New data on the mechanisms of intermediate layer formation in petroleum emulsions are reported. The possibility of structural phase transitions preceding the inversion points of these multicomponent media was experimentally demonstrated. Many features of these transitions are similar to the phase transitions in model dispersions of the Winsor III type. In manufacturing processes, the formation of undesirable "intermediate layers" can be interpreted as the appearance of a bicontinuous phase at ratios of the volume fractions of water and crude close to unity.