Irma the second major hurricane to hit the U.S.in two weeks and has already seen 14 fatalities, wiping out whole islands.
As of Thursday, about 3.8 million barrels of daily US refining capacity, or about 20 percent, was still shut.
"Hurricanes can have a lasting effect on refinery and industry demand", said Eugen Weinberg, head of commodities research at Commerzbank in Frankfurt.
Gasoline refineries were interrupted along the Texas coast, denting demand for crude oil.
Brent crude LCOc1 increased 16 cents at $54.65 a barrel by 1145 GMT, after earlier hitting its highest level since April at $54.80.
Brent ended the week up 1.9 percent while USA crude was up 0.4 percent, paring most of its earlier weekly gains on worries on the continued impact of hurricanes on demand and supply.
The capacity shutdowns have done worldwide oil prices good and now news of more possible supply disruptions are supporting them, too.
Domestic US oil production in the lower 48 states was also impacted, shrinking by 783,000 barrels to 8.29m.
Gas prices spike in Midstate after Harvey, ahead of Irma
With more than 50 inches of rain, Harvey set a record for the greatest amount of single-storm rainfall for the continental U.S. Franklin County and Adams County residents have to pay the highest prices at the pump in the area.
That brought US crude inventories up to 462.4 million barrels.
But the slowdown in refining and output are expected to be temporary.
"Irma looks like it will miss the key Gulf areas, and we're more anxious about shale", said Mark Watkins, regional investment manager at U.S. Bank.
U.S. Gulf Coast utilization rates dropped to 63.4 percent, the lowest rates since the EIA began collecting the data in 2010.
Analysts said that it can take weeks for normalisation of USA petroleum industry, which may again be affected as Irma is anticipated to hit Florida.
Hurricane Irma, which has become one of the biggest storms ever measured - picking up the Twitter hashtag #irmageddon - on Friday hit the Dominican Republic and Haiti, heading for Cuba and the Bahamas.
Another Atlantic storm, named Jose, is following on Irma's heels and has been upgraded to hurricane strength by the U.S. National Hurricane Centre.
Irma barreled into Caribbean islands overnight with wind speeds up to 185 miles per hour (295 kph) and was heading for Florida.