North Sea Crude-Trafigura buys 4 WTI cargoes, bids up Forties

LONDON, June 21 (Reuters) - U.S. WTI Midland crude differentials rose on Friday after Trafigura bought four cargoes, while differentials for North Sea grades increased due to strong bidding from Trafigura and Gunvor. * Keen buying interest across grades from the two trading firms has supported the market this week. * One trade source said, after Friday's spate of deals, he expected differentials to fall next week. PLATTS WINDOW * Indications are on a free-on-board (FOB) basis unless marked as cost, insurance and freight (CIF) or delivered at place (DAP). * WTI Midland: Trafigura bought four cargoes on a CIF Rotterdam basis, of which Exxon sold two and Phillips 66 and BP one each. * Three of the deals were at dated plus $2.45 and one at dated plus $2.35, resulting in an average of dated plus $2.43 or dated plus $1.18 on an FOB basis according to Reuters calculations, up from Thursday. * Forties: Trafigura bid for July 2-22 at dated Brent plus $1.25 cents, up from Thursday's bid. * Troll: Gunvor bid July 1-25 at dated plus $3.15, up from Thursday's bid. * Oseberg: Trafigura bid July 3-13 at dated Brent plus $2.75, up from Thursday's bid. * Brent: Gunvor bid July 1-25 at dated plus $1.45. * Ekofisk: Trafigura bid July 2-24 at dated Brent plus $2.40, up from Wednesday's bid. (Reporting by Alex Lawler, Editing by Josie Kao)