While strong, consumption of oil proved uneven through the first nine months of 2021, interrupted by outbreaks of the coronavirus Delta variant. This led the world’s largest cartel of crude producers to downgrade its demand outlook for the full year.

The Organization of the Petroleum Exporting Countries (OPEC), however, said Wednesday that lofty natural gas prices across Europe, Asia and South America could spur widespread switching from gas to oil this winter, creating a spike in oil demand late this year and into next.

“Soaring natural gas prices, which have reached record-high levels, particularly in Europe during September, have triggered a growing interest in switching from natural gas to liquid fuels at the industrial level, as energy companies attempt to drive down...