Encana going saline to reduce surface water use

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As Encana increases its level of development in the Dawson Creek region, responsible water use and sourcing are critical components for the company to fully realize the potential of British Columbia’s portion of the Montney resource play.

Water management approaches tailored for specific operating areas have long been at the heart of Encana’s stewardship philosophy and reflect an enterprise-wide mandate of continuous improvement. To this end, the company seeks innovative solutions and technologies to decrease its reliance on surface water sources wherever possible.

This commitment has taken on different forms throughout Encana’s operations; namely through, where feasible, such approaches as reuse, accessing wastewater, and tapping into saline sources that are unfit for typical human or agricultural use.

The latter option informs the company’s Water Resource Hub (WRH) facility located in the Cutbank Ridge area of Encana’s Montney operations. Scheduled to be completed by the end of 2014, the WRH is expected to meet 50 to 75 per cent of Encana’s water needs in the Dawson Creek area – significantly reducing the company’s reliance on surface water by replacing it with otherwise unusable water from a subsurface aquifer. In doing so, the project’s unique distribution and return system will also substantially reduce water hauling truck traffic and associated emissions, noise, and dust.

“Water is a critical component of natural gas production and crucial for the continued success of our industry, both the upstream sector and the many jobs it provides, as well as for B.C. to realize its LNG export potential,” says Richard Dunn, Encana’s vice-president, government relations Canada. “A facility such as the Water Resource Hub demonstrates our commitment to always seeking alternative sources to surface water for our operations.”

Designed for a maximum intake of 50,000 barrels per day, the facility accesses saline water from the Paddy Cadotte aquifer located 1,000 metres below ground. Encana began the project by converting two pre-producing gas wells into saline source water wells – the debut pair of what is projected to be up to 20 source wells. The unusable water flows via pipeline network  to the WRH. It is then filtered, stored and pumped through other pipelines to new well sites for use in hydraulic fracturing – and this is where the cycle begins anew.

In what is an innovative recycle and reuse loop, the flowback water returned from the formation after completions operations will be pipelined back to the central point of the WRH. Hydraulic fracturing water returns are then blended at the site with the saline source water and/or produced water and thereafter redistributed for use. This step further reduces Encana’s dependence on surface water.

The WRH is but one example of Encana’s innovative use of saline water in its operations. In the Horn River Basin of Northeastern B.C. Encana teamed up with Apache in 2010 to tap into the Debolt formation, an underground non-potable aquifer with water similarly too saline or salty for human or agriculture use. The formation and its associated water treatment plant ultimately provided about 98 per cent of the water needed for both companies’ hydraulic fracturing operations in the Two Island Lake area of the play.

In addition, Encana last year began the development of an unutilized water source project in the Pipestone area west of Grande Prairie, Alberta. This endeavour also targets a non-potable subsurface source in the Cardium formation and long-term plans include the transport of this water through a pipeline network to lined pits planned for the area.

“Each of our operating areas has its own unique geology and hydrology,” says Dunn. “The Water Resource Hub is a great example of how we fine-tune our water management approaches according to the specifics of each area in which we operate. Protecting and efficiently using water is crucial to the continued success of our business and the vitality of our operating communities. Using water as responsibly as possible, while seeking alternate saline or non-potable sources, represents a win-win from both an environmental and an economic perspective.”

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