A new report from the University of Houston estimates that a method known as carbon dioxide-enhanced oil recovery (CO2-EOR) could recover roughly 137 billion barrels of U.S. oil—with Texas and the Gulf Coast poised to play a major role.

A UH Energy-produced white paper, titled “Revitalization of Mature Oil Fields: Opportunities and Challenges of CO2-EOR,” looks at how CO2-EOR could increase U.S. energy supply, reduce carbon emissions and lower the carbon intensity of oil production.

CO2-EOR injects pressurized carbon dioxide into mature oil wells to loosen and push oil trapped underground toward the production wells, allowing operators to extract oil typically left behind. The process permanently stores some CO2 underground, reducing carbon emissions and carbon intensity.

“Injected CO2 works to revitalize mature oil fields by reducing oil viscosity, improving sweep efficiency and restoring reservoir pressure, resulting in incremental oil production beyond primary and secondary recovery,” the report reads. “CO2-EOR also supports permanent carbon storage and by virtue of this will produce uniquely low-carbon intensity oil for global markets.”

Authored by Charles McConnell, executive director of UH's Center for Carbon Management in Energy, and Zhiyuan Li, a UH petroleum engineering doctoral candidate, the paper says that much of the opportunity lies right under the feet of Texas oil companies.

Texas and the Gulf Coast, including its offshore resources, have half of the nation's oil resources considered favorable for the CO2-EOR technology, the report says. According to UH, conventional U.S. oil reservoirs contain 624 billion barrels, with 434 billion barrels still underground, including about 20 billion barrels of proven reserves.

Still, the paper argues that the economics behind CO2-EOR need to be considered. The process’ success depends on a number of factors, including costs of carbon capture, field redevelopment, operations, monitoring, transportation and available tax incentives, according to UH.

Logistically, developing CO2-EOR operations out of older wells and infrastructure presents pros and cons. While using older wells can be more economical, aging infrastructure may require more frequent monitoring, inspection, repair or re-plugging, according to UH.

Ultimately, the report recommends focusing CO2-EOR development on mature oil fields with existing infrastructure, well-understood geology and reliable CO2 supplies. This approach, UH says, could help extend the productive life of existing oil fields while supporting “lower carbon intensity oil for global markets and a significant contribution to energy security.”

Read the full report here.