Shearman & Sterling and White & Case have taken lead roles on a $20bn (£12.3bn) joint venture (JV) that will see Dow Chemical and Saudi Arabia's Aramco build a petrochemical complex in the Saudi city of Jubail.

US law firm Shearman has taken the lead role for Dow Chemical, fielding a team led by London managing partner Nick Buckworth, who worked alongside fellow project finance partner Ben Shorten.

The cross-border team also included two partners in the firm's Abu Dhabi office: project finance partners Iain Elder and Brian Clayton.

White & Case, meanwhile, is acting for Aramco with a London-based team led by Philip Stopford and Tom Bartlett. Beijing finance partner Steve Payne also assisted the team throughout the transaction.

When completed in 2016, the JV – which will be called Sadara Chemical – will be among the world's largest integrated chemical facilities to be built in one single phase and will aim to tap into high-growth markets in the EMEA region. Production is scheduled to start in the second half of 2015.

The project, which has been ongoing for over five years, entered a new phase last week (25 July), when the two companies announced that the boards of directors of both companies had approved the formation of the JV.

Buckworth said: "This announcement is the culmination of many years of hard work for client and adviser alike and we are honoured to have played our part. Saudi Arabia is a vitally important market for Shearman, and our involvement with Sadara is critical to our success there."

The companies estimate that the facility will produce revenues of about $10bn (£6.1bn) a year after the first few years of operation and sell about 45% of its products to buyers in the Asia-Pacific region.