Tullow Oil said on Friday its Shimela-1 well in Ethiopia has found water-bearing reservoirs.

The exploration group said Shimela-1, which is located in the South Omo Block in Ethiopia, was drilled to test a prospect in a north-western sub-basin of the vast Chew Bahir basin. The frontier wildcat well encountered lacustrine and volcanic rocks including almost 100 metres of net sandstone reservoir within siltstones and claystones. Trace thermogenic gas shows were recorded at 1,900 metres.

The Exalo 205 rig drilled Shimela-1 to a final depth of 1,940 metres. The rig will now be moved to drill the Gardim-1 wildcat exploration well in a completely separate sub-basin, in the south-eastern corner of the Chew Bahir basin.

Tullow operates the South Omo Block with 50 per cent equity and is partnered by Africa Oil Corporation and Marathon Oil Ethiopia.

“Although the Shimela well only found traces of thermogenic gas, it has provided key data to continue to build our understanding of the north-western part of the Chew Bahir basin. The prospectivity at the Gardim-1 well, which is targeting an independent petroleum system in a separate south-eastern sub-basin, is not affected by this result,” said exploration director Angus McCoss.

Tullow, which is quoted on the Irish, London and Ghanaian stock exchanges, has interests in over 140 exploration and production licences across 24 countries.