Abu Dhabi’s National Marine Dredging Company (NMDC) has won the contract to build four artificial islands at the offshore Upper Zakum oilfield, according to sources close to the project.

The deal is part of a project by the offshore oil and gas developer Zakum Development Company (Zadco) to increase oil production at the field to 750,000 barrels a day (b/d) from current levels of around 500,000 b/d which will cost an estimated $15bn.

Zadco plans to use the islands as drilling platforms and to house supporting infrastructure for the development, a move it says will cost 20-30 per cent less than using conventional offshore platforms.

The islands will be built at depths ranging from 6 metres to 14 metres, and will cover an area of 2.6km by 2km.

International contractors bid for the deal in August 2009. Sources at two rival firms say that NMDC will likely work in consortium with other dredging companies such as Royal Boskalis Westminster, Van Oord, both of the Netherlands, Jan de Nul, and Dredging International, both of Belguim.

The value of the contract is not known, and Zadco and NDMC declined to comment on the award.