Royal Dutch Shell on Tuesday again sought to assuage investor concerns over its planned $70 billion takeover of BG Group as it announced plans for further synergies and cost cuts aimed at making the deal work with oil prices in the mid-$60s a barrel.

The Anglo-Dutch group, which hopes to complete the deal early next year, said it now expected synergies to increase by $1 billion to $3.5 billion for the combination which will make Shell a leader in liquefied natural gas (LNG) and offshore oil production in Brazil.

Shell, which last week reported a huge loss in third-quarter earnings due to write-offs in Alaska and Canada, said it would reduce its costs by $11 billion in 2015 as it tackles a prolonged period of lower oil prices, currently trading below $50 per barrel.

"Shell is becoming a company that is more focused on its core strengths, a company that is more resilient and competitive at all points in the oil price cycle and that has a more predictable project development pipeline. We'll grow to simplify," chief executive officer Ben van Beurden said in a statement ahead of a company strategy day in London.

Investors have been concerned that the benefits from the deal would be at risk as a recovery in oil prices is now expected to take much longer than foreseen in April, when the merger with BG was announced.

Back then, Shell indicated it expected oil prices to recover to $90 a barrel by 2020.

Brent crude traded at around $59 per barrel when the deal was announced and has since traded in a range between about $42 and $69 amid a growing consensus among analysts that prices are set to stay "lower for longer".

Shell said it would maintain its dividend payout in 2015 and 2016 at $1.88 per share, turn off scrip dividends in 2017 and undertake a share buyback of at least $25 billion in the period 2017-2020. - Reuters