LONDON, Aug 29 (Reuters) - The loading of North Sea Forties crude oil cargoes is facing delays in September because of lower-than-expected output, two trade sources said on Tuesday, affecting supplies of the crude which helps set the Brent oil benchmark.
The Forties pipeline was originally scheduled to load 380,000 barrels per day (bpd) in September, a lower-than-usual rate due to planned seasonal maintenance at offshore oilfields connected to the line.
On Tuesday, UK oil company Serica Energy said the Erskine field, in which it holds a stake and which exports oil via the Forties pipeline, would restart after maintenance later than previously thought.
The field pumps about 8,000 bpd according to UK government data.
While the volume is small, this could have a further impact on Forties loadings in September, which are already subject to deferral options, trade sources said.
"Over the whole month it works out as quite a bit to lose from the program," a trade source said.
In addition, two trade sources said on Friday the larger, Total-operated Elgin-Franklin field was returning to operation from maintenance later than expected, also reducing Forties output.
Total did not respond to a request for comment.
Forties, together with the North Sea Brent, Oseberg and Ekofisk crudes, underpin the Brent benchmark used for most of the world's oil trades. (Reporting by Alex Lawler; Editing by Mark Potter)