* Output to fall on maintenace, upward Feb revisions
* Flotta programme yet to emerge for March
* February's total on course to be highest since June
By Alex Lawler
LONDON, Feb 7 (Reuters) - North Sea oil output is set to fall by at least 10 percent in March from February partly due to maintenance at Britain's largest oilfield, which may lend support to Brent oil prices.
Output from 11 of the 12 crude streams tracked by Reuters will average 1.83 million barrels per day (bpd) based on the latest loading schedules compiled on Thursday, down from 2.08 million bpd for all 12 in February.
Swings in output from the North Sea can have a significant impact on world prices because the region is home to the dated Brent benchmark, used to price much of the world's physical oil and part of the underlying market for Brent futures.
Countering lower supply, shipments of Forties crude to South Korea, a specialised trade that supports prices, may drop in coming weeks due to maintenance at South Korean refineries, leaving more oil in northwest Europe looking for buyers.
"The reported loading schedules do suggest lower output in March and this should tighten the market," said Eugene Lindell, senior crude analyat at JBC Energy in Vienna. "On the other hand, the Forties arbitrage would seem to be less viable."
Brent is based on four crude oils: Brent, Forties, Oseberg and Ekofisk (BFOE). They are set to pump around 871,000 bpd in March, loading programmes showed, down from an upwardly-revised rate in February of 986,000 bpd.
Work at the Buzzard oilfield, the largest of the fields contributing to Forties supply, is expected to curb Forties output in March. Supply of Ekofisk and Brent will be lower because delayed January shipments increased February's total.
The 200,000-bpd Buzzard field, operated by Canadian oil company Nexen is scheduled to undergo about four days of pipeline inspection and maintenance in early March, trade sources said.
Partly as a result of that work, Forties output is scheduled to average 368,000 bpd in March, down from a current expectation for February of 429,000 bpd.
February's North Sea total is set to be the highest since June 2012, according to monthly schedules tracked by Reuters, when output was 2.11 million bpd.
Loading programmes are usually issued to equity holders between the 1st and 10th of each month. Reuters attempts to track significant revisions based on actual production levels.
A programme for the smallest stream tracked by Reuters, Flotta, is not expected to emerge until next week. If Flotta loads two cargoes in March, March's total would be 1.87 million bpd - down 10 percent on February's figure.
Brent prices still reflect a perception of tight supply, although the premium at which oil for immediate delivery is trading has fallen in 2013. The first month contract was trading 91 cents above the second month on Thursday, down from $1.28 on Jan. 2.