What is oil

Oil is known as the "blood of industry", the oil industry is the pillar industry of the national economy because of the non-renewable nature of petroleum resources, the oil industry has an important strategic position
.
The use of oil is summarized in two aspects: First, oil and gas are the most important energy sources in the world today, the proportion of oil in the world's energy is more than 50%, and the proportion of natural gas is gradually increasing; Second, petroleum is an important chemical raw material, the current petroleum as raw material to produce more than 3,000 kinds of chemical products, widely used in agriculture, industry, national defense, science and technology and other fields
.

Petroleum is a complex natural organic compound, the main components are carbon (C) and hydrogen (H), but also contains a small amount of oxygen (0), sulfur (S), nitrogen (N).

C content is generally 80%-88%, H is 10% to 14%, 0, S, N and so on are only 0.
3% to 7%.

The compounds composed of these elements are mainly hydrocarbons, but there are also small amounts of non-hydrocarbon compounds
containing 0, S, and N.

The hydrocarbons in petroleum are mainly alkanes (saturated hydrocarbons), alkanes are a class of organic compounds, the carbon atoms in the molecules are connected by carbon-carbon single bonds, and the rest of the valence bonds are compounds combined with hydrogen, which are divided into two categories
: naphthenes and paraffins.
The general formula of paraffin is CnH2n+2, and the general formula of naphthenic hydrocarbon is CnH2n, which is the simplest class of organic compounds
.
The main source of alkanes is oil and natural gas, which is an important chemical raw material and energy material
.

The components of petroleum are oily, colloidal, carbon, asphaltene and so on
.
Asphaltene content is solid, and oil with high oil content is of good
quality.
The components of natural gas are methane, ethane, propane, butane and the like
.

Petroleum is formed at a depth of several kilometers underground, and has experienced millions or even hundreds of millions of years of evolutionary history, resulting in different components generated by different geological environments, resulting in different physical properties of petroleum, and different crude oil production density, viscosity, freezing point and initial boiling point of different
oilfields.
Most of the oil pair density is between 0.
75 and 1.
0, less than 0.
94 is light oil, greater than 0.
94 is heavy oil
.
The viscosity of petroleum varies greatly, and the viscosity of ground F is greater than 50rnPa•s as a heavy oil
.
The relative density of natural gas is mostly between 0.
6 and 1, and the viscosity is much
smaller than that of oil.