Shell has said it plans to raise $30bn from asset sales worldwide as it moves to offset the cost of the BG acquisition, completed last month just weeks after oil prices plunged to a 13-year low near $27 a barrel.  But the company has yet to identify in public precisely which fields will be under scrutiny.  “A review of all assets, including those in the North Sea, is under way as part of our commitment to the $30bn asset sale,” a Shell spokesman said on Sunday.  Shell has nearly 2,500 employees in the North Sea, where it has operated more than 33 offshore installations.  Ben van Beurden, the group’s chief executive, said last month the global disposals would take place between 2016 and 2018 and he expected less than $10bn of asset sales to take place during 2016.  “The buyers are there,” he said, naming other oil and gas companies and private equity groups as potential purchasers.