Skip to main content

Cenovus has found that the butane used at a well at its Christina Lake operation makes the bitumen flow faster and at greater rates.Kevin Van Paassen/The Globe and Mail

There is not much to see at well A022. On the surface, it looks like any of the hundreds of other wells sunk deep below the boreal forest around Fort McMurray into the oil sands. Pipes run across the ground, then dip into the earth. Steam goes down one set of pipes, to melt out the thick bitumen oil, which rises up through another set.

But at A022, there's something different mixed in with the steam and water: butane, the same substance you might find in a lighter. When that butane hits the oil sands, it mobilizes the crude oil in ways steam can't. In other words, mix in the butane and the bitumen flows faster, and at greater rates.

The butane is part of a new technology developed by Cenovus Energy Inc. , which calls it "Solvent-Aided Process," or SAP – although numerous other companies are working to perfect similar techniques, including Imperial Oil Ltd., Canadian Natural Resources Ltd. and Laricina Energy Ltd.

If solvents work the way Cenovus believes they will, they stand to change the oil sands. But if they are a success story, they may also temper the excitement of those who trumpet how technology will revolutionize the oil sands business. Solvents are not a brand new, science-fiction technology – they are, instead, a modification to an existing system. Yet even as a modification, it will take Cenovus 15 years to bring that change into limited commercial service. The first test took place in 2002; the first phase of Narrows Lake is on the books for 2017.

"You can come up with a great idea and by the time you can take that idea, implement it in the field, trial it, and get the knowledge that okay this idea works great – it's a pretty big cycle time," says Jason Abbate, a Cenovus leader in production engineering.

Those who travel through that long cycle can, however, shepherd big changes. Butane promises to substantially trim the environmental footprint in oil sands operations, cutting by 30 per cent the need for steam, which is made by burning natural gas. It stands to strip 15 per cent more oil from the sand than pure steam processes – and it stands to bring that oil to surface 30 per cent faster. For a single well, butane can bring 100,000 barrels to surface that might otherwise have remained locked below.

"For overall recovery of the bitumen in place, that's huge," said Jason Abbate, a Cenovus leader in production engineering who has worked with butane at the Christina Lake development. For greenhouses gas emissions, too, "it's huge."

Some 80 per cent of the 170 billion barrels in oil sands reserves will be extracted using non-mining methods, like the so-called "steam-assisted gravity drainage" system Cenovus employs. Any improvement to that technology, then, can make a substantial impact, environmentally and economically. Cenovus is bullish enough on its SAP that it plans to roll it out on a quarter of the wells drilled for the first and second phases of a future oil sands project called Narrows Lake. It may use SAP on all the wells on the third phase at Narrows Lake.

In the end, the calculation of whether it works is "all math," he says.

For Cenovus, it means also weighing the numerous solvent downsides. Butane is expensive to buy and ship to site – and the company only recovers 75 to 80 per cent of it, meaning it has to take into account the cost of burying a pricey product. And what butane is recovered isn't free, either. The additional equipment used to strip out the butane raises construction costs by 10 per cent to 20 per cent – although that's partly counterbalanced by a 10-per-cent cut to operating costs.

For that reason, A022 is the fourth well Cenovus has used the technique on. Each trial brought new data – and problems. At one test, the solvent spread underground so quickly that it spread into an adjoining well, compromising the results. That's why A022 was built specifically away from other wells. It began operation in 2009, and has allowed Cenovus to play with numerous factors: how much butane it injects, what pressure it uses, how much it scales back steam.

"There's a lot of factors that come into play," Mr. Abbate says.

And butane, at the end of the day, may not even be the best product to use. Cenovus, for example, has looked at using condensate instead. Condensate is a very light oil that is used to thin heavy bitumen so it can be pumped down pipelines. If it can work underground, it could do double duty: Bring more oil to the surface, then allow it to flow to market.

Down the road, it's even possible solvents could replace steam – Imperial Oil is already testing such a system in a different type of oil sands reservoir. In other words, even a decade after Cenovus started its butane experiment, it's still experimenting.

"Can we do it with a different solvent? Is butane the best solvent?" Mr. Abbate questions. He adds: "It all comes down to economics."

Editor's note: An earlier online version of this story and the original newspaper version of this story gave an incorrect percentage by which equipment used to strip out butane would raise construction costs. This online version has been corrected.