Founded in 1980 and based in Denver, Whiting Petroleum is an independent oil and natural gas company with operations primarily in the Bakken-Three Forks system of North Dakota and Montana, the D-J Basin in Colorado, and the Permian Basin in Texas. At year-end 2015, proved reserves were 780 million barrels of oil equivalent with net production of 163,000 boe per day. Oil represented approximately 80% of reserves and production.