North Sea Brent crude was up 25 cents at $53.25 a barrel by 0940 GMT. U.S. light crude was up 20 cents at $49.97 a barrel.

North Sea Brent crude oil LCOc1 was up 10 cents a barrel at $54.03 by 0950 GMT. U.S. light crude CLc1 was up 15 cents at $51.08 a barrel.

EIA forecasts Brent crude oil prices to average $43 per barrel (b) in 2016 and $52/b in 2017. West Texas Intermediate (WTI) crude oil prices are forecast to average about $1/b less than Brent prices in 2017. The values of futures and options contracts indicate significant uncertainty in the price outlook.

The balance between demand and supply in the oil market will shift earlier than previously expected due to OPEC's output cuts, with prices heading towards $60 a barrel next year, Statoil's chief executive said on Tuesday. Brent crude futures LCOc1 hit $55 a barrel on Monday, the highest level since July 2015, after OPEC agreed on Dec. 1 to curb production by 1.2 million barrels per day (bpd) from January.

International Brent crude oil futures LCOc1 were trading at $54.83 per barrel at 1127 GMT, down 11 cents from Monday's close. U.S. West Texas Intermediate crude was at $51.50 a barrel, down 29 cents.

Brent crude oil futures LCOc1, the global benchmark used to trade oil, soared to its highest since July 6, 2015 to $55.20 a barrel. It last traded at $55.08 a barrel, up 62 cents, or 1.1 percent, at 0946 GMT. WTI crude oil CLc1 traded up 54 cents, or 1 percent, at $52.22 a barrel.

Front-month Brent crude futures LCOc1 were down 45 cents, or 0.8 percent by 0951 GMT (4:51 a.m. ET) from their last settlement at $53.49 per barrel. The contract was up more than 13 percent this week, its biggest gain since March 2009. U.S. West Texas Intermediate (WTI) futures CLc1 were at $50.68, down 38 cents.

Oil prices slipped on Friday as some investors opted to cash out after Brent touched 16-month a high on Thursday, with optimism over this week's OPEC-Russia accord on cutting output giving way to questions on the "sticking point" of implementing the deal.

U.S. crude oil CLc1 added to overnight gains of 9 percent to reach $50.00 a barrel for the first time since October. Brent crude LCOc1, which soared $4 overnight, touched a six-week peak of $52.73 a barrel.

Brent crude, the international oil marker, rose more than $3.00, or 7.2 per cent, to $49.73 in the late morning in London.