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How is crude oil formed

Do you wonder how crude oil is formed? Then read this article!

The crude oil is formed underground in the process of decomposition of the marine organisms. It is formed over millions of years. The remains of the tiny organisms that lived in the sea and on land and the plants growing on the ocean floor mix with the sand and silt on the bottom of the ocean.

crude oil

These places, rich in organic components become the source for the crude oil formation. However, not all organic materials can be transformed into oil. Certain geological conditions are required to form the oil-saturated formations.

How is crude oil formed?

 The process of oil formation began millions of years ago with the development of life and continues to this day. Oil is declared as a non-renewable source of energy; man can’t create a new oil field in the short term period.

The deposit of crude oil is gradually getting bigger and bigger and gets deeper because of its own weight. When new oil pools accumulate on top the pressure on the lower layers increases in several thousand times and the temperature rises to several hundred degrees, the mud and sand harden and turn into shale and sandstone. Calcareous sediment and the remains of shells form limestone and the remains of dead organisms are transformed into crude oil and natural gas.

crude oil formed

Once the oil is formed, it starts to move up closer to the surface of the earth, since the density of the oil is less than the density of sea water, which fills the cracks in the sands and rocks that form the Earth's crust. Natural gas and crude oil seep into the microscopic pores of the oil pools which are located upper. Sometimes it happens that the oil gets into impermeable sediments or into the surroundings of a thick layer of the rock, which doesn’t allow it to move on. Oil falls into the trap and this is how the oil fields are formed.

 However, there is another theory of oil origin. Thomas Gold made this hypothesis. Gold's hypothesis was that there are hydrocarbons with a completely inorganic nature on our planet. As petroleum hydrocarbons are less dense compared to the watery fluids, Gold suggested that oil rises up through the fractures and cracks in the rock.

There were biological fragments found in the oil which made geologists believe that the oil substance has the organic origin. Gold believes that the micro flora of the subterranean formations is responsible for the presence of the biological residues in oil.

crude oil extracted

This hypothesis is accepted only by a limited number of geologists, engineers and oilmen and doesn’t contribute to the successful discovery of oil deposits under the layers of rocks. The methods of recreation of the hydrocarbons from inorganic substances are known to science but now there is no evidence that these processes take place beneath the earth's crust.

How is crude oil extracted?

Firstly, they need to select the site.

READ ALSO: How many litres of crude oil does Nigeria produced in per day

Once it’s done, scientists test the area and estimate the environmental impact of the extraction. The oil company needs to have a right and the agreement to drill the land.

After the legal issues are settled, they have to prepare the ground for drilling.

crude oil

In most cases, the oil fields are located at a considerable distance from the place where the oil is used: in the deserts, glaciers, in the jungle or far in the sea. The very long pipelines and big tankers are often the only means of delivering oil to the refineries, where it is distilled to obtain oil products which are ready for use.

The wells are often drilled at an angle to get to the places on the borders of the fields. The modern technologies allow drilling them down vertically and then horizontally to the side. Such a method is very good because it allows you to drill multiple wells from one point.

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