OGJ Washington Editor
WASHINGTON, DC, July 9 -- A North Dakota field test by one of the US Department of Energy’s regional carbon capture and storage partnerships demonstrated that an enhanced oil recovery method known as “huff and puff” can simultaneously assess geological formations’ carbon sequestration potential, DOE’s Fossil Fuels Office announced.
It said on June 28 that the test by the Plains CO2 Reduction Partnership, one of seven in DOE’s regional carbon program, is designed to assess the carbon sequestration potential of geologic formations while tapping more US oil resources. The partnership is working with independent producer Eagle Operating Inc. on the project in the Northwest McGregor oil field in Williams County, ND.
The huff-and-puff EOR method proceeds in three stages: injection (the huff stage), “soaking” for a short period, and production (the puff stage), according to DOE. It said the Plains CO2 partnership’s test was unique because its depth (3,500 ft) was among the greatest, its pressure (3,000 psi) and temperature (180° F.) were among the highest, and its tested formation was a carbonate instead of a clastic reservoir.
The test used a producing oil well in the Mission Canyon formation, part of the Madison group of Mississippian-age carbonate rocks in the western US, DOE said. During the test, 440 tons of liquid CO2 were injected into the well to a depth at which CO2 is miscible and blends with residual in-place oil. After 2 weeks of soaking, the well was placed back into production, DOE said.
It said production more than doubled over 3 months, increasing from a baseline rate of 1.5 stb/d to 3-7 stb/d. The percentage of oil in the produced fluid, commonly referred to as the “oil cut,” also increased, more than doubling from less than 3% to 6%, it added.
DOE said in addition to demonstrating the feasibility of combining CO2 storage along with EOR in carbonate rocks deeper than 8,000 ft, the test determined that two Schlumberger technologies—a reservoir saturation tool and vertical seismic profiling—may be effective ways to detect and monitor small-volume CO2 plumes in deep carbonate reservoirs to ensure safe and permanent sequestration.
Project outcomes may be applicable to many other sites in the Plains CO2 partnership’s region and in similar settings globally, DOE indicated.
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