Angola to launch tender for 10 new onshore oil blocks on May 30

(Adds details, estimates on reserves)

LUANDA, April 14 (Reuters) - Angola will start the tender process for onshore oil exploration at 10 new blocks in the Congo Basin and Kwanza Basin on May 30, state oil firm Sonangol said on Monday.

Companies that want to take part in the tender must submit documentation on their business structures, activities and finances by April 30 to enter the pre-qualifying stage, Sonangol said in a statement.

Angola, Africa's biggest oil producer after Nigeria, extracts nearly all its crude from offshore fields, but is seeking to develop its onshore potential.

Sonangol said in February that the 10 blocks may hold, on average, reserves of 700,000 barrels of oil each. The government puts Angola's total reserves at just under 13 billion barrels.

Seven of the new blocks are in the Kwanza basin and three in the Congo Basin.

Angola produced 1.73 million barrels of oil per day on average last year, with major international firms such as France's Total (NYSE: TOT - news) , Britain's BP (LSE: BP.L - news) and Chevron (Amsterdam: CHTEX.AS - news) of the United States among the leading operators.

Sonangol said on Monday that firms already operating in Angola would not be exempt from submitting documents for the pre-qualifying stage for the new onshore blocks. (Reporting by Shrikesh Laxmidas; Editing by Ed Cropley)