A method and system for both enhancing oil recovery of a reservoir and permanently sequestering carbon dioxide (CO2) is described. The method includes dissolving CO2 in a base fluid at a surface location of an injection formation, forming a dense CO2-brine solution, introducing the dense CO2-brine solution into an injection well, accumulating a volume of the dense CO2-brine solution in a structural low, displacing a native formation fluid from the injection well, increasing a fluid drive pressure from the injection well to a producing well, and displacing hydrocarbons of the producing well. The system includes an injection system in fluid communication with an injection well, a production well of the hydrocarbon production formation, and a dense CO2-brine solution that has a density greater than a native formation fluid of the injection formation.