Enhanced Oil Resources

Enhanced Oil Recovery, investing future energy dependence .

What is Enhanced Oil Recovery (EOR)?

Enhanced Oil recovery refers to the new advances in technology that allow us to extract oil from reservoirs that were unavailable with previous methods of extraction.

In the U.S. our traditional methods of oil extraction have been virtually exhausted.  Today, more advanced methods are needed to extract oil from reservoirs.  Crude oil production and development includes at least three phases: primary, secondary, and tertiary.  In the primary=- stage, the natural pressure of the reservoir drive oil into the wellbore and are combines with artificial extraction techniques such as pumps.  While this technique is cheap and easy, only approximately ten percent of a reservoir’s oil is typically produced with these methods.   Secondary techniques allow further extraction to an reservoir by injecting water or gas to displace oil and drive it into a production wellbore, leading to an addition 20 to 40 percent increase of the total extractable reservoir oil.

Much of the oil fields in the US have already undergone these first two methods of extraction. For this reason, tertiary or “enhanced” techniques are now required to extract the remaining oil.  The department of energy estimates that these enhanced oil recovery (EOR) techniques offer possibilities of recovering 30 to 60 percent, or more, of the remaining oil in the reservoirs in the U.S.  Three major categories of EOR that have been commercially proven to varying degrees include:

• Gas injection: uses gases such as nitrogen, natural gas, or carbon dioxide that expand in the reservoir to push additional oil into a production wellbore.  Other gases can dissolve in the oil to lower its viscosity to improve the oil’s flow rate. Gas injection accounts for nearly 50 percent of EOR production in the United States.
• Thermal recovery: involves the introduction of heat such as the injection of steam to thin the heavy, viscous oil.  This improves its ability to flow through the reservoir. Thermal techniques account for about 50 percent of U.S. EOR production.  It the primarily method used in California due to the favorable geological conditions.  It is not viable in other parts of the country.
• Chemical injection: can involve the use of long-chained molecules called polymers to increase the effectiveness of water floods, or the use of detergent-like surfactants to help lower the surface tension that often prevents oil droplets from moving through a reservoir. Chemical techniques account for less than one percent of U.S. EOR production.

Each of these techniques has been hampered by their relatively high costs, although these relative costs are decreasing due to the falling dollar and the rising global energy demand.

Benefits of CO2 injection

In 2007, carbon dioxide (CO2) – EOR attracted the most market interest and investment.
Invented in 1972, CO2- EOR has been used throughout North America where primary extraction methods have been exhausted.  Most of the carbon dioxide used for EOR has come from naturally-occurring sources until recently.  New industrial technologies such as natural gas processing, ethanol, fertilizer, and hydrogen plants have been developed to produce CO2 in areas where naturally occurring reservoirs are not available.  This has led to an increase in CO2 EOR opportunities.  One example of this is at the Dakota Gasification plant in Beulah, North Dakota.  There, they are producing CO2 then delivering it via a new 204-mile pipeline to the Weyburn oil field in Saskatchewan.  The oil field’s owner, Encanta, has successfully extended the fields productivity by injecting the CO2.  Encanta hopes to add another 25 years and as much 130 million barrels of oil that might otherwise have been abandoned.

The DOE has funded a project at the Hall-Gurney oil field in Kansas that seeks to prove the technology’s multiple benefits: energy, environmental, and economic.  Another program is underway at this facility that uses 4-D high resolution seismic monitoring of CO2 injection in shallow, mature carbonate reservoirs.  This method could dramatically improve the efficiency and economics of using CO2 EOR in many Mid-continent oil reserves.

As noted by the Department of Energy Website, The DOE is partnering with companies such as Enhanced Oil Resources Inc. to further the EOR technologies.

“New breakthroughs in CO2-EOR recovery technology could further enhance oil recovery in Texas and other oil producing states. One DOE-industry partnership project is investigating gravity-stable CO2 injection in the Permian Basin in West Texas, where the goal is to increase oil recovery in the Scurry Canyon Reef field.”

Additional EOR opportunities: Department Of Energy  Basin-Oriented CO2-EOR Assessments

In 2006, the Department of Energy Office of Fossil Energy acknowledged the significant potential of EOR technologies and their potential to significantly contribute to the potential extraction of remaining domestic oil reserves in the United States.  They estimate that there are approximately 90 billion barrels of oil, now stranded, could be extracted using these enhanced CO2- EOR technologies.

Additional research predicts future improvements in CO2-EOR technologies, beyond that of current state-of-the-art technology may further increase this potential.  These “game-changing” predictions and forecasts illustrate the wide-scale implementation of these next generation CO2-EOR technologies.  These technologies have a predicted to increased domestic oil recovery from thirty five to sixty percent.

An oil bearing “transitional” zone below the traditionally defined base of an oil reservoir is well established.  However, now clear as recently documented DOE Fossil Energy studies have shown is that, under certain hydrodynamic and geologic circumstances, a additional residual oil zone (ROZ) exists below this transition zone.  DOE estimates an additional 100 billion barrels of oil resources are present and that 20 Billion of those could be extracted using CO2-EOR methods.

Most exciting about the CO2-EOR technology is that with the increase in research and technology, these methods can be applied to domestic oil resources that have remained undeveloped because it was not economically feasible to pursue them.  In total, undeveloped domestic oil resources total 1,124 billion barrels.  Of this number, 430 billion barrels are estimated to be technically recoverable.  This figure includes undiscovered oil, unconventional oil (deep heavy oil and tar sands), new petroleum concepts (residual oil in reservoir transition zones), and “stranded” light oil amenable to CO2 enhanced oil recovery technologies.

It is important that in addition to investing in renewable energies, we invest in these EOR technologies so that we may have the security and ability to move into a more sustainable future.