Oil & Gas

Frozen Gas: A Coalbed Methane Primer

Click here to download a copy of Coalbed Methane [CBM] in Yukon? (Acrobat PDF, ~180K)

The evidence indicates that this kind of large-scale, industrial development could degrade our land, air and water for decades. And this in turn could profoundly affect animals, birds, fish, plants and ultimately our way of life.

What is coalbed methane?

To capture the methane gas held (usually) within coal seams by water pressure, the water must be removed and the gas then drawn to surface. Wells are drilled into coal seams, water is pumped from the well, methane is released, gathered and sent to market.

CBM wells usually require "dewatering" and extensive water disposal systems for many years. And because these are low-pressure wells it often takes hundreds of them to effectively dewater the coals and produce gas economically.

CBM requires numerous roads and trails for all phases - seismic exploration, development drilling and production. Many hundreds of wells may be drilled in each field, requiring intense infrastructure development. Pipelines and/or roads connect each well to water disposal sites. It all usually adds up to severe disturbance to the environment.

Where is it produced?

CBM is commercially produced in Alberta and in the states of Montana, Wyoming, Colorado, New Mexico, Arkansas, Kentucky, among others. CBM exploration has occurred in British Columbia - including in the Klappan coalfield south of Dease Lake, BC - and in Alaska.

Water is a big issue in all these areas, except for the Horseshoe Canyon area near Drumheller, Alberta. The Horseshoe Canyon coals are relatively dry, which is anomalous in the North American experience to date. Even around Horseshoe Canyon, local residents are very worried about the land, air and noise impacts of CBM - and about their water wells.

Water

Techniques to get rid of the water include surface disposal or reinjection. Surface disposal can include pumping the water into evaporation ponds, releasing it directly it into streams and rivers, spraying it into the air, or in some cases using for irrigation and livestock watering. Reinjection involves pumping it back deep underground.

Even if the water is of high quality, disposing of such large volumes can overwhelm receiving streams and lakes, leading to heavy erosion and siltation, degradation of aquatic habitats, and. changes in the abundance and diversity of aquatic species.

The water pumped to surface is often relatively warm, which in the North could exacerbate the impacts on aquatic systems and permafrost.

How much water are we talking about?

Tens of thousands of CBM wells have been proposed in the large Powder River Basin of Montana and Wyoming. In this arid landscape, huge volumes of water will be removed from underground. Aquifer levels could be lowered by more than 200 m and the aquifers are not expected to recover for more than 40 years after CBM production ends.

Where could CBM occur in the Yukon?

What are some other potential risks?

Aquifer depletion:
The drawdown of aquifers can cause ponds, seeps and springs to dry up. Where large amounts of water are pumped from relatively shallow geological formations, surface subsidence can occur.

Permafrost:
Disruption of permafrost by access construction, field operations and water disposal is a primary concern in the Yukon.

Methane migration and seepage:
When shallow coal aquifers are pumped, the methane will travel underground to areas of low pressure, primarily the gas wells. But if there are other low pressure areas, methane will move towards them. This can lead to contaminated water wells or even contaminated soils.

Flaring and venting:
Flaring (burning) and venting unwanted gas both can release large quantities of greenhouse gases. Flaring can be loud and a fire hazard while both venting and flaring can also release poisonous gases.

Noise and dust:
CBM wells often require water-pumping and compressor equipment, operating continuously, noisily, and often for the life of the field. Compressors can produce high levels of low-frequency noise, often felt rather than heard by humans. Drilling and well stimulation can produce noise as loud as a jet engine.

With lots of movement of equipment and trucks and industrial traffic over gravel roads, CBM is a dusty business.

Roads, seismic lines, and pipelines:
Sensitive northern species like woodland caribou, wolverine, and grizzly bears reduce their use of habitat near roads, seismic lines, pipelines and well sites.

Roads can also open up new areas to hunting.

Pipelines may interfere with wildlife movement and seasonal migrations and impede their free movement or causing avoidance.