Hidden among the pines and spruces of Alberta's vast boreal forest lies the technological and environmental gem of Canada's oil sands region.

Welcome to Jackfish, Devon's steam-assisted gravity drainage (SAGD) plant, which is named for the Cree translation of two local lakes.

The plant can produce 35,000 barrels of thermal heavy oil per day without using a drop of fresh water. Instead, it relies on steam generated from saline water unfit for consumption or irrigation. The water originates from a deep, salty aquifer and is continuously recycled, resulting in an astonishingly low volume of wastewater.

The easiest thing to do would have been to use fresh water. But we realized the growing concerns about freshwater use. Devon management supported the idea of using only saline water from its inception.

When Jackfish started production in 2007, it became the first commercial SAGD operation to rely completely on saline water for production. The same process is being used at Jackfish 2 and Jackfish 3.

The decision to forego fresh water involved extra up-front capital expenditures. It also increased our operational costs slightly, but we were — and remain — convinced that it was the right thing to do.

The Canadian Association of Petroleum Producers thought so, too. In 2008 the industry group presented its Steward of Excellence award to Devon for the company's water conservation practices at Jackfish.

Recycling requires several stages

The system works like this: The water, taken from a saline aquifer, is heated to create steam, which is injected through a well 1,200 to 1,500 feet into the earth. The steam liquefies a form of heavy oil called bitumen and separates it from sand. Once heated, the bitumen is collected in a production well that runs parallel below the steam-injection well.

Think of it like a jar of molasses. Once heated on a stove, it flows more easily.

Once the bitumen and condensed steam return to the central processing plant, the oil and water are separated. At this point, the return water contains 2,000 parts per million (ppm) of oil. It goes through a series of filtration efforts, the first of which can separate 3,600 barrels per hour. In this large cylinder, 90 percent of the oil is separated.

The water then moves through a skim tank and a giant frothing device, which further reduce the oil content to 20 ppm. After two more filtration steps — one of which involves finely ground walnut shells — the recycled water's oil content is less than 1 ppm. Virtually all of the produced water now is oil-free and ready to be cooled, mixed with saline water and then treated to make steam again.

Without each of these steps, this recycling process wouldn't be possible.

This process keeps wastewater disposal to a minimum. Of the 120,000 barrels of saline water that circulates at Jackfish 1 each day, fewer than 1,500 barrels become wastewater — an amazing figure considering the plant's oil output. Accomplishing this feat requires a labyrinth of pipe that would stretch 28 miles if placed end to end.

Nearby, Devon's Jackfish 2 and Jackfish 3 plants use this same process, each without using fresh water.

The Canadian government estimates there are about 170 billion barrels of recoverable oil remaining in the Canada oil sands. Of that amount, only 20 percent is recoverable through mining operations typically associated with the oil sands. The rest will require a process like steam-assisted gravity drainage. Devon is proud of its ability to produce heavy thermal oil profitably while remaining a good environmental steward.

Published: July 2014