Crude futures fell on Friday, with the U.S. benchmark posting a second consecutive week of declines as American oil output comes close to matching that of top producer Russia.
North Sea Brent crude's premium over West Texas Intermediate (WTI) futures remained near three-year highs above $10 a barrel, having surpassed $11 on Thursday. The premium has doubled in less than a month, as a lack of pipeline capacity in the United States has trapped a lot of output inland.
"The big story in the market right now is this emerged disconnect between Brent and WTI. This is a three-year high in the spread differential," said John Kilduff, founding partner at energy hedge fund Again Capital.
WTI crude fell $1.23, or 1.8 percent, to $65.81 a barrel. For the week, WTI was down 3 percent, adding to last week's near 5-percent decline and shrugging off a 3.6-million-barrel drop in U.S. crude stockpiles last week.