The UAE news agency \'WAM\' says two South Korean companies have signed a deal with the Abu Dhabi National Oil Company (ADNOC) to drill in three undeveloped oil fields in the United Arab Emirates. (South) Korea National Oil Corporation and GS Energy will share a combined 40 percent stake in the project announced Monday by WAM. ADNOC will retain a majority stake in the fields. The agreement is valid for 30 years, and covers exploration, development and oil production of the fields.