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10 January 2011 Tullow Oil plc (Tullow) announces that the Tweneboa-3 appraisal well in the Deepwater Tano licence offshore Ghana has successfully encountered gas condensate in excellent quality sandstone reservoirs. Results of drilling, wireline logs and samples of reservoir fluids, together with the wells down-dip position confirms the Greater Tweneboa Area resource base potential.

The well, located over six kilometres south-east of the Tweneboa-2 well and 12 kilometres south-east from the Tweneboa-1 discovery well, was planned with two deviated boreholes to test separate areas of the Tweneboa field. The first leg was drilled to calibrate the potential of an area with a very weak seismic response. Within prognosis, this leg encountered thin reservoir sands and approximately 9 metres of gas condensate pay. The well was then sidetracked 550 metres west, targeting the significant Ntomme anomaly, an area of strong seismic response. This leg successfully encountered a gross vertical reservoir interval of approximately 65 metres containing 34 metres of net gas condensate pay in two zones of high quality stacked reservoir sandstones. Work is underway to integrate seismic, pressure and hydrocarbon phase data in order to progress development options for the Tweneboa and Enyenra (Owo) fields in the Greater Tweneboa Area.

Tweneboa-3 was drilled by the Deepwater Millennium drillship to a total depth of 3,906 metres in a water depth of 1,601 metres. On completion of operations, the well will be suspended for future use in the field development. The rig will remain in the Deepwater Tano block to drill the top-hole section of the Tweneboa-4 appraisal well which will then be suspended before moving to drill the high impact Enyenra-2A well which will appraise down-dip from the Owo-1 oil discovery. The significant oil discovery, made by the Owo-1 exploration well has now been named the Enyenra field.

Tullow (49.95%) operates the Deepwater Tano licence and is partnered by Kosmos Energy Ghana (18%), Anadarko Petroleum (18%), Sabre Oil & Gas (4.05%) and the Ghana National Petroleum Corporation (GNPC) (10% carried interest).

Commenting today, Angus McCoss, Exploration Director, said:
Tweneboa-3 was a bold appraisal step-out in a vast stratigraphic trap. Confirming producible gas-condensate in excellent quality reservoirs at this location is a great result that also demonstrates the strong predictive capabilities of our seismic data and prospecting techniques. As a result, we can now move forward confidently to assess the development options for the Tweneboa and Enyenra (Owo) fields in the Greater Tweneboa Area.

FOR FURTHER INFORMATION CONTACT:
Tullow Oil plc
(+44 20 8996 1000)
Angus McCoss
Chris Perry
James Arnold

Citigate Dewe Rogerson
(+44 207 638 9571)
Martin Jackson
George Cazenove

Murray Consultants
(+353 1 498 0300)
Joe Murray
Ed Micheau

Notes to Editors
Tullow is a leading independent oil & gas, exploration and production group, quoted on the London and Irish Stock Exchanges (symbol: TLW) and is a constituent of the FTSE 100 Index. The Group has interests in over 85 exploration and production licences across 22 countries and focuses on four core areas: Africa, Europe, South Asia and South America.

In Africa, Tullow has production in Gabon, Cte d'Ivoire, Mauritania, Congo (Brazzaville) and Equatorial Guinea and two large appraisal and development programmes in Ghana and Uganda. Tullow also has exploration interests in Gabon, Cte d'Ivoire, Liberia, Sierra Leone, Mauritania, Senegal, Congo (DRC), Tanzania, Madagascar, Namibia and Ethiopia.

Tullows European interests are primarily focused on gas in the UK Southern North Sea where it has significant interests in the Caister-Murdoch System and the Thames area. The company also has interests offshore the Netherlands.

In South Asia, Tullow has exploration and production in Bangladesh and exploration interests in Pakistan. In South America, Tullow has exploration interests in Guyana, French Guiana and Suriname.