Under the contract, Petrofac will be responsible for the construction of six sulphur recovery trains.

The trains are expected to have additional facilities for sulphur and heavy duty oil handling, loading, unloading and storage, as well as a sour water stripper, flare system and waste water treatment plant.

Petrofac engineering, construction, operations and maintenance division CEO Marwan Chedid said: "This award builds on our portfolio of projects in the kingdom, and we are delighted to have been selected by Saudi Aramco to be part of the strategically important Fadhili gas programme.

"Petrofac has a strong track record of delivering projects involving sour gas handling and sulphur recovery and looks forward to bringing that experience to bear as we deliver the project."

The Fadhili gas plant is designed to process sour gas which will be sourced from the Khursaniyah oil field and Hasbah non-associated gas field.

With a capacity of around 2,500 million standard cubic feet per day (MMSCFD), the gas plant is scheduled to be operational by 2019.

Non-associated gas drilling has already commenced last year to supply it to the plant.

Saudi Aramco estimates the Fadhili gas plant, together with Wasit and Midyan gas plants, to add more than 5 billion standard cubic feet/day (scfd) of non-associated gas processing capacity.

The plant is estimated to cost around $5bn to $6bn, reported Reuters earlier.