Shell said it plans to sell $30 billion of assets in the two years following the expected completion of the $70 billion BG deal next year.

Although Shell would not provide specific details on which assets it would target, the ageing North Sea basin, whose production has sharply declined since its 1990s peak, is likely to be closely scrutinized.

"We will take a very good look at the North Sea and make sure that out of two strong portfolios will crystallise the strongest possible core," van Beurden told reporters.

"Like any province that gets mature, and certainly one where we have high cost structures and still a high tax regime, we will have to look at how to restructure this to bring it back to its most advantaged core."

"We have a very significant position in the North Sea that ranges from very mature assets to assets that are still under construction. BG has a very significant position as well," he said.

(Reporting by Ron Bousso; editing by David Clarke)