ONGC Videsh Ltd, the overseas arm of state-run Oil and Natural Gas Corp, has acquired stake in two oil blocks in Sudan for $136 million.

"OVL has bought out 26.125 per cent stake in exploration block 5A and 24.5 per cent stake in block 5B from Austria's OMV for $136 million," company sources said.

OVL will pay $102 million for block 5A and the balance $34 million for the other block.

The two sides have been in negotiations in London and Vienna for the past four months, sources said adding a deal to acquire the Austrian firm's stake was signed on Saturday.

The deal will now be vetted by Khartoum.

OVL already owns a 25 per cent stake in the Greater Nile Petroleum Operating Company in Sudan, which it bought from Talisman Energy of Canada earlier this year.

Earlier, OMV entered into an agreement by which OVL was given the exclusive right to sign the sale and purchase agreement by August 15.

The Empowered Committee of Secretaries -- comprising representatives of the ministries of petroleum, finance, law and external affairs -- had approved the deal in early August.

Block 5A, which has the undeveloped Thar Jath field with gross proven and probable oil reserves of 149.1 million barrels, has Petronas Carigali Overseas Sdn Bhd of Malaysia as operator with 68.875 per cent stake.

Austrian oil and chemical group OMV holds 26.125 and Sudan's national oil company Sudapet the remaining 5 per cent.

In Block 5B, Petronas has 41 per cent, Sudapet 10 per cent, OMV 24.5 per cent and Swedish oil concern Lundin Petroleum AB 24.5 per cent.