Foreign engineering firms have started to bid for the construction of the process packages related to Saudi Aramco's Shaybah natural gas liquids (NGL) project, which is estimated to cost $5 billion to $6 billion, industry sources said.

Shaybah NGL is one of two new gas projects the state oil giant plans to develop as it needs to boost gas output to meet rising domestic demand.

Aramco completed last year a massive crude expansion programme which included increasing capacity at Shaybah oilfield to 750,000 barrels per day (bpd). The other gas plant, Wasit would be the kingdom's largest.

Shaybah NGL is designed to process 2.4 billion cubic feet per day (cfd) of low-sulphur sweet gas and extract 264,000 bpd of NGL which will be shipped to Juaymah Gas Plant for further fractionation, Aramco said in the summer edition of its Dimensions International magazine.

Aramco has set December 4 as a deadline for companies to submit their proposals, industry sources said.

The project calls for the construction of a cogeneration facility, a gas treatment facility, an NGL recovery plant and facilities to handle gas.

'Development of the related Shaybah NGL Plant is well under way, with construction scheduled to start in summer 2011 and completion projected for fall 2014,' the magazine said.

South Korea's GS Engineering, SK Engineering, Samsung Engineering, France's Technip, Canada's SNC Lavalin and Italy's Saipem are among companies bidding for the three process packages.

Bids for the first package of work - a cogeneration plant - are due on November 22. Tenders for the engineering, procurement and construction (EPC) contracts are expected to be awarded in 2011, the magazine said.

US engineering firm KBR is conducting engineering and design work and provides project management services for the plant.-Reuters