Natural gas is produced by two different natural processes known as thermogenic and biogenic.
Thermogenic gas is produced over millions of years from decaying organic matter in reservoirs deep within the earth and under the sea.
There are three principal supplies of natural gas processed from thermogenic gas wells:
- Gas that is dissolved in crude oil or that is extracted from the top of the crude reservoir is known as associated gas.
- Gas that has been extracted from gas or condensate reservoirs that contain only trace elements of crude are known as non-associated gas.
Biogenic gas on the other hand is formed by methagenic organisms breaking down under high temperature anaerobic conditions being found in coal seams, landfill sites, and marshes.
Natural gas is extracted from coal seams and from the coal itself where the gas has been adsorbed into its surface. This is known as coalbed gas.
This is actually considered as renewable energy, being produced from our waste in numerous landfill sites.
Natural gas also exists in locations where it is difficult to extract it from, being trapped. This is due to the nature of the rock pores that are many times smaller than the human hair, and is known as “Tight Gas.”
World Leading Suppliers of Natural Gas
At present America is the world’s leading processor of natural gas, producing 22 trillion cubic feet (Tcf) in 2010. This knocked Russia off the pole position, and they are now the second largest producer coming in at 20.5 Tcf, with the Middle East being the third largest.
Once the gas has been discovered it must be recovered, processed, transported, and stored. These activities are elucidated in the following sections beginning with NG recovery and processing.