WAfrica Crude-Nigerian slips on poor refining margins

* Qua Iboe valued at dated BFOE plus $1.40, down 5 cents

* India's BPCL buyers Bonny Light and ultra light Agbami

* Angolan steady with signs of more Asian demand for January

* U.S. Gulf refining margins flat or negative and weakening

LONDON, Nov 11 (Reuters) - Nigerian crude oil differentials came under pressure on Wednesday, undermined by increasingly poor refining in the U.S. Gulf and weakening interest in distillate-rich crudes.

Angolan crudes appeared to stabilise after several days of lower differentials. Angolan crude oil differentials have weakened by between 20-40 cents this month, while lighter Nigerian crude differentials have softened by 10-20 cents.

"U.S. Gulf margins are very bad," said one trader with a large bank-owned company. "Gasoline has been fully nailed in the Gulf, distillate demand is poor and paraffinic grades are under real pressure."