Trillions of tons of carbon dioxide that might otherwise be added to global warming can be securely stored for millions of years in old oil and gas fields with a process that also promises to increase Canada's oil supplies by billions of barrels. It's called carbon sequestration and Canada is a world leader in the development and application of the technology.
"Carbon sequestration appears to be the quickest and cheapest route to fighting global warming," in the assessment of Business Week.14 Massachusetts Institute of Technology researcher Howard Herzog claims that "carbon sequestration is the only technology that can wean us off fossil fuels without too much of a shock to the system."15
The process involves capturing CO2 emissions, primarily from coal-burning plants, before they are vented into the atmosphere and injecting the gas into deep underground formations. If the gas is injected into an oil reservoir, it can act as a solvent in a process called miscible recovery to help clean out trapped molecules of oil that remain after other recovery methods have been completed. Primary production, which makes use of a reservoir's original pressure, typically enables the recovery of about a quarter to a third of the oil in place. Water flooding to restore reservoir pressure might double that, still leaving vast amounts of oil, some of which might be produced with miscible recovery using CO2.
EnCana and Dakota Gasification Company of Bismarck, North Dakota, began development in 1998 of one of the world's largest carbon sequestration and enhanced oil-recovery projects in the Weyburn field of southern Saskatchewan. Since October 2000, EnCana has been injecting CO2 into Weyburn's oil reservoirs at a rate of 5,000 tons a day, gas that would otherwise add to the accumulation of greenhouse gases in the atmosphere. During a 25-year period, EnCana expects to inject 14 million tons of CO2 at Weyburn, equivalent to taking 3.2 million cars off the road for one year. In the process, EnCana expects to recover an additional 130 million barrels of oil from a field that would otherwise be abandoned about now.