OPEC said Thursday worries about the Omicron variant of the coronavirus are steadily fading while the global economy heats up, supporting mounting oil demand that could soon surpass the cartel’s expectations reported only weeks earlier.

At the same time, needed supply increases are in the works but gathering momentum more slowly than hoped, OPEC said, further explaining the January spike in Brent crude prices. The international benchmark last month climbed about 20% and eclipsed $90/bbl. It has held above that level since early this month and topped $92 in intraday trading Thursday.

OPEC researchers in early January predicted global demand would rise by 4.15 million b/d and that consumption would exceed 100 million b/d in the third quarter, returning demand to pre-pandemic...