"We're doing some routine summer maintenance for a few days. We're not 100% sure how long it will last," he told Reuters.
Last year, work on the platform lasted around a day.
The maintenance work is scheduled to start on 1 August.
The Unity riser platform links the Bruce, Scott, Nelson, Britannia, and Graben Area fields to the main Forties oil line.
Britannia and Bruce are large gas fields, producing 261 and 134 million cubic metres of gas in March this year, according to government figures.
