The state oil major has not disclosed information about an adviser, and is dealing directly with lenders.
It has asked relationship banks to submit offers on three-, five- and seven-year terms.
Pricing for Aramco borrowing tends to be very low due to the state support enjoyed by the oil company as well as its size. In early 2015, the rates on its $10bn revolving credit facility gave lenders a tiny margin of between 13 and 16 basis points, according to Bloomberg.
Due to liquidity concerns in the GCC, pricing has risen in the past six months, but will still be relatively low.
Aramco and Chinas Sinopec formed a joint venture, Yanbu Aramco Sinopec Refining Company (Yasref), to build the $10bn 400,000 barrel-a-day refinery. It was completed in 2014.
Aramco has a 62.5 per cent equity stake in Yasref, with Sinopec owning the remainder.
Yasref did not respond to a request for comment.