North Sea Crude-Forties, Brent rise on tighter supply, Nigerian outages

LONDON, May 16 (Reuters) - * North Sea Forties and Brent differentials rose, supported by tighter June supply and Nigerian outages, although offers of Forties from floating storage limited the rise. * Ekofisk weakened slightly as Glencore (Xetra: A1JAGV - news) , which traders said had amassed a big June BFOE position, sold two cargoes, while Oseberg was unchanged.

WINDOW SUMMARY

* Forties: Total (LSE: 524773.L - news) offered a number of cargoes from floating storage including a May 26-31 cargo on a ship-to-ship transfer basis from the Maran Thetis at July cash BFOE minus 70 cents, equal to roughly dated Brent parity.

* Petroineos bid for Forties loading on May 27-June 5 at dated Brent plus 55 cents. The two indications valued Forties at dated plus 30 cents, up from about dated Brent plus 25 cents on Friday.

* Brent: The grade was valued at dated Brent plus 35 cents, higher than the last Reuters assessment.

* Ekofisk: Glencore sold cargoes loading on June 1-5 and May 31-June 2 at dated Brent plus $1.05 and plus 90 cents respectively, slightly lower than Friday's assessment.

* Oseberg: Was offered at dated Brent plus $1.30, in line with the last price assessment. (Reporting by Alex Lawler, editing by David Evans)