U.S. crude oil futures nearly 3 percent on Monday, but gasoline prices surged to two-year highs as Tropical Storm Harvey kept hammering the U.S. Gulf Coast, knocking out several refineries which backed up crude supplies and disrupted fuel production.
Massive floods caused by the storm forced refineries in the area to close. In turn, U.S. crude futures fell as the refinery shutdowns could reduce demand for American crude.
The reduced inputs to those Gulf refineries will result in an increase in crude inventories," said Tony Headrick, energy market analyst at CHS Hedging, "That outweighs the outages in crude oil production from the storm.
U.S. West Texas Intermediate (WTI) futures ended Monday's session down $1.30, or 2.7 percent, at $46.57 a barrel. Brent futures fell 66 cents, or 1.3 percent, to trade at $51.75 by 2:18 p.m. ET (1818 GMT).
The WTI discount versus Brent expanded to as much as $5.48 per barrel, its widest in two years.
Prompt U.S. gasoline differentials in the Gulf Coast hit a five-year high.
Spot prices for U.S. gasoline futures surged 7 percent to a peak of $1.7799 per gallon, the highest level since late July 2015, before easing to $1.7235.
Harvey is the most powerful hurricane to hit Texas in more than 50 years, killing at least two people, causing large-scale flooding, and forcing the closure of Houston port as well as several refineries.
The International Energy Agency in Paris said it was monitoring the storm are ready to respond to major oil supply disruptions.
The U.S. National Hurricane Center said Harvey was expected to linger close to the shore through Tuesday, with floods spreading from Texas eastward to Louisiana.
Texas is home to 5.6 million barrels per day (bpd) of refining capacity, and Louisiana has 3.3 million bpd. Over 2 million bpd of refining capacity was estimated to be offline as a result of the storm.
Sources said the Motiva Port Arthur refinery in Texas, the largest U.S. refinery, was considering a shutdown.
U.S. traders were seeking oil product cargoes from North Asia, several refining and shipping sources told Reuters, with transatlantic fuel exports from Europe expected to surge.
"Global refining margins are going to stay very strong," said Olivier Jakob, managing director of Petromatrix.
"If (U.S.) refineries shut down for more than a week, Asia will need to run at a higher level, because there's no spare capacity in Europe."
On Monday Mexico's Pemex said supply of fuel was guaranteed in light of Harvey.
About 22 percent, or 379,000 bpd, of Gulf production was idled due to the storm as of Sunday afternoon, the U.S. Bureau of Safety and Environmental Enforcement said.
There might also be around 300,000 bpd of onshore U.S. production shut in, trading sources said.
In Libya pipeline blockades by militia brigades have slashed the OPEC state's output by nearly 400,000 bpd.