Where Does Natural Gas Come From?

Until recently some of us didn’t have much knowledge about natural gas, and instead of asking someone else where does natural gas come from, we just figured it was located in some kind of natural wells or caverns underground, spewing forth like Etna when some groups such as gas companies “struck” gas. Well, yes and no. As a viable energy source, it actually has a lot more to it than just that. As it is categorized by those in the know and those concerned with it as a fine source to be tapped, natural gas comes from a few broad, general, and specific resources.

Natural Gas Broad Origins

Natural gas comes from two broad “places”: With a biogenic origin, natural gas comes from places such as bogs and landfills. With a methanogenic origin, natural gas comes from deeper within the earth’s layers, where it is hottest and more highly pressurized and where organic matter, material, or organisms and microorganisms give up what is understood as methane gas.

Natural Gas “Fields”, Intended vs. Unintended Appearances

Natural gas is that which is found in four general source areas:

Natural gas fields produce “non-associated” (not found while drilling for oil, for example, but in natural environs elsewhere), biogenic natural gas.
Oil fields contain “associated” or casinghead natural gas, often unwanted during drilling/excavating and thus determined to be “stranded” oil-associated natural gas.
Coal beds can be found to have ”associated” natural gas in general and, coming from such a methanogenic field, natural gas in particular known as coal bed methane.
Methanogenic beds such as landfills thus carry what is today wanted/ intended methane, also known as recycled natural gas.
The Less “Conventional” Natural Gas Formations

While not necessarily differently located, there is also a number of natural gas formations that are recently being considered as possibilities for replacing oil/coal as our primary energy source. People in the industry, such as gas companies, are seeking such unconventional source types:

Tight Gas—Natural gas that is tightly secured in bedrock and/or sand formations, tight gas in natural gas processing is the most challenging and the most expensive to access.
Sour Gas—Natural gas that carries more hydrogen sulfide than “sweet gas,” sour gas is highly toxic and, as well, most readily speeds up erosion/corrosion of the gas piping and equipment used to extract it (in a process called sulfide stress cracking), so efforts must be made to “sweeten” it—to remove its dangerous impurities.
Shale Gas—A potential primary source in the U.S. today, shale gas is natural gas found in shale formations. It is extracted by way of hydraulic fracturing, or “fracking”, done by technologies using sand, water, and a combination of chemicals to blast through the shale, splitting the rock and allowing the gas to be released.
Researchers like those on behalf of the Natural Petroleum Council are keeping us updated, announcing, for example, that outside the U.S. such unconventional gas resources as these have been for the most part overlooked as most are directing attention to only the conventional resources. Within the U.S., however, scientists to geologists to gas companies are seriously considering not only the conventional but the unconventional places as vast, long-term natural gas providers.