Just an hour west of Casper, carbon dioxide is being pumped into a partially depleted oil field in an attempt to recover some additional black gold.
During the first quarter of this year, Plano, Texas-based Denbury Resources Inc. began the first carbon dioxide injection into the Grieve field, in Natrona County about 45 miles outside of Casper, said Kristen Barrett, a Denbury facilities engineer and construction project manager. Denbury is involved in the project as part of a joint venture with Elk Petroleum Inc. of Sydney, Australia.
Injecting carbon dioxide underground to push out hard-to-get oil is part of an industry practice known as enhanced oil recovery. Oil had first been discovered in the Grieve field in 1954, Barrett said. Companies use enhanced oil recovery to coax remaining oil to the surface. When oil prices soar, enhanced oil recovery becomes economical.
Barrett said that the old field west of town isn’t producing oil yet. Carbon dioxide hasn’t filled the reserve. It can sometimes take two years, she said.
Meantime, workers are busy. They had to clear out old oil tanks and equipment from previous companies. They are currently building a facility that will remove carbon dioxide from the oil, Barrett said. Also under construction are transmission lines and a power substation. Although crews are currently getting electricity from a power line in the area, once full-blown enhanced oil recovery operations get going, more power will be needed, Barrett said.
Weather has proven to be a challenge to crews, many of whom are from the Gulf Coast.
“We don’t like those cold temperatures,” Barrett said. “We send a lot of our Southern guys here and they hate it.”
Cold temperatures and high winds in the winter can restrict operations. The drilling area is also a core area for sage grouse, a bird that is threatened to be listed under the Endangered Species Act. To protect the bird, crews are prohibited from new construction from March 15 to July 1 each year. But they can do maintenance, Barrett said.
“We’re restricted to a few months in the fall and one or two months in the spring,” she said.