A positive sequester: Grand Forks researchers put CO2 to good use
North Dakota is finding itself involved in the global discussion on climate change management, and not only because of the Bakken oil boom.
The Bakken propelled the state last year to become the second highest producer in the United States, which is expected to soon become the largest producer of oil in the world. North Dakota is also home to one of the foremost research centers dedicated to reducing the carbon footprint of human activity.
The Energy and Environmental Research Center is located in a facility at the eastern edge of the University of North Dakota campus in Grand Forks. Started in 1951 to conduct coal research for the U.S. Bureau of Mines, the center shifted its focus toward energy research during the 1970s.
Following its defederalization in 1983, like many other programs during the Reagan years, the EERC had to adapt itself to the private sector if it was to survive. Attached to the university, the center has not only survived but currently has more than 140 active contracts in 52 different countries, covering what amounts to a “huge array of projects,” said EERC director Gerry Groenewold. “And all these things are connected.”
EERC’s accomplishment has been in finding ways to reduce the overall carbon footprint without sacrificing productivity or profitability. By competitively finding ways to commercialize new technology, it has successfully been able to continue and expand into new areas of research.
“Very few enterprises are about commercializing technology,” said Groenewold.
“There’s not one penny for the EERC from the state,” adds John Harju, the EERC’s associate director for research.
The center does not receive grants, but rather contracts that are “only competitively-awarded, with no directed money. We have to be practical, live by our wits,” he said. Although there are some government contracts, the majority, about 90 percent, are with private firms.
Research at the EERC is primarily focused on reducing carbon emissions, whether that be through developing alternative fuels such as biodiesel and hydrogen or through various methods of carbon capture and storage. Through its Plains CO2 Reduction (PCOR) Partnership, the EERC has embarked on a multi-year collaboration with companies in both Canada and the United States.
There are different means of carbon sequestration, a process which takes CO2 and inters it underground. These include terrestrial, which consists of methods used to trap CO2 in sinks such as grasslands and wetlands, and geological. This latter would inject the gas deep underground in the various seams and cavities of geological formations.
The PCOR project is in its third phase, focused on using the vast layer of basal Cambrian sandstone covering the upper Midwest for geological sequestration of CO2 directly captured at large sources, such as power plants and gas refineries. In 2007, the EERC had successfully experimented with storing CO2 in lignite seams, which are well-suited as the gas molecules adsorb to the coal surface upon contact.
But the potential for CO2 sequestration does not lie only in disposing of or stashing away produced emissions.
“We’re looking at CO2 as a resource rather than a pollutant” or byproduct, Groenewald explained. The EERC is finding ways to use the gas, like any resource, in industrial processes to boost efficiency.
Together with Denbury Onshore LLC, of the Texas-based oil and gas exploration company Denbury Resources Inc., the EERC is implementing a commercial carbon dioxide enhanced oil recovery (CO2 EOR) project. The project should produce an extra 35 million barrels of incremental oil fuel that otherwise would be irretrievable by conventional means and adding an additional 20 years to the life of the Bell Creek field. The project involved construction of 230 miles of 22-inch pipe, which will deliver over 1 million tons of CO2 each year from the Lost Cabin gas plant in central Wyoming.
“Natural gas reserves contain small quantities of CO2,” Harju explained.
These reserves are relatively impure in natural gas streams and reservoirs, he said. Removed along with naturally-occurring moisture and impurities after extraction prior to natural gas’ transportation, CO2 can be captured at that point and used to feed Phase III operations in Bell Creek. Work on a pipeline connecting the two points had taken three years, finally completed last December.
“We are zeroing in on a very exciting point in time,” said Harju, who says the first injection will begin in May. For such a long pipeline, it takes a considerable amount of time for CO2 pressure to build up. Once pressure reaches above 1,100 pounds per square inch, the nature of the CO2 reaches “a supercritical state,” which Harju explained is liquidlike, even though temperatures are not nearly cold enough for it to become a real liquid. Once injection begins, the gas will be subject to pressures around 2,000 per square inch as, fluidlike, it mingles and blends with the petroleum in the reservoir.
The presence of CO2 will reduce overall viscosity (resistance to flow) and cause the mixture to swell, eventually creating enough pressure for oil to flow freely. The CO2 is then captured at the point of extraction, dehydrated and reinjected into the reservoir as part of a self-sustaining system.
Reaching that point will take time.
“At day one when we’re injecting that CO2, we will be recovering zero percent,” Harju said. “By around year one, that will increase to 5 or 10 percent.” The percent will increase over time.
As oil becomes less difficult to extract, the number of pumping units formerly needed to maintain production will be decommissioned. The project hopes to lower the number of units to around 700 wells, which in addition to significant cost-reduction and lessened pollution will improve the visual landscape.
Before natural gas can be transported for use, it has to be processed at the point of capture. Citing the PennWell worldwide gas-processing database, the EERC estimates there are around 1,300 natural gas processing facilities in the United States and Canada. The processing facilities are some of the only sources for relatively pure streams of CO2 on the scale needed, which make them ideal for use in CO2 EOR projects such as Phase III.
By the project’s conclusion, once the oil has been retrieved to the fullest extent possible, the sequestered CO2 can be left in its place.
Depending on the success of Phase III, similar capture and extraction systems could be implemented in North Dakota’s oilfields. While the potential for CO2 EOR in the Bakken Formation shale field is less dramatic, it can still make a substantial difference, according to EERC. Because the nature of shale makes the method for extraction different, in this case the CO2 could be used as a hydrocarbon-based fracturing fluid.
“Every extra one percent of output we can facilitate means another $150 billion,” estimated Groenewold of North Dakota’s Bakken field.
Increased output would mean increased revenues and would contribute to the country’s lessened reliance on foreign oil sources, all while working to reduce the atmospheric impact of the industry.
“By doing our job we make jobs,” Groenewold said. “On that front,” he added, “We’ve been doing quite well.”