LONDON (Reuters) – Crude oil futures eased on Wednesday in light of the prospect of a continued boom in U.S. shale oil output, although with OPEC determined to restrict its own production to prevent a global surplus of unused fuel, the price held just shy of 2019 highs.

Brent futures were at $66.14 a barrel, down 31 cents on the day by 1049 GMT, still within sight of Monday’s high for the year of $66.83. U.S. futures were at $55.88 a barrel, down 21 cents, having touched a 2019 peak of $56.39 earlier.

“Brent is trading in a narrow corridor at around $66.5 per barrel, while WTI is at around $56,” Commerzbank analysts said in a note.

“This still leaves them within spitting distance of the three-month high they achieved at the start of the week … It seems that the sharp rise in oil production in the U.S. is having a slowing effect after all.”

The U.S. Energy Information Administration said in a monthly report on Tuesday shale production alone will hit a record 8.4 million barrels per day next month, suggesting little chance of a near-term slowdown in overall U.S. crude output.

The oil price has risen by more than 20 percent so far this year, supported largely by an agreed 1.2 million bpd production cut by the Organization of the Petroleum Exporting Countries and several other major exporters such as Russia.

U.S. sanctions on the energy sectors of Iran and Venezuela have added to the drop in availability of the kind of crude oil that yields more valuable middle distillates, rather than cheaper fuels, such as gasoline.

Despite the sanctions, Iran’s crude exports were higher than expected in January, averaging around 1.25 million bpd, according to Refinitiv ship tracking data. Many analysts had expected Iran oil exports to drop below 1 million bpd after the imposition of U.S. sanctions last November, although it was much below the peak 2.5 million bpd reached mid-2018.

Barclays said U.S. sanctions meant “although there is no lack of resources, there is an increasing lack of access to them”.

BNP Paribas said surging U.S. output would feed into lower oil prices toward the end of the year, with Brent to dip to an average of $67 a barrel by the fourth quarter and WTI to average $61.

“U.S. oil production growth, driven by shale, will be increasingly exported in greater volumes to international markets while the global economy is expected to witness a synchronized slowdown in growth,” the bank said.