UK Business Update

Tullow Oil PLC 19 September 2006 Tullow Oil plc - UK Business Update 19 September 2006 - Tullow Oil plc (Tullow) announces that the Ketch-7 development well has been completed and tested at a rate of 45 mmscfd and that the Schooner NW appraisal well has encountered gas in the targeted Carboniferous reservoir section. FIRST PRODUCTION FROM KETCH-7 (Tullow 100%) The Ketch-7 horizontal production well, the second of the Schooner-Ketch redevelopment programme, was spudded on 2 June 2006 and, having encountered 540 feet of net pay, has been completed and tested on schedule at a rate of 45 mmscfd. The well, which encountered higher than expected reservoir pressures, will now be connected to the Ketch production facilities and first production through the Tullow-owned CMS infrastructure is scheduled to commence in early October. The addition of Ketch-7 is expected to increase the production capability of Schooner and Ketch to over 100 mmscfd. The forward programme includes the 3,000 foot horizontal Ketch-8 well which commenced drilling on 18 September, followed by Ketch-9. Concurrent with the drilling, well stimulation and remedial operations are in progress on other Ketch wells to further enhance production. SCHOONER NW APPRAISAL WELL (Tullow 90.35%) The NW Schooner appraisal well, targeting an extension of the main Schooner field, has encountered gas bearing reservoir sands. The section has been logged and indicates a net pay of some 275 feet. The well is now being completed for testing which is expected to commence at the end of September. Should the test yield commercial flow rates, the well will be suspended and the pipeline laid for tie-in to the Schooner platform in mid-2007. Commenting today, Aidan Heavey, Chief Executive of Tullow said: 'We are very pleased with the progress to date on the Schooner-Ketch redevelopment programme and the encouraging results from the NW Schooner appraisal well. Since acquiring the fields in early 2005 we have significantly improved reliability and uptime and are now materially enhancing production and reserve potential. With the ongoing strength of UK gas pricing we are seeing excellent returns from these assets.' For further information contact: Tullow Oil plc Citigate Dewe Rogerson Murray Consultants (+44 20 8996 1000) (+44 20 7638 9571) (+353 1 498 0300) Martin Jackson Joe Murray Aidan Heavey Tom Hickey Chris Perry 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 250 Index. The Group has interests in approximately 90 exploration and production licences across 17 countries and focuses on three core areas: NW Europe, Africa and South Asia. Tullow's NW Europe 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/Hewett areas and operates over 60% of its production. In Africa, Tullow has exploration and production in Gabon, Cote d'Ivoire, Congo (Brazzaville) and Equatorial Guinea and a large gas field development and appraisal programme in Namibia. Tullow also has exploration programmes in Mauritania, Senegal, Cameroon, Uganda, Congo (DRC), Madagascar, Angola and Ghana. In South Asia, Tullow has exploration and production in Pakistan and Bangladesh and high impact exploration activities in India. For further information please refer to our website at www.tullowoil.com ENDS This information is provided by RNS The company news service from the London Stock Exchange FBKDACD

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