DUBAI, July 10 (Reuters) - Saudi oil giant Aramco was set to raise $6 billion from its first bond issuance in three years, a document showed on Wednesday.

Aramco was set to sell $2 billion in 10-year bonds at 105 basis points (bps) over U.S. Treasuries, $2 billion in 30-year bonds at 145 bps over UST and $2 billion in 40-year bonds at 155 bps over UST, according to the document from one of the banks arranging the sale indicating the deal's final terms.

Demand for the three tranches topped $31.5 billion.

(Reporting by Yousef Saba Editing by Chris Reese)