Dana Gas and Crescent Petroleum announced the $1 billion in investments has lead to a daily production rate of 88,000 barrels of oil equivalent. It said much of the production came from more than four years of constant production at its Kor Mor field.
Both companies entered into agreements with the Kurdistan Regional Government in 2007.
"Dana Gas and Crescent Petroleum are proud to have delivered these important results, which are also a testament to the policies of encouraging private investment and local development that have been applied in the Kurdistan Region of Iraq," Crescent Chief Executive Officer Majid Jafar said in a statement.
Disputes over national oil laws have cast a shadow over the Iraqi energy sector. The central government in Baghdad says working with the Kurdish government may be illegal.
The Kurdish government in December said production from the semiautonomous region could add at least $8 billion to the Iraqi treasury. It halted oil production in the past, however, because of ongoing political disputes with Baghdad.