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. This process is called CO2 flooding.
The original oil production facilities at Weyburn were built in the mid-1950s. Waterflooding began in 1964, which involves injecting saline water into the reservoir to wash oil from the rocks. 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, as well as the site of the world’s largest geological greenhouse gas storage project. We’ve safely injected more than 29 million tonnes1 of CO2 underground at Weyburn since 2000.
Weyburn has the right reservoir temperature and pressure and suitable oil composition for CO2 to act well as a solvent. It cleans oil trapped in the extremely small pores of the reservoir rock. Compared to the recoveries normally seen by waterflooding alone, this greatly increases the recovery of oil from our reservoir because it allows the small traces of oil trapped in the pores of the rock to be loosened and pushed towards producing wells.
Carbon Dioxide (CO2) supply
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 the CO2 and transports it via pipeline to Weyburn. To increase the certainty of our CO2 supply, we began receiving CO2 from SaskPower’s coal-fired Boundary Dam Power Station, which is the site of an integrated carbon capture and storage (CCS) demonstration project, in 2014.
1 - This number is calculated based on production as of December 31, 2016.