Union Jack Oil PLC (LON:UJO) has told investors that oil is free-flowing at the Wressle field, in Lincolnshire.
It comes after successful operations to recomplete the Ashover Grit reservoir interval.
The well has now been placed on a continuous 24-hour production test.
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Presently, the well is in a normal clean-up phase, and, Union Jack highlighted that the well is being brought online carefully.
Produced oil will be transported by road tanker to the Phillips 66 Humber refinery, Union Jack noted.
Partners in the venture expect to provide more detailed production information once rates have stabilised.
Union Jack owns a 40% interest in the Wressle project.