By OGJ editors
HOUSTON, Sept. 18 -- BP Exploration (Angola) Ltd., on behalf of Angola's national oil company Sonangol EP and other partners, reported the Plutão oil discovery in ultradeepwater Block 31 off Angola, 248 miles northwest of Luanda. This is the second exploration well BP has drilled on Block 31, which lies in 4,922-8,203 ft of waterand covers an area of 5,349 sq km.
The Leiv Eiriksson semisubmersible drilling rig drilled Plutão-1 in 6,628 ft of water and reached a TD of 14,607 ft subsea. The well was tested through a 48/64-in. choke at a maximum rate of 5,357 b/d of oil. BP said further work would be required to more fully evaluate the extent of the Plutão discovery.
Sonangol awarded Block 31 in 1999 to BP—operator with a 26.67% equity—and its partners: ExxonMobil Corp. unit Esso Exploration & Production Angola 25%, Sonangol 20%, Statoil Angola AS 13.33%, Marathon Angola Petroleum Ltd. 10%, and TotalFinaElf SA unit EPA Ltd. 5%.
Deepwater potential
Plutão marks the first ultradeepwater discovery following numerous deepwater finds off Angola. The deepwater area off Angola is thought to be one of the most prolific regions in the world for new, light oil discoveries. Oil found to date has an API gravity of 32-39.5° and sulfur content of 0.12-0.14%.
Significant discoveries of major oil fields are on Block 14: Kuito and four others; Block 17: Girassol, Rosa, Dalia, Lirio, and six other finds; and Block 15: Kissanje, Marimba, Hungo, and nine other finds. Dalia field, which has an estimated 1 billion bbl in estimated reserves, will be developed using a floating production, storage, and offloading vessel as will Girassol field, which has an estimated 725 million bbl of reserves.
"A number of discoveries have been made on both Block 17 and Block 15, so it's gratifying that one has also been found on (ultradeepwater) Block 31," said Morten Rye-Larsen, Statoil's exploration manager for western Africa. "Girassol on Block 17 (TotalFinaElf, operator) came on stream last December and is producing as expected, while field development is now under way on Block 15," he added.
ExxonMobil's Esso operates deepwater discoveries on Block 15, which is 22 miles east of Plutão.
BP also operates the Greater Plutonio project on Block 18, a 50:50 joint venture with Royal Dutch/Shell Group. Front-end engineering and design is currently under way on that project.
On another ultradeepwater development off Angola, the initial well on TotalFinaElf-operated Block 32—the Gindungo (ultradeepwater) prospect—would be drilled in the fourth quarter, according to partner Marathon.
"The ultradeep offshore is a very large acreage—nearly virgin," said TotalFinaElf. "The work has been focused so far on some limited areas (20% of Blocks 31, 32, and 33) for seismic imaging and timing reasons. The huge efforts in seismic reprocessing presently in progress and further studies will mature the exploration potential."
TotalFinaElf holds a 30% interest in Block 32; its partners are Sonagol 20%, Prodev International Ltd. 20%, Esso 15%, Marathon 10%, and Petroleos de Portugal (Petrogal SA) 5%.
Esso operates ultradeepwater Block 33 with 45%, and its partners are Sonagol 20%, TotalFinaElf 15%, Falcon Oil Holding SA (Panama) 10%, NIR Angola Block 33 LLC 5%, and Petrogal 5%.
Sonangol itself operates Block 34, also ultradeep. The company holds a 20% interest and is partnering with Norsk Hydro AS 30%, which is providing technical assistance, Phillips Petroleum Co. (Now ConocoPhillips) 20%, Petroleo Brasileiro SA 15%, and Shell 15%.
Block 16 PSA awarded
The success of Angola's offshore discoveries has sparked increasing interest in its exploration blocks. Sonangol recently entered into a production-sharing agreement, effective Sept. 1, with CNR Ranger (Angola) Ltd., the wholly owned subsidiary of Canadian Natural Resources Ltd., Calgary, for an initial 4-year exploration of Block 16, which is in waters 985-4,920 ft deep.
Canadian Natural will operate the 1,219,831-acre block and retain a 50% working interest in it. CNR is partnering with Odebrecht Oil & Gas Angola Ltd. 30%, and Sonangol 20%.
"We have interpreted the 3D seismic data for the block and have selected two locations for drilling sometime over the next 2 years," Canadian Natural's Chairman Allan Markin said. "We believe the targets selected to date, based on our geological interpretation and 3D seismic, are significant world-class prospects," he said.
In addition to the four ultradeep concessions already licensed, there is reason to believe Angola will also open additional blocks in the ultradeep Kwanza basin. The country, largely due to its offshore reserves, has become sub-Saharan Africa's second largest oil producer behind Nigeria.
