Water-blocking compositions and their applications, water-blocking agents

Abstract

This invention relates to water-blocking compositions and their applications, and water-blocking agents, belonging to the technical field of chemical products for water blocking. The water-blocking composition of this invention mainly consists of epoxy resin, epoxy curing agent, epoxy curing accelerator, reactive diluent, foaming agent, surfactant, and hydrophobic silica aerogel; the pore size of the hydrophobic silica aerogel is 0.1–300 nm. The water-blocking composition of this invention is a liquid with good fluidity and stability, facilitating transportation. When used for water blocking in oil and gas wells, the water-blocking composition of this invention can solidify at formation temperature. During the solidification process, the foaming agent releases gas, generating bubbles that connect with the channels of the hydrophobic silica aerogel, which has a rich nanoporous structure, forming airflow channels and reducing gas flow resistance. Simultaneously, the hydrophobicity of the hydrophobic silica aerogel enables the connected channels to produce a water-blocking effect, thereby achieving gas-water selectivity.

Description

Technical Field

[0001] This invention relates to water-blocking compositions and their applications, as well as water-blocking agents, and belongs to the technical field of chemical products for water-blocking. Background Technology

[0002] As gas is produced in the gas well, the formation pressure gradually decreases, and water-infiltrated gas reservoirs will produce a large amount of water. For normal production, the gas must be able to carry the water from the bottom of the wellbore. However, if the water production is too high, the pressure gradient of the lifting fluid must also be large, which will lead to a decrease in gas production, or even water lock, causing the gas well to shut down. Therefore, chemical plugging agents are injected to reduce water production, increase gas production, and extend the production period. Chemical plugging agents can be classified into physical deposition type and chemical reaction type according to their mechanism of action. Physical deposition type uses inorganic particles such as calcium carbonate and mica, or organic particles such as water-swellable materials and rubber particles, to achieve a temporary plugging effect. Chemical reaction type typically uses inorganic materials such as cement and quicklime, or organic materials such as gels and resins, to solidify and cross-link within the formation, forming a whole with the formation, thereby achieving a sealing effect. Resin-based plugging agents, such as epoxy resins, have the best overall performance among chemical reaction type plugging agents. Although existing epoxy resin-based chemical plugging agents have advantages such as high mechanical properties, good resistance to chemical corrosion (acids, alkalis, and salts), and long service life, and can be applied to various gas wells, especially those containing hydrogen sulfide, they do not have gas-water selectivity. As a result, the gas well reservoir will neither produce water nor gas after plugging, reducing the gas production of the gas well. Summary of the Invention

[0003] The purpose of this invention is to provide a water-blocking composition that can solve the problem that current epoxy resin-based chemical water-blocking agents lack gas-water selectivity when used for water blocking in gas wells.

[0004] A second objective of this invention is to provide an application of a water-blocking composition in gas well water plugging.

[0005] A third objective of this invention is to provide a water-blocking agent.

[0006] To achieve the above objectives, the technical solution adopted by the water-blocking composition of the present invention is as follows:

[0007] A water-blocking composition mainly comprises the following components in parts by weight: 100 parts epoxy resin, 80-120 parts epoxy curing agent, 0.1-0.3 parts epoxy curing accelerator, 100-160 parts reactive diluent, 6-20 parts foaming agent, 0.2-1 parts surfactant, and 4-10 parts hydrophobic silica aerogel; wherein the pore size of the hydrophobic silica aerogel is 0.1-300 nm.

[0008] The water-blocking composition of this invention is a liquid with good fluidity and stability, facilitating transportation. When used for water plugging in oil and gas wells, the water-blocking composition of this invention can solidify at formation temperatures. During the solidification process, the foaming agent releases gas, generating bubbles that connect with the pores of the hydrophobic silica aerogel, which has a rich nanoporous structure, forming airflow channels and reducing gas flow resistance. Simultaneously, the hydrophobicity of the hydrophobic silica aerogel enables the connected channels to produce a water-blocking effect, thereby achieving gas-water selectivity.

[0009] Understandably, hydrophobic silica aerogel is a type of high-porosity gel porous material with advantages such as ultra-high porosity, high specific surface area, low density, and hydrophobicity.

[0010] It is understood that there are no specific requirements for the shape of the hydrophobic silica aerogel in this invention, and it can be spherical, square, rhomboid, needle-shaped, etc.

[0011] Preferably, the pore size of the hydrophobic silica aerogel is 2–100 nm. Preferably, the specific surface area of ​​the hydrophobic silica aerogel is 600–1500 m². 2 / g. Preferably, the density of the hydrophobic silica aerogel is 100-600 kg / m³. 3 .

[0012] In this invention, the hydrophobic silica aerogel can be commercially available or prepared by means of existing technologies. For example, the hydrophobic silica aerogel is a product with the catalog number QNJ-001 manufactured by Dipu Kelin (Xiamen) Technical Service Co., Ltd.

[0013] Preferably, the epoxy resin is bisphenol F epoxy resin and / or bisphenol A epoxy resin. Preferably, the epoxy equivalent of the bisphenol F epoxy resin is 100-230 g / mol. Preferably, the epoxy equivalent of the bisphenol A epoxy resin is 350 g / mol.

[0014] In this invention, epoxy equivalent refers to the mass of epoxy resin containing 1 mol of epoxy groups, expressed in g / mol, and is obtained by chemical titration.

[0015] Preferably, the epoxy curing agent is selected from one or any combination of phenolic resin curing agents, amine curing agents, acid curing agents, and acid anhydride curing agents.

[0016] Preferably, the epoxy curing accelerator is selected from one or any combination of tertiary amine curing accelerators, imidazole curing accelerators, acetylacetone metal salt curing accelerators, and boron trifluoride complex curing accelerators.

[0017] Preferably, the reactive diluent is a glycidyl ether type reactive diluent. More preferably, the glycidyl ether type reactive diluent is selected from one or any combination of ethylene glycol diglycidyl ether, glycidol, and butyl glycidyl ether.

[0018] In this invention, a foaming agent refers to a substance that can generate gas through vaporization or decomposition at formation temperatures. This includes chemical foaming agents and physical foaming agents. Chemical foaming agents are substances that, upon heating and decomposition, release gases such as carbon dioxide and nitrogen, forming fine pores in the cured form of the water-blocking composition. Physical foaming agents are substances that can vaporize under heating conditions and form fine pores in the cured form of the water-blocking composition. Chemical foaming agents include inorganic and organic foaming agents. Inorganic foaming agents mainly include carbonates, bicarbonates, water glass, silicon carbide, and carbon black. Organic foaming agents mainly include azo compounds, sulfonyl hydrazides, and nitroso compounds, such as azodicarbonamide, 2,2-azobisisobutyronitrile, 4,4-oxobisbenzenesulfonyl hydrazide, and dinitrospentamethylenetetramine. Physical foaming agents are mainly substances that can vaporize at formation temperatures, such as water, toluene, xylene, ethylene glycol monomethyl ether, and cyclohexanone.

[0019] Preferably, the foaming agent is a physical foaming agent and / or a chemical foaming agent. Preferably, the physical foaming agent is selected from one or any combination of water, toluene, xylene, ethylene glycol monomethyl ether, N,N-dimethylformamide, and cyclohexanone. Preferably, the chemical foaming agent is selected from one or any combination of carbonates, bicarbonates, azo compounds, sulfonyl hydrazides, and nitroso compounds.

[0020] Preferably, the surfactant is selected from one or any combination of anionic surfactants, cationic surfactants, and nonionic surfactants. Preferably, the anionic surfactant is selected from one or any combination of stearate, dodecylbenzene sulfonate, lignin sulfonate, alkyl glycerol ether sulfonate, and fatty alcohol sulfate. Preferably, the cationic surfactant is hexadecyltrimethylammonium chloride. Preferably, the nonionic surfactant is selected from one or any combination of Tween surfactants, alkyl glucosides, polyether polysiloxane copolymers, fatty alcohol polyoxyethylene ethers, ethylene oxide-propylene oxide block copolymers, and alkylated castor oil. Preferably, the polyether polysiloxane copolymer is a polydimethylsiloxane-polyoxyolefin copolymer. Preferably, the Tween surfactant is Tween 80.

[0021] The technical solution adopted in the application of the water-blocking composition of the present invention in gas well water plugging is as follows:

[0022] The water-blocking composition described above is used for water plugging in gas wells, wherein the temperature of the gas well is not lower than 90°C.

[0023] When the water-blocking composition of the present invention is used for water plugging in gas wells, it can be solidified in the gas well formation. During the solidification process, the foaming agent releases gas and generates bubbles, which can connect with the channels of the hydrophobic silica aerogel with abundant nanoporous structure to form airflow channels and reduce gas flow resistance. At the same time, due to the hydrophobicity of the hydrophobic silica aerogel, the connected channels can produce a water-blocking effect, thereby achieving gas-water selectivity. Thus, the gas well reservoir after plugging achieves both water-blocking and gas-permeability effects.

[0024] Preferably, the temperature of the gas well is 90–160°C.

[0025] Understandably, the temperature of the gas well should not be lower than the temperature at which the foaming agent is used in the water-blocking composition, for example, not lower than the vaporization temperature of the physical foaming agent or the thermal decomposition temperature of the chemical foaming agent; for example, when the foaming agent is bicarbonate, the temperature of the gas well should not be lower than 90°C; when the foaming agent is 2,2-azobisisobutyronitrile, the temperature of the gas well should not be lower than 125°C; when the foaming agent is N,N-dimethylformamide, the temperature of the gas well should not be lower than 160°C.

[0026] Preferably, the application includes the step of injecting the water-blocking composition into a gas well.

[0027] The technical solution adopted by the water-blocking agent of the present invention is as follows:

[0028] A water-blocking agent includes an epoxy resin matrix and a hydrophobic silica aerogel dispersed in the epoxy resin matrix; the water-blocking agent has a porous structure.

[0029] The water-blocking agent of the present invention has a porous structure. Since some of the pores are provided by hydrophobic silica aerogel, gas can pass through. In addition, due to the hydrophobicity of the pores of the hydrophobic silica aerogel, water can be restricted from passing through, thereby achieving water-gas selectivity.

[0030] Preferably, the water-blocking agent is formed by curing the above-mentioned water-blocking composition at 90-160°C.

[0031] Understandably, the curing temperature should consider not only the amount and type of epoxy resin, epoxy curing agent, and epoxy curing accelerator, but also the type of foaming agent in the water-blocking composition. The curing temperature should not be lower than the temperature at which the foaming agent is used in the water-blocking composition, for example, not lower than the vaporization temperature of a physical foaming agent or the thermal decomposition temperature of a chemical foaming agent. For example, when the foaming agent is bicarbonate, the curing temperature should not be lower than 90°C; when the foaming agent is 2,2-azobisisobutyronitrile, the curing temperature should not be lower than 125°C; and when the foaming agent is N,N-dimethylformamide, the curing temperature should not be lower than 160°C.

[0032] Preferably, the curing time is 8 to 16 hours. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the water-blocking composition of the present invention after curing or the water-blocking agent of the present invention; wherein, the reference numerals are as follows: 1-hydrophobic silica aerogel; 2-bubble; 3-epoxy resin matrix. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to specific embodiments. It should be noted that the purpose of this embodiment is to further illustrate the present invention and is not intended to limit the scope of protection of the present invention.

[0035] The hydrophobic silica aerogel used in Examples 1-3 and Comparative Examples 3-4 of this invention is a hydrophobic silica aerogel with product number QNJ-001 manufactured by Dipu Kelin (Xiamen) Technical Service Co., Ltd., with a pore size of 2-100 nm and a specific surface area of ​​600-1500 m². 2 / g, density is 100~600kg / m³ 3 .

[0036] I. Specific embodiments of the water-blocking composition of the present invention are as follows:

[0037] Example 1

[0038] The water-blocking composition of this embodiment consists of the following components in parts by weight: 100 parts epoxy resin, 80 parts epoxy curing agent, 0.3 parts epoxy curing accelerator, 100 parts reactive diluent, 6 parts foaming agent, 0.2 parts surfactant, and 4 parts hydrophobic silica aerogel; the epoxy resin is bisphenol F epoxy resin (epoxy equivalent = 100 g / mol), the epoxy curing agent is phenolic resin curing agent (manufacturer: Shandong Shengquan New Material Co., Ltd., product model: PF8011), the epoxy curing accelerator is amine curing accelerator (DMP-30), the reactive diluent is butyl glycidyl ether, the foaming agent is sodium bicarbonate, and the surfactant is sodium stearate.

[0039] The water-blocking composition of this embodiment is prepared by a method including the following steps: adding the prescribed amount of epoxy resin and epoxy curing agent to the prescribed amount of reactive diluent, mixing evenly, and then sequentially adding the prescribed amount of epoxy curing accelerator, foaming agent, hydrophobic silica aerogel and surfactant while stirring, and mixing evenly to obtain the final product.

[0040] Example 2

[0041] The water-blocking composition of this embodiment consists of the following components in parts by weight: 100 parts epoxy resin, 100 parts epoxy curing agent, 0.2 parts epoxy curing accelerator, 130 parts reactive diluent, 13 parts foaming agent, 0.6 parts surfactant, and 7 parts hydrophobic silica aerogel; the epoxy resin is bisphenol F epoxy resin (epoxy equivalent = 230 g / mol), the epoxy curing agent is an amine curing agent (N-methylethylenediamine), the epoxy curing accelerator is boron trifluoride ethylamine complex, the reactive diluent is glycidol, the foaming agent is 2,2-azobisisobutyronitrile, and the surfactant is sodium dodecylbenzenesulfonate.

[0042] The water-blocking composition of this embodiment is prepared by a method including the following steps: adding the prescribed amount of epoxy resin and epoxy curing agent to the prescribed amount of reactive diluent, mixing evenly, and then sequentially adding the prescribed amount of epoxy curing accelerator, foaming agent, hydrophobic silica aerogel and surfactant while stirring, and mixing evenly to obtain the final product.

[0043] Example 3

[0044] The water-blocking composition of this embodiment consists of the following components in parts by weight: 100 parts epoxy resin, 120 parts epoxy curing agent, 0.3 parts epoxy curing accelerator, 160 parts reactive diluent, 20 parts foaming agent, 1 part surfactant, and 10 parts hydrophobic silica aerogel; the epoxy resin is bisphenol A epoxy resin (epoxy equivalent = 350 mg / mol), the epoxy curing agent is an anhydride curing agent (glutaric anhydride), the epoxy curing accelerator is an imidazole curing accelerator (2-ethyl-4-methylimidazolium), the reactive diluent is ethylene glycol diglycidyl ether, the foaming agent is N,N-dimethylformamide, and the surfactant is ethoxylated castor oil.

[0045] The water-blocking composition of this embodiment is prepared by a method including the following steps: adding the prescribed amount of epoxy resin and epoxy curing agent to the prescribed amount of reactive diluent, mixing evenly, and then sequentially adding the prescribed amount of epoxy curing accelerator, foaming agent, hydrophobic silica aerogel and surfactant while stirring, and mixing evenly to obtain the final product.

[0046] Comparative Example 1

[0047] The comparative example of the water-blocking composition consists of the following components in parts by weight: 45 parts epoxy resin, 30 parts epoxy curing agent, 0.03 parts epoxy curing accelerator, and 30 parts solvent; the epoxy resin is bisphenol F epoxy resin (epoxy equivalent = 170 g / mol), the epoxy curing agent is linear phenolic resin (manufacturer: Shandong Shengquan New Material Co., Ltd., product model: PF8011), the epoxy curing accelerator is an imidazole curing accelerator (2-ethyl-4-methylimidazolium), and the solvent is methanol.

[0048] The comparative water-blocking composition was prepared by a method comprising the following steps: melting and mixing epoxy resin and epoxy curing agent in the prescribed amounts, then adding epoxy curing accelerator and solvent in the prescribed amounts, and stirring until homogeneous.

[0049] Comparative Example 2

[0050] The comparative example of a water-blocking composition consists of 100 parts by weight of xylene and 50 parts by weight of a main agent. The main agent comprises the following components in parts by weight: 35 parts epoxy resin E51, 44 parts calcium carbonate, 6.5 parts dicyandiamide, 0.8 parts azodicarbonamide AC, 0.3 parts zinc oxide, 0.3 parts zinc stearate, 0.5 parts vulcanizing agent BiBp, 0.5 parts curing agent dimethylaminopropionamide, and 7.5 parts ethylene methyl acrylate copolymer. The ethylene methyl acrylate copolymer is prepared by a method comprising the following steps: adding 1600 parts by weight of distilled water to a reactor, then sequentially adding 300 parts by weight of tert-butanol, 25 parts by weight of methacrylic acid emulsion, and 1.1 parts by weight of potassium persulfate, then introducing ethylene, maintaining the pressure inside the reactor at 20 MPa, heating the material inside the reactor to 80°C, and reacting for 6 hours to obtain the final product.

[0051] Comparative Example 3

[0052] The only difference between the water-blocking composition of this comparative example and the water-blocking composition of Example 1 is that the hydrophobic silica aerogel used in the water-blocking composition of this comparative example is 3 parts by mass.

[0053] Comparative Example 4

[0054] The only difference between the water-blocking composition of this comparative example and the water-blocking composition of Example 3 is that the hydrophobic silica aerogel used in the water-blocking composition of this comparative example is 12 parts by mass.

[0055] II. Specific embodiments of the application of the water-blocking composition of the present invention in gas well water plugging are as follows:

[0056] Any of the water-blocking compositions in Examples 1-3 can be injected into the gas well; when the water-blocking composition of Example 1 is injected, the temperature of the gas well is 90°C; when the water-blocking composition of Example 2 is injected, the temperature of the gas well is 125°C; when the water-blocking composition of Example 3 is injected, the temperature of the gas well is 160°C.

[0057] III. Specific embodiments of the water-blocking agent of the present invention are as follows:

[0058] Example 4

[0059] The water-blocking agent of this embodiment has a porous structure, comprising an epoxy resin matrix and a hydrophobic silica aerogel dispersed in the epoxy resin matrix; the water-blocking agent of this embodiment is formed by curing the water-blocking composition of Example 1 at 90°C for 16 hours. A schematic diagram of the structure of the water-blocking agent of this embodiment is shown below. Figure 1 As shown, it includes hydrophobic silica aerogel 1, bubbles 2 and epoxy resin matrix 3.

[0060] Example 5

[0061] The water-blocking agent of this embodiment has a porous structure, including an epoxy resin matrix and a hydrophobic silica aerogel dispersed in the epoxy resin matrix; the water-blocking agent of this embodiment is formed by curing the water-blocking composition of Example 1 at 125°C for 12 hours.

[0062] Example 6

[0063] The water-blocking agent of this embodiment has a porous structure, including an epoxy resin matrix and a hydrophobic silica aerogel dispersed in the epoxy resin matrix; the water-blocking agent of this embodiment is formed by curing the water-blocking composition of Example 1 at 160°C for 8 hours.

[0064] Experimental Example

[0065] First, the viscosity of the water-blocking compositions of Examples 1-3 and Comparative Examples 1-4 was tested. Then, a sand-filled pipe model was used to evaluate the water-blocking and air-permeability capabilities of the water-blocking compositions of Examples 1-3 and Comparative Examples 1-4 in water-blocking applications. The experimental methods are as follows:

[0066] (1) Clean, dry, and weigh the sand-filled pipe (30cm in length), fill it with quartz sand of a certain particle size (20-80 mesh), evacuate the vacuum and introduce simulated formation water until saturation, and determine the pore volume of the sand-filled pipe by weighing method; inject simulated formation water into the sand-filled pipe at a rate of 2mL / min using a pump, and after the pressure stabilizes, record the pressure difference between the two ends of the sand-filled pipe and measure the flow rate, and calculate the water permeability of the sand-filled pipe (before plugging); circulate nitrogen into the sand-filled pipe at a pressure of 0.1MPa using a nitrogen cylinder, and after the flow rate at the outlet end of the sand-filled pipe stabilizes, measure the flow rate at the outlet end of the sand-filled pipe and calculate the effective gas phase permeability of the sand-filled pipe (before plugging).

[0067] (2) Use a displacement pump to drive a 1PV pore volume of the water-blocking composition into the sand-filling pipe at a certain discharge rate. Then, seal the inlet and outlet of the sand-filling pipe and heat the sand-filling pipe to the curing temperature of the water-blocking composition (the curing temperatures of the water-blocking compositions in Examples 1-3 and Comparative Examples 1-4 are 90℃, 125℃, 160℃, 90℃, 90℃, 90℃, and 160℃, respectively) for 48 hours.

[0068] (3) Use a pump to inject simulated formation water into the sand-filled pipe at a rate of 2 mL / min. After the pressure stabilizes, record the pressure difference between the two ends of the sand-filled pipe and measure the flow rate. Calculate the water permeability of the sand-filled pipe (after plugging). Use a nitrogen cylinder to ventilate the sand-filled pipe at a pressure of 0.1 MPa. After the flow rate at the outlet end of the sand-filled pipe stabilizes, measure the flow rate at the outlet end of the sand-filled pipe and calculate the effective gas phase permeability of the sand-filled pipe (after plugging).

[0069] The viscosity and water-blocking and air-permeability of the water-blocking compositions of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1, wherein the blocking rate = (permeability before blocking - permeability after blocking) / permeability before blocking × 100%.

[0070] Table 1. Viscosity and water-blocking and air-permeability of the water-blocking compositions of Examples 1-3 and Comparative Examples 1-4

[0071]

[0072] The results show that the water-blocking compositions of Examples 1-3 exhibit good gas-water selectivity and low viscosity, facilitating on-site pumping. The water-blocking compositions of Comparative Examples 1-2 lack gas-water selectivity. While the water-blocking composition of Comparative Example 3 shows good water-blocking performance, its aeration effect is poor. Although the water-blocking composition of Comparative Example 4 possesses both water-blocking and aeration properties, its high viscosity due to the large content of hydrophobic silica aerogel makes on-site pumping difficult. When no hydrophobic silica aerogel is added to the water-blocking composition, the resulting water-blocking agent lacks aeration (gas-phase blocking rate is 100%).

[0073] When the surfactant in the plugging composition of Example 1 is replaced by Tween surfactants, alkyl glucosides, polyether polysiloxane copolymers, fatty alcohol polyoxyethylene ethers, ethylene oxide-propylene oxide block copolymers, lignin sulfonates, alkyl glycerol ether sulfonates, or fatty alcohol sulfates, the aqueous phase plugging rate and gas phase plugging rate obtained by the obtained plugging composition in the above-mentioned sand-filled pipe model experiment are similar to those obtained by the plugging composition of Example 1.

Claims

1. A water shutoff composition characterized by, The epoxy resin composition is mainly composed of the following components in mass fraction: epoxy resin 100 parts, epoxy curing agent 80-120 parts, epoxy curing accelerator 0.1-0.3 parts, active diluent 100-160 parts, foaming agent 6-20 parts, surfactant 0.2-1 part and hydrophobic silica aerogel 4-10 parts; the pore size of the hydrophobic silica aerogel is 2-100 nm; the specific surface area of the hydrophobic silica aerogel is 600-1500 m 2 / g; the density of the hydrophobic silica aerogel is 100-600 kg / m 3 ; the foaming agent is selected from one or any combination of carbonates, bicarbonates, N,N-dimethylformamide, azo compounds, sulfonhydrazide compounds and nitroso compounds.

2. The water shutoff composition of claim 1, wherein, The foaming agent is one of sodium bicarbonate, 2,2-azobisisobutyronitrile and N,N dimethylformamide.

3. The water shutoff composition of claim 1, wherein, The epoxy resin is bisphenol F epoxy resin and / or bisphenol A epoxy resin.

4. The water shutoff composition of claim 3, wherein, The epoxy equivalent weight of the bisphenol F epoxy resin is 100-230 g / mol; and the epoxy equivalent weight of the bisphenol A epoxy resin is 350 g / mol.

5. The water shutoff composition of any one of claims 1-4, wherein, The epoxy curing agent is one or any combination of phenol-formaldehyde resin curing agent, amine curing agent, acid curing agent and acid anhydride curing agent.

6. The water shutoff composition of any one of claims 1-4, wherein, The reactive diluent is glycidyl ether type reactive diluent or epoxy propyl alcohol; the glycidyl ether type reactive diluent is one or any combination of ethylene glycol diglycidyl ether and butyl glycidyl ether.

7. The water shutoff composition of any one of claims 1-4, wherein, The surfactant is one or any combination of anionic surfactant, cationic surfactant and non-ionic surfactant.

8. Use of the water shutoff composition according to any one of claims 1 to 7 for water shutoff in gas wells, characterized in that, The temperature of the gas well is not lower than 90℃.

9. A water shutoff agent characterized by, The water plugging agent is formed by curing the water plugging composition according to any one of claims 1-7 at 90-160℃; and the water plugging agent has a porous structure.

10. The water shutoff agent of claim 9, wherein, The curing time of the water plugging agent is 8-16 h.

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