Key potential environmental impacts

Land

Increased number and density of wells

What is the issue?

The "default" gas well spacing in Canada is typically one well per section, but because of the large resource in place, unusual gas storage mechanisms and lower productivity in NGC (coalbed methane) reservoirs, Canadian optimal NGC well density is estimated to be two to eight wells per section of land. This also applies to other unconventional reservoirs such as tight sands and gas shales.

What is industry doing?

Advanced directional drilling technology enables the drilling of multiple wells from a single pad, thereby reducing the surface footprint in some areas.

Many existing conventional gas reservoirs have been developed with more wells, up to 16 wells per section in some areas. In oil reservoirs, the well spacing can be even denser.

Compressor noise associated with NGC and gas shale production

What is the issue?

Low reservoir pressures are common in NGC (coalbed methane) and shale gas development, requiring several stages of compression that can create noise levels above those for conventional natural gas production.

What is industry doing?

Industry ensures noise levels for all its operations remain below the legislated maximum. Where possible, industry selects compressor locations well removed from human habitation. New technologies such as special baffles and mufflers are also installed when necessary to reduce the noise level of the machinery.

Habitat destruction and fragmentation

What is the issue?

Unconventional gas development requires roads, pipelines and production facilities and the use of heavy equipment, all of which may destroy habitat and pose hazards to wildlife.

What is industry doing?

As with conventional oil and gas development, regulations require certain standards and practices to which industry adheres. Facilities are fenced, pipelines buried and locations reclaimed and restored to their previous natural state. Where possible, multiple wells are drilled from the same surface location to reduce the environmental footprint. In many cases, the unconventional gas is being developed within an existing conventional development, and is able to use pre-existing infrastructure.

Subsidence

What is the issue?

Land subsidence has been associated with underground coal mining operations.

What is industry doing?

Subsidence is related to subsurface collapse due to inadequate support following the removal of large volumes of coal. As with conventional natural gas reservoirs, unconventional gas occupies existing pore spaces within a fairly rigid matrix. Removal of the natural gas does not affect the structural integrity of the reservoir, therefore no collapse or minimal compaction occurs, and subsidence is not likely to occur.

Coal fires associated with NGC production

What is the issue?

Coal fires have occurred in underground coal seams and at coal outcrops due to natural causes or following the removal of water and NGC (coalbed methane) in certain areas of the United States.

What is industry doing?

Coal fires can occur in outcropping or near-surface coals naturally or once water and NGC (coalbed methane) have been removed and the coal faces are exposed to oxygen. The surface fires are generally the result of lightening strikes. In Canada, NGC development targets deeper coals that are not being mined. There is no danger of either underground or surface fires due to this deeper NGC production.