Brent crude futures gained 9 cents, or 0.1 percent, to $86.15 a barrel by 0539 GMT. Earlier in the session, the contract touched its highest since Oct. 3, 2018, at $86.71.
U.S. West Texas Intermediate crude was up 29 cents, or 0.4 percent, at $84.11 a barrel, after hitting $84.78, the highest since Nov. 10, 2021, earlier in the session.
The gains followed a rally last week when Brent rose more than 5 percent and WTI climbed over 6 percent.
Frantic oil buying, driven by supply outages and signs the Omicron variant will not be as disruptive as feared for fuel demand, has pushed some crude grades to multi-year highs, suggesting the rally in Brent futures could be sustained a while longer, traders said.
“The bullish sentiment is continuing as (producer group) OPEC+ is not providing enough supply to meet strong global demand,” said Toshitaka Tazawa, an analyst at Fujitomi Securities Co. Ltd.
“If (investment) funds increase allocation weight for crude, prices could reach their highs of 2014,” he said.
The Organization of the Petroleum Exporting Countries, Russia, and their allies, together known as OPEC+, are gradually relaxing output cuts implemented when demand collapsed in 2020.
But many smaller producers cannot raise supply and others have been wary of pumping too much oil in case of renewed COVID-19 setbacks.
“What comes in view next is the summer demand bump, especially in Europe and the U.S., which could be bigger than last year’s, if the growing hope around the Omicron finally turning COVID from pandemic to endemic proves right,” said Vandana Hari, energy analyst at Vanda Insights.
Festering geopolitical threats to supply are also supporting bullish sentiment, Hari said.
U.S. officials voiced fears on Friday that Russia was preparing to attack Ukraine if diplomacy failed. Russia, which has amassed 100,000 troops on Ukraine’s border, released pictures of its forces on the move.
U.S. crude oil stockpiles, meanwhile, fell more than expected to their lowest since October 2018, but gasoline inventories surged due to weak demand, the Energy Information Administration said on Wednesday.
By Yuka Obayashi and Roslan Khasawneh