Validating CO2-EOR As a Ccus Technology

Anthropogenic carbon dioxide (A-CO₂) is currently being captured from industrial facilities and utilized for enhanced oil recovery (EOR) in several locations in North America. One commercial project is currently operational and several other major projects are under construction in the U.S. Gulf Coast region. Air Products and Chemicals, Inc. started capturing A-CO₂ from their steam methane reformers in Port Arthur, Texas, in December 2012. The captured A-CO₂ is being transported, along with natural CO₂ from the Jackson Dome in Mississippi, to the Denbury operated West Hastings Field near Houston for commercial EOR. The Petra Nova Carbon Capture Project, another major project in the U.S Gulf Coast region, is currently under construction. This project is designed to capture approximately 90 percent of the A-CO₂ produced by a 240 MW slipstream of flue gas and utilize 1.6 million tons of it per year for commercial EOR the West Ranch field. When completed, in 2016, the Petra Nova project will be the largest post combustion carbon capture project on an existing coal-fired power plant.

These projects undoubtedly fit the description of Carbon Capture Utilization and Storage (CCUS). However, an argument exist as to whether EOR represents a valid option for greenhouse gas emission reduction. The common concern does not question whether CO₂ geologic storage occurs or not during EOR, but whether the CO₂ volumes stored in the oil reservoir are countered by the CO₂ emissions associated with the refining and burning of the barrel of oil produced through EOR.

To address this concern we take a differential approach based on the realistic assumption that the barrel of oil will be produced to meet an oil demand, regardless of the technology applied (CO₂-EOR or another technology). Several technologies can be used to develop an oil field. It is true that CO₂-EOR is only applicable in oil reservoirs that meet the criteria for a technically feasible CO₂ flood. However, similar criteria define the reservoir requirements for the application of other tertiary recovery technologies, such as other solvent displacements (hydrogen, methane), chemical EOR (polymer, surfactant) and even thermal EOR.

The differential approach is grounded on the comparative analysis of the carbon balance of a CO₂-EOR process representative of the U.S. Gulf Coast region and the carbon balance of alternative technologies to CO₂-EOR that can be used to develop the same oil reservoir. The potential for greenhouse gas emission reduction is then given by the difference between the carbon emissions associated with the refining and burning of the oil produced through the selected alternative technologies and the carbon emissions associated with the oil produced through CO₂-EOR minus the CO₂ volumes stored in the oil reservoir during the CO₂-EOR process.