9.2. Commercial Carbon Dioxide Uses: Carbon Dioxide Enhanced Oil Recovery

Carbon Dioxide Market
The Global CCS Institute¹ has reported on market demand for carbon dioxide (CO₂). In 2011, the global demand for CO₂ was estimated at 80Mtpa, of which:

• 50Mtpa is utilized for Enhanced Oil Recovery, almost exclusively in North America, and
• the remaining 30Mtpa represents the global demand of all other uses, predominantly the mature industries of beverage carbonation and food industry uses.

The breakdown is shown in Figure 1.

CO₂ for beverage carbonation and food industry must meet stringent standards of purity; therefore it is usually obtained from sources such as corn-to-ethanol plants, breweries, etc. Otherwise, commercially-produced carbon dioxide is recovered from CO₂-producing wells, and hydrogen, synthetic natural gas, or ammonia production plants using natural gas, coal, or other hydrocarbon feedstocks.

Carbon Dioxide Enhanced Oil Recovery
By far the most extensive use of CO₂ in the United States is for enhanced oil recovery. Carbon dioxide enhanced oil recovery (CO₂ EOR) is a technique used to recover oil, typically from mature fields that have ceased being productive through traditional primary and secondary recovery methods. Primary and secondary recovery methods typically leave two-thirds of the original oil in place (OOIP). To put the potential of EOR into perspective, of the total of 600 billion barrels of oil that have been discovered in the United States, approximately 400 billion barrels are unrecoverable by conventional methods. Half of that unrecoverable oil (200 billion barrels) is at reasonable depths at which EOR may be applicable.

CO₂ EOR is an established technique in the United States, and is the only oil recovery technique that has shown any growth since the 1980s. In fact, CO₂ EOR now accounts for over 5% of the Nation's oil production. It can extend the productive life of an existing oilfield by several decades, and it can lead to recovery of millions of barrels of additional oil.

The basic principle behind CO₂ EOR is the mutual solubility of crude oil and CO₂ in the temperature and pressure conditions of a geologic reservoir. Given the right conditions, injected CO₂ is able to dissolve and displace oil residue that is trapped in rock pores (like a solvent is able to displace grease from a dirty bicycle chain). In a typical CO₂ flood operation, a pipeline delivers CO₂ to the oilfield, where it is directed to injection wells. These wells are strategically placed to optimize the areal sweep of the CO₂ through the reservoir. As the injected CO₂ moves through pore spaces in the rock, it encounters residual crude oil. The crude oil mixes with the CO₂, decreases oil viscosity, pressurizes it, and mobilizes it, forming a concentrated oil bank that is swept to producing wells. In this way, oil and gas companies are able to gain access to oil that would otherwise be left in the ground.

CO₂ EOR in Carbon Capture and Storage (CCS)

CO₂ EOR is additionally attractive because of its effectiveness and its ability to sequester gasification-created CO₂ emissions. Following CO₂ EOR operations, the CO₂ can remain underground in the reservoir, and is thereby prevented from entering the atmosphere.  The U.S. Department of Energy has significantly funded and supported CCS projects in the United States, resulting in the most robust portfolio of large-scale CCS projects in the world. Figure 2 shows large-scale projects in North America; 17 of the 19 projects in the U.S. include CO₂ EOR as the preferred storage type (the two others involve CO₂ storage in saline formations).

Background on CO₂ EOR
CO₂ EOR was first tested in the early 1970s in West Texas. Since then, it has been utilized successfully throughout the Permian Basin of West Texas and eastern New Mexico. It is currently being used in oilfields in Kansas, Mississippi, Wyoming, Oklahoma, Colorado, Utah, Montana, Alaska, and Pennsylvania. In the United States CO₂ EOR production has increased to over 300,000 barrels of oil per day². It is estimated that we have the potential to produce about 21.4 billion barrels of additional oil using current best practices, but using "next generation" CO₂ EOR technologies underdevelopment, the economically recoverable oil from existing domestic fields in the lower 48 states would increase to 63.3 billion barrels using advanced techniques.³

Industrially-Sourced CO₂
Until recently, most CO₂ EOR has depended on naturally-occurring underground deposits as the source of the CO₂. In recent years, however, industry has begun to utilize CO₂ that has been captured as a by-product of fossil fuel combustion, gasification, or other industrial processes. Because a ton of CO₂ costs up to $30 delivered, and each ton can yield 2-3 barrels of oil, there is a strong economic incentive to re-use industrially-sourced CO₂ from gasification plants, gas processing facilities, and power generation plants.

Benefits
CO₂ EOR represents a win-win strategy for beneficial use of industrially-sourced CO₂. From an economic standpoint, CO₂ EOR is a highly effective tool for re-invigorating oil production from mature fields that might otherwise be abandoned. From an environmental standpoint, it represents a practical way to recycle and utilize CO₂ while reducing overall atmospheric CO₂ emissions.

1. http://hub.globalccsinstitute.com/publications/accelerating-uptake-ccs-industrial-use-captured-carbon-dioxide/2-co2-market

2. Kuuskraa, V., & Wallace, M., CO₂-EOR set for growth as new CO₂ supplies emerge. Oil & Gas Journal, April 7, 2014.

3. Wallace, M.,  Kuuskraa, V., and DiPietro, J.P., An In‐Depth Look at “Next Generation” CO₂‐EOR Technology, September 23, 2013

Carbon Dioxide

• Carbon Dioxide Capture
• Commercial Carbon Dioxide Uses: Carbon Dioxide Enhanced Oil Recovery
• Carbon Dioxide Capture R&D
• Carbon Dioxide Use and Storage in Integrated Gasification Combined Cycle Projects
• Pre-Combustion Carbon Dioxide Control Program
• Carbon Storage Technology Program