Facts about Natural Gas

• Natural gas comes from two sources:

1. From source rocks rich in organic material from plants.
2. From normal oils converted to gas due to excessive heat from deep burial.

• Natural gases fall into two categories:

1. Combustible (methane, ethane, propane, butane, & hydrogen). Methane is the most abundant, comprising almost 80% of combustible gases. There are two types of combustible gas: dry gas (usually from rock sources and exposure to thermal and bacterial conditions) and wet gas (contains higher hydrocarbons and is generally associated with oil accumulations). 75% of gas resources are combustible.
2. Non-combustible (nitrogen, carbon dioxide, & hydrogen sulfide).

• Gas source rocks are more widespread and abundant than oil source rocks.

• Gas is being depleted at a much slower rate than oil due to the high cost of transporting gas (especially from remote areas).

• As much as 80% or more of gas is recoverable from a well/source versus about 50% of oil since oil tends to adhere to the sand grains in the formation.

• Gas is commonly re-injected into oil wells to maintain pressure and enhance oil production. Once oil production falls to a low level, many then convert the oil field into a gas field.