* November output up 17 pct to 2.109 mln bpd

* Poor outlook for refiners expected to dampen demand

* Potential strike at Grangemouth could impact Forties

LONDON, Oct (KOSDAQ: 039200.KQ – news) 11 (Reuters) – North Sea oil output tracked by Reuters will rise by 17 percent in November from October to a 2013 high, potentially putting downward pressure on prices.

Although most European refineries are scheduled to emerge from seasonal maintenance by November, poor margins may encourage some to remain idle or resort to run cuts, market participants said.

“Run cuts and maintenance are happening all over Europe and Asia along with refinery glitches in the United States,” a trader said.

But others pointed to uncertainties around a dispute at Grangemouth refinery in Scotland, where a strike could ultimately impact flows through the Forties pipeline.

“It’s very binary right now,” one trader said. “If all goes according to plan it will be higher, but Grangemouth would be a huge shock if it materialised.”

Output from 11 of the main British and Norwegian crude streams will average 2.109 million barrels per day (bpd) in November, according to loading schedules and trading sources, up from 1.802 million in October.

This level exceeds February’s 2.082 million barrels, the previous 2013 high, and reflects the fact that several Norwegian fields are expected to pump more as they return from seasonal maintenance.

Brent itself is expected to load 140,000 bpd, up from 97,000 bpd in October as maintenance on Taqa’s North Cormorant platform is likely to be complete. The planned maintenance was expected to interrupt production from the Causeway and Cormorant East oil fields for about six weeks from early September.

Together, the four North Sea crude streams that underpin the Brent benchmark will pump 980,000 bpd next month, including two delayed Ekofisk cargoes from October.

Norwegian and Danish streams such as DUC, Gullfaks, Statfjord, Troll and Asgard will also load more. The loading programme for Flotta, the smallest stream tracked by Reuters, has not yet emerged.

Given the poor outlook for the refining sector in Europe, traders said the extra volumes could put downward pressure on differentials and Brent crude oil futures.

“It’s plenty as refineries are extending maintenance where they can due to awful margins,” one trader said.

Even though European refineries are in the midst of autumn maintenance and margins should be relatively healthy, a Rotterdam-based refiner cracking Brent is currently only making about $1 a barrel, according to Reuters’ data.

This is down from $6.64 a barrel in June, and reflects heavy competition from U.S. refiners who have stepped up exports to Europe and West Africa, eroding European refiners’ market share.

On the flip side, another trader cautioned that “historically the North Sea has tended to overpromise and underdeliver”.

A flow restriction on the Forties pipeline that has limited output since August could pale into insignificance if workers at Grangemouth do decide to down tools.

BP (LSE: BP.L – news) ‘s Kinneil terminal, which processes Forties from the pipeline, relies on steam and power from Grangemouth for its trains. A strike at Grangemouth in 2008 shut down the pipeline entirely.