That puts pressure on refiners' profit margins and could cause them to reduce activity at the nation's refineries later this year, leading to an inventory buildup of crude oil, the feedstock for most fuels.
Kloza said Gulf Coast refiners would start feeling pressure if the cheapest conventional gasoline blend stock trades at $5 to $6 above a barrel of Light Louisiana Sweet crude, down from a spread of roughly $8 today.
Crude oil prices are down about 8 percent this year as rising U.S. production caps rallies fueled by short-selling and expectations that the Organization of the Petroleum Exporting Countries and other producer nations will extend a six-month deal to cut their output.
U.S. crude looked like it was on a path to settle between $49.50 and $52 a barrel after sinking to about $47 last month, Kloza said. However, it now appears that any disappointing news could send the commodity tumbling back down to $47, he added.
John Kilduff, founding partner at energy hedge fund Again Capital, believes oil prices could fall even further — to the November lows of $42 a barrel.
Last week's report on U.S. crude stockpiles showed a 1 million barrel decline, but refineries ratcheted up activity, again raising the specter of higher gasoline inventories, according to Kilduff.
"That will remove quickly any kind of thought that those supplies might get tight," he said.