Though gross production for 2013 slumped, Gulf Keystone Petroleum, active in the Kurdish oil sector of Iraq, said Thursday it had a successful year.

The company, which has headquarters in London, said gross production for 2013 declined more than 40 percent from the previous year to 496,921 barrels of oil. Its sales, all of which came from the Shaikan reserve area in the Kurdish north of Iraq, generated $6.7 million in revenue last year, compared with $32.2 million in 2012.

Chief Executive Officer Todd Kozel, however, said 2013 was a successful year for the company because it transitioned from an exploration company to a development and production company in large part because of its stake in Kurdish oil.

"We continue to be encouraged by the recent positive political developments in the Kurdistan Region of Iraq, where the fast pace of economic development was maintained in 2013, not solely but largely due to the burgeoning oil and gas sector," he said in a statement.

The company in June said the region's Shaikan field could hold as much as 10.5 billion barrels of oil. The semiautonomous Kurdistan Regional Government has said production could reach 250,000 bpd by 2018.

The KRG has been locked in a heated debate over oil revenue with the central government in Baghdad.