US base oils and lube output remained lower than usual in September even as it recovered from an 18-month low in August.

Low output contrasted with growing surplus supplies in markets like Europe and Asia-Pacific and supported prices at steep premiums to price levels in those markets.

The low output raised the prospect of limiting the size of the US supply overhang to clear during the final months of the year.

Output of 4.64mn bl (653,000t) in September recovered from 4.05mn bl the previous month, according to the EIA. The August volume had been the lowest since March 2021.

The September volume was still well below typical levels of more than 5.1mn bl/month in the year to July.

Output of 13.78mn bl in the third quarter of the year fell from 15.64mn bl during the previous three months to the lowest since the beginning of 2021.

US base oils output typically falls in the third quarter of the year amid a seasonal dip in demand.

Storm-related damage during the Atlantic hurricane season has also frequently impacted output.

Output fell in August and September this year even with an unusually inactive Atlantic hurricane season.

Plant maintenance work was one factor for the fall in output. The drop in production in August especially was unusually steep and rapid even with plant maintenance work.

Output rose in September on the back of a recovery in paraffinic base oils production in the Texas Gulf coast refining district.

Its output of 1.42mn bl in September rose from a 17-month low of 1.08mn bl the previous month. The September volume was still the second lowest during that period since early 2021.

Paraffinic base oils output in the US West coast region also recovered in September to a three-month high.

The rebound was relative.

Output of 145,000bl in September rose from 8,000bl in August and 26,000bl in July.

Output had averaged more than 430,000 bl/month in 2021.