HOW IS NATURAL GAS FORMED

Natural Gas is an example of fossil fuel. The term ‘fossil fuels’ is attributed to the theory that the formation took place many hundreds of millions of years ago before the time of the dinosaurs. The age of formation is the Carboniferous Period- a part of the Paleozoic Era.

Natural Gas is made up of a combination of gases that consist largely of methane plus lesser amounts of ethane, propane, butane, nitrogen, carbon dioxide etc. The individual proportions of each of the gases however vary in accordance with the location where the natural gas has been located.

Gas is an organic matter that is prevented from complete decay. It is typically found at the top of petroleum reservoirs where it is recovered through wells on-shore and off-shore. It mostly occurs co-currently with oil although it appears lower in the ground than oil at great pressure.

It has no odor and cannot be seen. It is therefore mixed with a chemical which gives it a strong odor of rotten eggs. This helps to identify a leak during storage and transportation.

Formation of Natural Gas

Natural Gas can be formed in different ways.

The popular theory is that natural gas is composed of the remnants of decayed plant and animal matter which has been subjected to very high pressure under the earth’s crust over millions of years. When plants and tiny sea animals were buried by sand and rock, layers of mud, sand, rock, plant and animal matter continued to build up until the pressure and heat turned them into oil and natural gas. This formation of natural gas is ascribed to as thermogenic methane.

Another theory admonishes that the earth is composed of primordial materials that happened to combine in space billions of years ago when the basic structure of the earth was evolving. These materials are still buried far deep into the earth’s crust where they have been trapped for over 4.5 billion years. Since light hydrocarbons that comprise natural gas are lighter than water and rock, the gas existing within the earth’s crust tend to move upward until they reach the surface or are trapped by an impermeable layer of rock.

Natural Gas can also be produced by micro-organisms breaking down organic matter and producing methane; a process known as biogenic methane. This kind of natural gas is either lost in the atmosphere or found close to the earth’s surface often as landfill gas owing to the decomposition of the waste in the landfill.

Geological mapping, surveys and aerial photographs are used to locate natural gas. For accurate findings, more recent technology are applied. They include:

  • Magnetic measurement- measures magnetic field of base rock to determine how mush sediment overlays it
  • Satellite imagery- help identify the surface structure and patterns needful in the search for probable underlying hydrocarbon deposits
  • Gravity mapping- determines the thickness of the sedimentary rock layer useful in identifying the base rock topography
  • Seismic sound wave reflection- measures the time to various rock units which reflect acoustic energy