Angola's subsalt oil reserves may resemble Brazil's

Geological similarities between Angola's and Brazil's subsalt areas suggest that future exploratory drilling on Angola's continental shelf may one day find oil reserves similar to Brazil's recent large discoveries, a Sonangol scientist said. Sonangol, Angola's state oil firm, has started preliminary studies into Angola's subsalt region over the last several months. The company is now preparing for seismic and other geological studies -- expected to cost hundreds of millions of dollars -- to assess the size of reserves in the country's subsalt region, said Luman Sebastiao, a geoscientist for Angola state oil firm Sonangol's exploration unit.

The first exploratory drilling of Angola's subsalt area may occur within three or four years, Sebastiao told, while attending the fourth Organization of Petroleum Exporting Countries International Seminar in Vienna. Angola's oil minister is OPEC's current president. "The Angolan and the Brazilian continental shelves have various similarities as they have been joined for a certain geological period," Sebastiao said.

Brazilian state-run oil firm Petroleo Brasileiro in the past two years has announced several massive oil finds in the subsalt area off Brazil's coast that together contain dozens of billions of barrels in reserves. Oil found in the area is usually at water depths of around 2,000 meters, and several thousand meters further below layers of sand, rocks and salt -- making exploration and production challenging and expensive. Angola's subsalt reserves could be "gigantic," and even as big as Brazil's, Sebastiao said, though he acknowledged Angola's subsalt exploratory drilling hasn't yet begun.

The subsalt is Angola's next exploration front, after deep and ultra-deep exploration, Sebastiao said, adding that unlike in Brazil, Angola's subsalt region is found both onshore and offshore. Angola's onshore subsalt region lies about 4,000 meters below the ground, while the offshore subsalt region lies even deeper, Sebastiao said. Brazil's Petrobras has been helping Sonangol in starting to study its subsalt region, and many Sonangol technicians have been trained in the area in Brazil, Sebastiao said. "Petrobras is our great example in this area," the Sonangol scientist said.
Angola's studies into its subsalt area at first are concentrating on the Kwanza onshore and offshore basin, and the Congo basin. At a later stage, Angola will study more southern regions (Fonte: Gas and Oil / Rigzone, 2009-03-18).