Protecting water and reducing our use of this valuable resource is a key priority for Canada's natural gas industry.
Water is essential to the recovery of natural gas from conventional and unconventional sources, such as shale rock. It is needed to drill and complete a well. Once that is done and the well starts producing for the next 20 to 30 years, it is rare water has to be used again.
Drilling a well into a reservoir that is relatively easy to access, called a conventional reservoir, requires about 400 to 600 cubic metres of water. About 86 per cent of Canada's natural gas production comes from conventional wells.
As conventional reservoirs are gradually depleted, industry is shifting its focus to natural gas resources trapped in unconventional reservoirs. That's the case in British Columbia, home of the Horn River and Montney plays, which are among North America's most promising unconventional natural gas fields.
Unconventional resources are developed by drilling horizontal wells into the shale formation, typically 2,000 to 3,000 metres deep. After the well is drilled, the horizontal leg of the well is hydraulically fractured to get the gas to flow to the wellbore and from there to the surface. This process requires between 5,000 and 110,000 cubic metres of water per well. The volume of water required depends on geological and reservoir characteristics.
While this appears to be a lot of water and it is, it is important to put these volumes into perspective. In a report released last November, the National Round Table on the Environment and Economy, using 2005 data, pointed out the oil and gas sector uses relatively little water nationally compared to other natural resource sectors, i.e. thermal electricity, manufacturing, pulp and paper, agriculture and mining. With a share of 0.6 per cent of the total water intake of Canada's natural resource sectors, the oil and gas sector uses the least water of those sectors. The report also shows the oil and gas sector has been successful in continuously reducing water use intensity (volume of water per unit of production) over the past three decades: oil and gas accounts for 23 per cent of economic output of the natural resource sectors, but only 0.6 per cent of the water intake.
This does not mean we cannot, or should not, continuously improve and further reduce our reliance on water, especially fresh surface water, such as rivers and lakes, from which most water used in natural gas development is withdrawn. This is accomplished by using alternatives to freshwater and recycling water for reuse.
CAPP's Hydraulic Fracturing Operating Practices, released in January 2012, specifically address this issue and commit natural gas producers to reduce their reliance on freshwater and recycle water as much as practical.
Alternatives to freshwater include brackish groundwater drawn from slightly saline aquifers that typically sit below freshwater aquifers, or deep saline groundwater. Reclaimed municipal waste water is another alternative.
An example where this is put into action is the Debolt Water Treatment plant, a joint venture between Encana and Apache Canada in the Horn River Basin. The plant, the first of its kind in North America, treats saline groundwater from an aquifer 700 metres below the surface for use in hydraulic fracturing operations. This has led to a drastic reduction in the volume of freshwater needed in both companies' hydraulic fracturing operations.
Recycling water for reuse is another option to reduce fresh water use. Flowback, which is the water and a very small amount of additives injected into the well during hydraulic fracturing that flows back to the wellbore, can also be reused for hydraulic fracturing.
In 2010, CAPP members voluntarily reported on water reuse in Western Canada shale and tight gas plays for the first time.
Based on the data received in 2010, four per cent of water was reused in these projects. Industry recognizes the level of reuse must be improved and is advancing a number of initiatives to address this issue. Water reuse reporting has become mandatory this year, and more complete and comprehensive data will be released at the end of the year.
Technology and innovation are key drivers as industry continuously improves its environmental performance. Yes, there are challenges, but we are candid about them, just as we are candid about demonstrating the progress industry makes in pursuing solutions to these challenges.
Natural gas is an important resource, and we will continue to develop this resource safely and responsibly.