more success at mputa 4

Successful Mputa-4 appraisal well in Uganda
02/10/2007

2 October 2007 – Tullow Oil plc (Tullow) announces the successful drilling and logging of the Mputa-4 appraisal well in Uganda’s Block 2 which the Group operates with a 100% interest.

Mputa 4 is located 1km east of the Mputa-1 discovery well and was drilled to test an adjacent fault block. The well reached a total depth of 1,073m and encountered three separate oil bearing zones with a total net pay of 15.4m. Downhole pressure testing and sampling indicated moveable light sweet crude with very good permeabilities as seen in the other Mputa wells.

Mputa-4 is the third and final well being drilled as part of the Kaiso-Tonya appraisal programme and has proved the lateral extent of oil bearing reservoirs across the region. The data from this programme, which includes ongoing 3D seismic and the possibility of further production testing on existing wells, will help to determine the ultimate reserve potential of the area and provide critical information for the Early Production System development.

Commenting today, Aidan Heavey, Chief Executive of Tullow said:

"We are very pleased with the results of the three-well appraisal programme in the Kaiso-Tonya area. The programme, which was completed on time and within budget, has improved our understanding of the ultimate reserve potential of this onshore region, and will be further enhanced over the coming months by the results from the ongoing 3D seismic acquisition. Activity in Uganda continues apace with the high impact Ngassa well scheduled to spud in October."