Oil prices climbed on Monday, adding to Friday's powerful rally, but gains were capped by an estimate of another strong weekly build in U.S. crude stocks, traders said.
A U.S. refinery strike, which theoretically meant higher crude supplies in the market, and disappointing U.S. consumer spending and manufacturing data also pared Monday's early gains.
U.S. crude closed up $1.33, at $49.57 a barrel, it highest in nearly a month. It hit an intraday high of $50.56 and session low of $46.67.
The spread between Brent and U.S. crude widened to above $5 a barrel, its biggest since November.
Benchmark Brent crude was last up $1.44 at $54.50 a barrel shortly, after swinging in a wide band of between $55.62 and $51.41.
Traders said oil services company Genscape estimated a stock build of 2.3 million barrels in the Cushing, Oklahoma, delivery point for U.S. crude last week, adding to already record-high oil inventories in the country.
The U.S. Energy Information Administration plans on Wednesday to report official stock numbers for Cushing and other oil market data for the week ended on Friday.
"We saw some strength in the market this morning, but that's being sold into," said Tariq Zahir, managing member of Tyche Capital Advisors in Laurel Hollow, New York.