* Firms hope Angola's pre-salt finds to match Brazil's
* Well produces over 3,700 bpd, 16.3 mln cm per day
* Find is fifth by Cobalt in Angola
By Shrikesh Laxmidas
LUANDA, May 1 U.S. firm Cobalt International Energy has discovered significant quantities of oil offshore Angola, state oil firm Sonangol said, calling the find the biggest so far in the promising pre-salt layer in the Kwanza Basin.
Oil drillers hope discoveries under a deep submerged salt crust off Angola known as pre-salt may match the prolific finds beneath similar deposits off Brazil on the other side of the Atlantic in recent years.
Analysts say Angola, Africa's No. 2 oil producer, could double its oil reserves, which are currently estimated at just under 13 billion barrels, if pre-salt drilling proves successful.
Drilling at Cobalt's Orca-1 well in Block 20/11 reached a depth of 3,872 metres and has successfully produced over 3,700 barrels of oil and 16.3 million cubic metres of gas per day, Sonangol said in a statement on Thursday.
"The results ... confirm the importance of the find, which is considered the biggest to date in the Kwanza basin," it added.
Cobalt estimates the well may hold between 400 million and 700 million barrels of oil.
Operator Cobalt, which counts Goldman Sachs Group and private equity firms Riverstone and First Reserve as investors, holds a 40 percent stake in block 20/11. Sonangol and BP own 30 percent each.
Cobalt said in a separate statement that the find was its fifth off Angola and followed one in the Lontra well in November, which it said at the time was "a discovery on a global scale".
The company also said it had started drilling the Cameia-3 well in the Cameia field in Angola's pre-salt offshore Block 21.
Analysts say 2014 will be a crucial year of exploration and testing in Angola's pre-salt play, with up to 15 wells set to be drilled. (Reporting by Shrikesh Laxmidas; editing by Jane Baird)