Fossil fuels.
Extraction of oil



Petroleum is a complex non-homogeneous mixture of hydrocarbons, composed / formed by hydrogen and carbon. The kinds of petroleums are very different from each other, can be from yellow and liquid to black and viscous. These differences are due to the relationships between the types of hydrocarbons. It is a non-renewable natural resource, raw material for numerous materials and products and, as a fossil fuel, the main primary energy source in the world.

The chemical components of petroleum are separated and obtained by distillation through a refinery process. From it different products are extracted, among others: propane and butane, gasoline, kerosene, diesel, fuel oil, lubricating oils, asphalts, coking coal ...

This mixture of hydrocarbons appears generally associated with large deposits of natural gas, in deposits closed for thousands of years underground, covered by the upper strata of the earth's crust.

Petroleum is a fossil fuel widely used to obtain fossil energy. Fossil energy refers to obtaining energy through a fossil fuel. Petroleum derivatives (gas oil or gasoline) are widely used in thermal engines and other industrial machines.

Origin of petroleum

The petroleum originates in shallow marine basins where large amounts of plankton proliferate. When they die, plankton accumulates along with a large amount of organic matter that remains among the mud from the bottom of the sedimentary basin. If these organisms are too long on the seabed, they will undergo an oxidation process.

Also, if they are left out of contact with the dissolved oxygen in the sea water when they are buried by an impermeable inorganic sediment, they will undergo a diagenetic process in conditions of anaerobiosis, where the increase in pressure and temperature along with the action of anaerobic bacteria They transform organic matter into hydrocarbons. In a first phase, the compaction and lithification of the sediment takes place at the same time: the bacteria degrade the living organisms with which they feed, and transform the waste into an insoluble organic substance with cyclic structures called querogen and which constitutes the raw material of petroleum.

Petroleum is produced by the transformation of the fatty acids of the querogen that are transformed into heavy hydrocarbons and that after a maturation process break down and originate liquid and gaseous hydrocarbons. Once the hydrocarbons are formed inside the sediment, two things can happen in its transformation:

  • That the petroleum remains inside the rock where it was formed, which is normally waterproof and of fine texture. These rocks are called bituminous shales, and their commercial exploitation is not very profitable, since it is necessary to carry out excavation, crushing and distillation of large quantities of rocks until liquid petroleum can be obtained. These are processes that require a large amount of water and generate a large amount of rocky waste (great ecological impact).
  • Petroleum migration. If the rock has been buried at a great depth, it is very possible that the fossil fuel escapes to higher zones to another material of greater porosity and permeability, due to the strong compaction.
  • Petroleum is not found in a certain type of rock but rather impregnates any rock that is sufficiently porous (that has strength holes). In addition to petroleum, methane and salt water are also found in these rocks from their formation process.

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    Last review: June 7, 2016