Oil prices jumped more than 2% on Wednesday, with US crude settling at its highest in 15 months after the government reported a surprisingly large drop in inventories for the sixth week out of seven.
The US Energy Information Administration (EIA) said crude stocks fell 5.2 million barrels in the week ended 14 October, versus forecasts for a 2.7 million-barrel build.
Crude stocks generally rise at this time of year as refineries go into maintenance. Refinery utilisation is down to 85% from nearly 94 percent in early September.
The EIA said US crude imports slid by 912,000 barrels per day last week to 6.47 million bpd, the lowest since November 2015, crimping inventories.
"This lowest import pace in some 16 months is surprising given the fact that Opec production has recently attained a record level that would imply easy availability," said Jim Ritterbusch of Chicago-based oil markets consultancy Ritterbusch & Associates.
US West Texas Intermediate crude's front-month contract, November, closed up $1.31, or 2.6%, at $51.60 a barrel for its highest settlement since 14 July. Its session peak of $51.93 was the highest in 15 months.
With expiry due on Thursday, the November contract saw lighter trades than December WTI, which hit a June high of $52.22. The December contract will be front-month from Friday.
London-traded Brent crude settled up 99 cents, or 1.9%, at $52.67.
Some market participants were not impressed by the crude inventory drop, citing instead the large gasoline build of 2.5 million barrels for last week versus forecasts for a 1.3 million-barrel drop.
"While the headline number was bullish, we wouldn't call it extremely bullish," said Tariq Zahir, crude trader at Tyche Capital Advisors in New York.
Oil prices have rallied 15% in the three weeks after Opec proposed to enforce from November its first output cut since 2008.
Khalid al-Falih, energy minister of Saudi Arabia, which dominates Opec, told the Oil & Money conference in London "fundamentals are improving and the market is clearly balancing" after prices fell below $30 from 2014 highs above $100.
But Rex Tillerson, chief executive of ExxonMobil, later told the same conference he expected US shale oil output, responsible for much of the glut, to rebound at current prices.
In industry news, Enbridge, Canada's largest pipeline company, said it was shedding 5% of its workforce, the second layoff of that size since oil prices crashed in 2014.