The U.S. Energy Department says crude oil production in Colorado rose 64 percent from 2007-11. The state may have as much as 2 billion barrels of oil.
Nighthawk said it was planning more work in the Arikaree Creek oil field. Production there from November through March yielded more than 30,000 barrels of oil.
Nighthawk Chairman Stephen Gutteridge said the company, as the major lease-holder in the area, sees a "major opportunity" for "extensive additional development activity in the second half of the year."
A two-well program at Arikaree Creek is under way. Gutteridge said the objective of the development plan is to increase production and reserve base in Colorado.
Gutteridge last month said the development would be financed through $5 billion in available funding.
Notable deaths of 2014 [PHOTOS]
EIA: Russia diversifying energy production