Petroleum

Petroleumis a naturally occurring yellowish-blackliquidmixture. It consists mainly ofhydrocarbons,and is found ingeological formations. The termpetroleumrefers both to naturally occurring unprocessed crude oil, as well as topetroleum productsthat consist of refined crude oil.
Conventional reserves of petroleum are primarily recovered bydrilling, which is done after a study of the relevantstructural geology,analysis of the sedimentary basin, andcharacterization of the petroleum reservoir. There are alsounconventionalreserves such asoil sandsandoil shalewhich are recovered by other means such asfracking.
Once extracted, oil is refined and separated, most easily bydistillation, into innumerable products for direct use or use in manufacturing. Products include fuels such asgasoline(petrol),diesel,keroseneandjet fuel;asphaltandlubricants; chemicalreagentsused to makeplastics;solvents,textiles,refrigerants,paint,synthetic rubber,fertilizers,pesticides,pharmaceuticals, and thousands of others. Petroleum is used in manufacturing a vast variety of materials essential for modern life,and it is estimated that the world consumes about 100 millionbarrels(16 millioncubic metres) each day. Petroleum production played a key role in industrialization and economic development.Some countries, known aspetrostates, gained significant economic and international power over their control of oil production and trade.
Petroleum exploitationcan be damaging to the environment and human health.Extraction,refiningandburningof petroleum fuels all release large quantities ofgreenhouse gases, so petroleum is one of the major contributors toclimate change. Othernegative environmental effectsinclude direct releases, such asoil spills, as well asairandwater pollutionat almost all stages of use. Theseenvironmental effectshave direct and indirect health consequences for humans. Oil has also been a source of internal and inter-state conflict, leading to bothstate-led warsand otherresource conflicts. Production of petroleum is estimated to reachpeak oilbefore 2035as global economies lower dependencies on petroleum as part ofclimate change mitigationand a transition towardsrenewable energyandelectrification.
The wordpetroleumcomes from Medieval Latinpetroleum(literally 'rock oil'), which comes from Latinpetra'rock' (from Greekpétraπέτρα) andoleum'oil' (from Greekélaionἔλαιον).
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".After that, the term was used in numerous manuscripts and books, such as in the treatiseDe Natura Fossilium, published in 1546 by the German mineralogistGeorg Bauer, also known as Georgius Agricola.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.
Petroleum, in one form or another, has been used since ancient times. More than 4300 years ago,bitumenwas mentioned when the Sumerians used it to make boats. A tablet of the legend of the birth ofSargon of Akkadmentions a basket which was closed by straw and bitumen. More than 4000 years ago, according toHerodotusandDiodorus Siculus,asphaltwas used in the construction of the walls and towers ofBabylon; there were oil pits near Ardericca and Babylon, and a pitch spring onZakynthos.Great quantities of it were found on the banks of the riverIssus, one of the tributaries of theEuphrates. AncientPersiantabletsindicate the medicinal and lighting uses of petroleum in the upper levels of their society.
The use of petroleum in ancientChinadates back to more than 2000 years ago. TheI Ching, one of the earliest Chinese writings, cites that oil in its raw state, without refining, was first discovered, extracted, and used in China in the first century BCE.In addition, the Chinese were the first to record the use of petroleum as fuel as early as the fourth century BCE.By 347 CE, oil was produced from bamboo-drilled wells in China.
In the 7th century, petroleum was among the essential ingredients forGreek fire, an incendiary projectile weapon that was used byByzantine Greeksagainst Arab ships, which were then attackingConstantinople.Crude oil was also distilled byPersian chemists, with clear descriptions given in Arabic handbooks such as those ofAbu Bakr al-Razi(Rhazes).The streets ofBaghdadwere paved withtar, derived from petroleum that became accessible from natural fields in the region.
In the 9th century,oil fieldswere exploited in the area around modernBaku,Azerbaijan. These fields were described by thePersian geographerAbu Bakr al-Raziin the 10th century, and byMarco Poloin the 13th century, who described the output of those wells as hundreds of shiploads.Arab and Persian chemistsalso distilled crude oil to produceflammableproducts for military purposes. ThroughIslamic Spain, distillation became available inWestern Europeby the 12th century.It has also been present in Romania since the 13th century, being recorded as păcură.
Sophisticated oil pits, 4.5 to 6 metres (15 to 20 ft) deep, were dug by theSeneca peopleand otherIroquoisinWestern Pennsylvaniaas early as 1415–1450. The French GeneralLouis-Joseph de Montcalmencountered Seneca using petroleum for ceremonial fires and as a healing lotion during a visit toFort Duquesnein 1750.
Early British explorers toMyanmardocumented a flourishing oil extraction industry based inYenangyaungthat, in 1795, had hundreds of hand-dug wells under production.
Merkwiller-Pechelbronnis 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.
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.There were engine-drilled wells in West Virginia in the same year as Drake's well.An early commercial well was hand dug inPolandin 1853, and another in nearbyRomaniain 1857. At around the same time the world's first, small, oil refinery was opened atJasłoin Poland (then Austria), with a larger one opened atPloieștiin 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.
In 1858, Georg Christian Konrad Hunäus found a significant amount of petroleum while drilling forligniteinWietze, Germany. Wietze later provided about 80% of German consumption in the Wilhelminian Era.The production stopped in 1963, but Wietze has hosted a Petroleum Museum since 1970.
Oil sands have been mined since the 18th century.InWietzein lower Saxony, natural asphalt/bitumen has been explored since the 18th century.Both in Pechelbronn as in Wietze, the coal industry dominated the petroleum technologies.
ChemistJames Youngin 1847 noticed a natural petroleum seepage in the coal mine at riddingsAlfreton,Derbyshirefrom 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 distillingcannel coalat 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.
The production of these oils and solidparaffin waxfrom 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. atBathgateinWest Lothianand E. Meldrum & Co. at Glasgow; their works at Bathgate were completed in 1851 and became the first truly commercial oil-works in the world with the first modern oil refinery.
The world's first oil refinery was built in 1856 byIgnacy Łukasiewiczin Austria.His achievements also included the discovery of how to distill kerosene from seep oil, the invention of the modernkerosene lamp(1853), the introduction of the first modern street lamp in Europe (1853), and the construction of the world's first modernoil "mine"(1854).atBóbrka, nearKrosno(still operational as of 2020).
The demand for petroleum as a fuel for lighting inNorth Americaand around the world quickly grew.
The first oil well in the Americas was drilled in 1859 byEdwin Drakeat what is now called theDrake WellinCherrytree Township, Pennsylvania.There also was a company associated with it, and it sparked a major oil drilling boom.
Thefirst commercial oil wellinCanadabecame operational in 1858 atOil Springs, Ontario(thenCanada West).BusinessmanJames Miller Williamsdug several wells between 1855 and 1858 before discovering a rich reserve of oil four metres below ground.Williams extracted 1.5 million litres of crude oil by 1860, refining much of it into kerosene lamp oil. Williams's well became commercially viable a year before Drake's Pennsylvania operation and could be argued to be the first commercial oil well in North America.The discovery at Oil Springs touched off anoil boomwhich brought hundreds of speculators and workers to the area. Advances in drilling continued into 1862 when local driller Shaw reached a depth of 62 metres using the spring-pole drilling method.On January 16, 1862, after an explosion ofnatural gas, Canada's first oil gusher came into production, shooting into the air at a recorded rate of 480 cubic metres (3,000 bbl) per day.By the end of the 19th century the Russian Empire, particularly theBranobelcompany inAzerbaijan, had taken the lead in production.
Access to oil was and still is a major factor in several military conflicts of the 20th century, includingWorld War II, during which oil facilities were a major strategic asset and wereextensively bombed.TheGerman invasion of the Soviet Unionincluded the goal to capture theBaku oilfields, as it would provide much-needed oil supplies for the German military which was suffering from blockades.
Oil exploration in North America during the early 20th century later led to the U.S. becoming the leading producer by mid-century. As petroleum production in the U.S. peaked during the 1960s, the United States was surpassed bySaudi Arabiaand theSoviet Unionin total output.
In1973, Saudi Arabia and otherArab nationsimposed anoil embargoagainst the United States, United Kingdom, Japan and other Western nations which supportedIsraelin theYom Kippur Warof October 1973.The embargo caused anoil crisis. This was followed by the1979 oil crisis, which was caused by a drop inoil productionin the wake of theIranian Revolutionand 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.They led to sustained reductions in demand as a result of substitution to other fuels, especially coal and nuclear, and improvements inenergy efficiency, facilitated by government policies.High oil prices also induced investment in oil production by non-OPEC countries, including Prudhoe Bay in Alaska, the North Sea offshore fields of the United Kingdom and Norway, the Cantarell offshore field of Mexico, and oil sands in Canada.
About 90 percent of vehicular fuel needs are met by oil. Petroleum also makes up 40 percent of total energy consumption in theUnited States, but is responsible for only one percent of electricity generation.Petroleum's worth as a portable, dense energy source powering the vast majority of vehicles and as the base of many industrial chemicals makes it one of the world's most importantcommodities.
The top three oil-producing countries as of 2018 are the United States,Russia, andSaudi Arabia.In 2018, due in part to developments inhydraulic fracturingandhorizontal drilling, the United States became the world's largest producer.
About 80 percent of the world's readily accessible reserves are located in theMiddle East, with 62.5 percent coming from the Arab five:Saudi Arabia,United Arab Emirates,Iraq,Qatar, andKuwait. A large portion of the world's total oil exists as unconventional sources, such asbitumeninAthabasca oil sandsandextra heavy oilin theOrinoco 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.
Petroleum consists of a variety of liquid, gaseous, and solid components. Lighter hydrocarbons are the gasesmethane,ethane,propaneandbutane. 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 amongoil fields.
Anoil wellproduces predominantly crude oil. Because the pressure is lower at the surface than underground, some of the gas will come out ofsolutionand be recovered (or burned) asassociated gasorsolution gas. Agas wellproduces predominantlynatural gas. However, because the underground temperature is higher than at the surface, the gas may contain heavier hydrocarbons such as pentane,hexane, andheptane("natural-gas condensate", often shortened tocondensate.) Condensate resembles gasoline in appearance and is similar in composition to somevolatilelight crude oils.
The hydrocarbons in crude oil are mostlyalkanes,cycloalkanesand variousaromatic hydrocarbons, while the other organic compounds containnitrogen,oxygen, andsulfur, and traces of metals such as iron, nickel, copper andvanadium. Many oil reservoirs contain live bacteria.The exact molecular composition of crude oil varies widely from formation to formation but the proportion ofchemical elementsvaries over fairly narrow limits as follows:
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.
The alkanes frompentane(C5H12) tooctane(C8H18) arerefinedinto gasoline, the ones fromnonane(C9H20) tohexadecane(C16H34) intodiesel fuel,keroseneandjet fuel. Alkanes with more than 16 carbon atoms can be refined intofuel oilandlubricating oil. At the heavier end of the range,paraffin waxis an alkane with approximately 25 carbon atoms, whileasphalthas 35 and up, although these are usuallycrackedin 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 eitherflared off, sold asliquefied 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.
Thearomatic hydrocarbonsareunsaturated hydrocarbonsthat have one or morebenzene rings. They tend to burn with a sooty flame, and many have a sweet aroma. Some arecarcinogenic.
These different components are separated byfractional distillationat an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbon fractions.
The components in an oil sample can be determined bygas chromatographyandmass spectrometry.Due to the large number of co-eluted hydrocarbons within oil, many cannot be resolved by traditional gas chromatography. Thisunresolved 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, andsaline waterwhich, 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 theAthabasca oil sandsin Canada, where it is usually referred to as crudebitumen. In Canada, bitumen is considered a sticky, black, tar-like form of crude oil which is so thick and heavy that it must be heated or diluted before it will flow.Venezuela also has large amounts of oil in theOrinoco oil sands, although the hydrocarbons trapped in them are more fluid than in Canada and are usually calledextra heavy oil. These oil sands resources are calledunconventional oilto distinguish them from oil which can be extracted using traditional oil well methods. Between them, Canada andVenezuelacontain an estimated 3.6 trillion barrels (570×10^m) of bitumen and extra-heavy oil, about twice the volume of the world's reserves of conventional oil.
Petroleum is afossil fuelderived fromfossilizedorganic materials, such aszooplanktonandalgae.Vast amounts of these remains settled to sea or lake bottoms where they were covered instagnant water(water with no dissolvedoxygen) orsedimentssuch asmudandsiltfaster than they coulddecompose aerobically. Approximately 1mbelow this sediment, water oxygen concentration was low, below 0.1 mg/L, andanoxic conditionsexisted. 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 askerogen, found in variousoil shalesaround the world, and then with more heat into liquid and gaseoushydrocarbonsvia a process known ascatagenesis. Formation of petroleum occurs from hydrocarbonpyrolysisin a variety of mainlyendothermicreactions at high temperatures or pressures, or both.These phases are described in detail below.
In the absence of plentiful oxygen,aerobicbacteriawere prevented from decaying the organic matter after it was buried under a layer of sediment or water. However,anaerobicbacteriawere able to reducesulfatesandnitratesamong the matter toH2SandN2respectively by using the matter as a source for other reactants. Due to such anaerobic bacteria, at first, this matter began to break apart mostly viahydrolysis:polysaccharidesandproteinswere hydrolyzed tosimple sugarsandamino acidsrespectively. These were further anaerobicallyoxidizedat an accelerated rate by theenzymesof the bacteria: e.g., amino acids went throughoxidative deaminationtoamino acids, which in turn reacted further toammoniaandα-keto acids.Monosaccharidesin turn ultimately decayed toCO2andmethane. The anaerobic decay products of amino acids, monosaccharides,phenolsandaldehydescombined intofulvic acids.Fatsandwaxeswere not extensively hydrolyzed under these mild conditions.
Some phenolic compounds produced from previous reactions worked asbactericidesand theactinomycetalesorder 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 modifiedlignin, 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.As a consequence, compounds of this mixture began to combine in poorly understood ways tokerogen. Combination happened in a similar fashion asphenolandformaldehydemolecules react tourea-formaldehyderesins, 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 calleddiagenesis, a word that means a transformation of materials by dissolution and recombination of their constituents.
Kerogen formation continued to a depth of about 1kmfrom the Earth's surface where temperatures may reach around 50°C. Kerogen formation represents a halfway point between organic matter andfossil fuels: kerogen can be exposed to oxygen, oxidize and thus be lost, or it could be buried deeper inside theEarth's crustand be subjected to conditions which allow it to slowly transform into fossil fuels like petroleum. The latter happened throughcatagenesisin which the reactions were mostlyradicalrearrangementsof 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 (anthraceneor products similar to it) and those with high H/C ratio (methaneor 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 reactionstoichiometry. Three types of kerogen exist: type I (algal), II (liptinic) and III (humic), which were formed mainly fromalgae,planktonandwoody plants(this term includestrees,shrubsandlianas) respectively.
Catagenesis waspyrolyticdespite 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 ofradioactivematerials of the crust, especiallyK,Th,UandU. The heat varied withgeothermal gradientand was typically 10–30 °C per km of depth from the Earth's surface. Unusualmagmaintrusions, however, could have created greater localized heating.
Geologists often refer to the temperature range in which oil forms as an"oil window".Below the minimum temperature oil remains trapped in the form of kerogen. Above the maximum temperature the oil is converted to natural gas through the process ofthermal cracking. Sometimes, oil formed at extreme depths may migrate and become trapped at a much shallower level. TheAthabasca oil sandsare one example of this.
An alternative mechanism to the one described above was proposed by Russian scientists in the mid-1850s, the hypothesis ofabiogenic petroleum origin(petroleum formed by inorganic means), but this is contradicted by geological andgeochemicalevidence.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."
Three conditions must be present for oil reservoirs to form:
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 inpetrochemicalplants andoil refineries.
Petroleum has mostly been recovered byoil 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 theporosityandpermeabilityof geologic reservoir structures).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.
Oil-eating bacteriabiodegradeoil that has escaped to the surface.Oil sandsare 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 inVenezuela. These two countries have the world's largest deposits of oil sands.
On the other hand,oil shalesare 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 calledkerogen. 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.
Thepetroleum industrygenerally classifies crude oil by the geographic location it is produced in (e.g.,West Texas Intermediate,Brent, orOman), itsAPI gravity(an oil industry measure of density), and its sulfur content. Crude oil may be consideredlightif it has low density,heavyif it has high density, ormediumif it has a density between that oflightandheavy.Additionally, it may be referred to assweetif it contains relatively little sulfur orsourif it contains substantial amounts of sulfur.
The geographic location is important because it affects transportation costs to the refinery.Lightcrude oil is more desirable thanheavyoil since it produces a higher yield of gasoline, whilesweetoil commands a higher price thansouroil 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 ofcrude oil assayanalysis in petroleum laboratories.
Barrelsfrom an area in which the crude oil's molecular characteristics have been determined and the oil has been classified are used as pricingreferencesthroughout the world. Some of the common reference crudes are:
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 atHardisty,Alberta, and for a Brent Blend delivered at Shetland, it may be a discounted Russian Export Blend delivered at the port ofPrimorsk.
Once extracted, oil is refined and separated, most easily bydistillation, into numerous products for direct use or use in manufacturing, such asgasoline(petrol),dieselandkerosenetoasphaltand chemicalreagents(ethylene,propylene,butene,acrylic acid,para-xylene) used to makeplastics,pesticidesandpharmaceuticals.
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 intofuel oiland gasoline, both importantprimary energysources. 84% by volume of the hydrocarbons present in petroleum is converted into fuels, including gasoline, diesel, jet, heating, and other fuel oils, andliquefied petroleum gas.
Due to its highenergy density, easy transportability andrelative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for manychemicalproducts, includingpharmaceuticals,solvents,fertilizers,pesticides, and plastics; the 16 percent not used for energy production is converted into these other materials. Petroleum is found inporousrock formationsin the upperstrataof some areas of theEarth's crust. There is also petroleum inoil sands (tar sands). Knownoil reservesare typically estimated at 190 km(1.2trillion(short scale)barrels) without oil sands,or 595 km(3.74 trillion barrels) with oil sands.Consumption is currently around 84 million barrels (13.4×10^m) per day, or 4.9 kmper year, yielding a remaining oil supply of only about 120 years, if current demand remains static.More recent studies, however, put the number at around 50 years.
Closely related to fuels for combustion engines areLubricants,greases, andviscositystabilizers.  All are derived from petroleum.
Manypharmaceuticalsare derived from petroleum, albeit via multistep processes.Modern medicine depends on petroleum as a source of building blocks,reagents, andsolvents.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.
In the 1950s, shipping costs made up 33 percent of the price of oil transported from thePersian Gulfto the United States,but due to the development ofsupertankersin 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.
Crude oil is traded as a future on both theNYMEXandICEexchanges.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.
According to the US Energy Information Administration (EIA) estimate for 2021, the world consumes 97.26 million barrels of oil each day.
This table orders the amount of petroleum consumed in 2011 in thousandbarrels(1,000 bbl) per day and in thousand cubic metres (1,000 m) per day:
Source: US Energy Information Administration
Population Data:
peak production of oilalready passed in this state
This country is not a major oil producer
In petroleum industry parlance,productionrefers to the quantity of crude extracted from reserves, not the literal creation of the product.
In order of net exports in 2011, 2009 and 2006 in thousandbbl/dand thousand m/d:
Source: US Energy Information Administration
peak productionalready passed in this state
Canadian statistics are complicated by the fact it is both an importer and exporter of crude oil, and refines large amounts of oil for the U.S. market. It is the leading source of U.S. imports of oil and products, averaging 2,500,000 bbl/d (400,000 m/d) in August 2007.
Total world production/consumption (as of 2005) is approximately 84 million barrels per day (13,400,000 m/d).
In order of net imports in 2011, 2009 and 2006 in thousandbbl/dand thousand m/d:
Source: US Energy Information Administration
Countries whose oil production is 10% or less of their consumption.
Source: CIA World Factbook
As of 2018, about a quarter of annual globalgreenhouse gas emissionsis the carbon dioxide from burning petroleum (plusmethane leaksfrom the industry).Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO2.Atmospheric CO2has risen over the last 150 years to current levels of over 415ppmv,from the180–300 ppmv of the prior 800 thousand years.The rise in Arctic temperature has reduced the minimumArctic ice packto 4,320,000 km(1,670,000 sq mi), a loss of almost half since satellite measurements started in 1979.
Ocean acidificationis the increase in the acidity of the Earth's oceans caused by the uptake ofcarbon dioxide(CO2) from theatmosphere.The saturation state of calcium carbonate decreases with the uptake of carbon dioxide in the ocean.This increase in acidity inhibits all marine life—having a greater effect on smaller organisms as well as shelled organisms (seescallops).
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,water-in-oil emulsion, andspecialty chemicalscalleddemulsifiersthat separate the oil from water. Oil extraction is costly and often environmentally damaging. Offshore exploration and extraction of oil disturb the surrounding marine environment.
Crude oil and refined fuelspillsfromtanker shipaccidents have damaged naturalecosystemsand human livelihoods inAlaska, theGulf of Mexico, theGalápagos Islands, France and manyother 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 theExxon Valdezoil 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 thinoil slickwhich 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 rapidlybulldozedaround 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 theSSTorrey Canyonwreck produced poor results;modern techniques would include pumping the oil from the wreck, like in thePrestigeoil spillor theErikaoil spill.
Though crude oil is predominantly composed of various hydrocarbons, certain nitrogen heterocyclic compounds, such aspyridine,picoline, andquinolineare reported as contaminants associated with crude oil, as well as facilities processing oil shale or coal, and have also been found at legacywood treatmentsites. These compounds have a very high water solubility, and thus tend to dissolve and move with water. Certain naturally occurring bacteria, such asMicrococcus,Arthrobacter, andRhodococcushave been shown to degrade these contaminants.
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 (seismicexploration,drilling, extraction, refining and combustion). Phenomena such asseepsandtar pitsare examples of areas that petroleum affects without man's involvement.
A tarball is a blob of crude oil (not to be confused withtar, 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 aquaticpollutantin most environments, although they can occur naturally, for example in the Santa Barbara Channel of Californiaor in the Gulf of Mexico off Texas.Their concentration and features have been used to assess the extent ofoil spills. Their composition can be used to identify their sources of origin,and tarballs themselves may be dispersed over long distances by deep sea currents.They are slowly decomposed by bacteria, includingChromobacterium violaceum,Cladosporium resinae,Bacillus submarinus,Micrococcus varians,Pseudomonas aeruginosa,Candida marinaandSaccharomyces estuari.
James S. Robbins has argued that the advent of petroleum-refined kerosene saved some species of great whales fromextinctionby providing an inexpensive substitute forwhale oil, thus eliminating the economic imperative for open-boatwhaling,but others say that fossil fuels increased whaling with most whales being killed in the 20th century.
In 2018 road transport used 49% of petroleum, aviation 8%, and uses other than energy 17%.Electric vehiclesare the main alternative for road transport andbiojetfor aviation.Single-use plastics have a high carbon footprint and may pollute the sea, but as of 2022 the best alternatives are unclear.
Control of petroleum production has been a significant driver of international relations during much of the 20th and 21st centuries.Organizations like OPEC have played an outsized role in international politics. Some historians and commentators have called this the "Age of Oil"With the rise ofrenewable energyand addressingclimate changesome commentators expect a realignment of international power away frompetrostates.
"Oil rents" have been described as connected with corruption in political literature.A 2011 study suggested that increases in oil rents increased corruption in countries with heavy government involvement in the production of oil. The study found that increases in oil rents "significantly deteriorates political rights". The 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".
Petroleum production has been linked with conflict for many years, leading to thousands of deaths.Petroleum deposits are in hardly any countries around the world; mainly in Russia and some parts of the middle east.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 the2020 Russia–Saudi Arabia oil price war.Other conflicts start due to countries wanting petroleum resources or other reasons on oil resource territory experienced in theIran–Iraq War.
Consumptionin the twentieth and twenty-first centuries has been abundantly pushed by automobile sector growth. The1985–2003 oil gluteven fueled the sales of low fuel economy vehicles inOECDcountries. 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.TheBRICS(Brasil, Russia, India, China, South Africa) countries might also kick in, as China briefly had the largest automobile market in December 2009.In the long term, uncertainties linger; theOPECbelieves 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 theEnergy Information Administration(EIA) kept lowering their 2020 consumption estimates during the past five years.A detailed review ofInternational Energy Agencyoil projections have revealed that revisions of world oil production, price and investments have been motivated by a combination of demand and supply factors.All together, Non-OPEC conventional projections have been fairly stable the last 15 years, while downward revisions were mainly allocated to OPEC. Upward revisions are primarily a result of UStight 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 asTupi, Guara andTiberdemand high investments and ever-increasing technological abilities. Subsalt reservoirs such as Tupi were unknown in the twentieth century, mainly because the industry was unable to probe them.Enhanced Oil Recovery(EOR) techniques (example:DaQing, China) will continue to play a major role in increasing the world's recoverable oil.
The expected availability of petroleum resources has always been around 35 years or even less since the start of the modern exploration. Theoil constant, an insider pun in the German industry, refers to that effect.
A growing number of divestment campaigns from major funds pushed by newer generations who question the sustainability of petroleum may hinder the financing of future oil prospection and production.
Peak oilis a term applied to the projection that future petroleum production, whether for individual oil wells, entire oil fields, whole countries, or worldwide production, will eventually peak and then decline at a similar rate to the rate of increase before the peak as these reserves are exhausted.The peak of oil discoveries was in 1965, and oil production per year has surpassed oil discoveries every year since 1980.However, this does not mean that potential oil production has surpassed oil demand.
It is difficult to predict the oil peak in any given region, due to the lack of knowledge and/or transparency in the accounting of global oil reserves.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.
In 2020, according toBP's Energy Outlook 2020, peak oil had been reached, due to the changing energy landscape coupled with theeconomic 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.
Unconventional oilis petroleum produced or extracted using techniques other than the conventional methods. The calculus for peak oil has changed with the introduction ofunconventionalproduction methods. In particular, the combination ofhorizontal drillingandhydraulic fracturinghas resulted in a significant increase in production from previously uneconomic plays.Certain rockstratacontain 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.
OnSaturn'slargest moon,Titan, lakes of liquid hydrocarbons comprising methane, ethane, propane and other constituents, occur naturally. Data collected by the space probeCassini–Huygensyield an estimate that the visible lakes and seas of Titan contain about 300 times the volume of Earth's proven oil reserves.Drilled samples from the surface ofMarstaken in 2015 by theCuriosityrover'sMars Science Laboratoryhave found organic molecules ofbenzeneandpropanein 3-billion-year-old rock samples inGale Crater.