Equatorial Atlantic drilling update

Published on: 15 October 2009

Tullow Oil plc (Tullow) announces that the Mahogany-4 appraisal well has successfully encountered 43 metres of net pay and the South Grand Lahou-1 well encountered the targeted reservoir sands on prognosis but found them water-bearing at that location.

Mahogany-4 appraisal well offshore Ghana extends Jubilee field eastwards

The Mahogany-4 appraisal well, located in the West Cape Three Points licence offshore Ghana, has intersected light oil columns in sandstone reservoirs. In total, 43 metres of net hydrocarbon pay have been penetrated.

Mahogany-4 is the eastern-most well on the Jubilee field to date and has been drilled to evaluate its lateral extent and to explore deeper potential reservoir targets.

Results of drilling, wireline logs and samples of reservoir fluid confirm that the Jubilee field extends beyond this location, which is 3.3 kilometres southeast of Mahogany-2 and 3.8 kilometres northeast of Mahogany-3. Oil bearing sands have been encountered on prognosis with 15 metres of net pay in the main Jubilee reservoirs.

Below the main Jubilee reservoirs, the well has intersected 20 metres of net oil pay in a new sand, a 4 metre wet gas sand and 4 metres of net oil pay in Mahogany Deep-aged reservoirs. The potential of these underlying reservoirs will be investigated with further exploratory wells in the area.

Mahogany-4 was drilled by the Atwood Hunter semi-submersible rig to a depth of 3,680 metres in a water depth of 1,079 metres. Following the conclusion of operations, the rig will move to drill the J-03 Jubilee development well.

Also in the West Cape Three Points licence, approximately 5 kilometres southwest of the Mahogany-4 well, the Aban Abraham drillship has commenced drilling Mahogany Deep-2. The well will appraise the field’s southern extent and a result is expected in November.

Tullow has a 22.896% interest in the West Cape Three Points licence and its partners are Kosmos Energy (Operator) and Anadarko Petroleum Corporation, (30.875% each), the E.O.Group (3.5%), Sabre Oil & Gas (1.854%) and the Ghana National Petroleum Corporation (GNPC) (10% carried interest).

South Grand Lahou-1 wildcat result

The South Grand Lahou-1 wildcat has been drilled offshore Côte d’Ivoire in the CI-105 licence. It encountered the targeted reservoir sands on prognosis but found them water-bearing at this particular location. However, the data gained will provide valuable proprietary insights into the ongoing prioritisation of the numerous Jubilee-type prospects in the Equatorial Atlantic inventory.

South Grand Lahou-1 was drilled by the Belford Dolphin drillship to a depth of 4,556 metres in a water depth of 1,876 metres.

Tullow has a 22.368% interest in the CI-105 licence and its partners are Anadarko Petroleum Corporation (Operator, 50%), Thani Côte D’Ivoire (12.632%) and the Societé Nationale d’Opérations Pétrolières de Côte D’Ivoire (Petroci) (5% plus a 10% carried interest).

Commenting today, Angus McCoss, Exploration Director, said:

“Extending the Jubilee field eastwards with the Mahogany-4 well and encountering new hydrocarbon bearing reservoirs is an excellent result and strongly supports our current interpretation of the Jubilee field resources. We look forward to drilling the two remaining wells in the current Jubilee appraisal programme by early next year to further refine our understanding of the upside potential.

“The South Grand Lahou-1 wildcat follows a remarkable opening run of 10 successful exploratory wells in our Equatorial Atlantic licences. This well found the reservoirs to be water-bearing at this location but provides critical knowledge to guide the forward programme which targets a number of Jubilee-like prospects in this exciting play fairway.”

For further information contact

  • Tullow Oil plc

    • Chris PerryInvestor Relations
    • Nicola RogersInvestor Relations
    • George CazenoveMedia Relations
    • London

  • Murray Consultants

    • Pat Walsh
    • Joe Heron
    • Dublin

Notes to editors

Tullow is a leading independent oil & gas, exploration and production group, quoted on the London, Irish and Ghanaian stock exchanges (symbol: TLW). The Group has interests in over 80 exploration and production licences across 15 countries which are managed as three Business Teams: West Africa, East Africa and New Ventures.