The Organisation of the Petroleum Exporting Countries agreed on Wednesday its first oil output reduction since 2008 after de-facto leader Saudi Arabia accepted "a big hit" and dropped a demand that arch-rival Iran also slash output.
Benchmark Brent crude for February was up 70 cents at $52.54 a barrel by 1140 GMT. On Wednesday, the expired January Brent contract ended up $4.09 or 8.8% at $50.47.
US light crude oil rose above $50, trading at $50.04, up 60 cents 10 cents on the day.
The Opec deal triggered frenzied trading, with Brent futures trading volumes for February and March, when the supply cut will start to be visible in the market, hitting record volumes.
The March 2017 Brent futures contract traded a record 783,000 lots of 1,000 barrels each on Wednesday, worth $39 billion and beating a previous record of just over 600,000 reached in September.
Despite the agreed deal, doubts were widespread.
"Scepticism remains on individual countries' follow-through, which is keeping prices below year-to-date highs (of $53.73 per barrel in October) for now," Morgan Stanley analysts said.
Opec produces a third of global oil, or around 33.6 million bpd, and the deal aims to reduce output by 1.2 million bpd from January 2017, similar to January 2016 levels.
Analysts said the cuts could leave the field open for other producers, especially US shale drillers.
"We do not believe that oil prices can sustainably remain above $55 per barrel, with global production responding first and foremost in the US," Goldman Sachs said.