Definition - What does Formation Gas mean?
Formation Gas is the first stream of natural gas produced from an underground reservoir. When plankton, algae, proteins and organisms that live in the sea die, they drop down to the seabed and get buried with the accumulating sediment. When they reach an adequate temperature, something above 50 to 70 °C, they transform into liquid hydrocarbons which migrate and become an oil and gas reservoir.
Petropedia explains Formation Gas
The formation of gas just like oil takes millions of years. Formation gas is naturally occurring, colorless, odorless and combustible. It is mostly found in warm and shallow oceans which contain dead organic material such as plankton and algae, proteins and sea organisms. When these organisms die they get buried with bacteria, which produces methane while they decompose the organic material. The intense heat and high pressure at the seabed, enables the transformation of the organisms into hydrocarbons. Formation gas can also be found in adsorbed porous solids which are known as sorbents.