The lime-green pipes and valves at EnCana Corp.'s Weyburn oil field in south Saskatchewan are the only visible sign of the revolution taking place 1,500 metres underground.
A kilometre and a half from the surface, the pipes feed a steady stream of carbon dioxide into the rock containing light oil, pushing it sideways toward a wellhead where it can be pumped above ground. At that depth, carbon dioxide turns into a liquid -- and into money, as EnCana and the rest of the oil industry are discovering.
Carbon-dioxide injection will allow EnCana to extract another 140 million barrels of oil from its 51-year-old Weyburn field, an enormous volume at a time when the average new well drilled in Western Canada yields a mere 50,000 barrels. EnCana says it hopes to repeat that feat elsewhere in the Western Canada Sedimentary Basin, which stretches across the Prairies and into British Columbia and the Northwest Territories. "How big is the opportunity? Obviously, we'd love to find another Weyburn," says Jeff Wojahn, president of EnCana's Canadian plains region.
Happy as EnCana is, the company is still leaving a lot of oil in the ground, nearly two-thirds of the total 1.4 billion barrels it knows are in the reservoir. That fact might shock outsiders, but it is a simple fact of life in the petroleum industry that the vast majority of oil never sees the light of day. In Western Canada, for every barrel of oil pumped out of a well, another three remain trapped underground. For some reservoirs, as much as 95 per cent of the discovered oil cannot be extracted, or at least not at a low enough cost to turn a profit.
"I think it surprised me, when I first looked at it," says Eddy Issacs, managing director of the Alberta Energy Research Institute.
An oil reservoir that has been drained to the point of being unprofitable is often called a dry well, but that term is misleading. In fact, it's more like a wet sponge: You can wring it once, and get a lot of water. A second squeeze will extract a bit more. Eventually, your efforts are in vain -- even though that sponge is still wet.
Now, better technology and high crude prices are about to shift an enormous amount of oil into the grasp of the industry. As many as five billion barrels could be added, according to Mr. Issacs. That would more than double Canada's conventional oil reserves.
Others have even higher hopes. Richard Baker, president of Epic Consulting Services in Calgary, says eight billion barrels could be added to reserves, a figure that would include the widespread injection of water into existing wells. "It'd be like finding eight giant reservoirs," says Mr. Baker, who is working on a report for the industry that is aiming to nail down the opportunity presented by enhanced recovery. "It's a question of when it's going to occur, not if it's going to occur."
The rise of four-dimensional seismic technology -- a 3-D model in real time -- is enhancing the prospects of enhanced recovery. At Calgary's Computer Modelling Group Ltd., 4-D imaging is used to simulate the effect of carbon-dioxide flooding, for instance, on actual reservoirs. Ron Kutney, vice-president of marketing, says he has just one Canadian company at the moment -- EnCana -- among his client list of 200, but that he expects interest to soar along with commodity prices, matching the investment spree in other areas of the oil patch. "Just look at the investment in the tar sands," he says.
