ARCHIVED - Fact Sheet - Coalbed Methane
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Fact Sheet - Coalbed Methane
What is coalbed methane?
Coalbed methane is natural gas that is found in coal seams. It can also be called natural gas from coal. It is primarily composed of methane with varying amounts of nitrogen and carbon dioxide.
Coalbed methane is created during coalification, which is the natural process that converts organic matter into coal over time. Rock or water covers the coal seams and the gas stays "attached" to the coal. Small cracks in the coal, called cleats, allow the gas to escape from the seams under certain conditions.
Where does it exist?
Coal deposits containing natural gas exists in many regions across Canada including British Columbia, Saskatchewan, Nova Scotia and Alberta, which has the largest reserves in the country.
Development of coalbed methane as a resource is new in Canada. The industry has only been producing for about six years. Despite being so new, the future looks quite promising. Alberta, specifically, has many areas that are rich in coalbed methane.
This photo shows coal in a mine and the nature of the fracture
or cleat system of the coal.
How do you extract coalbed methane?
Coalbed methane is removed from the coal by reducing the pressure. The pressure can be reduced by drilling a well or by pumping the water that naturally exists in the coal out. In both cases, a process called fracturing enlarges the cleats within the coals which allows the gas to flow at higher rates. Fracturing is achieved by pumping a fluid, primarily nitrogen, at high pressure into the cleats.
What are some of the issues concerning coalbed methane?
The development of coalbed methane has raised issues for the public, provincial governments and the industry.
Water is a major issue with coalbed methane due to negative public perception associated with developments in the U.S., especially in the Powder River Basin of Wyoming. In that situation, water is pumped out to allow extraction of the gas from the coal. That water was then approved for surface use, disposal into streams, containment ponds or sprayed on agriculture land.
In some cases, minerals in the water reacted with the soil and caused damage to agricultural operations. In other cases, the quantity of water and/ or the quality difference in water had a negative effect on other water bodies.
In Alberta, fresh water disposal requires a special permit from Alberta Environment. Salt water must be re-injected into a deeper aquifer. This is in alignment with conventional oil and gas regulations. The Horseshoe Canyon coals in Alberta are somewhat unusual since they generally do not contain any water.
Some concern has been raised over well spacing in coalbed methane developments. In Alberta, currently the only location for development to date, conventional gas production starts with one well per section of land per pool. The producer has to apply for an increase in well density. For coalbed methane production, it is expected that two to eight wells will be required with four wells being the average so far. The upper range of coalbed methane well density is similar to what is currently accepted on conventional oil sites at four to eight wells per section and less than heavy oil which is up to 32 wells per section.
Well spacing has been raised as an issue for the development
of the coalbed methane industry. Currently in Alberta,
there are rules for the number of wells a company can have in one area.
As with other energy development projects, there is some concern with the impact of the project on affected lands. Companies seeking regulatory approval are required to assess these impacts and provide options for mitigation. Some of the mitigation measures used have been to drill several wells from the same surface location (called pad drilling), directional drilling and using existing pipeline corridors. Noise may also be a concern with field compression systems.
Land access and ownership
Although there is a clear distinction on Crown land between coalbed methane and coal mineral rights, this isn't always the case on freehold land. The Alberta Energy & Utilities Board has determined that the gas in coal belong to the owner of the petroleum and gas rights, not the holder of the coal rights. However, litigation may be involved to establish who has rights to which resource.
For more information on the Horseshoe Canyon coalbed methane development, see Horseshoe Canyon - The Potential for Coalbed Methane Development - Energy Brief.
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