(Adds details, estimates on reserves)
LUANDA, April 14 (Reuters) - Angola will start the tenderprocess for onshore oil exploration at 10 new blocks in theCongo Basin and Kwanza Basin on May 30, state oil firm Sonangolsaid on Monday.
Companies that want to take part in the tender must submitdocumentation on their business structures, activities andfinances by April 30 to enter the pre-qualifying stage, Sonangolsaid in a statement.
Angola, Africa's biggest oil producer after Nigeria,extracts nearly all its crude from offshore fields, but isseeking to develop its onshore potential.
Sonangol said in February that the 10 blocks may hold, onaverage, reserves of 700,000 barrels of oil each. The governmentputs Angola's total reserves at just under 13 billion barrels.
Seven of the new blocks are in the Kwanza basin and three inthe Congo Basin.
Angola produced 1.73 million barrels of oil per day onaverage last year, with major international firms such asFrance's Total, Britain's BP and Chevron of the United States among the leading operators.
Sonangol said on Monday that firms already operating inAngola would not be exempt from submitting documents for thepre-qualifying stage for the new onshore blocks. (Reporting by Shrikesh Laxmidas; Editing by Ed Cropley)