The company said it made the discovery with the Enyenra-4A appraisal well in the deepwater Tano licence.
The well, accortding to the company, hit 32 metres of net oil pay, saying the oil found was in touch with that of other wells in the Enyenra light oilfield including the Owo-1 discovery well.
The well was drilled to test the southern extension of the field, just under seven kilometres south west of Enyenra-2A and almost 21 kilometres south of the field’s northern extension, the Enyenra-3A well.
Drilled by drillship Ocean Olympia, the Enyenra-4A well reached a total depth of 4174 metres, with wireline logging indicating a continuous oil column of about 600 metres.
Tullow stated that injectivity tests on the well were underway, with the well to be suspended for later use on completion of operations.
Exploration director Angus McCoss said the company would continue to appraise the field through monitoring pressure gauge systems deployed in several wells within the system.
Tullow holds an operating 49.95% stake in the Deepwater Tano licence, with Kosmos Energy and Anadarko Petroleum each holding 18% stakes, Sabre with 4.05% and the Ghana National Petroleum Corporation holding a 10% carried interest.