Hydrogen production by downhole electrolysis of reservoir brine for enhanced oil recovery

Systems and methods of enhancing oil recovery with an electrochemical apparatus include introducing the electrochemical apparatus into an injection well bore. The electrochemical apparatus includes an anode, a cathode and an interior wall, the interior wall defining an interior that contains both the anode and the cathode. The electrochemical apparatus is operated such that injection water of the injection well bore is introduced into the interior of the electrochemical apparatus. Electrical power is introduced to the electrochemical apparatus such that a portion of the injection water is converted into a product gas, the product gas including hydrogen gas and oxygen gas. The electrochemical apparatus is operated such that the product gas forms product gas bubbles and the product gas bubbles travel into a formation, where the product gas bubbles react with a reservoir hydrocarbon of the formation to form a production fluid that is produced through a production well bore.