Brent oil futures fell by $1 a barrel on Wednesday, touching 6-week lows on easing worries that tensions in Ukraine would escalate, while U.S. crude oil rose ahead of the contract's expiration.
Russian President Vladimir Putin signed a treaty on Tuesday making Crimea part of Russia, but said he did not plan to seize any other regions of Ukraine. Western sanctions imposed on Monday targeted individuals and not broad trade.
U.S. crude oil stockpiles soared nearly 6 million barrels last week, more than double forecasts, as refinery utilization fell during a time of low seasonal demand, U.S. Energy Information Administration data showed on Wednesday.
But West Texas Intermediate rose modestly in spite of the build, as traders covered short positions. Also supporting U.S. crude was a 989,000 barrel draw at the Cushing, Oklahoma, oil hub.