More Carbon Dioxide Means More Oil
Authors: Rassenfoss Stephen 
Published: February 2015

Carbon dioxide (CO2) injected into oil fields is “the gift that keeps giving.” The description comes from David Schechter, an associate professor of petroleum engineering at Texas A&M University, who is researching whether CO2 can be used to coax billions more barrels of oil from unconventional formations.

In the United States, 318,000 B/D of oil production is credited to the injection of 3,443 billion ft3 of carbon dioxide. That estimate is based on a joint study by the US Department of Energy (DOE) and the University of Wyoming, which forecast that this technique for enhancing oil production could nearly double by 2018. That assumes a surge in the amount of CO2 captured from industrial sources to meet the growing demand.

Offshore Brazil, carbon dioxide removed from natural gas produced in the Lula field is being reinjected into that reservoir to reduce carbon emissions. It offers a rare test for learning how injecting CO2 affects the output of a young field, and Petrobras has said reinjection will be applied to other large offshore fields.

A growing body of evidence indicates that below the aging giant oil reservoirs in west Texas, is a large untapped layer known as the residual oil zone (ROZ) that could produce billions of barrels if enough CO2 is available to coax crude out of formations with low oil saturations.

Some people working to find ways to reduce CO2 emissions see selling CO2 to increase oil production as one of the only currently available methods to financially justify capturing the gas blamed for global warming and store it.

The growth potential is strong if a lot more carbon dioxide is available at the right price. “The biggest problem with carbon dioxide is there is not enough of it. There are far more projects than carbon dioxide,” said David Vance, a geologist who is a principal scientist at Arcadis. Vance moved a decade ago to Midland, Texas, to become part of a community of people there who are focused on turning what is still seen as a west Texas thing into something far larger.

The nature of that vision is on display annually at the CO2 Flooding Conference and at its sister event, the EOR Carbon Management Workshop, both held during the same week in December 2013 in Midland, Texas. The pair of meetings, which go back more than a decade, is evidence of the marriage of necessity that has sprung up between those who see CO2 as a means to greater oil production and those who see oil reservoirs as the only growing option now for long-term CO2 storage. As with many things related to CO2 EOR, the relationship is complicated.

Europe’s grand plan to pay to store carbon dioxide as a waste product in saline aquifers sunk with the carbon credit market, where the cost of buying the right to emit CO2 has dropped to around USD 5.50/t, far less than the cost of pumping it into a deep aquifer forever. Those using CO2 to enhance oil production will pay far more for the gas, giving them a strong motivation to ensure a valuable commodity does not escape into the atmosphere.

At the Midland conference, speakers played up how CO2 EOR can be used to pay for carbon capture, utilization, and storage (CCUS). It is a positive environmental message, but convincing environmental regulators that injected carbon dioxide will remain stored in the ground permanently, is a problem to be solved.