Alabama Project Plans to Store Carbon Dioxide, Boost Oil Production.
David Anna - DOE/NETL - Sept. 6, 2006
CO2 sequestration like this pilot project in Kansas also increases oil output.
WASHINGTON, DC - The Department of Energy today announces the selection of a cost-shared project that will inject carbon dioxide (CO2) into an oil reservoir to maximize domestic oil production. At the same time, the project will assess the potential for later storing CO2 in the reservoir once the oil is depleted rather than emitting it into the atmosphere.
Such storage of CO2 is called sequestration, and the idea is gaining more attention as concerns mount over possible global climate change caused by rising emissions of greenhouse gases.
Growing interest in CO2 sequestration dovetails with strong growth in the use of CO2 as a means to enhance oil and natural gas recovery. Injecting CO2?the same gas that gives soda pop its fizz?into an oil reservoir thins crude oil left behind, pressurizes it, and helps move it to producing wells. So-called CO2 flooding is the fastest-growing technique for enhanced oil recovery (EOR) and now accounts for almost five percent of the Nation's oil production at 237,000 barrels per day.
Commercial CO2 EOR flood projects in the United States have been limited largely to the prolific oil reservoirs of the Permian Basin of West Texas and New Mexico. CO2 flooding is a costly operation, and the process generally is uneconomic-even at today's high oil prices-without a readily available, low-cost source of the gas nearby. This explains why roughly half of the world's CO2 floods are in the Permian Basin, not far from some of the biggest natural sources of CO2 in the United States.
With the proper incentives, R&D, and CO2 availability to underpin an accelerated program, current technology applied to existing fields has the potential to increase CO2-enhanced oil production to 500 thousand barrels per day by 2012, and by at least 2 million barrels per day by 2020.
An EOR project that uses an industrial source of CO2 that otherwise would be vented to the atmosphere would have the added environmental benefit of sequestering the greenhouse gas. The potential for sequestering CO2 in depleted oil and gas reservoirs is enormous. One study conducted for DOE estimated that the global sequestration capacity in depleted oil- and gas fields equates to 125 years of current worldwide CO2 emissions from fossil fuel?fired power plants.
Recognizing the dual energy and environmental benefits of CO2 EOR/sequestration, Congress mandated in the Energy Policy Act of 2005 that DOE pursue demonstration projects to promote the capture, transportation, and injection of produced CO2 for sequestration into oil and gas fields while boosting oil and natural gas production. Accordingly, DOE announced a funding opportunity earlier this year to fund new research in conducting EOR projects while increasing sequestration of the greenhouse gas.
The project selected under this funding opportunity was proposed by the University of Alabama-Birmingham (UAB), of Birmingham, AL. It calls for implementing a CO2 flood in Citronelle oilfield in Mobile County, Ala. Citronelle field, Alabama's largest producer, is an ideal site for a CO2 flood because of its reservoir's relatively uniform structure. A mature field that has already undergone primary and secondary recovery (waterflooding) efforts, Citronelle is now a candidate for tertiary recovery, or EOR. Typically 20 percent more of the original-oil-in-place in a reservoir can be recovered using CO2 EOR. In Citronelle's case, it is estimated that 64 million barrels of oil could be recovered using this technique.
When all remaining economically recoverable oil is produced, the reservoir and adjacent formations can provide sites for storage of CO2 produced from the combustion of fossil fuels in power plants and other processes that generate large amounts of CO2. One of America's largest generators of electricity, Southern Company of Atlanta, Ga., is evaluating the capacity of such reservoirs as possible locations for permanent sequestration of CO2 separated from coal and natural gas combustion products in its power plants.
The selected project will introduce CO2 EOR for tertiary recovery from Alabama's uniquely structured oil reservoirs. At the same time, it will provide oilfield operators and CO2 producers with improved estimates of the oil yields from EOR and the capacity of depleted reservoirs to sequester CO2. Another objective of the project is to improve the reliability of computer simulations of the oil yield and sequestration capacity of a given geologic formation and the rate at which CO2 can be introduced into the underground formations. The Citronelle simulations will be integrated with computer visualizations of the migration of oil, water, and CO2, making the data accessible to reservoir engineers, geologists, utility planners, and climate-change modelers.
Partners with UAB and Southern Company in the project are Citronelle field owner and operator Denbury Resources Inc., Plano, Texas; University of Alabama, Tuscaloosa, Ala; Alabama A&M University, Huntsville, Ala; Geological Survey of Alabama, Tuscaloosa; and the University of North Carolina at Charlotte, N.C.
Total project cost is about $6 million, with DOE's share just under $3 million.
A successful demonstration of the technology in this project could open the door to commercial CO2 EOR/sequestration efforts across the Nation, offering a potential "two-for-one" solution to America's crucial energy security and environmental concerns.