Tullow Oil Regulatory News (TLW)

News Release

Kenya exploration and appraisal update

11 March 2015 - Tullow Oil plc (Tullow) provides an update on exploration and appraisal activities in onshore Kenya Block 10BB, 13T and Block 10BA.

Engomo-1 exploration well

The Engomo-1 exploration well in Block 10BA was drilled to a total depth of 2,353 metres utilising the SMP-106 rig. The well encountered interbedded sandstones, siltstones and claystones but no significant oil or gas shows were encountered and the well has been plugged and abandoned. Engomo-1 was the first well drilled in the large North Turkana Basin and is located west of Lake Turkana where numerous naturally occurring oil slicks and seeps have been observed. Analysis is being focused on high-grading the remaining prospectivity in the basin. The SMP-106 rig will now be demobilized.

South Lokichar Basin appraisal activity

Tullow is continuing its extensive exploration and appraisal programme in the South Lokichar Basin in Blocks 10BB and 13T, which has the joint objectives of proving reservoir quality and defining the resource estimates to ultimately progress the development of the discovered resources.

The SMP-5 rig recently installed well completions in Amosing-1 and Amosing-2A in preparation for an Extended Well Test ("EWT") of the field and the rig has now been released. The EWT involves test production and injection to provide dynamic flow characterisation of the Amosing stacked oil reservoirs. Both wells have been completed in five zones with hydraulically controlled selective completions that permit independent tests of selected intervals without well intervention. Initial rig-less clean-up testing has been concluded on both wells with excellent results. The Amosing-1 well flowed at a combined maximum rate of 5,600 bopd from five zones and the Amosing-2A well flowed at a combined maximum rate of 6,000 bopd from four zones, the fifth zone being in the aquifer. Both wells demonstrated high quality reservoir sands and flowed 31 to 38o API dry oil under natural flow. Pressure data during the initial clean-up flows shows connectivity between the two completed wells in the upper three zones with further production testing required to test connectivity in the lower two zones. These findings support the static pressure data which indicated connectivity between the Amosing-1, 2, 2A and 3 wells in multiple zones. The Amosing EWT forward programme is to conduct longer-term oil flow and water injection tests, commencing mid-March with results expected in the second quarter of this year.

The PR Marriott 46 rig recently drilled the Ngamia-7 appraisal well to a final depth of 2,914 metres. The well was drilled to test the Ngamia oil field's eastern flank and was located 1,800 metres north-east of Ngamia-1 and 1,300 metres east of Ngamia-3. The well encountered up to 132 metres of net oil pay and has expanded the proven extent of the field. The well has now been suspended for future use. Static pressure data from the Ngamia-1, 3, 5, 6 and 7 wells supports connectivity between the wells at multiple reservoir horizons which will be tested with the planned Ngamia EWT.

Planning is also under way to conduct an EWT of the Ngamia field. The PR Marriott 46 rig, which is currently drilling the Amosing-4 well with a result expected in April, will mobilize back to the Ngamia field to drill and complete the Ngamia-8 well which will be the main producer for the EWT. Additionally, two of the existing suspended Ngamia wells will be completed as EWT wells. Initial flow testing of the Ngamia EWT wells is expected to commence around mid-year.

The Weatherford 804 rig is currently drilling the Ekales-2 appraisal well to test an eastern fault block on the structure and also test a deeper exploration objective within the Lokhone shale source rock that has tested oil elsewhere in the basin. The well is currently at a depth of 2,817 meters and has drilled through the primary objective and encountered 50 to 70 metres of potential net oil pay. Final results from the well should be available in April. Following completion of this well, the Weatherford 804 rig will be released.

Finally, the 3D seismic survey data set over along the western basin bounding fault discoveries has been processed and is being interpreted. These data already indicate significantly improved structural and stratigraphic definition and additional prospectivity not evident on the 2D seismic.

Tullow Operates Blocks 10BB, 13T and 10BA with 50% equity and is partnered by Africa Oil Corporation, also with 50%.

Commenting today, Angus McCoss, Exploration Director, said:

"Whilst we would have hoped for basin opening success in the North Turkana Basin's first wildcat well, Engomo-1, we still have a vast amount of undrilled acreage with identified prospects and leads providing significant remaining exploration potential.

"There is further good news from our appraisal programme in Northern Kenya where the Ngamia-7 well has successfully tested and extended the eastern flank area of the oil field. This result, and the promising initial flows from the Amosing oil field extended well test, give us further confidence in the size and scale of our two cornerstone fields for the development of the South Lokichar Basin. The results to date from Ekales-2 are also very encouraging and we are very pleased with the results from the 3D seismic survey which reveals there is important additional prospectivity in this exciting new oil province."

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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 130 exploration and production licences across 22 countries which are managed as three regional business units: West & North Africa, South & East Africa and Europe, South America and Asia.

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