Petro Rabigh estimated that project cost to be between $6bn-$8bn.
Saudi Aramco is planning to secure funding for the project for which feasibility studies have been completed.
The Petro Rabigh complex has been designed to produce 2.4 million tonnes of petrochemical solids and liquids, along with large volumes of gasoline and other refined products.
Previously, Aramco and Sumitomo entered into a deal on the plant expansion in 2009 although contracts were scheduled to be announced last year.
Saudi Aramco which holds a 37.5% stake in Petro Rabigh, while Japan’s Sumitomo Chemical Company has 37.5% and the Saudi Arabian public holds the remaining 25%.
