Fabrication of the billion-dollar topsides destined for the Maersk Oil-operated US $4.5 billion U.K. North Sea megaproject, Culzean, has started, the company said in a news release.

The steel-cutting ceremony for the first of three topsides modules took place at the Sembcorp Marine Offshore Platforms (SMOP) Admiralty Yard in Singapore on April 7.

Maersk Oil said Culzean is the largest hydrocarbon discovery in the U.K. North Sea for over a decade. The field is about 145 miles east of Aberdeen and is expected to produce between 60,000-90,000 boe/d at plateau production, producing for at least 13 years. The project was sanctioned in August 2015. Maersk Oil’s partners are JX Nippon Exploration & Production (UK) Ltd. (34.01%) and BP (16%).

The more than $1-billion contract with SMOP was awarded in September 2015. The contract includes the building of the central processing facility plus two connecting bridges, wellhead platform and utilities and living quarters platform topsides for the Culzean field development, the release said.