Well Update - French Guiana

RNS Number : 9280N

Tullow Oil PLC

09 September 2011

News Release

Zaedyus exploration well makes oil discovery offshore French Guiana

9 September 2011 - Tullow Oil plc (Tullow) announces that the Zaedyus exploration well (GM-ES-1), offshore French Guiana, has made an oil discovery having encountered 72 metres of net oil pay in two turbidite fans. Results of drilling, wireline logs and samples of reservoir fluids show that the well has encountered good quality reservoir sands on prognosis.

The objective of the Zaedyus well was to test whether the Jubilee-play, successfully established in West Africa, was mirrored on the other side of the Atlantic. This discovery therefore opens a new hydrocarbon basin within which several neighbouring prospects have been mapped. This result also reduces the exploration risk associated with Tullow's prospect inventory offshore French Guiana, Suriname and Guyana. An appraisal programme and extensive follow-up exploration activities will now be considered.

The Zaedyus well is being drilled in the Guyane Maritime licence using the ENSCO 8503 deepwater semi submersible. The well was drilled in water depths of 2,048 metres and has been drilled to a depth of 5,711 metres. Drilling operations will now continue and the well will be deepened to over 6,000 metres to calibrate the deeper geology. The well will then likely be sidetracked to enable cores to be obtained over the reservoir sections.

Tullow (27.5%) operates the Guyane Maritime license and is partnered by Shell (45%), Total (25%) and Northpet (2.5%), a company owned 50% by Northern Petroleum plc and 50% by Wessex Exploration plc.

Angus McCoss, Tullow's Exploration Director, commented today:

"The discovery at Zaedyus has proved the extension of the Jubilee-play across the Atlantic and made an important new discovery in French Guiana. Tullow has built a commanding and unique acreage position in South America and this result marks the start of a significant and potentially transformational long-term exploration and appraisal campaign in the region."

Analyst and Investor call

In conjunction with this release, Tullow is conducting a conference call at 8am UK time.

To access the call please dial the appropriate number below shortly before the call and ask for the Tullow Oil plc conference call. The telephone numbers and access codes are:

UK & International Participants +44 (0)20 3450 9987

Irish Participants +353 (0)1 6590423

Tullow Group Overview

Tullow is a leading independent oil & gas, exploration and production group, quoted on the London, Irish and Ghanaian (symbol: TLW) stock exchanges and is a constituent of the FTSE 100 Index. The Group has interests in over 90 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 Ghana, Gabon, Côte d'Ivoire, Mauritania, Congo (Brazzaville) and Equatorial Guinea with two large appraisal and development programmes in Ghana and Uganda. Tullow also has exploration interests in Gabon, Côte d'Ivoire, Liberia, Sierra Leone, Mauritania, Senegal, Tanzania, Madagascar, Namibia, Kenya and Ethiopia.

Tullow's European interests are focused on gas in the UK Southern North Sea where it has significant interests in the Caister-Murdoch System and the Thames area and in the Netherlands where it has offshore gas production, development and exploration opportunities.

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.

For further information please refer to our website at www.tullowoil.com.

FOR FURTHER INFORMATION CONTACT:

Tullow Oil plc
(+44 20 3249 9000)

Chris Perry - Investor Relations

James Arnold - Investor Relations

George Cazenove - Media Relations

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

Kate Lehane

Murray Consultants
(+353 1 498 0300)
Joe Murray

Ed Micheau

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