|The CO2 pipeline route from synfuels plant to oilfield.|
DOE Secretary Samuel W. Bodman today announced that the Department of Energy (DOE) co-funded Weyburn Project successfully sequestered five million tons of CO2 into the Weyburn Oilfield in Saskatchewan, Canada, while doubling the field’s oil recovery rate.
The CO2 used in the project is piped from the Great Plains Synfuels Plant near Beulah, ND, and is a byproduct of the plant’s coal gasification process.
The International Energy Agency has estimated that wide-spread deployment of the Carbon Sequestration-Enhanced Oil Recovery (CO2-EOR) methodology used in the Weyburn Project could eventually store 130 billion metric tons of CO2 worldwide.
Geological sequestration of the type represented by the Weyburn project is one of the two main avenues being explored for the long-term storage of CO2, the other being deep ocean storage.
In the first phase of the Weyburn project carbon dioxide was injected into the Weyburn Oilfield in Saskatchewan, Canada. The CO2 increased the underground pressure of the field and reduced the viscosity of the remaining oil to help more of it to the surface.
The project increased the field’s oil production by an additional 10,000 barrels per day and demonstrated the technical and economic feasibility of permanent carbon sequestration: the capture and permanent storage of carbon dioxide in geologic formations.
|The estimated production impact of CO2 flooding on the Weyburn field|
Primary oil recovery, which uses natural underground pressure to bring oil to the surface, typically produces only 10% of an oilfield’s reserves. In secondary efforts, operators flood the field with water to force the oil into the wellbore and increase recovery to 20% to 40%.
Enhanced oil recovery (EOR), the technique used in the project, has the potential to increase an oil field’s ultimate oil recovery up to 60%, according to the DOE, and extend the oilfield’s life by decades.
The project team expects that 50% of the CO2 will remain locked up with the oil that remains in the ground. The 50% that comes to the surface with the produced oil will come out of solution as the pressure drops and be recycled back to the injection wells.
Scientists involved in the project estimate that, by using knowledge gained from the Weyburn Project, the Weyburn Oilfield could remain viable for another 20 years, produce an additional 130 million barrels of oil, and sequester as much as 30 million tons of CO2.
Before the Weyburn Project, much of the CO2 used in similar U.S. EOR projects has been taken at considerable expense from naturally occurring reservoirs. Using an industrial source of CO2—such as the from the synfuels plant—sequesters this emission that would normally be vented into the atmosphere.
The Weyburn Project now moves into a second phase in which researchers will compile a best practices manual to serve as a reference in the design and implementation of CO2 sequestration in conjunction with enhanced oil recovery projects.
They will also expand their efforts to the neighboring Midale Unit, develop more rigorous risk-assessment modeling techniques, improve injection efficiencies, and monitor CO2 flooding and storage with a variety of methods, including seismic wave technologies and geochemical surveys.
The Weyburn CO2 Storage and Monitoring Project is a multinational effort led by Canada’s Petroleum Technology Research Centre in Regina, Saskatchewan, and cosponsored by the oilfield operator, EnCana Corporation of Calgary, Alberta. The project receives funding from the U.S. Department of Energy, as well as industry and government organizations in Canada, Japan, and the European Commission.