Oil prices may rise by 20 percent this year as energy producers outside the U.S. keep a lid on how much crude they pump, said analysts at Citigroup.

“With a continuation of the OPEC/non-OPEC producer deal in the second half of 2017 and the expected associated inventory draw-down, we expect oil prices to move above $60 a barrel by the second half of the year,” the analysts said in a report obtained by CNBC.

West Texas Intermediate crude has doubled in price since reaching a bottom of about $26 a barrel in February 2016. The Organization of the Petroleum Exporting Countries, which includes major oil producers like Saudi Arabia, Iran and Venezuela, agreed last year to curb output and help stabilize prices.

Citigroup’s analysts had estimated in February that oil prices would rise to $70 a barrel this year as supply and demand levels continued to rebalance, CNBC reported.

U.S.