Demulsifiers, their preparation and use in oil bearing formations

The invention comprises a polymeric demulsifier, methods of producing the demulsifier and methods of using the demulsifier. The demulsifier is the reaction product of at least one amine-containing group, and optionally a second amine-containing group which includes a tertiary amine group, with a diepoxy- or diglycidyl compound and an additional amine compound subsequently reacted with unreacted epoxy groups. This polymeric composition is subsequently reacted with N-alkylating agent containing compounds to produce novel demulsifiers useful to demulsify oil bearing formations.