London Brent crude for December delivery LCOc1 was down 29 cents, or 0.6 percent, at $49.42 a barrel by 0750 GMT after settling down 76 cents on Friday. NYMEX crude for December delivery CLc1 was trading down 29 cents, or 0.6 percent, at $48.41 a barrel, after closing down $1.02 on Friday.

Brent crude LCOc1 was up 22 cents at $50.20 a barrel as of 0845 GMT (4:45 a.m. ET), after falling in the last three days. U.S. crude gained 10 cents to $49.28.

The North American market has continued to "grind slowly upwards" as the rig count, particularly in the US, ticks ahead from troughs seen six months ago, Martin Craighead said during a quarterly conference call with analysts. But "customers need to be more confident of the durability of those prices before making any significant change to their spending patterns," Craighead said.

The worsening OPEC equation presents Saudi Arabia with a difficult choice after its Algiers U-turn: carry a greater burden within the group, ceding market share to other producers, or lose credibility by softening the terms of the deal. In a worst-case scenario, Saudi Arabia will have to cut production by more than 1 million barrels a day, sending the kingdom’s output to a two-year low.

Brent crude futures LCOc1 were down 51 cents, or 1 percent, at $50.28 a barrel as of 0648 GMT. Prices hit $50.13 earlier in the session, the lowest since Oct. 3. U.S. crude CLc1 was at $49.37 per barrel, down 59 cents, or 1.2 percent, from its settlement on Tuesday. It dropped to $49.21 earlier, the lowest since Oct. 10.

Russia is the world's largest producer of crude oil (including lease condensate) and the second-largest producer of dry natural gas. Russia also produces significant amounts of coal. Russia's economy is highly dependent on its hydrocarbons, and oil and natural gas revenues account for more than 40% of the federal budget revenues.

The World Bank is raising its 2017 forecast for crude oil prices to $55 per barrel from $53 per barrel as members of the Organization of the Petroleum Exporting Countries (OPEC) prepare to limit production after a long period of unrestrained output.

A senior Iranian oil official here on Monday voiced Tehran readiness to join the Organization of Petroleum Exporting Countries (OPEC) oil freeze plan to help stabilize prices in international markets.

“We should be producing 9 million if it wasn’t for the wars,” said Falah Al Amri, the director general of state oil marketing company SOMO.

Brent crude futures LCOc1 were down 18 cents at $51.60 a barrel by 0725 ET. U.S. West Texas Intermediate (WTI) crude CLc1 was down 37 cents at $50.48.

U.S. West Texas Intermediate (WTI) crude CLc1 was trading at $50.59 a barrel at 0652 GMT, down 4 cents from its last settlement. Brent crude futures LCOc1 were up 7 cents at $51.45 per barrel.

However, Russian oil and natural gas companies’ capital investment programs have been less affected, if at all.

The economic consequences of cheap oil have been severe for Saudi Arabia. Riyadh is burning through foreign-exchange reserves, government contractors have gone unpaid, and civil servants, who make up two-thirds of the labor force, will get no bonus this year. The country’s fiscal deficit is more than 10 percent of gross domestic product, the highest ratio of any Group of 20 nation. The International Monetary Fund forecasts that Saudi economic growth will slow to about 1 percent next year, the worst since 2009. A few banks predict a recession.

U.S. West Texas Intermediate (WTI) crude oil futures were trading at $50.81 per barrel at 0011 GMT, up 52 cents, or 1 percent, from their last settlement. International Brent crude futures were at $52.14 a barrel, up 46 cents, or 0.9 percent.

We expect global GDP to more than double over the next 20 years, while energy demand increases by only 30%. The difference between those two things is improving energy efficiency or declining energy intensity. That is critical in underpinning the shift we expect to see in the rate of growth of carbon emissions. We think the energy intensity of GDP will decline much more rapidly than we’ve ever seen before.