Oil prices fell on Thursday amid concerns over demand as U.S. Gulf Coast refineries shut operations as Tropical Storm Harvey was forecast to turn into a major hurricane.
Benchmark Brent crude was down 59 cents, or 1.1 percent, a barrel at $51.98 by 2:15 p.m. ET (1815 GMT). U.S. light, sweet crude ended Thursday's session down 98 cents, or 2 percent, at $47.43 a barrel.
Meanwhile, U.S. gasoline prices were up 3 percent at $1.668.
The divergence of crude oil and gasoline prices appears to be a clear sign that traders are engaging in so-called crack spread buying, said John Kilduff, founding partner at energy hedge fund Again Capital.
Anticipating refinery outages on the U.S. Gulf Coast, traders were buying refined products like gasoline and selling crude oil, the primary feedstock at refineries, he told CNBC.
U.S. gasoline margins and cash prices in the Gulf Coast rose to the highest levels in almost a year ahead of the storm. Margins were on track for the biggest percentage gain since Feb.21.