Drilling update - Mozambique and French Guiana

RNS Number : 8857J

Tullow Oil PLC

23 July 2013

News Release

Drilling update - Mozambique and French Guiana

23 July 2013 - Tullow Oil plc (Tullow) gives the following update on exploration wells in Mozambique and French Guiana.

Mozambique

The Cachalote-1 exploration well in Area 2 offshore Mozambique has discovered a gas bearing reservoir in an Upper Cretaceous deepwater channel system.

This well is the first deepwater exploration well drilled in Area 2 and targeted several geological plays associated with the regionally important Ibo High. 38 metres of good quality gas bearing reservoir sandstones were found in an Upper Cretaceous objective on the outboard flank of the Ibo High. However, based on the initial evaluation, it is unlikely to be commercial on a standalone basis. The deeper target did not have any indication of hydrocarbons.

The Cachalote-1 well was then sidetracked to target older sandstone reservoirs which were expected to be developed on the inboard flank of the Ibo High. Thick sandstones were encountered in this section but were not of reservoir quality. Wet gas shows were seen in the well, providing important evidence for a working petroleum system. Following completion of logging operations, the well has been plugged and abandoned.

The Discoverer Americas dynamically positioned drill ship drilled Cachalote-1 to a final depth of 2,475 metres in water depths of 688 metres. The sidetrack was then drilled to a final depth of 3,191 metres below sea level. The drill ship will now move to drill the Buzio-1 wildcat well in the east of the licence, on the outboard flank of the Ibo High.

Tullow has a 25% interest in Areas 2 and 5 in the Romuva Basin, offshore Mozambique. Statoil 40% are the operator while INPEX have a 25% non-operated interest. ENH (Empresa Nacional de Hidrocarbonetos, E.P.) have a 10% carried interest.

French Guiana

The GM-ES-4 exploration well in French Guiana has been drilled to a total depth of 6,292 metres and penetrated both the primary and secondary reservoir objectives of the Cebus prospect and these intervals have been logged. Provisional interpretation of all drilling and geological data indicates that whilst there was extensive development of the targeted sands, no indications of hydrocarbons were observed. The well is now being plugged and abandoned.

The Stena ICEMax drillship will now drill the GM-ES-5 well, the final well of a four-well programme following the Zaedyus-1 oil discovery.

Tullow has a 27.5% stake in the Guyane Maritime licence and is partnered by Shell, who are operator and hold a 45% stake, Total (25%) and Northpet (2.5%), a company owned 50% by Northern Petroleum plc and 50% by Wessex Exploration plc.

Angus McCoss, Exploration Director, Tullow Oil plc commented today,

"Discovering gas outboard on the vast Ibo High through drilling Cachalote-1 is encouraging although this is not a standalone commercial discovery. The potential for discovering oil in this region remains after we encountered wet gas shows in the deeper sidetrack. We will integrate this valuable data into our regional model to improve our chances of unlocking the oil play potential offshore Mozambique.

"The Cebus-1 well was an ambitious wildcat exploration well which did not encounter hydrocarbons. The current French Guiana campaign now concludes with the GM-ES-5 well. This well will be located on the Cingulata fan with the objective of determining the oil water contact of the Zaedyus-1 discovery by measuring the pressure in the water-leg as well as gathering geological data from deeper unpenetrated sections."

FOR FURTHER INFORMATION CONTACT:

Tullow Oil plc

(London)
(+44 20 3249 9000)

Chris Perry (Investor Relations)

James Arnold (Investor Relations)

George Cazenove (Media Relations)

Citigate Dewe Rogerson

(London)
(+44 207 638 9571)
Martin Jackson

Jack Rich

Murray Consultants
(Dublin)

(+353 1 498 0300)
Joe Murray

Joe Heron

Notes to Editors

Tullow Oil plc

Tullow is a leading independent oil & gas, exploration and production group, quoted on the London, Irish and Ghanaian stock exchanges (symbol: TLW) and is a constituent of the FTSE 100 Index. The Group has interests in over 150 exploration and production licences across 26 countries which are managed as three regional business units: West & North Africa, South & East Africa and Europe, South America and Asia.

Follow Tullow on:

Twitter: www.twitter.com/TullowOilplc You Tube: www.youtube.com/TullowOilplc
Facebook: www.facebook.com/TullowOilplc LinkedIn: www.linkedin.com/company/Tullow-Oil