We explain what oil is, how it originated, the types that exist and their properties. Also, what are its characteristics and various uses.

Oil is a non-renewable natural resource of great economic value.

What is oil?

It is called petroleum (from the Latin petra“stone”, and oil“oil”) to a bituminous substance, dark in color and slimy in texture. It is composed of a mixture of organic hydrocarbons insoluble in water. It is a non-renewable natural resource of gigantic economic value.

Although the oil has been known since ancient timesIt was not until the Industrial Revolution of the 18th century that the scope of its capabilities was understood. It began to be valued as a raw material and energy source and began to be calledblack gold either crude.

Today it is used as source of obtaining complex materials (derived) or from fossil fuels such as gasoline. Many countries subsist based on the exploitation of this resource and international oil prices are a source of stability or conflict in many regions of the planet.

On the other hand, oil and its derivatives have a very high environmental impact. Extraction, burning of fossil fuels, mass production of plastics, and oil spills are the dark side of this material.

These “collateral damage” negatively affect life on the planet and on climate stability. They come to cause the destruction of ecosystems and the increase of greenhouse gases. It has been proven that it causes the acceleration of global warming, that is, climate change.

See also: Mining

origin of oil

Oil can come from fossils, zooplankton, or algae.

The origin of this substance is unknown for sure, but There are two theories about it..

One theory considers it a hydrocarbon of fossil origin, that is, the product of the millennial accumulation of large amounts of organic matter. that stuff can come from zooplankton and algae, belonging to former dried lake regions. Over the centuries, the anoxic (oxygen-free) bottoms of these desiccated lakes and rivers were covered by layers of sediment.

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This is how the conditions of pressure and heat were generated that in theory unleashed the chemical and physical processes of transformation. due to this natural cracking organic matter it was converted into new substances: bitumen, natural gases and oil.

The other theory about its origin considered to come from abiogenetic sources, that is, not from organic matter. This position has the support of only a minority of scholars on the subject, since it does not explain many of the oil contents, which are clearly organic in nature.

Oil Composition

Oil, as we have said, is a highly varied mixture of hydrocarbons, which includes the following:

  • Paraffins (saturated hydrocarbons).
  • Oleifins (ethylenic hydrocarbons).
  • Acetylene hydrocarbons.
  • Cyclic or cyclanic hydrocarbons.
  • Benzene or aromatic hydrocarbons.
  • Oxygenated compounds (by oxidation and polymerization).
  • sulfur compounds.
  • Cyclic nitrogenous compounds.
  • Dissolved content of nitrogen, sulfur, oxygen, cholesterol, porphyrins and traces of nickel, vanadium, cobalt and molybdenum.

types of oil

light oil
Light oil presents gravities above 31.1 °API.

The following types of oil are distinguished, based on their API gravity (scale created by the American Petroleum Institute), that is, their density:

  • Light or light crude. It presents gravities above 31.1 °API.
  • Medium or medium crude. It ranges from 22.3 to 31.1 °API.
  • Heavy oil. It presents gravities between 10 and 22.3 °API.
  • Extra heavy crude. It has gravities less than 10 °API.

Note that the lower the gravity, the denser the oil and the more difficult to extract. This is due to the fact that the lighter oils float in the water, being less dense than it.

Oil properties

oil is a thick, viscous liquid, colored tending to black or yellow (according to its hydrocarbon concentration). Its unpleasant odor is due to its content of sulfates and nitrogen.

Its enormous caloric power reaches 11,000 kilocalories per kilogram. These properties will vary according to the type of oil.

What is oil used for?

petroleum - detergent
Petroleum is essential to make substances such as detergents and lubricants.

Is a powerful source of industrial materials. It is essential in the manufacture of solvents, fuels, fuels, alcohols and plastics. Entire industries are supported by oil and its chemical properties.

To achieve these products, crude oil is subjected to various refining and distillation processessuch as fractional distillation. Thanks to these processes it is possible to separate and extract its different ingredients.

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The petrochemical and refining industry deals with it, and provides raw materials to various secondary industries: pharmaceutical, automotive, manufacturing, gas, detergent, lubricant, etc.

Furthermore, it is the main ingredient of fuels, which support various types of human transportation on land, air and sea. Oil is one of the most useful substances discovered by humans.

Petroleum derivatives

kerosene oil
Kerosene or kerosene was used as fuel for lamps.

Progressively heated from 20 °C to 400 °C, the oil separates into phases, useful for obtaining various derivative substances:

  • Natural gas (20°C). Combustible hydrocarbon gases such as ethane, propane, and butane (so-called “liquefied petroleum gases”), which are used for cooking or heating.
  • Naphtha or ligroin (150 °C). Also called benzine or petroleum ether, it is a mixture of highly flammable and volatile compounds, used as a nonpolar solvent and as a base to make other organic compounds.
  • Gasoline (200°C). The most popular fuel for internal combustion engines, such as those in motor vehicles, which varies in rank according to its octane number or purity.
  • Kerosene (300 °C). Kerosene is a fuel of low purity and poor performance, but it is much cheaper and easier to obtain than gasoline, since it does not require as many subsequent interventions. It is used as a solvent, base for pesticides and for lighting (lamps) or cooking (rural kitchens).
  • Diesel (370 °C). Also called diesel, it is a fuel made almost entirely of paraffins. It is ideal for heaters and outboard motors (or diesel engines), which are cheaper but have much lower performance.
  • Fuel oil (400 °C). The heaviest fuel that can be derived at atmospheric pressure from petroleum. It is used to feed boilers, ovens and also as distillation material, in obtaining asphalt, lubricating oils, etc.

How is oil extracted?

Oil deposits are found in the lower layers of the earth’s crust.

The oil it is extracted massively from its formation places in the subsoil. For this, facilities known as wells are used, which are located on the oil fields. In general, these deposits are found in places close to those of natural gas.

oil deposits found in the lower layers of the earth’s crust. From there the liquid can be extracted using various techniques, according to the nature of the soil and the geographical layout, which can be on the mainland or on the sea bed or rivers, lakes, etc.

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The way of extraction also depends on the type of crudesince some are heavier than others (see point 3).

Main exporters in the world

The extraction and commercialization of oil is an economic activity of great importance in several countries:

  • In Africa. Algeria, Angola, Gabon, Equatorial Guinea, Libya and Nigeria.
  • In the Middle East. Saudi Arabia, United Arab Emirates, Iraq, Kuwait and Qatar.
  • In Europe. Nordic countries such as Norway, Denmark and the United Kingdom, as well as Russia, Romania, Serbia, Ukraine, Poland, Bulgaria, Croatia and Georgia.
  • In Oceania. Australia and New Zealand.
  • In America. United States, Canada, Mexico, Argentina, Brazil, Guyana, Suriname, and especially Ecuador and Venezuela, the latter with the largest proven world reserves.

oil spills

oil spills
Oil spills catastrophically harm fauna and flora.

oil spills They are a real ecological tragedy.. They are known as “oil slick” and affect the entire ecosystem where they occur. They catastrophically harm the fauna and flora, as well as the economic activities that depend on them (fishing, tourism, etc.).

Its effects can be quite long-lasting and its compounds can pass into the body same of animals, entering the food chain. In addition, they can obstruct the photosynthesis of plants, deteriorating animal life by contact or preventing species from behaving in an ordinary way.


opec oil
In Vienna is the headquarters of OPEC, which groups 14 countries.

The Organization of the Petroleum Exporting Countries (OPEC or OPEC for its acronym in English) was founded in 1960 and is currently headquartered in Vienna, Austria. It is an international organization that ensures the understanding of the countries that depend to a large extent on the oil market.

Your goal is to achieve a joint action in favor of the stability of oil prices. The danger of a fluctuating market is that it causes inequities, poverty and economic crisis not only in the countries that comprise it, but in the rest of the planet.

At the moment Fourteen countries are members of OPEC: Angola, Saudi Arabia, Algeria, Qatar, Ecuador, United Arab Emirates, Gabon, Equatorial Guinea, Iran, Iraq, Kuwait, Libya, Nigeria and Venezuela.


  • “Oil” on Wikipedia.
  • “What is oil?” (Video) of PEDECIBA.
  • “Petroleum” in The Encyclopaedia Britannica.
  • “What is oil and what uses does it have?” in Forum of the Spanish Nuclear Industry.
  • “All about oil” at Repsol.

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