Saudi Aramco has invited bids for the construction of a new refinery in Jizan, an underdeveloped province bordering Yemen, industry sources said.
Aramco has also asked for revised offers for one of nine construction packages to expand the Rabigh petrochemical complex with Sumitomo Chemical, they said on Thursday.
The refinery in Jizan will have a capacity of 400,000 barrels per day and is far from oilfields on the Gulf coast.
Expected to be in operation in 2016, the refinery is part of plans by Aramco, increasingly looking to expand in downstream activities, to raise its domestic refining output capacity to 3.5 million bpd by 2016.
Bidding for the nine Jizan packages - including a hydrocracker, diesel hydrotreater, hydrogen production unit, crude distillation unit, vacuum distillation unit, and other units - was due to close mid-August, sources said.
Aramco and Sumitomo asked bidders to revise their proposals for a package called CP1 for cumene, phenol and cyclohexanone by May 30 with bidding validity due at the end of June.
The revision is due to the cancellation of the CP2 package for caprolactam and Nylon-6, as CP1 provides feedstock for the cancelled package.
South Korean group Daelim Industrial had submitted the lowest bids for CP1.
Sources said last week, British company Petrofac and South Korea group Engineering and Construction (006360.KS) were among contractors that will be part of building the second phase.