The company estimates that the discovery, called Valemon Nord, holds the equivalent of 20m to 75m barrels of recoverable oil and gas.
“We are very satisfied with making a new discovery in the close proximity of the Valemon gas and condensate field currently under development," said Irene Rummelhoff, the company's senior vice president for exploration in Norway.
“By proving additional volumes in the area we increase the reserves base in the Valemon Unit area and add value to the Valemon field development.”
The Valemon field, discovered in 1985 has recoverable reserves of some 206 million barrels of oil equivalent, making it one of the company's biggest ongoing developments.
The field is expected to start up in the fourth quarter of 2014.