The company is cutting more than 10,000 jobs across the world, with 2,800 of those connected with the BG deal.
Shell plans to close the Thames Valley Park campus by the end of the year.
All Aberdeen-based onshore operations will move to Tullos, with BG’s offices at Albyn Place closing, as will Shell’s Brabazon House office in Manchester.
Shell said the decisions were subject to the outcome of staff consultation.
The company is also planning to open a voluntary redundancy arrangement at Thames Valley Park.