Natural gas is a gaseous hydrocarbon produced by the slow transformation, metamorphism and pyrolysis of ancient remains deposited underground for a long time. Natural gas is flammable, mainly accompanied by the exploitation of oil fields.
Commercial production of natural gas mainly comes from oil and gas fields.
Natural gas often coexists in the same rock formation and can be siphoned off in oil Wells.
In addition, natural gas will be found in coal mines, Devonian shales, pressurized saline and tightly structured sandstones.
However, extracting gas from it is expensive and the technology has been slow to develop.
When organic materials such as plants, garbage, sewage and animal waste are fermented, biogas, which has similar properties to natural gas, is produced.
In the past, natural gas was burned as a waste product in the process of refining oil because it was less useful than the oil produced.
As reserves are depleted, however, the role of natural gas in supply is rising.
Natural gas occurs in underground pore strata, including oil field gas, gas field gas, coalbed methane, mud volcanic gas and biogenic gas, and a small amount of natural gas from coal seam.