Saudi Aramco and Dow Chemicals are expected to award the engineering, design and project management contracts for the giant Ras Tanura petrochemical plant by the end of July, industry sources said.

Dow's investment in the plastics and chemicals plant would be the largest foreign investment to date in the Saudi energy sector.

Ras Tanura, a joint venture with Aramco, would be one of the biggest plants of its kind worldwide to be built from scratch and has an estimated cost of over $20 billion.

US engineering and construction companies KBR, Flour and Foster Wheeler were competing for the front-end engineering and design (FEED) and project management contracts for Ras Tanura, sources said.

'The companies were expecting to hear the outcome before the end of the month,' said one source.

The FEED contract would be worth around $130-$140 million, sources said.

Dow and Aramco signed a memorandum of understanding to build the plant in May. The companies plan to float a 30 per cent stake in Ras Tanura.

Dow is the largest US chemical maker by sales. Reuters