2009 will be remembered for its significant offshore oil and gas discoveries worldwide. Of the 10 top discoveries for the year, two were made in the GOM, two were found off Australia, and one each off Brazil, China, Israel, the UK, Venezuela, and West Africa.
Tweneboa & Sankofa
Two discoveries in 2009 are likely to be tied back to Ghana’s Jubilee field, one of West Africa’s biggest oil fields, which is estimated to contain recoverable reserves of 1.2 billion barrel of oil equivalent (bboe). Jubilee is being developed via a Floating Production Storage and Offloading (FPSO). First production is expected in late 2010.
Jubilee is located on two licenses, Deepwater Tano and West Cape Three Points.
The first of two additional discoveries in the area, Tweneboa, is in the Deepwater Tano License which was drilled by the Eirik Raude semisbumersbile in March 2009, is in 3,766 ft of water.
Tullow, the operator, holds a 49.95% interest with Kosmos Energy 18%, Anadarko 18%, Sabre Oil & Gas 4.05%, and the Ghana National Petroleum Corp. 10%.
The second is the Sankofa oil and gas field, which was drilled by the Blackford Dolphin semi-submersible, and in 2,841 ft of water in the Cape Three Points Block.
Vitol Group operates the discovery with a 90% interest and Ghana National Petroleum Corporation (GNPC) holds the remaining 10%.
Carna exploration gas well, which was drilled by Venture Production, completed in March.
The well tested at a gross rate of 9 Million Cubic Feet per Day (MMcf/d) on a 48/64th choke from a vertical well penetrating the Carboniferous formation.
Venture Production operates the well with 56% interest.
Liwan 3-1 field, which was drilled by West Hercules semi-submersible, is located on Block 29/26 in the South China Sea.
The major discovery was announced by Husky Energy in February.
Husky operates the field with China National Offshore Oil Corporation (CNOOC), which has the right to participate in the development for up to 51% working interest.
Gulf of Mexico:
Buckskin well started Chevron’s major oil discoveries this year, located about 44 mile (mi) west of Chevron’s 2004 Jack discovery.
Buckskin was drilled by The Stena DrillMax drillship, and Chevron operates the field with a 67.5% working interest, while Repsol holds 12.5% and Maersk 20%.
BP also saw a major discovery; Tiber Prospect was drilled in Keathley Canyon, and on Block 102.
Tiber, which was drilled by Transocean’s Deepwater Horizon semi-submersible, is said to likely contain more than 3 Bbbl of oil.
BP operates Tiber with a 62% percent working interest with co-owners Petrobras 20% and ConocoPhillips 18%.
Abare West well was discovered by Petrobras in September. Abare West is in 2,163 m of water and was proved via oil, natural gas, and carbon gas content sampling via a cable test carried out in reservoirs at 5,000 m deep.
Petrobras operates the Abare West well with 45% with partners BG Group 30% and Repsol 25%.
The perla field was discovered in shallow waters of the Gulf of Venezuela on the Cardon IV block in September. Perla is considered as the largest gas discovery in Venezuela and may be one of the world’s largest natural gas discoveries.
A Joint Operating Company equally shared by Eni and Repsol operates the Cardón IV block. Petróleos de Venezuela S.A. owns a 35% back-in right in the development phase and, if exercised, Eni and Repsol will each hold a 32.5% interest in the project.
Joint Venture of Karoon Gas announced the ignificant discovery, Poseidon, in the Browse Basin offshore Western Australia.
The Sedco 703 semisubmersible drilled Poseidon-1, which is operated by ConocoPhillips. Poseidon-1 is the first well in a multi- well drilling program in the Browse Basin permits WA-314-P, WA-315-P, and WA-398-P.
The WA-314-P, WA-315-P wells are owned by Karoon Gas Australia Ltd. 49% and ConocoPhillips 51%. WA-398-P is owned by ConocoPhillips 60% and Karoon Gas Australia Ltd 40%.
Greater Pluto Project / Martell
Woodside made a discovery in the Greater Pluto Project in Western Australia’s Carnarvon Basin. The Martell-1 exploration well in permit WA-404-P indicated a gross gas column of about 110 m in good quality reservoir sandstones.
Woodside operates WA-404-P with a 50% interest and Hess Exploration (Carnarvon) Pty Ltd. holds the remaining 50%.