Press releases

16 Mar 2012

Enyenra-4A appraisal well successful

Tullow Oil plc (Tullow) announces that the Enyenra-4A appraisal well, in the Deepwater Tano licence offshore Ghana, has successfully encountered oil in very good quality sandstone reservoirs. Good evidence of communication with the Owo-1 discovery wells and the Enyenra appraisal wells confirms the significant extent of the Enyenra light oil field.

Located just under seven kilometres south west of Enyenra-2A and almost 21km south of the Enyenra-3A well which defined the northern end of the Enyenra oil field, the Enyenra-4A well was drilled to define the southern extent of the field.  Results of drilling, wireline logs, samples of reservoir fluids and pressure data show that Enyenra-4A has intersected 32 metres of net oil pay. Pressure data from the oil leg has demonstrated that the oil is in static communication with the oil seen in the other wells in the field and indicate a continuous oil column of approximately 600m.

The Ocean Olympia drillship drilled Enyenra-4A to a total depth of 4,174 metres in water depths of 1,878 metres. Wireline logging has been completed and injectivity tests are under way to provide important data for the design of the water injection system. On completion of operations, the well will be suspended for later use. The drillship will return at a later date to the Deepwater Tano block to perform a drill stem test on the oil zone in the Ntomme-2A well.

Tullow (49.95%) operates the Deepwater Tano licence and is partnered by Kosmos Energy (18.00%), Anadarko Petroleum (18.00%), Sabre (4.05%) and the Ghana National Petroleum Corporation (GNPC) (10% carried interest).

Commenting today, Angus McCoss, Exploration Director, said:
"This bold step out is an excellent result which is further enhanced by the quality and thickness of the reservoirs found at this downdip location.  Proving a 600m oil column over a distance of 21km with three appraisal wells is a significant achievement which was only possible through the use of highly refined geophysical techniques. The appraisal of the Enyenra field will now continue with the monitoring of the pressure gauges deployed in several wells to determine the level of dynamic connectivity within the system and to further refine the estimates of oil in place."

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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