A method of recovering petroleum from dormant oil wells or increasing the production of oil wells. An alkali or alkali earth carbonate is introduced into a water layer associated with a subterranean petroleum reservoir and/or an explosive composition is introduced into an oil layer associated with a subterranean petroleum reservoir. CO2 gas is produced by reacting the alkali or alkali earth carbonate with an acid and/or by detonating the explosive composition. An explosive composition can be introduced and detonated to achieve sufficient CO2 gas production to increase pressure within the subterranean petroleum reservoir.