London- Oil prices reached seven-year highs on Friday as geopolitical tensions continue to raise supply concerns.

Brent crude futures were up $1.91, or 2.1%, at $91.25 a barrel by 1436 GMT, having hit $91.41 on Friday for their highest since October 2014.

U.S. West Texas Intermediate (WTI) crude futures rose $1.83, or 2.11%, to $88.44 a barrel. WTI also reached a fresh seven-year high of $88.76 earlier in Friday's session.

Both Brent and WTI are on track for their six-weekly gain in what would be the longest run of weekly gains since October.

Supply scarcity has pushed the six-month market structure for Brent into steep backwardation of $6.62 a barrel, the widest since 2013. This means that current levels are higher than those in later months, which usually encourages traders to release oil from storage to sell it promptly.

Oil prices continue to receive support from concerns that the Ukraine crisis could disrupt energy markets. U.S. President Joe Biden and his European Union counterpart Ursula von der Leyen on Friday pledged to cooperate on guaranteeing Europe's energy security as well as Ukraine's amid the standoff triggered by Russia amassing troops at Ukraine's border. 

"The risk premium on the oil price is now likely to be almost $10/bbl" said Commerzbank commodities analyst Carsten Fritsch.

The market is focused on a Feb. 2 meeting of the Organization of the Petroleum Exporting Countries (OPEC) and allies led by Russia, collectively known as OPEC+.

The OPEC+ producer group is likely to stick with a planned rise in its oil output target for March, several OPEC+ sources told Reuters. 

On the demand side, crude oil imports in China, the world's biggest importer of the commodity, could rebound by a much as 7% this year, analysts and oil company officials said. 

Swedish bank SEB raised its Brent crude forecast on Friday to $85 a barrel for the first and second quarters of this year, up $10 and $5 respectively.

(Reporting by Rowena Edwards Editing by David Goodman and Louise Heavens) ((;))