LONDON, Sept 11 (Reuters) – Nigerian crude oil differentials were weak on Thursday as a global glut of physical supply encouraged buyers to choose competitively priced crude from other regions. Nearly half of the 63 Nigerian cargoes for October export were still available about a week before November-loading cargoes come to market. Strong margins for European refiners failed to provide support for Nigerian crude. The gasoline crack was at its highest since July, a factor that would n