Listen to Encana's management team discussing the company's Q1 2013 results in a live webcast and see the quarterly results documents.
We use a tailored approach when sourcing water for our operations. There is no one-source-fits-all solution.
There are four primary sources of water used in developing natural gas: surface water, shallow subsurface aquifers, deep subsurface aquifers and recycled water. We may use any, or all, of these sources throughout our operations.
Much of the water used in hydraulic fracturing currently comes from fresh surface water sources, such as lakes and rivers. However, we may use groundwater to supplement surface water supplies where it’s available in sufficient quantities. We also seek opportunities to use unutilized sources of water where we can. This water could be located far deeper than typical water wells and drinking aquifers. It could also be water which is of too poor a quality for household or other industrial use. There is no universal solution for our water needs and we employ a variety of water sourcing strategies depending on the characteristics of each resource play.
Surface water sources include lakes, rivers and run-off. Surface water, which is generally fresh water, is preferable where supplies are readily available because little or no pre-treatment is required. We often work with our community stakeholders, who may have a direct interest in using the same water sources, in addressing our water needs. We use fresh water during initial drilling operations to avoid contamination of any shallow groundwater aquifers.
As with surface water sources, shallow subsurface aquifers usually contain fresh water. These subsurface aquifers often include unconsolidated sands, gravels and shallow sandstone bedrock. Typically, as the depth of these aquifers increases, so does the salt content (salinity) of the water.
Deep subsurface aquifers are found hundreds of metres below ground. In the case of our Debolt water treatment plant in northeast British Columbia, subsurface water is extracted from between approximately 600 and 1,100 metres (2,000 and 3,600 feet) below ground surface. Over time, water in these aquifers has dissolved naturally-occurring salts, making the water unsuitable for domestic or livestock use. We use deep subsurface water in some of our operations during hydraulic fracturing. As an example, the Debolt formation provides more than 90 percent of the water we need for hydraulic fracturing operations in the Two Island Lake area of the Horn River Basin.
Sources of recycled/reused water can include municipal waste water or produced water. Produced water is found underground with natural gas and often has the same chemical characteristics of the producing formation. Produced water might also include water injected into the formation during hydraulic fracturing and may be referred to as flowback. While this water is unsuitable for use during drilling, it can be used in hydraulic fracturing operations if treated properly.