Carbon dioxide enhanced oil recovery
At the Weyburn oilfield, we’ve demonstrated that oil production from a mature field can be enhanced in an environmentally responsible manner by using and then storing carbon dioxide (CO2) that otherwise would have been vented into the atmosphere. We call this CO2 enhanced oil recovery.
The original oil production facilities at Weyburn were built in the mid-1950s. In 1964, waterflooding technology was introduced, which involves injecting produced water back into the reservoir to displace oil from the oil-bearing formation. In 2000, CO2 flooding was introduced alongside waterflooding to maximize oil recovery. Today, about 60 percent of the Weyburn field is under CO2 flood. The Weyburn project is Canada’s largest CO2 enhanced oil recovery operation and is recognized as the world’s largest geological CO2 storage project. From 2000 to 2012, Weyburn was also the site of the International Energy Agency (IEA) Greenhouse Gas Weyburn-Midale CO2 Monitoring and Storage Project, an example of global collaboration and a model for academics, governments and researchers from around the world to learn about CO2 injection and storage.
We’ve safely injected approximately 30 million tonnes of CO2 underground at Weyburn since 2000.
Weyburn’s reservoir (the Midale formation) has favourable conditions, such as temperature, pressure and oil composition, that allow CO2 to act as a solvent. It extracts oil trapped in extremely small pores of the reservoir rock and sweeps it towards the producing wells. Compared to the recoveries normally seen with waterflooding alone, this greatly increases the ultimate recovery of oil from our reservoir.
Ensuring we have a consistent and adequate supply of CO2 is critical to maintaining and expanding our CO2 enhanced oil recovery project at Weyburn. We purchase CO2 from two sources. Since 2000, we have been receiving it from a coal gasification plant in North Dakota that captures theCO2 and transports it via pipeline to Weyburn. To increase the certainty of our supply, we entered into an agreement in 2012 to purchase CO2 from SaskPower’s coal-fired Boundary Dam Power Station, which is the site of an integrated carbon capture and storage project. Deliveries from the Boundary Dam project began in October 2014.