North Sea Crude-Nigerian outage seen supportive

LONDON, May 13 (Reuters) - * The market was very quiet on Friday, but differentials were expected to be supported next week by outages from competing Nigerian light sweet crude oil.

* Exxon Mobil (Swiss: XOM.SW - news) confirmed on Friday that it had declared a force majeure on Nigeria's Qua Iboe crude oil grade (BFO-QUA), and that a portion of production had been curtailed.

* This adds to partial or full outages for Bonny Light, Forcados and Escravos grades, as well as outages in Canada and Libya.

* OPEC said the global oil market is over-supplied and signalled the glut may increase this year, as surging output from its members makes up for losses from other countries whose production has been hit by a price fall.

* Glencore (Xetra: A1JAGV - news) has built up one of the largest positions in part of the Brent crude market which acts as a benchmark for global oil prices since the start of the year, when Royal Dutch Shell (Xetra: A0ET6Q - news) deployed a similar strategy, trade sources say.

WINDOW SUMMARY

* There was a bid from Chevron (Euronext: CHTEX.NX - news) for a 6-10 loading June Forties cargo at dated Brent plus 10 cents that was withdrawn.

* There was also a bid from PetroIneos for a June 5-10 loading cargo at dated Brent plus 20 cents.

* There were no trades. (Reporting by Simon Falush; Editing by Elaine Hardcastle)