Abstract: A system for recovering ammonia from an endothermic reaction in a subsurface formation may comprise a subsurface formation; a wellbore fluidly connected to the subsurface formation; a tubing string positioned within the wellbore, wherein the wellbore and an exterior of the tubing string together define a wellbore annulus; a wellhead comprising one or more injection lines and one or more return lines fluidly connected to the wellbore; one or more fluid injection pumps configured to supply an endothermic fluid composition to the subsurface formation through the one or more injection lines and the tubing string, the endothermic fluid composition operable to form ammonia when reacted; and one or more ammonia retention vessels fluidly connected to the return lines for receiving the ammonia through the wellbore annulus.

Abstract: A crosslinked endothermic fluid composition may comprise an aqueous solution; ammonium chloride; a polymer; and a crosslinker. A method of thermally shocking a subsurface formation may comprise introducing the crosslinked endothermic fluid composition into a wellbore fluidly connected to the subsurface formation; exposing the crosslinked endothermic fluid composition to the subsurface formation, such that a temperature of the subsurface formation at least partially breaks a crosslink of the crosslinked endothermic fluid composition and exposes at least a portion of the ammonium chloride; reacting the ammonium chloride in the crosslinked endothermic fluid composition with fluids of the subsurface formation, thereby decreasing a temperature of the subsurface formation and producing ammonia; and thermally shocking the subsurface formation via the decreased temperature and produced ammonia, thereby inducing one or more fractures in the subsurface formation.

Abstract: A thermochemical engine that includes a reaction chamber having a nitrite source inlet, an ammonium source inlet, and a gas outlet, and a gas-driven energy transducer coupled to the reaction chamber such that a gas produced in the reaction chamber moves the gas-driven energy transducer in a process of exiting the reaction chamber via the gas outlet. The thermochemical engine is configured to produce the gas under pressure by reacting in the reaction chamber a nitrite source comprising a nitrite ion and an ammonium source comprising an ammonium ion in the presence of water at a reaction temperature of 50 to 150° C.

Abstract: A method of thermally shocking a subsurface formation may comprise introducing an endothermic fluid composition into a wellbore fluidly connected to the subsurface formation, the endothermic fluid composition comprising an aqueous solution, ammonium chloride, and sodium hydroxide; reacting the ammonium chloride and sodium hydroxide, thereby decreasing a temperature of the endothermic fluid and producing ammonia; and exposing the reacted endothermic fluid composition to the subsurface formation, thereby thermally shocking at least a portion of the subsurface formation and inducing one or more fractures in the same.

Abstract: A system for recovering ammonia from an endothermic reaction in a subsurface formation may comprise a subsurface formation; a wellbore fluidly connected to the subsurface formation; a tubing string positioned within the wellbore, wherein the wellbore and an exterior of the tubing string together define a wellbore annulus; a wellhead comprising one or more injection lines and one or more return lines fluidly connected to the wellbore; one or more fluid injection pumps configured to supply an endothermic fluid composition to the subsurface formation through the one or more injection lines and the tubing string, the endothermic fluid composition operable to form ammonia when reacted; and one or more ammonia retention vessels fluidly connected to the return lines for receiving the ammonia through the wellbore annulus.

Abstract: A method of thermally shocking a subsurface formation may comprise introducing an endothermic fluid composition into a wellbore fluidly connected to the subsurface formation, the endothermic fluid composition comprising an aqueous solution, ammonium chloride, and sodium hydroxide; reacting the ammonium chloride and sodium hydroxide, thereby decreasing a temperature of the endothermic fluid and producing ammonia; and exposing the reacted endothermic fluid composition to the subsurface formation, thereby thermally shocking at least a portion of the subsurface formation and inducing one or more fractures in the same.

Abstract: A thermochemical engine that includes a reaction chamber having a nitrite source inlet, an ammonium source inlet, and a gas outlet, and a gas-driven energy transducer coupled to the reaction chamber such that a gas produced in the reaction chamber moves the gas-driven energy transducer in a process of exiting the reaction chamber via the gas outlet. The thermochemical engine is configured to produce the gas under pressure by reacting in the reaction chamber a nitrite source comprising a nitrite ion and an ammonium source comprising an ammonium ion in the presence of water at a reaction temperature of 50 to 150° C.

Abstract: A thermochemical engine that includes a reaction chamber having a nitrite source inlet, an ammonium source inlet, and a gas outlet, and a gas-driven energy transducer coupled to the reaction chamber such that a gas produced in the reaction chamber moves the gas-driven energy transducer in a process of exiting the reaction chamber via the gas outlet. The thermochemical engine is configured to produce the gas under pressure by reacting in the reaction chamber a nitrite source comprising a nitrite ion and an ammonium source comprising an ammonium ion in the presence of water at a reaction temperature of 50 to 150° C.

Abstract: A thermochemical engine that includes a reaction chamber having a nitrite source inlet, an ammonium source inlet, and a gas outlet, and a gas-driven energy transducer coupled to the reaction chamber such that a gas produced in the reaction chamber moves the gas-driven energy transducer in a process of exiting the reaction chamber via the gas outlet. The thermochemical engine is configured to produce the gas under pressure by reacting in the reaction chamber a nitrite source comprising a nitrite ion and an ammonium source comprising an ammonium ion in the presence of water at a reaction temperature of 50 to 150° C.