Aging oilfields could turn CO2 pipe dreams into reality
Pilot projects put harmful emissions deep underground
Dave Cooper
The Edmonton Journal
Sunday, October 12, 2008
EDMONTON - A "bullet" truck pulls up to an oilfield battery near Redwater. The pure carbon dioxide in the long pressurized tank could have gone to the Coca-Cola plant to add the fizz to soft drinks, or to any of a number of other uses.
But today, the stop is on farmland dotted with oil wells, with the gas intended to go deep underground.
Alberta hopes to turn this declining oilfield into a giant storage area for carbon dioxide, a greenhouse gas produced in large amounts by the local chemical and petroleum industry.
Burying the gas can burnish the province's environmental reputation. Oilsands plants are big emitters of CO2, resulting in critics targeting Alberta.
The provincial government will spend $2 billion to encourage several carbon dioxide capture and storage projects. Injecting the gas into oilfields is a win-win situation: Not only does it keep the CO2 from being released into the atmosphere, the added pressure makes it easier to pull the oil out of the ground.
The destination for this load of CO2 is the Redwater reef, formed 400 million years ago when the area was a tropical coast. The launch of the Alberta oil boom in the late 1940s saw more than 1,000 wells sunk in the 600-square-kilometre once mighty oil reservoir, but half now stand abandoned and many more produce little oil.
Enter the Alberta Research Council and its Heartland Area Redwater Project, a long-term carbon storage study that could eventually cost $50 million. The council hopes to see large amounts of CO2 sent into the 1,000-metre deep formation by 2015.
ARC Energy purchased most of the wells from Imperial Oil in 2005, intending to use carbon dioxide to enhance recovery of the remaining oil.
The research council is studying large capacity storage areas, and was more interested in the 80 per cent of the reef that did not contain oil, but saline water, where the carbon dioxide would also be injected.
"Right now we are studying drilling cores to understand the geology. This spring ARC Energy will sink a data well for us," says Brent Lakeman, manager of the research council's carbon and energy management program.
ARC Energy itself has begun to inject small amounts of CO2 into the formation in order to recover more oil.
"We got the tanks up and began the process in July. Typically pilot wells like the one we have will inject 100 to 200 tonnes a day," said Doug Bonner, senior vice-president for corporate development at ARC Energy.
A commercial-sized operation would inject 10,000 tonnes per day. That's the equivalent of taking 650,000 cars off the road, but not a huge amount in the total Alberta picture -- the province produces more than 230 million tonnes of carbon dioxide each year.
The Redwater reef alone could store more than a billion tonnes of CO2, scientists believe. And with Alberta and southern Saskatchewan as rich in sedimentary rocks as they are in oil and gas, there are many similar, albeit less well-known, potential storage sites.
Surface monitoring is in place in Redwater, although the solid formation is not expected to leak.
"The oil there has been trapped for many millions of years," said Bonner, adding that if it was going to move, it would have done so by now.
Until large-scale commercial sources of carbon dioxide can be captured, however, ARC Energy is buying food-grade CO2 from suppliers in the Fort Saskatchewan area.
"The CO2 we buy can go into Coke," said Bonner.
Stefan Bachu, the research council's principal scientist for CO2 geological storage, says there are three key elements to choosing the correct site.
"You must have the capacity in the formation," he said, so the column can hold the gas under high pressure and in a very dense form.
"Second, you need injectivity -- permeability in the rock. And third, you need to have complete containment."
The gas that will be injected into the saline portion of the Redwater reef will be under several caprock -- or hard rock -- layers.
Injecting gas is not new in Alberta. Since gas flaring was stopped in 1989, that "acid gas" has been injected at 40 sites in the province. The volumes are small, however -- about one million tonnes a year -- compared with how much carbon dioxide will have to be injected in the future.
For instance, Suncor alone produces eight million tonnes a year of CO2.
Capturing carbon dioxide from the manufacturing and upgrading processes used by chemical plants and the oilsands is "the low-hanging fruit," said Bachu.
"The real issue is coal, not the oilsands," said Bachu.
It is much more difficult and expensive to capture gases after combustion, he said. TransAlta's Sundance coal-fired electrical generation plant at Lake Wabamun, for example, produces 16 million tonnes of CO2 a year.
Re-injecting CO2 found in natural deposits has been done since the 1970s to revitalize Texas oilfields. But injecting synthetic CO2 is new.
Canada's major project is in Weyburn, Sask. EnCana pipes in a supply from a North Dakota coal gasification plant and injects it to produce more oil. Begun in 2000, the pilot project pumps in one million to two million tonnes a year and has been closely followed by researchers from around the world.
What has been learned there can be applied to other CO2 enhanced oil production projects.
Enhance Energy is proposing a pipeline to take CO2 from Fort Saskatchewan emitters to oilfields in the Lacombe area.
"Having a market with oil firms helps pay for the infrastructure," said Enhance president Susan Cole, who worked on the Weyburn project.
"I'd say half the oil pools can benefit from this. We can recover another 20 per cent of the oil from a field, and that could eventually mean billions of barrels of new oil production for Alberta," she said. Pipeline construction could start as early as 2010.
A government-funded study in co-operation with major oil and chemical companies, called the ICON project, has several proposed pipeline options, with a construction target of 2015.
Shell is also planning capture carbon both from its existing Scotford upgrader and the expansion that is now being built.
Depending on the market, the firm may sell the gas and store the surplus in a nearby reservoir, says Rob Seeley, manager of the Quest project.
While the upgrader built in 1999 will be retrofitted for CO2 capture, so will the expansion unit.
"It was designed five years ago," said Seeley.
In a world fearful of climate change and demanding a different way of doing business, that seems like a long time ago.
