Shares in Anglo-Irish exploration firm Tullow Oil shot up more than 6pc at one stage yesterday following the resolution of a maritime dispute between Ghana and Ivory Coast.
The agreement between the two west Africa countries means that Tullow's huge offshore TEN oil fields off Ghana will not be impacted by any change in national boundaries.
Tullow is the operator of the TEN (Tweneboa, Enyenra, Ntomme) fields and the ruling over the weekend by the Hamburg-based International Tribunal of the Law of the Sea (ITLOS) means it will now be able to recommence drilling by the end of the year.
The rate of oil production at the fields is expected to eventually increase from about 50,000 barrels of oil a day to the TEN field designed capacity output of 80,000 barrels a day.
Tullow owns a 47pc stake in the TEN fields. It also has a 35pc holding in the huge Jubilee oil field, which is also offshore in Ghanaian waters and close to the TEN project.
The decision by ITLOS is the culmination of a four-year battle by Ivory Coast to push for a redrawn national boundary that could have placed at least part of the vast oil fields under its control and had significant implications for Tullow.
The Ivory Coast government said that it has accepted the ITLOS ruling.
"A clear ruling that does not alter the jurisdiction of any part of the TEN development area and is accepted by both countries is the best outcome Tullow could have hoped for," said James Hosie, an analyst at Barclays, one of Tullow's own corporate brokers.
"Although we believe this outcome was widely viewed as the most likely amongst market commentators, it is nevertheless positive and removes a significant source of uncertainty from the Tullow investment case," Mr Hosie said.
He added that the ruling "smooths the process" of the on-going $2.5bn (€2.1bn) debt refinancing by Tullow that should be confirmed during the final quarter of this year.
Tullow, whose chief executive is Paul McDade, has undergone significant restructuring over the past couple of years as low oil prices weighed on producers and explorers.
Earlier this year, the company - which is also exploring in Kenya, Jamaica and Suriname - raised $750m (€631m) in a rights issue and cut its debt from $4.8bn (€4bn) to $3.8bn (€3.2bn).
"While the TEN fields have performed well during the period of the drilling moratorium, we can now restart work on the additional drilling planned as part of the TEN fields' plan of development and take the fields towards their full potential," said Mr McDade.
There are 13 development wells at TEN still to be drilled. To date, 11 wells have been drilled and completed.
Tullow impaired the value of its interest in the TEN fields by $572m (€481m) during the first half of the year, as a result of lower oil prices.
The impairment recorded by the company was taken when oil was priced around the mid-$40 (€33) a barrel range.
The price of Brent oil is currently hovering close to $58 (€48) a barrel, up from around $50 (€42) during the summer.
The impairment resulted in Tullow Oil reporting a $518.8m (€436m) loss in the first half of the year. That compared to a $24.1m (€20m) profit in the first six months of 2016.
Revenue at the group rose 46pc to $788m (€663m) in the first half of 2017.