LONDON, Oct 28 (Reuters) - Supply of the five North Seacrude oil grades underpinning the dated Brent benchmark willaverage about 833,000 barrels per day (bpd) in December,compared with 820,000 bpd in November, loading programmesshowed.

Dated Brent is based on the Brent, Ekofisk, Oseberg, Fortiesand Troll crude streams.

(Reporting by Alex Lawler; editing by Jason Neely) ((alex.lawler@thomsonreuters.com;))