A bond sale by energy giant Saudi Aramco to raise $10 billion towards its purchase of a controlling stake in chemicals behemoth SABIC closes Wednesday, Riyadh's energy minister said.

Khalid al-Falih told an energy conference in the Saudi capital yesterday that international investors had so far made bids totalling three times the value of the bonds.

"The bond issue is at a very critical stage. The roads how is ongoing (and) the deal will close on Wednesday," said Falih, who is also chairman of state-owned Aramco, the world's largest energy company.

The firm announced last month it was buying a 70-per cent stake in SABIC from Saudi Arabia's main sovereign wealth fund, the Public Investment Fund, for $69.1 billion.

Aramco made $111 billion in net profit last year, making it the most profitable company in the world. It said it will pay for most of the SABIC purchase in cash.