Sentiment remained negative, however, as investors grappled with weakening demand and worries about oversupply.
Heating oil futures
"The complex is piecing together a modest advance so far today but only one that offsets a miniscule portion of recent losses," Jim Ritterbusch, president of Ritterbusch and Associates, said in a note.
The markets slumped on Tuesday, extending recent declines. Global benchmark Brent tumbled to a session low of $55.89 a barrel, a bottom last reached in October 2017. WTI sank to $45.79, the weakest since August 2017.
Broader financial markets have been under pressure on worries about higher U.S. interest rates. As expected, the U.S. Federal Reserve raised interest rates on Wednesday and noted that "some" further gradual rate hikes would be needed.
Oil prices pared gains following the decision as the U.S. dollar index trimmed losses. A stronger dollar makes greenback-denominated commodities more expensive for holders of other currencies.
"There's slight disappointment that the Fed is not done (raising rates)," said Phil Flynn, analyst at Price Futures Group in Chicago. "People are a little bit concerned that if the Fed raises the rates, that could slow the economy and hurt oil demand at the same time."
Brent and WTI have fallen more than 30 percent since the beginning of October as crude supply has increased.
The Organization of the Petroleum Exporting Countries and other oil producers including Russia agreed this month to curb output by 1.2 million barrels per day (bpd) in an attempt to drain tanks and boost prices.
Russian oil output has been running at a record 11.42 million bpd so far this month, an industry source told Reuters.
Saudi Arabia's energy minister, Khalid al-Falih, said on Wednesday he expected global oil stocks to fall by the end of the first quarter.