by blockades. Oil exploration in North America made the United States the leading producer by mid-century, until Saudi Arabia and the Soviet Union surpassed it in total output after the U.S. peaked in the 1960s.

  During the 1973 oil crisis, Saudi Arabia and other Arab nations imposed an embargo on the United States, the United Kingdom, Japan, and other Western nations that supported Israel in the Yom Kippur War. The 1979 oil crisis followed, triggered by a drop in production after the Iranian Revolution, sending prices to more than double. These shocks drove substitution to coal and nuclear and spurred investment in non-OPEC fields, including Prudhoe Bay in Alaska and the North Sea fields of the United Kingdom and Norway.

  In 2018, thanks in part to hydraulic fracturing and horizontal drilling, the United States became the world's largest producer. About 80 percent of readily accessible reserves lie in the Middle East, with 62.5 percent from the Arab five: Saudi Arabia, the United Arab Emirates, Iraq, Qatar, and Kuwait. Some petroleum-rich countries, known as petrostates, gained significant influence in the latter half of the 20th century. Oil rents have been tied to corruption, with a 2011 study finding that rising rents significantly deteriorate political rights.

• 8. The Reckoning

  ›

  About a quarter of annual global greenhouse gas emissions comes from the carbon dioxide released by burning petroleum, plus methane leaks from the industry. Atmospheric carbon dioxide has climbed over the last 150 years to levels above 415 parts per million, up from the 180 to 300 range of the prior 800,000 years. The rise in Arctic temperature has cut the minimum Arctic ice pack to 4,320,000 square kilometres, a loss of almost half since satellite measurements began in 1979.

  Oil spills from tanker accidents have damaged ecosystems in Alaska, the Gulf of Mexico, the Galapagos Islands, and France. The Exxon Valdez spill showed how even smaller releases devastate ecosystems, while events like the Deepwater Horizon spill ranged into hundreds of thousands of tons. James S. Robbins has argued that refined kerosene saved some great whales from extinction by replacing whale oil, though others say fossil fuels increased whaling, with most whales killed in the 20th century.

  Production is estimated to reach peak oil before 2035, and the peak of oil discoveries already came in 1965. Yet hydrocarbons are not unique to Earth. On Saturn's largest moon, Titan, lakes of liquid methane, ethane, and propane occur naturally. Data from the Cassini-Huygens probe estimate those visible lakes and seas hold about 300 times the volume of Earth's proven oil reserves.