LONDON, Nov 6 (Reuters) -Crude differentials for U.S. WTI Midland, North Sea Forties and Ekofisk weakened on Wednesday after lower offers and a lack of buying interest.

PLATTS WINDOW

* Indications are free on board (FOB) unless marked as cost, insurance and freight (CIF) or delivered at place (DAP).

* No deals, a trade source said.

* WTI Midland: Gunvor offered CIF Rotterdam Nov. 28-Dec.2 at dated Brent plus $1.55, down 25 cents from a deal on Tuesday. It equated to about dated plus 59 cents on an FOB basis, Reuters calculations show.

* Forties: Mercuria offered a cargo at dated plus 50 cents, down 30 cents from a bid on Tuesday.

* Ekofisk: Eni offered Nov. 24-26 at dated Brent plus $1.25, down from indications on Tuesday. Allowing for the Platts quality premium of 69 cents for November cargoes, that is equal to dated Brent plus 56 cents, Reuters calculations show.

* As a result, Forties becomes the cheapest of the benchmark grades and sets the dated Brent value.

Reporting by Alex Lawler
Editing by David Goodman

Alexandra Hudson NORTH SEA CRUDE OIL DIFFERENTIALS AND OUTRIGHT PRICES: 0#BFO-DIF 0#C-E Dated BFO BFO- Brent BFO-BRT BFO-E Forties BFO-FOT FOT-E Oseberg BFO-OSE OSE-E Ekofisk BFO-EKO EKO-E Monthly North Sea crude loading programmes O/LOAD OPEC OPEC NSEA North Sea CRU crude oil PROD oil products DRV derivatives PRO/E European products OILOIL NYMOIL, IPEOIL, OILSPD, OILARB CRDWLDPRODEUR, PRODUS, APROD ENERGY energy speed guide CRUDE/1 crude speed guide