Global energy demand is set to increase by almost 50% in the period to 2040, with the overall energy mix continuing to be led by fossil fuels at almost 78%

“You also need a low cost structure and a strong balance sheet for a strong credit rating with good access to the debt markets,” Lance said. “A company like ours also needs to be able to react quickly to developments.”

OPEC said it now assumes the price of the reference basket of crude oil produced by its members would be $70 a barrel in 2020, rising to $95 a barrel by 2040.

"OPEC can't take a unilateral decision, for example, to cut production and others ... raise production. Either we all go to cut production to really defend prices or we have to wait and see,"

"First of all, our policy calls for maintaining production at 525-530 million tonnes (a year), according to our energy strategy"

Flexibility and the ability to survive through the price cycle are more important to oil producers and consumers than flaky forecasts about where prices are going over the next 3, 5 or 10 years.

The United States has estimated Islamic State was selling as much as $40 million a month of oil, which was then spirited on trucks across the battle lines of the Syrian civil war and sometimes farther.

Brent LCOc1, the global benchmark, was at $37.74 at 0440 GMT, down 18 cents from its last settlement after rising slightly earlier on Tuesday.

Natural-gas prices plunged to a 14-year low, as the warmest start to winter on record in the U.S. saps demand for the heating fuel and deals another blow to struggling energy companies.

Shell is consulting experts and commercial partners about what to do with the reinforced concrete base structures, each of which rises 160m from the seabed and weighs about 300,000 tonnes. The low oil price has put companies under pressure to shut facilities as cheaply as possible.