Gas is formed in the bowels of the earth from organic matter of animal origin, i.e. from the sediments of organisms that lived a very long time, under the influence of high pressure and temperature.
What makes natural gas
Dead living organisms sank to the bottom of the sea and found themselves in conditions where they could not decay either as a result of oxidation (there is practically no air and oxygen at the bottom of the sea) or under the influence of microbes. As a result, these organisms formed silty sediments.
Under the influence of geological movements, these sediments sank to ever greater depths, penetrated into the bowels of the earth. For millions of years, precipitation has been exposed to high pressures and temperatures. As a result of this impact, a process took place in these deposits, in which the carbon contained in them passed into compounds called hydrocarbons.
High molecular weight hydrocarbons (with large molecules) are liquid substances. Of these, oil was formed. But low molecular weight hydrocarbons are gases. Natural gas is formed from the latter. Higher temperatures and pressures are required only for gas formation. Therefore, there is always natural gas in an oil field.
Over time, deposits of oil and gas went to great depths. For millions of years they were blocked by sedimentary rocks.
Natural gas is a mixture of gases, not a homogeneous substance. The main part of this mixture, about 98%, is methane gas. In addition to methane, natural gas contains ethane, propane, butane and some non-hydrocarbon elements - hydrogen, nitrogen, carbon dioxide, hydrogen sulfide.
Where is natural gas located
Natural gas is found in the bowels of the earth at a depth of about 1000 m and deeper. There, he fills microscopic voids - pores that are interconnected by cracks. Through these cracks, gas in the earth can move from high-pressure pores to low-pressure pores.
Also, gas can be located in the form of a gas cap over the oil field. In addition, it can be in a dissolved state - in oil or water. Pure natural gas is colorless and odorless.
Gas production and transportation
Gas is extracted from the ground using wells. Due to the fact that the pressure is greater at depth, gas is ejected from the wells through the pipe.
To facilitate transportation and storage, natural gas is liquefied by exposure to low temperatures and elevated pressures. Methane and ethane cannot exist in a liquid state, so the gas is separated. As a result, only a mixture of propane and heavier hydrocarbons is transported in cylinders.