Development of the Breagh gas field could have cost £600m
The Aberdeen-based Faroe Petroleum has sold its share of the Breagh gas field for £25.3m because it said it could not afford to develop it.
The Breagh field was one of the largest discoveries of its kind in the last 10 years and was owned by six firms.
Faroe said although it was an outstanding discovery, development would have cost about £600m.
The six-company partnership has agreed to sell 70% of the field to the German company RWE Dea.
It is described as a much larger company which will be able to fund the development costs.
Faroe said it would reinvest the cash from the sale in further "value-creating opportunities".