Gel breaking temporary plugging agent and preparation method thereof

Abstract

The invention relates to the technical field of oil and gas development materials, and particularly discloses a gel breaking temporary plugging agent and a preparation method thereof. The gel breaking temporary plugging agent is prepared from the following raw material components: beta-mannase, a calcium salt solution, ammonium persulfate microcapsules, oxidation modified bacterial powder, silicon dioxide microspheres, beta-mannan-based gel and water. The gel breaking temporary plugging agent provided by the invention effectively solves the problems of incomplete gel breaking, easy generation of secondary plugging and poor controllability of gel breaking time of a traditional temporary plugging agent.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development materials technology, specifically disclosing a gel-breaking and temporary plugging agent and its preparation method. Background Technology

[0002] In the oil and gas development sector, fracturing is a core means of coping with the dry season in domestic oilfields, and it is of great significance for extending well life, improving formation crude oil utilization efficiency, and alleviating dependence on oil imports. Currently, my country's oil and gas development situation is severe, with most mature oilfields entering their dry season. Even after water injection, 65%-75% of the crude oil remains trapped in the formation. The effectiveness of fracturing directly depends on the plugging and unplugging effect of the temporary plugging agent.

[0003] However, current temporary plugging agents primarily rely on ammonium persulfate oxidation to break down the gel, which presents problems such as incomplete gel breaking and the risk of secondary blockage. Furthermore, the breaking time of these agents is poorly controllable; external temperature fluctuations can delay the breaking process or cause premature failure of the agent, severely impacting fracturing effectiveness. These issues not only limit the efficiency of fracturing enhancement technology but may also damage the reservoir, further increasing the difficulty of crude oil extraction. Therefore, providing a highly efficient temporary plugging agent that breaks down completely, eliminates the risk of secondary blockage, and allows for controllable breaking time has become a pressing technical problem in the oil and gas development field. Summary of the Invention

[0004] To address the problems of incomplete gel breaking, the risk of secondary blockage, and poor controllability of gel breaking time in existing temporary plugging agents that rely on ammonium persulfate oxidation, as well as the significant impact of external temperature fluctuations, this invention provides a gel breaking temporary plugging agent and its preparation method. The gel breaking temporary plugging agent provided by this invention achieves complete gel breaking through the synergistic effect of its various raw material components, eliminating the risk of secondary blockage and meeting the demand for temporary plugging agents in fracturing and production enhancement in the oil and gas development field.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a temporary plugging agent, comprising the following raw material components in parts by weight: 6-9 parts of β-mannanase, 75-85 parts of calcium salt solution, 140-160 parts of ammonium persulfate microcapsules, 70-90 parts of oxidized modified bacterial powder, 380-420 parts of silica microspheres, 7400-8200 parts of β-mannan-based gel, and 1400-1600 parts of water; wherein the ammonium persulfate microcapsules contain ethylenediaminetetraacetic acid chelated iron.

[0006] Compared to existing technologies, the gel-breaking and temporary plugging agent provided by this invention achieves stable plugging and controllable gel breaking through multi-component synergy. Specifically, the β-mannan-based gel forms an ionic cross-linked network under the action of calcium salts, providing structural strength and rapidly filling pore channels after injection into the formation, forming a highly efficient plugging barrier. Silica microspheres, embedded within this inorganic framework, restrict molecular chain movement and enhance compressive strength and temperature resistance, thus ensuring good temporary plugging capability under formation conditions. Furthermore, β-mannanase preferentially acts on the β-mannan-based gel, breaking the polymer chains into low-molecular-weight fragments, transforming the gel structure from dense to loose, providing more active sites for subsequent reactions. Subsequently, ammonium persulfate microcapsules release an oxidant triggered by changes in formation temperature, generating sulfate radicals under the catalysis of ethylenediaminetetraacetic acid chelated iron, further oxidizing and breaking down the enzymatically degraded organic framework, thereby achieving complete gel breaking.

[0007] The oxidized modified bacterial powder mainly plays an adsorption and catalytic role in the system. Its surface is rich in polar functional groups and has a porous structure, enabling it to adsorb small molecule residues generated during delamination and promote their further oxidative degradation, preventing residue deposition in the pores and reducing the risk of secondary blockage. Furthermore, since ammonium persulfate exists in microcapsule form, its release is temperature-controlled. The system remains stable at low temperatures, while the delamination reaction is triggered only at high temperatures, thus achieving effective control over the delamination time. In summary, the delamination and temporary blockage agent provided by this invention achieves complete delamination through the synergistic effect of its components, without the risk of secondary blockage, effectively solving the problems of incomplete delamination, easy secondary blockage, and poor controllability of delamination time in traditional temporary blockage agents.

[0008] Preferably, the preparation method of the ammonium persulfate microcapsules includes the following steps: S1. Mix ammonium persulfate, ethylenediaminetetraacetic acid chelated iron, and water, and stir at 50-70℃ for 20-30 min to obtain an aqueous phase; S2. Mix poly(N-isopropylacrylamide), dichloromethane, and Span 80 to obtain the oil phase; S3. Mix the aqueous phase and the oil phase, emulsify to obtain an emulsion, and polymerize and solidify the emulsion at 30~40℃ to obtain the ammonium persulfate microcapsules.

[0009] More preferably, in S1, the mass-to-volume ratio of ammonium persulfate, ethylenediaminetetraacetic acid chelated iron, and water is (4-5) g:(0.03-0.035) g:(90-110) mL.

[0010] More preferably, in S2, the mass-to-volume ratio of poly(N-isopropylacrylamide), dichloromethane, and Span 80 is (1.4-1.6) g:(55-65) mL:(80-85) g.

[0011] More preferably, in S3, the volume ratio of the aqueous phase to the oil phase is 1:(5-7).

[0012] More preferably, in S3, the emulsification speed is 12000-15000 rpm and the time is 5-15 min.

[0013] More preferably, in S3, the reaction time for polymerization and curing is 2-3 hours.

[0014] Preferably, the method for preparing the β-mannan-based gel includes the following steps: Step a: Add β-mannan to water and stir at 55-65℃ for 30-35 min; then heat to 80-90℃ and stir again for 35-45 min to obtain the first solution; Step b: Disperse nano-silica in water to obtain a nano-silica dispersion; Step c: Add the nano-silica dispersion to the first solution, then add calcium chloride solution, stir for 20-30 minutes, cool, and obtain the β-mannan-based gel.

[0015] More preferably, in step a, the mass-to-volume ratio of the β-mannan to water is 1 g:(50-60) mL.

[0016] More preferably, in step b, the mass percentage of nano-silica in the nano-silica dispersion is 0.05%-0.1%.

[0017] More preferably, in step c, the concentration of the calcium chloride solution is 0.1-0.2 mol / L.

[0018] More preferably, in step c, the amount of calcium chloride solution added is 5%-10% of the volume of the first solution.

[0019] More preferably, in step c, the volume ratio of the nano-silica dispersion to the first solution is 1:(4-6).

[0020] Preferably, the preparation method of the oxidized modified bacterial powder includes the following steps: The bacterial powder was inoculated onto a culture medium and cultured at 45-60℃ and pH 7-8 for 36-42 hours to obtain a bacterial solution. The bacterial solution was then heated to 80-90℃, and an ammonium persulfate aqueous solution was added for oxidation treatment. The solution was then freeze-dried to obtain the oxidized modified bacterial powder.

[0021] After high-temperature oxidation treatment, the surface of the oxidized bacterial powder is rich in polar functional groups such as carboxyl and hydroxyl groups, and has a certain porous structure, which gives it both strong adsorption capacity and certain catalytic activity. On the one hand, these functional sites can adsorb organic fragments generated during the decomposition process and prevent them from re-aggregating and depositing in the pores. On the other hand, its surface active structure can further promote the oxidative decomposition of residual organic matter, thereby achieving continuous reduction of residues.

[0022] More preferably, the bacterial powder is Bacillus thermophilus, numbered BNCC136223.

[0023] More preferably, the number of viable bacteria in the bacterial solution is 1×10⁻⁶. 8 -1×10 9 CFU / mL; More preferably, the concentration of the ammonium persulfate aqueous solution is 0.05 mol / L to 0.1 mol / L; More preferably, the mass ratio of the ammonium persulfate aqueous solution to the bacterial solution is (0.1~0.5):100; More preferably, the oxidation treatment time is 60-80 minutes.

[0024] Secondly, the present invention provides a method for preparing the aforementioned adhesive-breaking and temporary plugging agent, comprising the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres and the remaining raw materials at 50~70℃ until homogeneous to obtain the gel breaking and temporary blocking agent.

[0025] Preferably, in step one, the concentration of the calcium salt solution is 0.5-1 mol / L.

[0026] More preferably, the calcium salt solution is a calcium chloride solution.

[0027] Preferably, in step two, the bacterial cell concentration in the bacterial suspension is 1×10⁻⁶. 8 ~1×10 9 CFU / mL.

[0028] Preferably, in step two, the buffer solution is a phosphate buffer solution with a pH of 7.0 to 7.2.

[0029] Preferably, in step two, the mass-to-volume ratio of the silica microspheres to the bacterial suspension is 1 g:(2~3) mL.

[0030] Preferably, in step two, the pressure of vacuum adsorption is -0.07 to -0.09 MPa; and the vacuum adsorption time is 20-30 min.

[0031] Thirdly, the present invention provides the application of the aforementioned gel-breaking and temporary plugging agent in the field of oil and gas development.

[0032] In summary, the temporary plugging agent provided by this invention utilizes the stable plugging structure formed by β-mannan gel and calcium salt, employs β-mannanase for directional chain scission pretreatment, achieves oxidative plugging through ammonium persulfate microcapsules, and simultaneously utilizes oxidative modified bacterial powder to adsorb and further degrade the residue. Furthermore, the controlled release effect of the microcapsule structure and the porous silica carrier structure enables time regulation of the plugging process, thereby achieving complete plugging without the risk of secondary blockage. This effectively solves the problems of incomplete plugging, easy secondary blockage, and poor controllability of plugging time in traditional temporary plugging agents. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are merely one embodiment of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The preparation method of the ammonium persulfate microcapsules used in the following examples or comparative examples includes the following steps: S1. Mix 5g ammonium persulfate, 0.03g ethylenediaminetetraacetic acid chelated iron and 95mL water at 60℃ and stir for 25min to obtain an aqueous phase; S2. Mix 1.5g of poly(N-isopropylacrylamide), 60mL of dichloromethane and 80g of Span 80 to obtain the oil phase; S3. The aqueous phase is slowly added dropwise to the oil phase at a volume ratio of 1:6. The mixture is then treated with a shear emulsifier at 12000 rpm for 8 minutes to form an emulsion. Finally, the emulsion is interfacially polymerized and cured at 35°C for 3 hours to obtain the ammonium persulfate microcapsules.

[0035] The preparation methods of the β-mannan-based gels used in the following examples or comparative examples include the following steps: Step a: Add 50g of β-mannan to 3000mL of water and stir at 60℃ for 35 min; then heat to 85℃ and stir again for 40 min to obtain the first solution; Step b: Disperse 0.5g of nano-silica in 600mL of water to obtain a nano-silica dispersion; Step c: Add the nano-silica dispersion to the first solution, then add 250 mL of 0.1 mol / L calcium chloride solution, stir for 25 min, cool, and obtain the β-mannan-based gel.

[0036] The preparation method of the oxidatively modified bacterial powder used in the following examples or comparative examples includes the following steps: Bacillus thermophilus powder was inoculated onto a culture medium and cultured at 48°C and pH 7.2 for 38 hours, yielding a viable count of 1×10⁻⁶. 8 -1×10 9 Thermophilic Bacillus thermophilus bacterial suspension (CFU / mL) was used. 100 mL of the bacterial suspension was heated to 85°C, and 0.3 mL of 0.1 mol / L ammonium persulfate aqueous solution was added for oxidation treatment for 65 min. The solution was then freeze-dried to obtain the oxidized modified bacterial powder. The culture medium consisted of the following components per 1 L: 15 g glucose, 10 g soluble starch, 12 g peptone, 8 g yeast extract, 20 g corn steep liquor, 4 g NaCl, 2 g K₂HPO₄, 1 g KH₂PO₄, 0.5 g MgSO₄·7H₂O, 0.2 g CaCl₂, 0.01 g FeSO₄·7H₂O, 0.005 g MnSO₄·H₂O, and the remaining deionized water. The initial pH was adjusted to 7.2.

[0037] Example 1 This embodiment provides a temporary plugging agent and its preparation method, specifically including the following: The temporary plugging agent comprises the following raw material components in parts by weight: 8 parts β-mannanase, 80 parts calcium chloride solution, 150 parts ammonium persulfate microcapsules, 78 parts oxidatively modified bacterial powder, 410 parts silica microspheres, 7600 parts β-mannan-based gel, and 1500 parts water; wherein the concentration of the calcium chloride solution is 0.8 mol / L.

[0038] The preparation method of the temporary plugging agent includes the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption under a vacuum of -0.08 MPa for 20 min to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres, and the remaining raw materials at 65°C until homogeneous to obtain the gel breaking and temporary blocking agent.

[0039] Example 2 This embodiment provides a temporary plugging agent and its preparation method, specifically including the following: The temporary plugging agent comprises the following raw material components in parts by weight: 9 parts β-mannanase, 76 parts calcium chloride solution, 148 parts ammonium persulfate microcapsules, 75 parts oxidatively modified bacterial powder, 420 parts silica microspheres, 7500 parts β-mannan-based gel, and 1600 parts water; wherein the concentration of the calcium chloride solution is 0.6 mol / L.

[0040] The preparation method of the temporary plugging agent includes the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption under a vacuum of -0.08 MPa for 20 min to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres, and the remaining raw materials at 60°C until homogeneous to obtain the gel-breaking and temporary blockage agent.

[0041] Example 3 This embodiment provides a temporary plugging agent and its preparation method, specifically including the following: The temporary plugging agent comprises the following raw material components in parts by weight: 9 parts β-mannanase, 76 parts calcium chloride solution, 155 parts ammonium persulfate microcapsules, 78 parts oxidatively modified bacterial powder, 390 parts silica microspheres, 7900 parts β-mannan-based gel, and 1500 parts water; wherein the concentration of the calcium chloride solution is 1 mol / L.

[0042] The preparation method of the temporary plugging agent includes the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption under a vacuum of -0.08 MPa for 20 min to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres, and the remaining raw materials at 68°C until homogeneous to obtain the gel breaking and temporary blocking agent.

[0043] Comparative Example 1 This comparative example provides a temporary plugging agent and its preparation method, which differs from Example 1 in that the ammonium persulfate microcapsules do not contain ethylenediaminetetraacetic acid chelated iron. Specifically, it includes the following: The temporary plugging agent comprises the following raw material components in parts by weight: 8 parts β-mannanase, 80 parts calcium chloride solution, 150 parts ammonium persulfate microcapsules, 78 parts oxidatively modified bacterial powder, 410 parts silica microspheres, 7600 parts β-mannan-based gel, and 1500 parts water; wherein the concentration of the calcium chloride solution is 0.8 mol / L.

[0044] The preparation method of the temporary plugging agent includes the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption under a vacuum of -0.08 MPa for 20 min to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres, and the remaining raw materials at 65°C until homogeneous to obtain the gel breaking and temporary blocking agent.

[0045] The preparation method of the ammonium persulfate microcapsules includes the following steps: S1. Mix 5g of ammonium persulfate and 95mL of water at 60℃ and stir for 25min to obtain the aqueous phase; S2. Mix 1.5g of poly(N-isopropylacrylamide), 60mL of dichloromethane and 80g of Span 80 to obtain the oil phase; S3. The aqueous phase is slowly added dropwise to the oil phase at a volume ratio of 1:6. The mixture is then treated with a shear emulsifier at 12000 rpm for 8 minutes to form an emulsion. Finally, the emulsion is interfacially polymerized and cured at 35°C for 3 hours to obtain the ammonium persulfate microcapsules.

[0046] Comparative Example 2 This comparative example provides a temporary plugging agent and its preparation method, which differs from Example 1 in that the β-mannanase is replaced with an equal amount of galactomannanase, specifically including the following: The temporary plugging agent comprises the following raw material components in parts by weight: 8 parts galactomannanase, 80 parts calcium chloride solution, 150 parts ammonium persulfate microcapsules, 78 parts oxidatively modified bacterial powder, 410 parts silica microspheres, 7600 parts β-mannan-based gel, and 1500 parts water; wherein the concentration of the calcium chloride solution is 0.8 mol / L.

[0047] The preparation method of the temporary plugging agent includes the following steps: Step 1: Mix galactomannanase, calcium salt solution and β-mannan-based gel to obtain an enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption under a vacuum of -0.08 MPa for 20 min to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres, and the remaining raw materials at 65°C until homogeneous to obtain the gel breaking and temporary blocking agent.

[0048] The temporary plugging agents used in Examples 1-3 and Comparative Examples 1-2 were tested, and the specific testing methods included the following steps: Simulated formation water with a salinity of 8000 mg / L sodium chloride and 5000 mg / L calcium chloride was prepared. The gelling and plugging agents prepared in Examples 1-3 and Comparative Examples 1-2 were placed in a high-temperature, high-pressure reactor and reacted at 90°C for 12 h. After the reaction, the residue was collected and calcined at high temperature. The residue rate was determined according to GB / T 1725-2007. Simultaneously, the permeability recovery rate after gelling was determined by core damage experiments. The initial permeability K0 was measured first, and the permeability K1 was measured after injecting the gelling and plugging agent. The permeability recovery rate was calculated using the following formula: Permeability recovery rate = K1 / K0 × 100% The test results are shown in Table 1.

[0049] Table 1

[0050] Plugging performance test: An artificial core with a permeability of 100 mD was selected. A baseline pressure difference ΔP0 was established by injecting clean water at a rate of 1 mL / min. Subsequently, 0.5 PV of temporary plugging agent was injected, and the stable pressure difference ΔP1 was recorded. The plugging rate was calculated using the formula: Plugging rate = (ΔP1 / (ΔP0)) / (ΔP0 / ΔP0) ΔP0) / ΔP0×100%; the test results are shown in Table 2; Breaking performance test: The breaking and temporary plugging agent was aged at a constant temperature of 120℃. The changes in the system were observed at regular intervals, and the viscosity change after 6 hours was measured using a rotational rheometer. The test results are shown in Table 2. Table 2

[0051] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A temporary plugging agent, characterized in that, The raw material components include the following parts by weight: 6-9 parts β-mannanase, 75-85 parts calcium salt solution, 140-160 parts ammonium persulfate microcapsules, 70-90 parts oxidized modified bacterial powder, 380-420 parts silica microspheres, 7400-8200 parts β-mannan-based gel, and 1400-1600 parts water; wherein the ammonium persulfate microcapsules contain ethylenediaminetetraacetic acid chelated iron.

2. The temporary plugging agent according to claim 1, characterized in that, The preparation method of the ammonium persulfate microcapsules includes the following steps: S1. Mix ammonium persulfate, ethylenediaminetetraacetic acid chelated iron, and water, and stir at 50-70℃ for 20-30 min to obtain an aqueous phase; S2. Mix poly(N-isopropylacrylamide), dichloromethane, and Span 80 to obtain the oil phase; S3. Mix the aqueous phase and the oil phase, emulsify to obtain an emulsion, and polymerize and solidify the emulsion at 30~40℃ to obtain the ammonium persulfate microcapsules.

3. The temporary plugging agent according to claim 2, characterized in that, In S1, the mass-to-volume ratio of ammonium persulfate, ethylenediaminetetraacetic acid chelated iron, and water is (4~5) g:(0.03~0.035) g:(90~110) mL; In S2, the mass-to-volume ratio of poly(N-isopropylacrylamide), dichloromethane, and Span 80 is (1.4~1.6)g:(55~65)mL:(80~85)g; In S3, the volume ratio of the aqueous phase to the oil phase is 1:(5~7).

4. The temporary plugging agent according to claim 2, characterized in that, In S3, the emulsification speed is 12000~15000 rpm and the time is 5~15 min; In S3, the reaction time for polymerization and curing is 2-3 hours.

5. The temporary plugging agent according to claim 1, characterized in that, The preparation method of the β-mannan-based gel includes the following steps: Step a: Add β-mannan to water and stir at 55-65℃ for 30-35 min; then heat to 80-90℃ and stir again for 35-45 min to obtain the first solution; Step b: Disperse nano-silica in water to obtain a nano-silica dispersion; Step c: Add the nano-silica dispersion to the first solution, then add calcium chloride solution, stir for 20-30 minutes, cool, and obtain the β-mannan-based gel.

6. The temporary plugging agent according to claim 1, characterized in that, In step a, the mass-to-volume ratio of β-mannan to water is 1 g:(50~60) mL; In step b, the mass percentage of nano-silica in the nano-silica dispersion is 0.05%~0.1%; In step c, the concentration of the calcium chloride solution is 0.1~0.2 mol / L; In step c, the amount of calcium chloride solution added is 5% to 10% of the volume of the first solution; In step c, the volume ratio of the nano-silica dispersion to the first solution is 1:(4~6).

7. The temporary plugging agent according to claim 1, characterized in that, The preparation method of the oxidatively modified bacterial powder includes the following steps: The bacterial powder was inoculated onto a culture medium and cultured at 45-60℃ and pH 7-8 for 36-42 hours to obtain a bacterial solution. The bacterial solution was then heated to 80-90℃, and an ammonium persulfate aqueous solution was added for oxidation treatment. The solution was then freeze-dried to obtain the oxidized modified bacterial powder.

8. The temporary plugging agent according to claim 7, characterized in that, The bacterial powder is Bacillus thermophilus powder, with the number BNCC136223; The number of viable bacteria in the bacterial solution is 1×10⁻⁶. 8 ~1×10 9 CFU / mL; The concentration of the ammonium persulfate aqueous solution is 0.05 mol / L to 0.1 mol / L; The mass ratio of the ammonium persulfate aqueous solution to the bacterial culture is (0.1~0.5):100; The oxidation treatment time is 60-80 minutes.

9. A method for preparing the temporary plugging agent according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Mix β-mannanase, calcium salt solution and β-mannan-based gel to obtain enzyme-gel mixture; Step 2: Disperse the oxidized modified bacterial powder in a buffer solution to obtain a bacterial suspension; disperse the silica microspheres in the bacterial suspension and perform vacuum adsorption to obtain bacterial microspheres; Step 3: Mix the enzyme gel mixture, the microbial microspheres and the remaining raw materials at 50~70℃ until homogeneous to obtain the gel breaking and temporary blocking agent.

10. The method for preparing the unclogging agent according to claim 9, characterized in that, In step one, the concentration of the calcium salt solution is 0.5~1 mol / L; In step two, the bacterial cell concentration in the bacterial suspension is 1×10⁻⁶. 8 ~1×10 9 CFU / mL; In step two, the buffer solution is a phosphate buffer solution with a pH of 7.0 to 7.2; In step two, the mass-to-volume ratio of the silica microspheres to the bacterial suspension is 1 g:(2~3) mL; In step two, the pressure of vacuum adsorption is -0.07 to -0.09 MPa; the vacuum adsorption time is 20-30 min.

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