How about making it, if you don’t controll an oil rich territory, all unit movemt, except INF and ART (they could use horses for that) have only half their movement, and may not blitz.
MECH, ARM, BB, DD,TP and SS move only 1
CV,CA and fig move 2
BOMBERS move 3
Could also be used in AAR and if defined also AARHE… Just define oil rich territories first.