Royal Dutch Shell has confirmed it is reviewing the case for selling some of its North Sea assets in the wake of its £35bn takeover of rival oil and gas producer, BG Group.

Neil Atkinson, head of the IEA’s Oil Industry and Markets Division, said in Singapore on Wednesday. About $300 billion is needed to sustain the current level of production, and nations including the U.S., Canada, Brazil, and Mexico are facing difficulty in keeping up investments, he said.

U.S. companies are welcome to invest in Iran's oil and gas industry, the Iranian oil minister said.

Sparking fears for the long-term future of the industry, the UK upstream segment is expected to approve fewer than £1 billion in spending on new North Sea projects compared with an average of £8 billion/year over the past 5 years, according to Oil & Gas UK’s 2016 Activity Survey.

Mining and exploration investment declined 35% in 2015, the second largest year-over-year decline since the U.S. Bureau of Economic Analysis (BEA) began reporting the series in 1948.

“To develop the joint fields and enhance recovery of oil reservoirs as well as secure development targets, we need investment totaling 200 billion dollars,”

North American oil and natural gas drillers will need to cut an additional 30 percent from their capital budgets to balance their spending with the cash coming in their doors even if crude rises to $40 a barrel, according to an analysis by IHS Inc.A group of 44 North American exploration and production companies are planning to spend $78 billion on capital projects this year, down from $101 billion last year.

Possible Japanese investment in Iran could include petroleum, natural gas resource developments, refinery upgrades, petrochemical plants and distribution systems, according to industry sources.

Gazprom held the eleventh annual Investor Day in New York and London.

Oil companies are cutting investment, slashing jobs and selling off pipelines and other assets as crude prices plunge. “It’s going to be a very turbulent year for our industry,” says BP CEO Bob Dudley.