10 January 2011 – Dana Petroleum, the operator of the Cormoran-1 exploration well in Mauritania, in which Tullow Oil plc (Tullow) is a 16.20% partner, today issued the following press release:
10 January 2011 – Dana Petroleum advises that the Cormoran-1 exploration well has been drilled to a total depth of 4,695 metres below sea level and has been plugged and abandoned as a gas discovery. Stabilised gas flow rates of between 22 and 24 million standard cubic feet per day (MMscfpd) were obtained during a test of one of the four separate gas columns encountered by the well.
The Cormoran-1 exploration well is located in Block 7, offshore Mauritania. It lies approximately 2km to the south of the Pelican-1 gas discovery well, which was drilled in late 2003. The well was drilled by Dana Petroleum, as Operator of Block 7, using the Maersk Deliverer deep water semi-submersible drilling rig. Water depth at the well location is approximately 1,630m.
The primary purpose of the Cormoran-1 well was to test the Cormoran prospect, which adjoins but lies at a greater depth than the Pelican discovery. A secondary exploration objective was the Petronia prospect, which lies beneath the Cormoran prospect. A further objective of the well was to provide appraisal information on the Pelican gas discovery.
The Cormoran-1 well encountered generally thin but good quality, gas-bearing, sands within the Pelican Group at depths between 3,376m and 3,711m true vertical depth subsea (TVDSS). This interval comprised two gas columns, one in the Upper Pelican Group (3,376 to 3,420m TVDSS) and one in the Lower Pelican Group (3,691 to 3,711m TVDSS).
Good quality, gas-bearing, sands were also encountered within the Cormoran prospect, in the gross interval from 4,351 to 4,471m TVDSS, and at the top of the Petronia prospect, in the gross interval from 4,660m to 4,695m TVDSS.
Drilling was stopped at a depth of 4,695m TVDSS for operational reasons (elevated pore pressures). The well was still in gas-bearing reservoir section at this depth.
A drill stem test was carried out across a 33m interval in the Lower Pelican Group (3,679 to 3,712 TVDSS). Stabilised flow rates of up to 22 to 24 MMscfpd were obtained on a 32/64” choke, the flow rate being constrained by the need to avoid sand production. Substantially higher flow rates could have been achieved were it not for this operational constraint.
Following the DST, the Cormoran-1 well was plugged and abandoned, this being done in such a way that the well could be re-entered in the future.
Participating interests in Block 7 are:
Dana Petroleum (E&P) Limited (Operator) 36.00%
GDF SUEZ Exploration Mauritania B.V. 27.85%
Tullow Petroleum (Mauritania) Pty Ltd 16.20%
C Mauritania I Pty Ltd 15.00%
Roc Oil (Mauritania) Company 4.95%
Dana Petroleum is a wholly owned subsidiary of the Korean National Oil Corporation (KNOC).
FOR FURTHER INFORMATION CONTACT:
Tullow Oil plc
(+44 20 8996 1000)
Angus McCoss
Chris Perry
James Arnold
Citigate Dewe Rogerson
(+44 207 638 9571)
Martin Jackson
George Cazenove
Murray Consultants
(+353 1 498 0300)
Joe Murray
Ed Micheau
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 100 Index. The Group has interests in over 85 exploration and production licences across 22 countries and focuses on four core areas: Africa, Europe, South Asia and South America.
In Africa, Tullow has production in Gabon, Côte d’Ivoire, Mauritania, Congo (Brazzaville) and Equatorial Guinea and two large appraisal and development programmes in Ghana and Uganda. Tullow also has exploration interests in Gabon, Côte d’Ivoire, Liberia, Sierra Leone, Mauritania, Senegal, Congo (DRC), Tanzania, Madagascar, Namibia and Ethiopia.
Tullow’s European 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 area. The company also has interests offshore the Netherlands.
In South Asia, Tullow has exploration and production in Bangladesh and exploration interests in Pakistan. In South America, Tullow has exploration interests in Guyana, French Guiana and Suriname.
For further information please refer to our website at www.tullowoil.com.