US-12618305-B2 - Systems and methods for recovering ammonia from a subsurface formation

US12618305B2US 12618305 B2US12618305 B2US 12618305B2US-12618305-B2

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.

Inventors

Fahad Khan
Mohamed Ahmed Nasr Aldeen Mahmoud
Arshad RAZA
Murtadha J. AlTammar
Shirish PATIL

Assignees

KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS
SAUDI ARABIAN OIL COMPANY

Dates

Publication Date: 20260505
Application Date: 20240610

Claims (14)

1 . A system for recovering ammonia from an endothermic reaction in a subsurface formation, the system comprising: 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; one or more ammonia retention vessels fluidly connected to the return lines for receiving the ammonia through the wellbore annulus; a hydrochloric acid storage vessel comprising hydrochloric acid; a mixing apparatus fluidly connected downstream from the one or more ammonia retention vessels and the storage vessel comprising the hydrochloric acid; and a recycled ammonium chloride storage vessel fluidly connected downstream from the mixing apparatus for receiving a recycled ammonium chloride stream from the mixing apparatus.
2 . The system of claim 1 , wherein the endothermic fluid composition comprises an aqueous solution and at least one of: ammonium chloride; ammonium chloride and sodium hydroxide; or ammonium chloride and barium hydroxide.
3 . The system of claim 1 , wherein the tubing string further comprises a packer assembly positioned on the exterior of the tubing string, the packer assembly configured to form a seal against the wellbore when actuated, thereby isolating the wellbore annulus from a surface of the wellbore to the packer assembly.
4 . The system of claim 1 , further comprising one or more coolant loops configured to cool the ammonia or the recycled ammonium chloride stream.
5 . The system of claim 1 , further comprising a condenser fluidly connected downstream from the mixing apparatus, the condenser configured to condense gaseous ammonium chloride in the recycled ammonium chloride stream.
6 . The system of claim 5 , further comprising a recrystallization unit positioned downstream of the mixing apparatus, the condenser, or both, the recrystallization unit configured to convert the recycled ammonium chloride stream to a solid ammonium chloride product.
7 . The system of claim 1 , further comprising a hydrocracker fluidly connected downstream from the one or more ammonia retention vessels, the hydrocracker configured to crack the ammonia in the presence of a hydrocracking catalyst to produce hydrogen gas and nitrogen.
8 . A method for recovering ammonia from a subsurface formation fluidly connected to a wellbore, the method comprising: introducing an endothermic fluid composition into the wellbore through one or more injections lines fluidly connected to a wellhead, the wellhead fluidly connected to the wellbore, and the endothermic fluid composition introduced via one or more fluid injection pumps; reacting an ammonium chloride component of the endothermic fluid composition, thereby decreasing a temperature of an aqueous solution in the endothermic fluid and producing ammonia; 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; recovering the ammonia through one or more return lines fluidly connected to the wellhead, wherein: the endothermic fluid composition is injected into the wellbore through a tubing string positioned within the wellbore, the tubing string fluidly connected to the wellhead and the one or more injection lines, and the ammonia is recovered up a wellbore annulus defined by the wellbore and an exterior of the tubing string, the wellbore annulus fluidly connected to the wellhead and the one or more return lines; circulating the ammonia recovered through the one or more return lines to an ammonia retention vessel; introducing the ammonia from the ammonia retention vessel and hydrochloric acid from a hydrochloric acid storage vessel to a mixing apparatus; and mixing the ammonia and hydrochloric acid, thereby forming a recycled ammonium chloride stream.
9 . The method of claim 8 , further comprising: prior to introducing the endothermic fluid composition into the wellbore, actuating a packer assembly positioned on the exterior of the tubing string, thereby forming a seal against a surface of the wellbore and isolating the wellbore annulus from a surface of the wellbore to the packer assembly; and after exposing the reacted endothermic fluid composition to the subsurface formation, de-actuating the packer assembly to enable flowback of the ammonia and endothermic fluid up the wellbore annulus.
10 . The method of claim 8 , further comprising recycling the recycled ammonium chloride stream to one or more fluid injection pumps configured to introduce the endothermic fluid composition into the wellbore through the one or more injection lines.
11 . The method of claim 8 , further comprising: exposing the ammonia from the ammonia retention vessel to one or more coolant loops prior to introducing to the mixing apparatus; exposing the recycled ammonium chloride stream to the one or more coolant loops; or both.
12 . The method of claim 8 , further comprising introducing the recycled ammonium chloride stream to a condenser, thereby condensing gaseous ammonium chloride in the recycled ammonium chloride stream.
13 . The method of claim 12 , further comprising introducing the recycled ammonium chloride stream to a recrystallization unit, thereby forming a solid ammonium chloride product.
14 . The method of claim 8 , further comprising exposing the ammonia to a hydrocracking catalyst in a hydrocracker, thereby producing hydrogen and nitrogen.

Description

FIELD The present disclosure generally relates to methods, compositions, and systems for producing fluids from subsurface formations. More particularly, embodiments herein relate to methods and compositions for thermally shocking a subsurface formation, as well as systems and methods for recovering ammonia therefrom, as detailed herein. BACKGROUND Unconventional reservoir rocks are typically characterized by very low permeability and porosity. To make cost-effective production from these reservoirs, unconventional means such as horizontal drilling and hydraulic fracturing are typically practiced. In hydraulic fracturing, also referred to as ‘fracking’, a fluid is pumped at high pressure into the subsurface formation, generating one or more elongated fractures in the subsurface formation that may be propped open by a subsequently placed proppant. These propped open fractures form a higher permeability conduit within the formation, enabling increasing recovery of fluids from the same. However, during hydraulic fracturing, the formation breakdown pressure (pressure at which the first fractures begin to form) is of great importance and depends on geomechanical characteristics (strength and Poisson's ratio). As previously mentioned, typically great pressures and large amounts of injected fluid are needed to achieve initial formation breakdown, adding substantial cost and material needs to the process. SUMMARY Thus, continuously desired are alternative or supplemental methods to reduce the amount of fluid and/or pressure need to fracture subsurface formations. Embodiments herein fulfill the aforementioned need by providing compositions and methods for inducing thermal shock in the subsurface formation, which is often are present at elevated temperatures, thereby softening and/or forming one or more fractures in the same. The resultant softening and/or one or more fractures may operate to decrease a compressive strength and Poisson's ratio of the subsurface formation, thereby also decreasing the formation breakdown pressure. The net result is that subsequent hydraulic fracturing operations may need to use less fluid and less pressure to adequately fracture the subsurface formation, thereby resulting in considerable cost and materials saving. Particularly, in one more embodiments herein, an endothermic fluid composition is provided that may rapidly decrease in temperature when reacted, also forming ammonia. When exposed to a subsurface formation, the reacted endothermic fluid may reduce the temperature of the same, inducing thermal shock in the subsurface formation. Furthermore, to recycle and/or further utilize the ammonia produced from the reacted endothermic fluid, methods and systems are provided for recovery of the ammonia from the subsurface formation. Particularly, ammonia gas may be recovered from the backside of the wellbore, i.e., the wellbore annulus, wherein the ammonia gas may be recycled back into ammonium chloride for re-use or converted into hydrogen gas as a fuel source. In accordance with one embodiment of the present disclosure, 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. In accordance with another embodiment of the present disclosure, a method for recovering ammonia from a subsurface formation fluidly connected to a wellbore may comprise introducing an endothermic fluid composition into the wellbore through one or more injections lines fluidly connected to a wellhead, the wellhead fluidly connected to the wellbore; reacting an ammonium chloride component of the endothermic fluid composition, thereby decreasing a temperature of an aqueous solution in the endothermic fluid and producing ammonia; 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; and recovering the ammonia through one or more return lines fluidly connected to the wellhead. BRIEF DESCRIPTION OF THE DRAWINGS The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like referenc