Where does the CO₂ come from and where does it go? Today, most of the CO₂ used in EOR operations is from natural underground ‘domes’ of CO₂. With the natural supply of CO₂ limited, man-made CO₂ from the captured CO₂ emissions of power plants and industrial facilities can be used to boost oil production through EOR.

Once CO₂ is captured, it is compressed and transported by pipeline to oil fields. During EOR operations, CO₂is injected into the oil formation where it mixes with the oil and helps move the oil through the formation and to the production wells. CO₂ that emerges with the oil is separated and re-injected into the formation. CO₂-EOR projects resemble a closed-loop system where the CO₂ is injected, produces oil, is stored in the formation, or is recycled back into the injection well.

Is CO₂-EOR safe? CO₂ is non-flammable and nonexplosive. It is not defined as a hazardous substance, but a Class L, highly volatile, nonflammable/nontoxic material (CFRg, CFRe, Appendix B, Table 4). (WRI, 2008)

Operating for 40 years, CO₂ pipelines have an excellent safety record with no serious injuries  or fatalities ever reported. Today there are over 3,900 miles of pipeline transporting CO₂ for EOR use at wells producing 281,000 (MIT 2011) barrels of oil per day. The industry has operated for decades under existing policy and regulatory oversight at the local, state and federal level.

Geologic storage of CO₂ is also regulated under existing policies and regulations. CO₂ is contained by a series of physical and chemical trapping mechanisms over time. Most formations that hold oil for thousands of years also have the ability to contain CO₂. As an example, research by the University of Texas Bureau of Economic Geology’s Gulf Coast Carbon Center on the SACROC oil field, where CO₂ has been injected for EOR since 1972, has found no evidence of CO₂ leakage (TBEG). Experience from this decades-old CO₂-EOR project and current commercial-scale CO₂-EOR projects today shows that CO₂-EOR can be performed in a manner that is safe for both human health and the environment.

References:

• World Resources Institute, “Guidelines for Carbon Dioxide Capture, Transport, and Storage,” 2008.
• MIT Energy Initiative, “Role of Enhanced Oil Recovery in Accelerating the Deployment of Carbon Capture and Sequestration,” 2011.
• See the SACROC Research Project website for a complete list of studies. www.beg.utexas.edu/gccc/sacroc.php