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US-12624275-B1 - Temperature-resistant and salt-tolerant in-situ plugging enhanced gel compositions, gels, preparation methods and applications

US12624275B1US 12624275 B1US12624275 B1US 12624275B1US-12624275-B1

Abstract

A temperature-resistant and salt-tolerant in-situ plugging-enhanced gel composition, a gel, and their preparation method and application are provided. The gel composition includes a first monomer, a second monomer, a first crosslinking agent, a second crosslinking agent, an initiator, an enhancer, and water; optionally, the composition further includes a third monomer. The gel can undergo re-crosslinking under stimulation by high temperature and CO 2 -acidic conditions to form the bulk gel, thereby avoiding issues associated with in-situ gel systems such as crosslinking uncertainty, chromatographic separation, and susceptibility to reservoir damage, while simultaneously achieving enhanced plugging capability under in-situ reservoir conditions.

Inventors

  • Zhenhua Rui
  • Yang Zhao
  • Jun Ni
  • Xin Wen
  • Liu Yang
  • Youwei He
  • Jirui ZOU
  • Fengyuan ZHANG
  • Ting Hu

Assignees

  • CHINA UNIVERSITY OF PETROLEUM-BEIJING

Dates

Publication Date
20260512
Application Date
20251203
Priority Date
20250724

Claims (16)

  1. 1 . A composition for a temperature-resistant and salt-tolerant in-situ plugging-enhanced gel, wherein the composition comprises a first monomer, a second monomer, a first crosslinking agent, a second crosslinking agent, an initiator, an enhancer, and water; optionally, the composition further comprises a third monomer; the first monomer is selected from at least one of 2-acrylamidomethyl-2-methylpropanesulfonic acid, sodium styrenesulfonate, vinylsulfonic acid, p-styrenesulfonic acid, 4-styrenesulfonic acid, methyl acrylate sulfobutyl ester, and acrylic acid hydroxypropylsulfonic acid ester; the second monomer is selected from at least one of N-vinylpyrrolidone, acrylic diethylenaminoethyl ester, methyl acrylate dimethylaminoethyl ester, vinyl imidazole, vinylpyridine, and acrylic hydroxyethyl ester; the third monomer is selected from at least one of N-isopropylacrylamide, acrylic hydroxyethyl ester, and N-(3-aminopropyl)methylacrylamide; the first crosslinking agent is polyethylene glycol bisacrylate; the second crosslinking agent is selected from a second acid-sensitive crosslinking agent and/or a second temperature-sensitive crosslinking agent; the second acid-sensitive crosslinking agent is selected from at least one of benzylboronic acid phenyl ether, boronic acid tributyl ester, boronic acid triethyl ester, boronic acid diglyceride, and boronic acid trimethyl ester; the second temperature-sensitive crosslinking agent is selected from at least one of 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, hexamethylene diisocyanate-butyrolactone end-capped compound, and bis(tri methylsilyl)amino propyl triethoxysilane; and based on a total weight of the composition, a content of the first monomer is 5 wt %-40 wt %, a content of the second monomer is 5 wt %-30 wt %, a content of the third monomer is 0 wt %-10 wt %, a content of the first crosslinking agent is 0.01 wt %-1 wt %, a content of the second crosslinking agent is 0.01 wt %-1 wt %, a content of the enhancer is 0.01 wt %-10 wt %, a content of the initiator is 0.01 wt %-1 wt %, and a remainder is the water.
  2. 2 . The composition according to claim 1 , wherein based on the total weight of the composition, the content of the first monomer is 10 wt %-35 wt %, the content of the second monomer is 8 wt %-20 wt %, the content of the third monomer is 0 wt %-5 wt %, the content of the first crosslinking agent is 0.05 wt %-0.5 wt %, the content of the second crosslinking agent is 0.05 wt %-0.5 wt %, the content of the enhancer is 0.05 wt %-5 wt %, the content of the initiator is 0.05 wt %-0.5 wt %, and the remainder is the water.
  3. 3 . The composition according to claim 1 , wherein the enhancer is a nanoparticle material having an average particle diameter of 10 nm-200 nm; and/or, the enhancer is selected from at least one of nano-bentonite, nano-silica, nano-titanium oxide, nano-aluminum oxide, nano-calcium carbonate, carbon nanotubes, and graphene.
  4. 4 . The composition according to claim 3 , wherein the initiator is selected from at least one of ammonium per sulfate, sodium per sulfate, potassium per sulfate, tetramethyl ethylenediamine, and azobis(isobutyronitrile).
  5. 5 . A method for preparing a temperature-resistant and salt-tolerant in-situ plugging-enhanced gel, wherein the method uses the composition according to claim 1 , and comprises: mixing and contacting various components of the composition to obtain the gel.
  6. 6 . The method according to claim 5 , wherein a step of performing the mixing and the contacting comprises: (1) in presence of the water, subjecting the enhancer to ultrasonic dispersion treatment to obtain solution 1; (2) performing a first contact between the solution 1 and a monomer material containing the first monomer and the second monomer to obtain solution 2; and the monomer material optionally further containing the third monomer; (3) sequentially adding the first crosslinking agent, the second crosslinking agent, and the initiator to the solution 2 to perform a second contact, and subjecting resulting solution 3 to gelation treatment to obtain intermediate product 1; and (4) subjecting the intermediate product 1 to drying treatment to obtain the gel.
  7. 7 . The method according to claim 6 , wherein in step (1), a time for the ultrasonic dispersion treatment is 20 min-60 min; and/or, in step (2), conditions for the first contact comprise: a temperature of 20-60° C., a time of 0.5-3 h, and a stirring speed of 500-1500 rpm; and/or, in step (3), conditions for the second contact comprise: a temperature of 20-60° C., a time of 1-6 h, and a stirring speed of 500-1500 rpm; and conditions for the gelation treatment comprise: a temperature of 30-90° C. and a time of 4-24 h; and and/or, in step (4), conditions for the drying treatment comprise: a temperature of 40-90° C. and a time of 20-72 h.
  8. 8 . The method according to claim 6 , wherein the method further comprises, in step (2), after performing the first contact, first adjusting a pH value of the solution 2 to 7-8, and then performing step (3).
  9. 9 . A gel prepared by the method according to claim 5 .
  10. 10 . A use of the gel according to claim 9 in at least one field selected from the group consisting of oilfield extraction, subterranean CO 2 channeling control, and CO 2 geological storage.
  11. 11 . The gel according to claim 9 , wherein in the method, a step of performing the mixing and the contacting comprises: (1) in presence of the water, subjecting the enhancer to ultrasonic dispersion treatment to obtain solution 1; (2) performing a first contact between the solution 1 and a monomer material containing the first monomer and the second monomer to obtain solution 2; and the monomer material optionally further containing the third monomer; (3) sequentially adding the first crosslinking agent, the second crosslinking agent, and the initiator to the solution 2 to perform a second contact, and subjecting resulting solution 3 to gelation treatment to obtain intermediate product 1; and (4) subjecting the intermediate product 1 to drying treatment to obtain the gel.
  12. 12 . The gel according to claim 11 , wherein in the method, in step (1), a time for the ultrasonic dispersion treatment is 20 min-60 min; and/or, in step (2), conditions for the first contact comprise: a temperature of 20-60° C., a time of 0.5-3 h, and a stirring speed of 500-1500 rpm; and/or, in step (3), conditions for the second contact comprise: a temperature of 20-60° C., a time of 1-6 h, and a stirring speed of 500-1500 rpm; and conditions for the gelation treatment comprise: a temperature of 30-90° C. and a time of 4-24 h; and and/or, in step (4), conditions for the drying treatment comprise: a temperature of 40-90° C. and a time of 20-72 h.
  13. 13 . The gel according to claim 11 , wherein in the method, the method further comprises, in step (2), after performing the first contact, first adjusting a pH value of the solution 2 to 7-8, and then performing step (3).
  14. 14 . The method according to claim 5 , wherein in the composition, based on the total weight of the composition, the content of the first monomer is 10 wt %-35 wt %, the content of the second monomer is 8 wt %-20 wt %, the content of the third monomer is 0 wt %-5 wt %, the content of the first crosslinking agent is 0.05 wt %-0.5 wt %, the content of the second crosslinking agent is 0.05 wt %-0.5 wt %, the content of the enhancer is 0.05 wt %-5 wt %, the content of the initiator is 0.05 wt %-0.5 wt %, and the remainder is the water.
  15. 15 . The method according to claim 5 , wherein in the composition, the enhancer is a nanoparticle material having an average particle diameter of 10 nm-200 nm; and/or, the enhancer is selected from at least one of nano-bentonite, nano-silica, nano-titanium oxide, nano-aluminum oxide, nano-calcium carbonate, carbon nanotubes, and graphene.
  16. 16 . The method according to claim 15 , wherein in the composition, the initiator is selected from at least one of ammonium per sulfate, sodium per sulfate, potassium per sulfate, tetramethyl ethylenediamine, and azobis(isobutyronitrile).

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS This application is based upon and claims priority to Chinese Patent Application No. 202511028929.X, filed on Jul. 24, 2025, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD This invention relates to the field of oilfield chemical technology, and specifically to a temperature-resistant and salt-tolerant in-situ plugging enhanced gel composition, the gel, as well as its preparation method and application. BACKGROUND Geological resources such as crude oil, natural gas, natural gas hydrates, and geothermal fluids are all stored in underground reservoirs. To achieve efficient development, it is necessary to inject fluids (water, CO2, steam, polymer solutions, etc.) into the ground to supplement formation energy, thereby extracting these resources from the underground. In addition, underground space utilization technologies such as carbon sequestration and gas storage also require injecting fluids into underground reservoirs to achieve stable storage of fluids. The prerequisite for the successful application of the above technologies is that the injected fluids can achieve balanced migration and distribution within the reservoirs. However, geological reservoirs often exhibit strong heterogeneity due to the influence of multiple factors such as sedimentation, tectonism, diagenesis, and fluids. After fluids are injected into the ground, they are prone to channeling, leakage, and other phenomena along faults, natural fractures, artificial fractures, micro-fractures, and high-permeability layers. This has become a key factor restricting the efficient development of geological energy and the safe utilization of underground space. To address the above-mentioned issues of fluid channeling and leakage, the use of gels to plug channeling and leakage paths has long been regarded as an economical and effective method to reduce reservoir heterogeneity. Underground crosslinking systems are widely used channeling-plugging systems in oilfield sites. Typically, polymers, crosslinking agents, and other chemical agents are formulated into gel-forming solutions, which are then injected into the ground. These solutions form gels at a certain temperature in the formation, thereby plugging the formation. Nevertheless, such gels often face uncertainties during the gel-forming process, resulting in poor plugging performance. On one hand, after being injected into the ground, the gel-forming solution tends to enter non-target layers, and gel formation in these layers causes damage to the reservoir. On the other hand, when the gel-forming solution passes through the porous media of the formation, the different interactions between various components in the solution and the rock surface lead to differences in migration rates. This phenomenon of chromatographic separation affects the subsequent gel-forming performance of the gel system. Different from the above-mentioned channeling-plugging systems, pre-crosslinked particle gel systems are prepared by forming gels on the ground first, then processing them into gel particles. These gel particles are formulated into suspensions and injected into the ground, which avoids the uncertainties of gel-forming reactions under formation conditions. At present, a variety of particle gel channeling-plugging systems have been proposed at home and abroad in an attempt to solve the problem of formation heterogeneity. CN116023917A discloses a CO2-responsive gel system, its preparation method, and a method for preventing CO2 leakage in oil reservoirs. This system has low viscosity in the absence of CO2, making it easy to inject. After reacting with CO2, it forms a gel structure crosslinked by carbamates, achieving the effect of plugging CO2. During CO2 flooding or sequestration processes, injecting the CO2-responsive gel into formations that have leaked or are prone to leakage can effectively prevent and control CO2 leakage in oil reservoirs. CN119529180A discloses a dual-network CO2-responsive particle gel and its application method. The components of this system include 15%-20% acrylamide, 5%-10% zwitterionic monomer, 5%-10% CO2-responsive monomer, 0.25%-1% emulsifier, 0.05%-0.25% crosslinking agent, 0.075%-0.15% initiator, and the balance being water. Among them, the CO2-responsive monomer is composed of vinylpyridine and N,N-dimethylaminoethyl methacrylate at a mass ratio of (0.5-1):1. Subsequent laboratory core flooding experiments showed that when CO2 flooding was conducted in a core with a temperature of 60° C., a salinity of 10% in mineralized water, and a fracture width of 0.3 mm, the plugging rate of the gel particles reached 99.0%. CN105504158A discloses an intelligent gel particle capable of re-crosslinking under formation conditions and its preparation method. After entering the formation, these gel particles can re-crosslink with each other under formation conditions to form a high-strength gel, achieving effective p