Tullow Oil plc (Tullow) announces that the Mercury-2 exploratory appraisal well in Sierra Leone and the Kosrou-1 exploration well in Côte d'Ivoire have both encountered water bearing reservoirs with oil shows.

Mercury-2 - Sierra Leone
The Mercury-2 well was drilled 12 kilometres northwest of the Mercury-1 oil discovery, targeting an area where the extensive 3D seismic coverage indicated a high probability of finding thick reservoir quality sandstones. It intersected over 270 metres of reservoir quality sandstones which were water bearing with oil shows at this location.

The Discoverer Spirit drillship drilled Mercury-2 to a final depth of 5,142 metres in water depths of 1,815 metres.

Anadarko (55%) is Operator of offshore Block SL-07B-11 along with partners Repsol (25%) and Tullow (20%).

Kosrou-1 - Côte d'Ivoire
The Kosrou-1 well was drilled in the CI-105 block, 17 kilometres east south east of the previous South Grand Lahou-1 well, targeting a channel system identified on the 3D seismic survey acquired in 2010. It intersected 90 metres of reservoir quality sandstones with oil shows in the primary target and over 120 metres in total in the well.

The Eirik Raude semi-submersible drilled Kosrou-1 to a final depth of 5,241 metres in water depths of 2,275 metres. On completion of operations the rig will return to the Paon-1 location to complete the drilling of that well. Paon-1 is a high impact prospect which is geologically independent from Kosrou and closer to our discoveries in Ghana.

Anadarko (50%) is Operator of offshore Block CI-105 along with partners Tullow (22%), Petroci (15%) and Thani (13%).

Commenting today, Angus McCoss, Exploration Director, said:
"Kosrou-1 and Mercury-2 encountered significant reservoir sands which were water bearing with oil shows. The existence of thick sandstone fairways and a working hydrocarbon system, proven by every well in our exploration campaign, mean that our West African Transform Margin acreage remains highly prospective. The well data will now be integrated into our regional models to improve our chances of making a hub-class discovery with the ongoing campaign which includes the Strontium-1 well in Liberia and the Paon-1 well in Côte d'Ivoire.