U.S. crude oil prices slipped below $50 per barrel on Monday but stayed close to multi-month highs as traders braced for a potential stockpile build, expected later this week.
"They're still working out the aftermath of the hurricanes," said John Kilduff, a partner at Again Capital Management in New York. "The big thing about this week is that the inventory reports are going to be bearish for crude."
U.S. West Texas Intermediate crude futures ended Monday's session up 2 cents at $49.91, posting a seven-week high. They remained close to Thursday's near-four month high of $50.50.
Brent crude futures were 12 cents lower at $55.50 a barrel, near an almost five-month high of $55.99 touched on Thursday.
Even as oil refineries restart, imports at reopened ports are likely to drive up stockpiles, Kilduff said.
Oil refineries across the Gulf of Mexico and the Caribbean were restarting after being shut as hurricanes Harvey and Irma battered the region over the past three weeks.
Royal Dutch Shell's Deer Park refinery in Texas was among the latest, beginning its restart on Sunday. The plant can process 325,700 barrels per day.
The refinery restarts are occurring "as signs emerge of stalling growth in the U.S. shale industry. The number of rigs drilling for oil in the U.S. fell sharply last week," ANZ said.
U.S. energy firms cut seven oil rigs in the week to Sept. 15, bringing the total to 749, the fewest since June, energy services company Baker Hughes said on Friday.
Speculators raised their net long positions in Brent futures and options by 16,962 contracts to 430,699 in the week to Sept. 12, InterContinental Exchange (ICE) data showed, the highest level since March. The increase was the first in four weeks.
"Demand forecasts from OPEC and IEA ... continued to improve sentiment in the market. Refineries are also reporting a much better recovery from the recent hurricanes," ANZ bank said in a note.
Hedge funds and other money managers cut their bullish bets on U.S. crude futures and options in the week to Sept. 12, the U.S. Commodity Futures Trading Commission reported on Friday.