Natural gas is a mineral of a group of sedimentary rocks, which is a mixture of gases. This resource arose as a result of the decomposition of organic matter in the bowels of the Earth. Ecologists recognize natural gas as the cleanest type of fossil fuel.
Characteristics and types of natural gas
The characteristic of natural gas depends on its composition. It is lighter than air by 1.8 times, auto-ignition temperature is 650°C. Dry gas has a density of 0.68 kg/m 3 to 0.85 kg/m 3 and liquid 400 kg/m 3 . A mixture of gas and air from 5% to 15% by volume is explosive. Specific heat of combustion from 8-12 kWh/m 3 . When using natural gas in internal combustion engines, the octane number is from 120 to 130.
Most natural gas is a mixture of gaseous hydrocarbons. The main part is methane (CH 4 - up to 98%), as well as heavy hydrocarbons - ethane C 2 H 6, propane C 3 H 8, butane C 4 H 10. The composition also includes other non-carbon substances: hydrogen H 2, hydrogen sulfide H 2 S, carbon dioxide CO 2, nitrogen N 2, helium He.
Pure natural gas is colorless and odorless. To make it easier to determine the location of the leak, odorants, substances with an unpleasant odor, are mixed into it.
Types of natural gas:
- liquefied (SUG);
- marsh;
- oil;
- carbonic;
- gas hydrates;
- slate;
- lighting;
- coke;
- compressed or compressed (CNG);
- associated oil;
- by tiers and sub-tiers of the earthen layer of the Cretaceous period, from where it is mined today - Turonian, Cenomanian, Valanginian, Achimov.
Natural gas field
Basically, natural gas deposits are located in the sedimentary shell of the earth's crust. Huge reserves of natural gas are owned by Russia (Urengoyskoye field), in Europe - by Norway, the Netherlands, most of the Persian Gulf countries, Iran, Canada, the USA, there are large deposits in Azerbaijan, Uzbekistan, Turkmenistan and Kazakhstan. Gas hydrates are present in large quantities at great depths under the seabed, as well as underground.
Natural gas production
Before mining, exploration is first carried out - gravitational, magnetic, seismic or geochemical. However, the only reliable way to find out if there is a supply of gas under you is to drill a well. Natural gas is located at a depth of one kilometer. In the bowels of the Earth, gas is located in microscopic pores, which are interconnected by channels - cracks, through which, under high pressure, this important resource penetrates into pores of lower pressure until it is inside the wells. All this is carried out in accordance with Darcy's law - the filtration of gases and liquids in a porous medium. Gas comes out of the bowels as a result of the fact that in the wells it is under pressure, which is several times higher than atmospheric pressure.
Gas is produced using wells, which are evenly distributed over the entire area of the field. This is done for a uniform drop in reservoir pressure in the reservoir. The produced gas is prepared for transportation. Gas is transported by pipelines, special gas carriers, railway tanks.
Use of natural gas
Natural gas is used as a highly economical fuel for power plants, for the cement and glass industries, for ferrous and non-ferrous metallurgy, for the production of building materials, and for the production of various organic compounds. This important resource is used for and for household needs. The source of energy for megacities, motor fuel, paint, glue, vinegar, ammonia - all this we have thanks to natural gas.
