A bridging-adhesive leak sealing agent, its preparation method and application

Abstract

This invention discloses a bridging-adhesive plugging agent, its preparation method, and its application, relating to the field of oil drilling plugging technology. The bridging-adhesive plugging agent comprises bridging plugging particles and an adhesive coating layer covering the surface of the bridging plugging particles; the bridging plugging particles are calcium carbonate particles and / or walnut shell particles; the adhesive coating layer comprises thermosetting adhesive powder, which is coated and cured on the surface of the bridging plugging particles by a liquid-assisted adhesive. This invention also provides a method for preparing the bridging-adhesive plugging agent. This invention features low cost, high yield, significantly improved pressure resistance and disturbance resistance, and effectively solves the problems of insufficient cohesion, easy instability, and complex preparation processes in existing plugging agents.

Description

Technical Field

[0001] This invention relates to the field of oil well plugging technology, specifically to a bridging-adhesive plugging agent, its preparation method, and its application. Background Technology

[0002] Loss of circulation is a common and complex issue in oil drilling, especially in deep fractured formations where the leakage channels are wide, temperatures are high, and pressures are significant, making it difficult for conventional plugging materials to form a stable seal. Currently used bridging plugging materials (such as calcium carbonate particles, walnut shell particles, and fibers) rely on the mechanical bridging and filling action between particles to form a plugging layer. However, these plugging layers lack cohesion and are easily damaged or failed by pressure fluctuations or drill string vibrations, leading to repeated losses.

[0003] To address this issue, new plugging materials such as self-consolidating plugging agents, thermally induced consolidation plugging systems, and microencapsulated adhesives have been developed in recent years. For example, fluidized bed coating technology is used to coat the surface of plugging particles with epoxy resin or phenolic resin, which then cures and bonds at downhole temperatures. However, existing technologies still have the following shortcomings: (1) The coating process is complex, often requiring specialized fluidized bed or electrostatic equipment, resulting in high costs and low yields; (2) Some adhesives have slow onset of action in drilling fluid environments, insufficient bonding strength, or poor temperature resistance; (3) There is a lack of methods for matching and controlling the suspension stability, particle size distribution, and fracture width of the plugging slurry, leading to a low success rate of plugging. Therefore, there is an urgent need for a bridging-bonding plugging agent that is simple to prepare, low in cost, has reliable bonding, and is suitable for deep fractures. Summary of the Invention

[0004] To address the aforementioned shortcomings in the prior art, this invention provides a bridging-adhesive sealing agent, its preparation method, and its application, effectively solving the problems of insufficient cohesion in the sealing layer, easy instability, and complex preparation process of existing sealing agents.

[0005] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is: to provide a bridging-adhesive sealing agent, comprising bridging and sealing particles and an adhesive coating layer covering the surface of the bridging and sealing particles.

[0006] Furthermore, the bridging and sealing particles are calcium carbonate particles and / or walnut shell particles.

[0007] Furthermore, the particle size of the bridging and sealing particles is 0.78-2.85 mm.

[0008] Furthermore, the density of calcium carbonate particles is 2.5-2.7 g / cm³. 3 .

[0009] Furthermore, the density of the calcium carbonate particles is 2.6 g / cm³. 3 .

[0010] Furthermore, the density of walnut shell particles is 1.2-1.4 g / cm³. 3 .

[0011] Furthermore, the density of the walnut shell particles is 1.3 g / cm³. 3 .

[0012] Furthermore, the adhesive coating layer includes thermosetting adhesive powder.

[0013] Furthermore, the thermosetting adhesive powder is coated and cured on the surface of the bridging and sealing particles by a liquid-assisted adhesive.

[0014] Furthermore, the thermosetting adhesive powder is a thermosetting phenolic resin powder.

[0015] Furthermore, the thermosetting phenolic resin powder has a particle size of 150-250 mesh, a softening point of 95-115℃, and a bonding and curing temperature of 120-180℃.

[0016] Furthermore, the thermosetting phenolic resin powder has a particle size of 200 mesh, a softening point of 110℃, and a bonding and curing temperature of 150℃.

[0017] Furthermore, when the bridging and sealing particles are calcium carbonate particles, the liquid auxiliary adhesive is an aqueous polyurethane emulsion.

[0018] Furthermore, the mass fraction of the waterborne polyurethane emulsion is 50-80%.

[0019] Furthermore, the waterborne polyurethane emulsion has a mass fraction of 80%.

[0020] Furthermore, when the bridging and sealing particles are walnut shell particles, the liquid auxiliary adhesive is an aqueous epoxy resin emulsion.

[0021] Furthermore, the mass fraction of the waterborne epoxy resin emulsion is 55-65%.

[0022] Furthermore, the waterborne epoxy resin emulsion has a mass fraction of 60%.

[0023] Furthermore, the viscosity of the waterborne epoxy resin emulsion is 100-450 mPa·s.

[0024] Furthermore, the viscosity of the waterborne epoxy resin emulsion is 200 mPa·s.

[0025] Furthermore, the waterborne epoxy resin emulsion is prepared by compounding epoxy resin and polyamide curing agent (650) at a mass ratio of 3.5:1.

[0026] The preparation method of the above-mentioned bridging-adhesive sealing agent includes the following steps: S1. Clean, dry and stir the bridging and sealing particles; S2. Spray liquid auxiliary adhesive onto the surface of the bridging and sealing particles, then add thermosetting adhesive powder and continue stirring. After ventilation and drying, a bridging-adhesive sealing agent is obtained.

[0027] Furthermore, in step S1, the mixture is stirred in a dry powder coating machine.

[0028] Furthermore, in step S1, the stirring speed is 30-60 r / min.

[0029] Furthermore, in step S2, spraying is performed using a spray gun.

[0030] Furthermore, in step S2, the spraying rate is 0.5-2.0 L / h.

[0031] Furthermore, in step S2, the spraying rate is 1 L / h.

[0032] Furthermore, in step S2, the surface of the particles is uniformly wetted.

[0033] Furthermore, if it is necessary to thicken the coating layer, step S2 can be repeated.

[0034] Furthermore, in step S2, the mass ratio of bridging and sealing particles, liquid auxiliary adhesive, and thermosetting adhesive powder is 15-40:1-4:2-7.

[0035] Furthermore, in step S2, the mass ratio of the bridging and sealing particles, the liquid auxiliary adhesive, and the thermosetting adhesive powder is 40:2:5.

[0036] The above-mentioned bridging-bonding plugging agent is used in the preparation of plugging slurry for sealing lost formations in underground wells.

[0037] Furthermore, the temperature of the formation used should be ≥90 ℃.

[0038] Furthermore, the injection pressure is ≥3 MPa.

[0039] In summary, the present invention has the following beneficial effects: 1. In this invention, bridging plugging particles serve as a skeleton material, bridging the fracture to form an initial pressure-bearing structure. Thermosetting binder powder softens, melts, and solidifies at downhole temperatures, bonding adjacent particles and particles to the fracture wall as a single unit, significantly improving the resistance to damage and stability of the plugging layer. A liquid-assisted binder is used to uniformly adhere the thermosetting binder powder to the particle surface at room temperature, forming a stable coating layer.

[0040] 2. This invention employs liquid-assisted dry powder coating technology, requiring simple equipment (ordinary particle agitator), eliminating the need for fluidized bed or electrostatic equipment, resulting in low cost, high output (up to 300 kg / h), and easy process scaling. The coating layer is stable at room temperature and shows no adhesion after 7 days of storage; under downhole temperature (≥90℃) and pressure, the phenolic resin cures to form a high-strength bond, with the calcium carbonate-based plugging agent's adhesive clusters achieving a compressive strength of up to 1.56 MPa, and the walnut shell-based reaching 0.91 MPa.

[0041] 3. The plugging agent has good compatibility with drilling fluid and its suspension stability is controllable. This can be achieved by adjusting the particle size distribution (0.6 < R b The addition of <0.9% of the total amount of filler material and ≥10% can form a "throat-sealing" bond inside the crack, significantly improving the pressure-bearing capacity and disturbance resistance of the sealing layer, increasing the pressure-bearing capacity from 3.5MPa to over 7MPa. Compared with the prior art, the sealing agent of this invention has low cost, high yield, and superior overall performance. Attached Figure Description

[0042] Figure 1 Comparison images of calcium carbonate-based adhesive sealant before and after curing in a humid heat environment at 150℃ for 4 hours; Figure 2 Comparison of walnut shell-based adhesive sealant before and after curing in a humid heat environment at 150℃ for 4 hours; Figure 3 Comparison of walnut shell-based adhesive sealant before and after aging in a humid environment at 150℃ for 1 hour; Figure 4 Comparison of walnut shell-based adhesive sealant before and after aging in a humid environment at 150℃ for 2 hours; Figure 5 This is a graph showing the results of the compressive strength test. Figure 6 Figures illustrating the formation of bridging-bonding sealing layers under different injection pressures; Figure 7 This diagram illustrates the formation of bridging-bonding sealing layers at different temperatures. Detailed Implementation

[0043] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, conditions in the examples are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are commercially available products. The polyamide curing agent (650) was sourced from Shanghai Maclean Reagents.

[0044] Example 1 A bridging-adhesive sealing agent includes calcium carbonate particles and an adhesive coating layer covering the surface of the calcium carbonate particles; the adhesive coating layer includes thermosetting phenolic resin powder, which is coated and cured on the surface of the bridging-sealing particles by an aqueous polyurethane emulsion.

[0045] The preparation method of the above-mentioned bridging-adhesive sealing agent includes the following steps: S1. Wash and dry the calcium carbonate granules, and stir them at 40 r / min. The particle size of the calcium carbonate granules is 0.78-2.85 mm, and the density is 2.6 g / cm³. 3 ; S2. Spray an 80% concentration of waterborne polyurethane emulsion onto the surface of calcium carbonate particles at a rate of 1 L / h, then add thermosetting phenolic resin powder and continue stirring. The particle size of the thermosetting phenolic resin powder is 200 mesh. The mass ratio of calcium carbonate particles, waterborne polyurethane emulsion and thermosetting phenolic resin powder is 40:2:5. Dry and cure in a dry powder coating machine to obtain a bridging-adhesive sealing agent.

[0046] Example 2 A bridging-adhesive sealing agent includes walnut shell particles and an adhesive coating layer covering the surface of the walnut shell particles; the adhesive coating layer includes thermosetting phenolic resin powder, which is coated and cured on the surface of the bridging-sealing particles by an aqueous epoxy resin emulsion.

[0047] The preparation method of the above-mentioned bridging-adhesive sealing agent includes the following steps: S1. Wash and dry the walnut shell particles, then stir at 30 r / min. The particle size of the walnut shell particles is 0.78-2.85 mm, and the density of the walnut shell particles is 1.2 g / cm³. 3 ; S2. A 60% concentration of waterborne epoxy resin emulsion with a viscosity of 100 mPa·s is sprayed onto the surface of walnut shell particles at a rate of 0.5 L / h. The waterborne epoxy resin emulsion is prepared by compounding epoxy resin and polyamide curing agent (650) at a mass ratio of 3.5:1. Then, thermosetting phenolic resin powder is added and stirred. The particle size of thermosetting phenolic resin powder is 200 mesh. The mass ratio of walnut shell particles, waterborne epoxy resin emulsion and thermosetting phenolic resin powder is 40:2:5. After ventilation, drying and curing, a bridging-adhesive sealing agent is obtained.

[0048] Example 3 A bridging-adhesive sealing agent includes walnut shell particles and an adhesive coating layer covering the surface of the walnut shell particles; the adhesive coating layer includes thermosetting phenolic resin powder, which is coated and cured on the surface of the bridging-sealing particles by an aqueous epoxy resin emulsion.

[0049] The preparation method of the above-mentioned bridging-adhesive sealing agent includes the following steps: S1. Wash and dry the walnut shell particles, then stir at 60 r / min. The particle size of the walnut shell particles is 0.78-2.85 mm, and the density of the walnut shell particles is 1.4 g / cm³. 3 ; S2. Spray a 55% concentration of waterborne epoxy resin emulsion onto the surface of walnut shell particles at a rate of 2 L / h. The viscosity of the waterborne epoxy resin emulsion is 200 mPa·s. The waterborne epoxy resin emulsion is compounded with epoxy resin and polyamide curing agent (650) at a mass ratio of 3.5:1. Then, add thermosetting phenolic resin powder and continue stirring. The particle size of the thermosetting phenolic resin powder is 200 mesh. The mass ratio of walnut shell particles, waterborne epoxy resin emulsion and thermosetting phenolic resin powder is 40:2:5. After ventilation, dry and cure to obtain a bridging-adhesive sealing agent.

[0050] Comparative Example 1 The preparation method of the self-consolidating sealant includes the following steps: S1, mica, walnut shell, basalt fiber and other sealing materials are sequentially washed with water, soaked in dilute sulfuric acid, soaked in coupling agent (KH-550) and dried for pretreatment; S2. Coating material (epoxy resin + 8% curing agent + 2% accelerator DL-1 + 1.5% coupling agent + 2.0% calcium stearate) is dissolved in ethanol / water according to the formula to prepare an atomizable liquid; S3. Place the pretreated plugging material and coating material into a fluidized bed coating machine, and set the blower speed to 60 m / s. 3 Spraying and drying are performed at a spray gun rate of 1 L / h, with a jet pressure of 0.5 MPa, an inlet air temperature of 80℃, an outlet air temperature of 30℃, and a spray gun speed of 1 L / h. The coating is then cooled and bagged.

[0051] Comparative Example 2 The preparation method of the bridging and sealing-thermally induced solidification plugging agent includes the following steps: S1. Synthesis of thermosensitive self-curing resin: F011 type organic resin + accelerator is dissolved in anhydrous ethanol, stirred at room temperature, vacuum dried at 60°C for 30 h, and then pulverized. S2. Preparation of thermo-cured rigid sealing material: The aggregate is washed with hydrogen peroxide and dried at 40°C; it is immersed in an anhydrous ethanol solution containing 8% thermosensitive resin and calcium stearate is added; after stirring at room temperature, it is vacuum dried at 60°C for 30 h and then pulverized to the required particle size. S3, Leak-stopping system compound: Mix bentonite slurry + 48% of the above rigid materials + 3% temperature-sensitive resin + 3% walnut shell + 8% high-temperature resistant fiber at room temperature to obtain the solution.

[0052] Comparative Example 3 A method for preparing microencapsulated epoxy resin adhesive includes the following steps: S1. Epoxy resin E-51 and ethyl acetate (volume ratio 5:1) were mixed to form the core material. A Tween80 (1.5 wt.%) + GA (3 wt.%) solution was stirred and then added to the core material. The mixture was emulsified at 5000 rpm and 25°C for 10 min, transferred to a flask, and stirred at 850 rpm and 40°C for 1.5 h. A GE (3 wt.%) solution was slowly added, and after 20 min, the pH was adjusted to approximately 4 with acetic acid. The mixture was stirred for 30 min, cooled in an ice bath to approximately 10°C, and kept for 1 h to form a GA-GE shell. S2. Adjust the pH of the above mixture to approximately 5.5 with sodium hydroxide, add tannin, crosslink at 400 rpm and 30℃ for 7 h, wash, filter, and dry to obtain ER-GA-GE microcapsules, disperse the microcapsules in calcium chloride solution, and add sodium carbonate solution dropwise while stirring to form a calcium carbonate outer shell, thus obtaining the product.

[0053] Experimental Example 1 The downhole bonding environment is humid and hot, and the drilling fluid is a complex colloidal solution with alkalinity. The most critical performance characteristic of the bridging-bonding plugging agent is its ability to bond effectively in this complex, humid, alkaline environment. The bridging-bonding plugging agents prepared in Example 1 and Example 2 were added to the drilling fluid and placed in an aging tank. The drilling fluid properties were designed to ensure that the bridging-bonding plugging agents settled at the bottom of the aging tank, and two heavy iron objects were used to apply gravity to the upper surface to achieve close contact. The tank was then heated in a 150°C oven for 4 hours. The test results of Example 1 are as follows: Figure 1 As shown, the test results of Example 2 are as follows: Figure 2 As shown. Figure 1 and Figure 2 In the diagram, (a) represents the image before removal, and (b) represents the image after removal.

[0054] Depend on Figure 1 and Figure 2 It can be seen that the calcium carbonate-based adhesive plugging agent bonds tightly to the gravel placed inside, exhibiting high strength. The walnut shell-based adhesive plugging agent also bonds into clusters, exhibiting high strength and adhering tightly to the aging vessel wall, making it impossible to remove; it needs to be broken up before removal. This demonstrates that the bridging-adhesive plugging agent can achieve high-strength curing and bonding in the downhole drilling fluid environment.

[0055] Experimental Example 2 To verify the time required for bonding to complete in a humid and hot environment, the bridging-bonding plugging agent prepared in Example 2 was added to the drilling fluid, suspending the walnut shell-based plugging agent in the drilling fluid. The plugging slurry was then poured into an aging reactor, which was subsequently placed in a 150°C drying oven and heated for 1 hour. After the required aging time was met, the aging reactor was removed and cooled. The aged walnut shell-based plugging agent was obtained by filtration using a sieve and then dried at 150°C for 1 hour. The results are as follows. Figure 3 As shown. Figure 3 In the above, (a) is taken out after aging at 150 ℃ for 1 h, and (b) is taken out after drying and heating at 150 ℃ for 1 h.

[0056] Depend on Figure 3 It can be seen that the walnut shell-based adhesive sealant, after being heated and dried for 1 hour, clumps together, and the sealant still retains its adhesive ability after being heated again.

[0057] Following the above experimental procedure, the walnut shell-based adhesive sealant, aged for 2 hours in a humid heat environment at 150 ℃, was then dried and heated again at 150 ℃ for 1 hour. The results are as follows. Figure 4 As shown. Figure 4 In the above, (a) is taken out after aging at 150 ℃ for 2 h, and (b) is taken out after drying and heating at 150 ℃ for 1 h.

[0058] Depend on Figure 4 It can be seen that the plugging agent is in granular form and not bonded together, indicating that the plugging agent has completely bonded during the aging process. Therefore, it can be concluded that the bridging-bonding plugging agent needs to be heated for more than 2 hours in a humid and hot environment of 150℃ from preparation to well injection.

[0059] Experimental Example 3 Using a stainless steel cylindrical mold with an inner diameter of 50 mm and a height of 50 mm, the bridging-adhesive sealing agents prepared in Examples 1-2 were respectively mixed with a density of 1.3 g / cm³. 3 The polysulfonated drilling fluid was mixed and poured into a mold. Steel balls and a pressure rod were applied to the top, and the mixture was then subjected to hydrothermal curing at 150℃ and 5 MPa injection pressure for 4 hours. After demolding, the compressive strength was tested according to GB / T 19139-2012. The test results are as follows: Figure 5 As shown. Figure 5 In the image, (a) represents coarse particles based on calcium carbonate granules, and (b) represents coarse particles based on walnut shell granules.

[0060] Depend on Figure 5It can be seen that the compressive strength of the clusters prepared in Example 1 is 3.06 kN and the compressive strength is 1.56 MPa, while the compressive strength of the clusters prepared in Example 2 is 1.78 kN and the compressive strength is 0.91 MPa. After the compressive strength test destroyed the adhesive structure, the calcium carbonate-based adhesive sealant clusters remained relatively intact after being crushed, only bulging outward from the center without causing particle dispersion. After being crushed, the calcium carbonate-based adhesive sealant clusters scattered in large pieces around the perimeter, while a large adhesive cluster remained intact in the center. This indicates that the bridging-adhesive sealant can effectively stabilize and seal the internal structure after bonding. Even if the sealing layer is crushed, large fragments will form in the cracks, and the reopening of the cracks will facilitate the re-formation of the sealing layer.

[0061] Test Example 4 (1) Injection pressure is the driving force for the formation of the sealing layer. Higher injection pressure is beneficial for the bridging-bonding plugging agent to form a seal. For the formation of the sealing layer, the higher the injection pressure, the denser and more stable the bridging-bonding sealing layer formed after successful plugging. However, for practical engineering, high injection pressure means an increased risk of well leakage in other formations. Therefore, the formation of the bridging-bonding sealing layer obtained in Example 1 was tested under various injection pressures as follows: Figure 6 As shown. Figure 6 In the diagram, (a)-(c) represent the sealing layers formed at 3 MPa, 5 MPa, and 7 MPa, respectively.

[0062] Depend on Figure 6 It can be seen that the bridging-bonding plugging agent achieves good bonding at 3 MPa. In actual field use, the injection pressure can be reasonably adjusted according to the bearing capacity of the open hole formation.

[0063] (2) The bonding temperature test determines the application conditions of the bridging-bonding sealant. The bonding conditions at various temperatures are as follows: Figure 7 As shown. Figure 7 In the figure, (a)-(d) represent the bonding conditions under humid and hot environments of 150℃, 130℃, 90℃ and 70℃, respectively.

[0064] Depend on Figure 7 It is known that the minimum temperature at which the bridging-bonding plugging agent achieves bonding under an injection pressure of at least 3 MPa is 90 ℃. The geothermal gradient is approximately 3 ℃ / 100m, therefore the recommended well depth for the bridging-bonding plugging agent is >3000 m.

[0065] In summary, the method for controlling the stability of the bridging-bonding sealing layer is as follows: R b ( R b For feature granularity D 90 With the width of the crack entrance WA The ratio of the filler material to the total filler material is greater than 0.6, the total filler material content reaches 10%, the injection pressure is greater than 3 MPa, and the temperature of the formation is greater than 90℃.

[0066] Experimental Example 5 The relevant performance test results of Example 1 and Comparative Examples 1-3 are shown in Table 1.

[0067] Table 1 Relevant performance test results

[0068] As shown in Table 1, Example 1, compared to Comparative Examples 1-3, has the lowest cost (15 yuan / kg), the highest production efficiency (300 kg / h), and the widest particle size range (0.5). The significant advantage of 4 mm) in its adhesive strength (0.63) The strength of the first invention (1.56 MPa) is superior to that of Comparative Example 1 (0.51 MPa), and it has a wider density range and meets conventional temperature requirements. Although Comparative Examples 2 and 3 have higher bonding strength, their costs are extremely high (25-31 yuan / kg) and their production volume is extremely low (1-5 kg / h), making them unsuitable for practical engineering applications. Therefore, this invention has significant advantages in terms of overall cost-effectiveness, large-scale production capacity, and field adaptability.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bridging-adhesive sealing agent, characterized in that, It includes bridging and sealing particles and an adhesive coating layer covering the surface of the bridging and sealing particles; the bridging and sealing particles are calcium carbonate particles and / or walnut shell particles; the adhesive coating layer includes thermosetting adhesive powder, which is coated and cured on the surface of the bridging and sealing particles by a liquid-assisted adhesive.

2. The bridging-adhesive sealing agent as described in claim 1, characterized in that, The bridging and plugging particles have a particle size of 0.78-2.85 mm, and the calcium carbonate particles have a density of 2.5-2.7 g / cm³. 3 The density of walnut shell particles is 1.2-1.4 g / cm³. 3 .

3. The bridging-adhesive sealing agent as described in claim 1, characterized in that, The thermosetting adhesive powder is a thermosetting phenolic resin powder with a particle size of 150-250 mesh, a softening point of 95-115℃, and a bonding and curing temperature of 120-180℃.

4. The bridging-adhesive sealing agent as described in claim 1, characterized in that, When the bridging and sealing particles are calcium carbonate particles, the liquid auxiliary adhesive is a water-based polyurethane emulsion; when the bridging and sealing particles are walnut shell particles, the liquid auxiliary adhesive is a water-based epoxy resin emulsion.

5. The bridging-adhesive sealing agent as described in claim 5, characterized in that, The waterborne polyurethane emulsion has a mass fraction of 50-80%, and the waterborne epoxy resin emulsion has a mass fraction of 55-65%.

6. The method for preparing the bridging-adhesive sealing agent according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Clean, dry and stir the bridging and sealing particles; S2. Spray liquid auxiliary adhesive onto the surface of the bridging and sealing particles treated in step S1, then add thermosetting adhesive powder and continue stirring, then ventilate and dry to cure, to obtain the bridging-adhesive sealing agent.

7. The preparation method according to claim 6, characterized in that, In step S1, the stirring speed is 30-60 r / min.

8. The preparation method according to claim 6, characterized in that, In step S2, the spraying rate is 0.5-2.0 L / h.

9. The preparation method according to claim 6, characterized in that, In step S2, the mass ratio of bridging and sealing particles, liquid auxiliary adhesive, and thermosetting adhesive powder is 15-40:1-4:2-7.

10. The use of the bridging-bonding plugging agent according to any one of claims 1-5 in the preparation of a plugging slurry for sealing lost formations in underground wells.

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