In-reservoir carbon dioxide release for enhanced hydrocarbon recovery

A method comprising:

• introducing a carbonated aqueous fluid into a subterranean reservoir, the carbonated aqueous fluid comprising carbon dioxide dissolved in an aqueous fluid;
• introducing an aqueous flooding fluid into the subterranean reservoir prior to introducing the carbonated aqueous fluid, the carbonated aqueous fluid having a higher density than the aqueous flooding fluid;
• introducing a first salt into the subterranean reservoir;
• introducing a second salt into the subterranean reservoir;
• contacting the first salt with the second salt within the carbonated aqueous fluid in the subterranean reservoir under conditions where the first salt and the second salt undergo an exothermic reaction;
• heating the carbonated aqueous fluid with heat produced via the exothermic reaction;
• wherein at least a portion of the carbon dioxide is released from the carbonated aqueous fluid upon heating and migrates from a lower portion to an upper portion of the subterranean reservoir, and a decarbonated saline solution is generated from the carbonated aqueous fluid from which the carbon dioxide is released;
• mobilizing hydrocarbons in the upper portion of the subterranean reservoir toward a production well with the carbon dioxide that migrates to the upper portion of the subterranean reservoir;
• wherein the decarbonated saline solution promotes mobilization of hydrocarbons in a middle portion of the subterranean reservoir toward the production well, and the carbonated aqueous fluid promotes mobilization of hydrocarbons in the lower portion of the subterranean reservoir toward the production well;
• and
• producing at least a portion of each of the hydrocarbons from the production well.

A method comprising:

• introducing a carbonated aqueous fluid into a subterranean reservoir, the carbonated aqueous fluid comprising carbon dioxide dissolved in an aqueous fluid;
• introducing a first salt solution comprising a first salt into the subterranean reservoir after introducing the carbonated aqueous fluid, the first salt comprising a nitrite anion;
• introducing a second salt solution comprising a second salt into the subterranean reservoir after introducing the carbonated aqueous fluid, the second salt comprising an ammonium cation;
• contacting the first salt with the second salt in the subterranean reservoir under conditions where the nitrite anion of the first salt and the ammonium cation of the second salt undergo an exothermic reaction;
• heating the carbonated aqueous fluid with heat produced via the exothermic reaction;
• wherein at least a portion of the carbon dioxide is released from the carbonated aqueous fluid upon heating and migrates from a lower portion to an upper portion of the subterranean reservoir, and a decarbonated saline solution is generated from the carbonated aqueous fluid from which the carbon dioxide is released;
• wherein the decarbonated saline solution has a lower density than the carbonated aqueous fluid;
• and
• introducing an aqueous flooding fluid into the subterranean reservoir prior to introducing the carbonated aqueous fluid, the carbonated aqueous fluid having a higher density than the aqueous flooding fluid and the decarbonated saline solution.