Danish energy company Maersk Oil said it started production from a North Sea platform that should provide Denmark with new reserves for the next 30 years.

Maersk said it started production from the unmanned Tyra Southeast-B platform in the Danish waters of the North Sea. The facility is expected to add around 50 million barrels of oil equivalent to the Danish market for the next 30 years.

Peak production is expected by 2017 through investments of more than $650 million. The investment represents the largest ever made by a Danish energy consortium, for which Maersk serves as the operator, since 2007.

"This is an important step in Maersk Oil's growth journey and it demonstrates that Denmark continues to be a core area for us," Maersk Oil Chief Executive Officer Jakob Thomasen said in a statement.

Analysis from Wood Mackenzie found the region brought in $19 billion in capital spending last year. With oil prices falling more than 50 percent since June, data show exploration and production activity was slowing down.

Exploration activity in 2014 was off 18 percent from the previous year. Only four fields were brought online, the report found.