Drilling started in May. The well was sidetracked in July and completed at the end of August.
One-Dyas then asked the Oil and Gas Authority for permission to conduct and extended well test.
The well was drilled using the Valaris 121 rig.
David Moseley, senior analyst at Westwood Global Energy Group, said in October that it could be assumed that hydrocarbons had been discovered.
An One-Dyas spokesperson said today: “One-Dyas and its partners are pleased with the encouraging results of the Ossian-Darach exploration well and can confirm that oil has been encountered. Further evaluations are ongoing to assess the commercial potential of the area.”