Carbon dioxide enhanced oil recovery
At the Weyburn oilfield, we have demonstrated that oil production from a mature field can be enhanced in an environmentally responsible manner by utilizing and then sequestering carbon dioxide (CO2) that otherwise would have been vented to the atmosphere. This process is also called CO2 flooding.
The original facilities at Weyburn were built in the mid-1950s to handle oil and water production, plus a very small amount of solution gas. In 2000, the field began operating on CO2 miscible flood.
Cenovus purchases CO2 from a coal gasification plant in North Dakota and, via a network of medium pressure gas gathering lines, transports solution gas and CO2 from the production facilities to a central compression station. At the station, recycled CO2 is blended with the purchased CO2 and injected in to the reservoir. This procedure enhances oil recovery by increasing reservoir pressure, which pushes oil to producing wells.
Under the right temperature, pressure and oil composition conditions, CO2 acts as a solvent, cleaning oil trapped in the microscopic pores of the reservoir rock. This miscible process greatly increases the recovery of oil from a reservoir compared to the recoveries normally seen by waterflooding. About 60 percent of the Weyburn field is now under CO2 flood.