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by Bunkerist
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The word oil comes from Latin petra, “rock” and oleum, “oil“.

Known for more than 4000 years, oil has been used since ancient times in one way or another, initially for medical, lighting, construction of castle and castle walls, and is important throughout society, including economy, politics and technology in modern life. Its rise in importance is due to the invention of the internal combustion engine, the rise in commercial aviation, and the importance of petroleum in industrial organic chemistry, especially the synthesis of plastics, fertilizers, solvents, adhesives and pesticides.

It is a naturally occurring yellowish-black liquid found in geological formations below the earth’s surface. Various types of fuel are obtained by refining. The components of the petroleum are separated by a technique called fractional distillation, the separation of a liquid mixture into fractions that differ in boiling point, using a partition column.

It consists of naturally occurring hydrocarbons of various molecular weights and contains various organic components. The name petroleum encompasses both naturally occurring unprocessed crude oil and all petroleum products consisting of refined crude oil. Oil, a fossil fuel, is formed when dead organisms, mostly zooplankton and algae that have been buried under sedimentary rocks, exposed to intense heat and pressure.

Oil Production

Oil is mostly recovered by oil drilling. Drilling is carried out after completion of structural geology (reservoir scale), sedimentary basin analysis and reservoir characterization (especially in terms of porosity and permeability of geological reservoir structures).

It is most easily separated by distillation from gasoline and kerosene to asphalt and chemical reagents (ethylene, propylene, butene, acrylic acid, para-xylene) into numerous consumer products used in plastics, pesticides and pharmaceuticals. Oil is used in the production of a wide variety of materials and it is estimated that the world consumes around 95 million barrels every day.

The usage of oil as fuel is an important cause of global warming and ocean acidification. Unless fossil fuels, including oil, are withdrawn from the industry, they will keep having serious, widespread and irreversible affects for people and ecosystems.

Access to oil was and still is a key factor in various military conflicts of the twentieth century, including World War II, when oil facilities were an important strategic asset and were extensively bombed.

In 1973, Saudi Arabia and other Arab countries imposed an oil embargo on the United States, United Kingdom, Japan, and other Western countries that supported Israel in the October 1973 Arab-Israeli War. The embargo caused an oil crisis with many short and long-term impacts on global politics and the global economy.

Today, approximately 90% of the vehicle fuel need is met by petroleum. Oil also accounts for 40 percent of total energy consumption in the United States, but is responsible for only 1 percent of electricity generation. The value of oil as a portable, dense energy source that powers the vast majority of vehicles and as the basis of many industrial chemicals makes it one of the world’s most important commodities.

Largest Oil Producers

The top three oil producing countries are Saudi Arabia, USA and Russia. In 2018, the United States became the world’s largest producer, partly due to advances in hydraulic fracturing and horizontal drilling. Around 80 percent of the world’s easily accessible reserves are in the Middle East and 62.5 percent in Saudi Arabia, the United Arab Emirates, Iraq, Qatar and Kuwait. Much of the world’s total oil is found in unusual resources such as bitumen in the Athabasca oil sands and extra heavy oil in the Orinoco Belt. While significant amounts of oil are extracted from petroleum sands, especially in Canada, oil extraction involves logistical and technical barriers as it requires large amounts of heat and water, making the net energy content considerably lower than conventional crude oil. Therefore, Canada’s oil sands are not expected to provide more than a few million barrels a day in the foreseeable future.


Fossil petroleum

Oil is a fossil fuel derived from ancient fossilized organic materials such as zooplankton and algae. The majority of these residues settle on the sea or lake floors where they are covered more quickly than they can be decomposed aerobically by stagnant water (water without dissolved oxygen) or sediments such as sludge and silt. Temperatures remain constant about 1 m below this deposit.

As more layers settle in the sea or lake bed, intense heat and pressure builds up in the lower regions. This process causes organic matter to turn into liquid and gaseous hydrocarbons with more heat. Oil formation occurs mainly in various endothermic reactions from hydrocarbon pyrolysis, at elevated temperature or pressure, or both.


Three conditions must be present for oil reservoirs to form:

A source rich in hydrocarbon material buried deep enough for underground heat to turn it into oil, a porous and permeable reservoir rock where it can accumulate, a cap (gasket) or other mechanism to prevent oil from coming to the surface. However, there is a layer of water under the oil layer and a layer of gas above it. Because most hydrocarbons are less dense than rock or water, they migrate upward from adjacent rock layers either until they reach the surface or are trapped in porous rocks (known as reservoirs) by impermeable rocks above. However, the process is affected by groundwater flows, causing the oil to migrate horizontally for miles and even down short distances before it becomes trapped in a reservoir. When the hydrocarbons condense in a gripper, an oil field is created where the liquid can be removed by piercing and pumping.

Unconventional oil reservoirs

Oil-eating bacteria biodegrade the part that escapes to the surface. Oily sands are partially biodegradable oil reservoirs that are still in the process of escape and biodegradation, but they contain so much migrating oil that although most of it has escaped, they contain greater quantities of oil than can be found in conventional oil reservoirs. For example, an extremely heavy form of crude oil called crude bitumen in Canada or reservoirs containing extra heavy crude oil in Venezuela are such formations. These two countries have the world’s largest oil-sand deposits.

On the other hand, oil shales are source rocks that are not subjected to heat or pressure for long enough to convert their trapped hydrocarbons into crude oil. Technically speaking, oil rocks (shale). Although found in many countries, the United States has the largest shale beds in the world.


Oil includes not only crude oil but all liquid, gaseous and solid hydrocarbons. Under surface pressure and temperature conditions, lighter hydrocarbons exist as methane, ethane, propane and butane gas, while pentane and heavier hydrocarbons are in liquid or solid form. However, the proportions of gas, liquid and solid in an underground oil reservoir depend on the underground conditions and the phase diagram of the oil mixture.

An oil well mainly produces crude oil, with some dissolved natural gas in it. Because the pressure is lower at the surface than underground, some of the gas will exit the solution and be recovered (or burned) as the associated gas or solution gas. A gas well produces mainly natural gas. However, since the underground temperature and pressure is higher than the surface, the gas may contain heavier hydrocarbons such as gaseous pentane, hexane and heptane. At surface conditions, they condense from gas to form “natural gas condensation”, this condensate is similar in appearance to gasoline and in composition to volatile light crude oil.

The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hydrocarbons, while other organic compounds contain nitrogen, oxygen, sulfur and metals such as trace amounts of iron, nickel, copper, vanadium. Many oil reservoirs contain live bacteria. The exact molecular composition of crude oil varies greatly from formation to formation, but the ratio of chemical elements varies over fairly narrow limits.


Oil extraction is simply the extraction of oil from a reservoir (oil pool). Oil is usually recycled as a water emulsion and special chemicals called emulsifiers are used to separate the oil from water. Oil extraction is costly and often harmful to the environment. Offshore exploration and oil extraction disturb the surrounding marine environment.

Wells are drilled in oil reservoirs to extract crude oil. The “natural lift” production methods that rely on natural reservoir pressure to bring the oil to the surface are usually sufficient for a period of time after the first application to reservoirs. In some reservoirs such as the Middle East, the natural pressure is sufficient for a long time. However, the natural pressure in most reservoirs eventually dissipates. The oil must then be extracted using “artificial lift” tools.

Over time, these “primary” methods become less effective and “secondary” methods of production can be used. A common secondary method is ‘overflow’ or water injection into the reservoir to increase the pressure and force the oil into the drilled shaft or ‘wellbore’.

Finally, “tertiary” or “enhanced” oil recovery methods can be used to increase the flow characteristics of the oil 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 oil produced daily, 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 the use of methods such as extracting and heating the sand or shale or injecting heated fluids into the deposit and then pumping it.


Crude oil can be considered light if its density is low and heavy if its density is high; and may be called sour if it contains a significant amount of sulfur, or sweet if it contains relatively little sulfur.

Geographical location is important as it affects transportation costs to the refinery. While light crude oil is more desirable than heavy oil as it produces a higher gasoline yield, sweet oil demands a higher price than sour oil because it has fewer environmental problems and requires less refining to meet the sulfur standards applied to fuels in consuming countries.

Oil, in which the molecular properties of crude oil are determined and the oil is classified, is used as a pricing reference worldwide. Some of the common crude oil references are:



Oil references valid in the Oil Market and used by refineries are Brent, WTI and Oman oil. Other well-known metrics can be listed as OPEC Reference Basket, Dubai Crude Oil, Shanghai Crude Oil, and Urals Oil. Two-thirds of all oil deals in the world are made on Brent oil. Therefore, Brent oil can be called the most common oil reference type.


The oil industry is involved in global exploration, extraction, refining, shipping (usually by oil tankers and pipelines) and marketing of oil products. The largest volume products of the sector are fuel oil and gasoline. Petroleum is also the raw material of many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics.

Petroleum is vital to many industries, and is of importance to the maintenance of industrialized civilization itself, and thus is a critical concern to many nations. Oil accounts for a large percentage of the world’s energy consumption, ranging from a low of 32 percent for Europe and Asia, up to a high of 53 percent for the Middle East, South and Central America (44%), Africa (41%), and North America (40%).

The world at large consumes 30 billion barrels (4.8 km3) of oil per year, and the top oil consumers largely consist of developed nations. In fact, 24 percent of the oil consumed in 2004 went to the United States alone, though by 2007 this had dropped to 21 percent of world oil consumed.


In the 1950s, shipping costs accounted for 33 percent of the price of oil transported from the Persian Gulf to the United States, but due to the development of supertankers in the 1970s, shipping costs dropped to just 5 percent of the price of oil. The price of Iranian oil in the USA, due to the increase in the value of crude oil in the last 30 years, the share of shipping cost on the final cost of the delivered goods was less than 3% in 2010.


After the collapse of the pricing system managed by OPEC in 1985 and a brief experiment with netback pricing, oil-exporting countries adopted a market-dependent pricing mechanism. Market-based pricing, first adopted by PEMEX in 1986, gained wide acceptance and in 1988 became and still is the main method of pricing crude oil in international trade.

Environmental effects

Leakage and spill

Because of the oil is being a naturally occurring substance, its presence in the environment need not be the result of human causes such as accidents and routine activities (seismic exploration, drilling, extraction, refining and burning). Examples include areas affected by oil without human intervention, such as natural spills and tar pits. Regardless of source, the effects of oil are similar when released into the environment.

Global warming

When burned, petroleum releases carbon dioxide, a greenhouse gas. Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO2. Atmospheric CO2 has risen over the last 150 years to current levels of over 415 ppmv, from the 180–300 ppmv of the prior 800 thousand years.This rise in temperature has reduced the minimum Arctic ice pack to 4,320,000 km2 (1,670,000 sq mi), a loss of almost half since satellite measurements started in 1979. Because of this melt, more oil reserves have been revealed. About 13 percent of the world’s undiscovered oil resides in the Arctic.

Ocean acidification

Ocean acidification is the increase in the acidity of the world’s oceans caused by the release of carbon dioxide (CO2). This increase in acidity affects all marine life. It has a greater effect on small organisms and crustaceans.


A tarball is a blob of crude oil (not to be confused with tar, which is a man-made product derived from pine trees or refined from petroleum) which has been weathered after floating in the ocean. Tarballs are an aquatic pollutant in most environments, although they can occur naturally, for example in the Santa Barbara Channel of California or in the Gulf of Mexico off Texas.Their concentration and features have been used to assess the extent of oil spills. Their composition can be used to identify their sources of origin, and tarballs themselves may be dispersed over long distances by deep sea currents. They are slowly decomposed by bacteria, including Chromobacterium violaceum.


There are those who argue that the advent of kerosene has saved some large whale species from extinction by providing a cheap substitute for whale oil, thus eliminating the economic imperative of offshore boat whaling.


In oil-producing countries with little refinery capacity, oil is sometimes burned to generate electricity. Renewable energy technologies such as solar power, wind power, micro hydro, biomass and biofuels are used, but the primary alternatives remain large-scale hydroelectric, nuclear and coal-fired generation.

Alternative fuels

Vehicles using alternative fuels used in standard or modified internal combustion engines such as natural gas vehicles, pure ethanol vehicles, flexible fuel vehicles, biodiesel powered vehicles, propane autogas and hydrogen vehicles.

Vehicles with advanced propulsion systems that reduce or replace oil use, such as battery-electric vehicles, plug-in hybrid electric vehicles, hybrid electric vehicles and hydrogen fuel cell vehicles.


As nearly all economic sectors rely heavily on oil, when the oil peaks, there is a partial or total collapse of the markets. In a sense, the excrement of the world, which is formed in the earth’s sewage infrastructure system and moves along the drainage lines, is a problem in several wise whether it is on earth or not, besides being an extremely active economic element. Perhaps, it is better to use it as an economic commodity and deal with the threats faced by humanity in this process, because as it finds a way coming on earth will anyway threaten the world and living things unless it is processed by human.


While there has been a lot of focus on the historically highest oil supply, it is still being assessed how the geopolitical position of 156 countries could change if more and more countries switch to renewable energy and then the world manages to switch fully to renewable energy sources. In this case, former oil exporters are expected to lose power, while the positions of former oil importers and countries rich in renewable energy resources are expected to strengthen.

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