The company said the results from a recently completed appraisal well could make the discovery one of the largest in this part of the North Sea for several years.
E.ON board of management member Jørgen Kildahl said, "This successful discovery in UK is an important step for our growing upstream business."
"Tolmount will significantly contribute to the implementation of our business strategy," Kildahl added.
E.ON E&P CEO Frank Sivertsen said, "The well results will now be incorporated into development studies, with the aim of an optimised development in a short timeframe."
"Tolmount could be one of the largest discoveries made in the Southern North Sea in the last decade," Sivertsen added.
Tolmount is located in Block 42/28d, some 50km off the Yorkshire coast. E.ON E&P operates the block with 50% interest, while Dana Petroleum holds the rest.
E.ON E&P executive vice-president business development and exploration Haakon Haaland said, "We would like to thank our partner Dana Petroleum for its support and teamwork in reaching this significant milestone."
"The Tolmount success shows there is still potential for significant volumes of hydrocarbons to be found in the UK North Sea," Haaland added.
