(Reuters) - U.S. crude oil stocks rose to a fresh record last week, the Energy Information Administration said on Wednesday, as a surge in imports and rising domestic production more than offset a hike in refinery runs.
Crude stocks in the world's top oil consumer have been building since the beginning of the year and undermining hopes that an OPEC-led deal to cut production will reduce a persistent global glut.
Crude inventories hit a record 533.1 million barrels after surging 5 million barrels in the week to March 17, nearly double expectations for a 2.8 million-barrel build, as imports soared 1.1 million barrels per day.
U.S. production rose modestly to 9.1 million bpd last week, but has been growing steadily and is higher than year-ago levels.
"The market remains nervous about rising U.S. production, which is also reducing the effectiveness of output cuts by the OPEC and some non-OPEC countries," said Abhishek Kumar, Senior energy analyst at Interfax Energy in London.
Imports from the Middle East remained stubbornly high, despite the Organization of the Petroleum Exporting Countries' agreement to limit supply from Jan. 1. Imports from Saudi Arabia, which had dropped sharply a week earlier, rose by 207,000 bpd to 1.3 million bpd.
Imports were also notably higher from Iraq and Kuwait, offsetting oil received from Nigeria and Venezuela. Canada, the largest exporter to the United States, also boosted imports by nearly 100,000 barrels to 3.32 million bpd last week.
Crude stocks at the Cushing, Oklahoma, delivery hub for U.S. crude futures rose 1.4 million barrels, the EIA said.
U.S. West Texas crude futures extended losses to trade as low as $47.01 a barrel after the data. It settled down 20 cents to $48.04 a barrel. Brent crude, meanwhile, broke through $50 a barrel for the first time since Nov. 30; it settled down 32 cents to $50.64 a barrel.
On the bullish side, the data showed a notable increase in crude processing as refiners come out of seasonal maintenance and begin to gear up for the summer driving season in the United States.
Refinery crude runs rose 329,000 bpd as utilization rates jumped 2.3 percentage points to 87.4 percent of capacity, led by higher runs at U.S. Gulf Coast and Midwest refiners.
"This is evidence that refinery maintenance is wrapping up for this season," said David Thompson, executive vice-president at Powerhouse, an energy commodities broker in Washington. "Expect to see increases on balance over the next six to eight weeks."
Gasoline stocks fell 2.8 million barrels, compared with analysts' expectations in a Reuters poll for a 2.0 million-barrel drop.
Distillate stockpiles, which include diesel and heating oil, fell by 1.9 million barrels, versus expectations for a 1.4 million-barrel drop, the EIA data showed.
Reporting By David Gaffen; additional reporting by Ethan Lou and Scott DiSavino; Editing by Marguerita Choy