Thermochemical cycling for thermal shocking of subsurface formations

Abstract

A method of thermally shocking a subsurface formation may comprise introducing an endothermic fluid composition comprising a first aqueous solution and ammonium chloride into the subsurface formation via a wellbore fluidly connected to the subsurface formation; reacting the ammonium chloride with fluids of the subsurface formation, thereby decreasing a temperature of the subsurface formation, producing ammonia, and thermally shocking the subsurface formation, thereby inducing one or more fractures in the subsurface formation; introducing an exothermic fluid composition comprising a second aqueous solution, an ammonium-containing compound, and a nitrite-containing compound into the subsurface formation; and reacting the ammonium-containing compound and the nitrite-containing compound in the subsurface formation, thereby increasing the temperature of the subsurface formation, producing nitrogen, and inducing one or more additional fractures in the subsurface formation.