4 May 2012 Teak-4A appraisal well update

Kosmos Energy, the Operator of the Teak-4A appraisal well offshore Ghana, in which Tullow Oil plc (Tullow) is a 26.396% partner, yesterday evening, issued the following press release:

DALLAS, Texas, May 3, 2012 - Kosmos Energy (NYSE: KOS) announced results from the Teak-4A appraisal well, located in the West Cape Three Points Block, offshore Ghana. Located 6.1 kilometers (3.8 miles) northwest of the Teak-1 discovery well, the Teak-4A well was targeting the stratigraphic extension of the Teak discovery area. The well encountered thin, non-commercial reservoirs and is being plugged and abandoned. Kosmos and partners have begun integrating well results into the Teak field model to determine forward appraisal and development plans.

The Atwood Hunter rig drilled Teak-4A to a total depth of 2,850 meters (9,348 feet) in water depth of 554 meters (1,817 feet). Following the completion of operations at the Teak-4A well, the drilling rig will set gauges at the Teak-2A well and perform a drill stem test at the Akasa oil discovery on the West Cape Three Points Block.

Kosmos Energy is the operator of the West Cape Three Points Block with a 30.875 percent interest. The Company's partners include Anadarko Petroleum Corporation (30.875 percent), Tullow Oil plc (26.396 percent), Sabre Oil & Gas Holdings Ltd. (1.854 percent), and the Ghana National Petroleum Corporation (10 percent carried).

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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