Abu Dhabi Oil Refining Company (Takreer) has been forced to delay the bid deadlines for the two main construction deals on its estimated $8bn expansion of the Ruwais refinery.

The state firm had originally asked companies bidding on the engineering, procurement and construction (EPC) contracts to submit bids by the end of September. Contractors say it has extended the deadline for the deals until 21 October, after numerous requests from bidders.

“We needed more time to get our prices together and really get a good feel together for how much the project was going to cost,” says a senior executive at one of the bidding firms.

Firms handed in technical bids on 19 August to explain how they would carry out the engineering work.

The expansion will increase the Ruwais facility’s capacity by 400,000 barrels a day (b/d) to 817,000 b/d when it starts operating in 2014.

The winner of the first contract will build the crude distillation unit at the plant. The unit breaks down crude oil into its components, such as the petroleum product naphtha and basic chemical benzene. Bidders include SK Engineering & Construction of South Korea, Japan’s Toyo, Italy’s Tecnimont and Spain’s TR.

The winner of the second contract will build the residual fluid catalytic cracker, which breaks up the heavier components of crude oil to produce more valuable petroleum products.

The bidders for this contract include South Korea’s GS Engineering & Construction, Japan’s JGC, Italy’s Saipem, France’s Technip, and the UK’s Petrofac.

Commercial bids for the three remaining infrastructure deals on the plant are due on 23 October.