Anti-shrinkage liquid bridge plug material and preparation method thereof

Abstract

The invention discloses an anti-shrinkage liquid bridge plug material and a preparation method thereof, the liquid bridge plug material is prepared by taking a glue hardening agent, a bonding reinforcing agent and thermal expansion particles as raw materials, and the mass ratio of the glue hardening agent to the bonding reinforcing agent to the thermal expansion particles is (15-25): (65-70): (5-10). The preparation method comprises the following steps: mixing and stirring the glue hardener, the bonding enhancer and the thermal expansion particles according to the proportion, and curing in a drying oven to obtain the liquid bridge plug material. According to the invention, the thermal expansion particles are doped in the material and the solid connection monomer is modified, so that the volume shrinkage of the liquid bridge plug material in the curing process is successfully reduced, and the stability of the material is remarkably improved; and the adhesive property of the material is improved, the adhesive capacity of the material and the wall surface of a shaft or a leakage channel is enhanced, and challenges in fracturing and leaking stoppage construction can be effectively handled.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of shale gas reservoir development and drilling and production technology, and particularly relates to a shrinkage-resistant liquid bridge plug material and a preparation method thereof, which is used for segmented fracturing temporary plugging construction of a deep shale gas complex casing deformation well or plugging construction of a serious leakage well. BACKGROUND

[0002] The deep shale gas casing deformation well faces the problem of difficult entry of a mechanical bridge plug, the existing liquid bridge plug has insufficient pressure bearing capacity, and the resin bridge plug faces the problem of shrinkage after solidification, resulting in plugging failure. During drilling plugging, when serious leakage is encountered, the resin solidification material also faces the problem of shrinkage after solidification, and cannot effectively plug the fracture-cave type leakage. The resin curing agent releases a large amount of heat during solidification, and the volume expands greatly at an early stage, and shrinks when the temperature decreases to the formation environment temperature at a later stage, resulting in the detachment of the solidification material from the wall surface of the wellbore or leakage passage, and thus the solidification material cannot effectively plug (the pressure bearing strength is generally less than 20 MPa).

[0003] The main material for plugging in the prior art is an epoxy resin solidification material, but the volume shrinkage at the formation environment temperature cannot be effectively reduced (the expansion coefficient of the traditional material is greater than 200 x 10 -6 / K). At present, some people add heat-expandable microcapsule materials to achieve the purpose of preventing shrinkage by releasing the core material, but such materials face the problem of ineffective release of the microcapsule, and the preparation cost of the microcapsule material is high, and the microcapsule material cannot be uniformly mixed in the resin material, and may face the problem of serious local heat expansion performance due to sedimentation.

[0004] In view of this, the present patent application is proposed. SUMMARY

[0005] To solve the above problems, the purpose of the present patent application is to provide a shrinkage-resistant liquid bridge plug material and a preparation method thereof, which successfully reduces the volume shrinkage of the liquid bridge plug material during the solidification process by doping heat-expandable particles and modifying the solidification monomers (glue hardener and adhesion enhancer), greatly improves the adhesion performance of the material, and enhances the adhesion capacity of the material to the wall surface of the wellbore or leakage passage, and has significant advantages in complex fracture plugging and serious casing deformation wellbore temporary plugging.

[0006] The present application is implemented by the following technical solutions:

[0007] The first purpose of the present application is to provide a shrinkage-resistant liquid bridge plug material, which is prepared from a glue hardener, an adhesion enhancer and heat-expandable particles, and the mass ratio of the glue hardener, the adhesion enhancer and the heat-expandable particles is (15-25):(65-70):(5-10).

[0008] The volume shrinkage of the liquid bridge plug material during the curing process is successfully reduced by doping thermal expansion particles and modifying the solidification monomer (glue hardener and adhesion enhancer) in the material, significantly improving the stability of the material. The use of modified solidification monomer greatly improves the bonding performance of the material, enhancing its adhesion to the wall surface of the wellbore or lost circulation channel. The use of thermal expansion particles can avoid the technical defects of microcapsule materials, such as ineffective release and uneven mixing. Thus, under the dual synergistic effect of reducing volume shrinkage during curing and enhancing material adhesion to the wall surface of the wellbore or lost circulation channel, the stability of the liquid bridge plug material is significantly improved, making the material suitable for complex environments with high temperature and high pressure (100-160℃, greater than 20MPa), effectively addressing the challenges in fracturing and plugging operations, especially in complex fracture plugging and severe casing deformation wellbore temporary plugging. Specifically:

[0009] The glue hardener can accelerate the curing process of the glue, making it form a strong connection faster. By chemically reacting with other components in the glue, it can enhance the adhesion strength and wear resistance of the glue.

[0010] The adhesion enhancer can significantly improve the adhesion strength of the glue or adhesive, making the connection more secure and reliable. It can improve the heat resistance and chemical resistance of the glue or adhesive, allowing it to maintain stable performance in high-temperature or corrosive environments. It can improve the impact resistance of the glue or adhesive, making it perform better under impact or vibration.

[0011] Thermal expansion particles: In resin curing materials, shrinkage occurs during thermal curing, while thermal expansion particles can partially offset this shrinkage by expanding during curing, thereby reducing or relieving internal stress in the material, helping to prevent cracks or deformation in the material.

[0012] In an optional embodiment, the glue hardener is a phenolic novolac with an epoxy equivalent weight of 110-150g / eq.

[0013] The main role of phenolic novolac in this invention is as a cross-linking agent, reacting with other compounds to form a three-dimensional network structure, thereby enhancing the adhesion performance and durability of the glue. In addition, phenolic novolac can also provide good water resistance and chemical corrosion resistance for the glue, allowing it to maintain stable performance in different environments.

[0014] At the same time, the adhesion enhancer can interact with the resin in the phenolic novolac, enhancing its adhesion and wear resistance, and improving the durability of the material. Thermal expansion particles can combine with the resin in the phenolic novolac, playing a role in filling and enhancing performance, while reducing the impact of thermal expansion on the shrinkage of the material after exothermic curing, improving the stability and heat resistance of the material.

[0015] In an optional embodiment, the adhesion enhancer is a combination of one or both of bisphenol A epoxy resin, triethoxysilyl-functionalized bisphenol A novolac epoxy resin;

[0016] The triethoxysilyl-functionalized bisphenol A novolac epoxy resin is prepared from a hydroxylated novolac epoxy resin, an isocyanate coupling agent, N,N-diisopropylethylamine, and toluene, and the mass ratio of the hydroxylated novolac epoxy resin, the isocyanate coupling agent, the N,N-diisopropylethylamine, and the toluene is (25-35):(5-15):(3-8):(45-55).

[0017] The adhesion enhancer can chemically react with the adhesive or physically adsorb, enhancing the adhesion between the resin and other materials, improving the strength and wear resistance of the composite material.

[0018] The thermal expansion particles can be added to the bisphenol A novolac epoxy resin as a filler to control the thermal expansion coefficient of the material, improve the thermal expansion performance of the material, and also increase the strength and stiffness of the composite material.

[0019] The hydroxylated novolac epoxy resin can undergo crosslinking reactions with other materials, forming a network structure. This network structure can enhance the mechanical properties, heat resistance, and chemical corrosion resistance of the material. It can provide additional hydroxyl functional groups, which are beneficial for forming hydrogen bonds or other chemical bonds with the surface of other materials, thereby improving the adhesion performance of the material. The addition of the hydroxylated novolac epoxy resin can also affect the rate and mode of the curing reaction, thereby adjusting the curing characteristics of the material, such as curing time, curing temperature, etc.

[0020] The isocyanate functional groups in the isocyanate coupling agent can undergo addition reactions with the hydroxyl groups in the hydroxylated novolac epoxy resin, forming urea bonds. This chemical reaction helps to effectively connect organic substances with silane-functionalized materials, thereby enhancing the compatibility and interfacial bonding strength of the materials.

[0021] N,N-diisopropylethylamine can participate in the curing reaction of the epoxy resin as a curing agent or catalyst. Its presence can accelerate the chemical reaction between the epoxy resin and the silane-functionalized material, promoting the curing and crosslinking of the material, thereby improving the mechanical properties and chemical resistance of the material.

[0022] Toluene can act as a solvent to dissolve various reactants during the reaction, facilitating the mixing and mass transfer of the reactants, and promoting the progress of the reaction.

[0023] In an optional embodiment, the hydroxylated phenolic epoxy resin is prepared from bisphenol A novolac epoxy resin, phenol, toluene, triphenylphosphine, and the mass ratio of the bisphenol A novolac epoxy resin, phenol, toluene, and triphenylphosphine is (45-60):(3-8):(40-50):(0.2-0.8).

[0024] The bisphenol A novolac epoxy resin in the present application serves as a main base resin and plays a basic role in the preparation of the hydroxylated phenolic epoxy resin. It provides a main structural basis for the reaction and affects the performance of the final product. The introduction of the bisphenol A novolac epoxy resin can improve the heat resistance and mechanical properties of the hydroxylated phenolic epoxy resin, thereby enhancing the overall performance of the material.

[0025] Phenol, as one of the raw materials for the synthesis of the hydroxylated phenolic epoxy resin, participates in the reaction and undergoes chemical reactions. The hydroxyl functional group in phenol can play an important role in the reaction, allowing phenol to introduce a hydroxylated structure in the reaction, thereby changing the properties and functions of the resin. The introduction of phenol can adjust the performance of the hydroxylated phenolic epoxy resin, such as improving the solubility and curing performance of the resin, thereby affecting the performance of the final product.

[0026] Toluene, as a solvent in the reaction system, helps to dissolve the reactants together and promotes the progress of the reaction. At the same time, toluene can also be used as a solvent to assist in the separation and purification of the product after the reaction.

[0027] Triphenylphosphine, as a catalyst, participates in the synthesis of the hydroxylated phenolic epoxy resin, promotes the reaction and accelerates the reaction rate, and helps to improve the yield and purity of the product.

[0028] In an optional embodiment, the epoxy equivalent weight of the bisphenol A epoxy resin is 150-220 g / eq.

[0029] In an optional embodiment, the hydroxylated phenolic epoxy resin is a substance having any one of the following structural formulas, or a combination of substances having any one of the following structural formulas:

[0030]

[0031] In an optional embodiment, the isocyanate coupling agent includes one or a combination of several of stearic acid, isophorone diisocyanate, 3-(triethoxysilyl)propyl isocyanate, and isocyanate silane coupling agent.

[0032] In an optional embodiment, the thermal expansion particles are any one or a combination of several of silicon dioxide, oil-soluble modified expanded graphite, Al2O3, and MgO.

[0033] In the system, silica as a filler material, can play a role in filling the gap in the resin, reducing the shrinkage of the resin system. By filling effect, silica helps to reduce the internal stress caused by resin shrinkage, improve the stability and durability of the product.

[0034] Oil-soluble modified expanded graphite has good thermal stability, can maintain stability at high temperature, not easy to burn and oxidation, helps to improve the overall thermal stability of the resin system. Expanded graphite itself has excellent thermal conductivity, can effectively conduct heat, so that the resin system in the curing process heat is more evenly distributed, helps to reduce internal stress and prevent shrinkage.

[0035] Al2O3 has good high temperature resistance, can enhance the heat resistance of the resin system, reduce the shrinkage phenomenon caused by heat in the curing process, thereby improving the stability of the product. Appropriate amount of Al2O3 can improve the mechanical properties of the resin system, increase its hardness and strength, reduce the stress concentration caused by shrinkage, improve the overall performance of the product.

[0036] MgO has a high thermal expansion coefficient, which can expand during the curing process of the resin, thereby offsetting the impact of resin shrinkage. This helps to reduce the shrinkage rate of the resin system, reduce internal stress, and improve the stability of the product. MgO has good high temperature resistance, which can enhance the heat resistance of the resin system, reduce the shrinkage phenomenon caused by heat in the curing process, thereby improving the stability of the product.

[0037] In an optional embodiment, the particle size of the silica is 50-200 nm;

[0038] The preparation process of the oil-soluble modified expanded graphite is as follows: dry graphene oxide powder is added to n-octanol and stirred;

[0039] The insoluble substance is centrifuged and dispersed in vinyl acetate monomer containing initiator azobisisobutyronitrile under stirring;

[0040] After centrifuging the insoluble intermediate, heat drying under nitrogen atmosphere, and stirring the obtained powder in n-hexane solution to remove residual vinyl acetate, centrifuging and drying to obtain oil-soluble modified expanded graphite.

[0041] The second object of the present application is to provide a preparation method of the anti-shrinkage liquid bridge plug material as claimed in any one of the above, mixing and stirring the glue hardener, the adhesion enhancer and the thermal expansion particles according to the proportion, curing in the oven, and obtaining the liquid bridge plug material.

[0042] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0043] The volume shrinkage of the liquid bridge plug material during the curing process is successfully reduced by doping thermal expansion particles in the material and modifying the solidification monomer (glue hardener and adhesion enhancer) in the embodiments of the present application, and the stability of the material is significantly improved. The use of modified solidification monomers greatly improves the adhesion performance of the material and enhances the adhesion of the material to the wall surface of the wellbore or lost circulation channel. Thus, under the dual synergy of reducing the volume shrinkage during the curing process and enhancing the adhesion of the material to the wall surface of the wellbore or lost circulation channel, the stability of the liquid bridge plug material is significantly improved, so that the material can be applied to complex environments with high temperature and high pressure, and can effectively cope with the challenges in fracturing and plugging operations, especially in complex fracture plugging and wellbore plugging in severe casing deformation. DETAILED DESCRIPTION

[0044] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application combined with embodiments, and the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and not as a limitation to the present application.

[0045] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be practiced without these specific details. In other embodiments, well-known methods are not specifically described in order to avoid obscuring the present application.

[0046] Throughout the specification, the mention of “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present application. Therefore, the phrases “one embodiment”, “an embodiment”, “one example” or “an example” appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. In addition, specific features, structures or characteristics can be combined in one or more embodiments or examples in any appropriate combination and / or subcombination.

[0047] In the description of the present application, the orientation or positional relationship indicated by the terms “front”, “back”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inner”, “outer” and the like is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation to the scope of protection of the present application.

[0048] Embodiment 1:

[0049] A shrinkage-resistant liquid bridge plug material has the following formula:

[0050] phenol novolac hardener (20 parts by mass), adhesion enhancer (triethoxysilyl-functionalized bisphenol A novolac epoxy resin, 75 parts by mass), and silica thermal expansion particles (5 parts by mass).

[0051] The above raw materials are mixed and uniformly mixed according to the ratio, and then cured in an oven at 180 degrees for 3h to obtain the anti-shrinkage liquid bridge plug.

[0052] The epoxy equivalent of the phenol novolac is 110 g / eq.

[0053] The preparation method of the triethoxysilyl-functionalized bisphenol A novolac epoxy resin is as follows:

[0054] (1) Bisphenol A novolac epoxy resin (epoxy value 210 g / Eq), phenol, toluene, and triphenylphosphine are mixed in a mass ratio of 50:4.5:45:0.5, heated and stirred at 90°C for 20 min, and then the solvent is removed by rotary evaporation after cooling to obtain a hydroxylated phenolic epoxy resin. The structural formula of the hydroxylated phenolic epoxy resin is:

[0055] (2) The hydroxylated phenolic epoxy resin, 3-(triethoxysilyl) propyl isocyanate, N,N-diisopropylethylamine and toluene are mixed and stirred in a mass ratio of 30:10:8:45, and reacted at 100°C for 16h to obtain a triethoxysilyl-functionalized bisphenol A novolac epoxy resin.

[0056] The particle size of the silica thermal expansion particles is 50-200 nm.

[0057] Example 2:

[0058] An anti-shrinkage liquid bridge plug material has the following formula:

[0059] Raw materials: phenol novolac hardener (20 parts by mass), adhesion enhancer (triethoxysilyl-functionalized bisphenol A novolac epoxy resin, 70 parts by mass), and oil-soluble modified expanded graphite (10 parts by mass). The above raw materials are mixed and uniformly mixed, and then cured in an oven at 180 degrees for 3h to obtain the anti-shrinkage liquid bridge plug.

[0060] The epoxy equivalent of the phenol novolac is 150 g / eq.

[0061] The preparation method of the triethoxysilyl-functionalized bisphenol A novolac epoxy resin is as follows:

[0062] (1) The bisphenol A novolac epoxy resin (epoxy value 210 g / Eq), phenol, toluene, triphenylphosphine were mixed and stirred, the mass ratio was 50:4.5:45:0.5, heated and stirred at 90℃ for 20 min, after cooling, the solvent was removed by rotary evaporation to obtain a hydroxylated novolac epoxy resin; the structural formula of the hydroxylated novolac epoxy resin is:

[0063] (2) The hydroxylated novolac epoxy resin, 3-(triethoxysilyl)propyl isocyanate, N,N-diisopropylethylamine and toluene were mixed and stirred, the mass ratio was 30:10:8:45, reacted at 100℃ for 16h to obtain a triethoxysilyl functionalized bisphenol A novolac epoxy resin.

[0064] The method for preparing the oil-soluble modified expanded graphite is as follows: 2wt% of air-dried graphene oxide powder is placed in 40wt% of n-octanol in a closed container, and the mixture is kept stirring at ambient temperature for 48h. Insoluble materials are separated by centrifugation, and then dispersed in 55wt% of vinyl acetate monomer containing 0.4wt% of azobisisobutyronitrile as an initiator under stirring. After centrifugation to separate the insoluble intermediates, heating is performed at 50℃ for 24h under a nitrogen atmosphere. The prepared powder is stirred in n-hexane solution for 20min to remove residual vinyl acetate, and the final product is obtained after centrifugation and drying at 50℃ for 24h.

[0065] Example 3:

[0066] A liquid bridge plugging material for preventing shrinkage, the formula is as follows:

[0067] Raw materials: phenolic novolac hardener (20 parts by mass), adhesion enhancer (bisphenol A epoxy resin, 70 parts by mass) and oil-soluble modified expanded graphite (10 parts by mass). The above raw materials are uniformly mixed and then cured in an oven at 180 degrees for 3h to obtain a liquid bridge plugging material for preventing shrinkage.

[0068] The epoxy equivalent weight of the phenolic novolac hardener is 130g / eq.

[0069] The method for preparing the oil-soluble modified expanded graphite is as follows: 3wt% of air-dried graphene oxide powder is placed in 45wt% of n-octanol in a closed container, and the mixture is kept stirring at ambient temperature for 48h. Insoluble materials are separated by centrifugation, and then dispersed in 50wt% of vinyl acetate monomer containing 0.5wt% of azobisisobutyronitrile as an initiator under stirring. After centrifugation to separate the insoluble intermediates, heating is performed at 50℃ for 24h under a nitrogen atmosphere. The prepared powder is stirred in n-hexane solution for 20min to remove residual vinyl acetate, and the final product is obtained after centrifugation and drying at 50℃ for 24h.

[0070] Example 4:

[0071] A liquid bridge plug material for preventing shrinkage, the formulation of which is as follows:

[0072] Raw materials: phenolic novolac hardener (30 parts by mass), adhesion enhancer (bisphenol A epoxy resin, 60 parts by mass), Al2O3 (5 parts by mass), and MgO (5 parts by mass). The above raw materials are mixed and uniformly blended, and then cured in an oven at 180 degrees for 3 hours to obtain a liquid bridge plug material for preventing shrinkage.

[0073] The epoxy equivalent weight of the phenolic novolac hardener is 150 g / eq.

[0074] The Al2O3 used is purchased from Shandong Dening Chemical Group Co., Ltd., and the MgO is purchased from Dongguan Dongchao New Material Technology Co., Ltd.

[0075] Comparative Example 1:

[0076] A liquid bridge plug material, the composition of which is a mixture of E51 epoxy resin and 650 polyamide curing agent in a weight ratio of 2:1.

[0077] Comparative Example 2:

[0078] The difference between this comparative example and Example 1 is that the heat-expandable particles are replaced with expanded vermiculite for comparison.

[0079] Test:

[0080] The liquid bridge plug materials obtained in Examples 1-4 and Comparative Examples 1 and 2 are tested: the thermal expansion coefficient of the material is measured using a mechanical analyzer. The sample size is selected to be 16 mm x 4 mm x 0.1 mm. Heat at a heating rate of 2℃ / min to different test temperatures.

[0081] The material is consolidated in a steel pipe with a size of 50 mm, and then the test temperature is maintained, high-temperature water at the test temperature is injected, and the maximum injection pressure is tested, which is the pressure-bearing capacity of the liquid bridge plug material.

[0082] Table 1 Comparison of expansion coefficients and pressure-bearing properties of materials with different formulations (100℃)

[0083]

[0084]

[0085] As can be seen from Table 1, the materials obtained in Examples 1-4 have smaller expansion coefficients at 100 DEG C and the bearing strength reaches 20.0 MPa. The materials in Examples 1 and 2 have smaller expansion coefficients and larger bearing strength at 100 DEG C, while the materials in Examples 3 and 4 have larger expansion coefficients and relatively smaller bearing strength at 100 DEG C. It can be seen that the materials using the formulations in Examples 1 and 2 have better performance. The performance of the materials in Comparative Examples is obviously poorer.

[0086] Table 2 Comparison of expansion coefficients and bearing properties of materials in Examples and Comparative Examples using different formulations (120 DEG C)

[0087] Formulation Expansion coefficient, 10 -6 / K]] 50 mm wellbore pressure, MPa Example 1 51 39.4 Example 2 59 35.0 Example 3 128 26.1 Example 4 156 18.6 Comparative Example 1 256 0.2 Comparative Example 2 181 4.1

[0088] As can be seen from Table 2, the materials obtained in Examples 1-4 have smaller expansion coefficients at 120 DEG C and larger bearing strength. The performance of the materials in Examples 1 and 2 is better than that in Examples 3 and 4.

[0089] Table 3 Comparison of expansion coefficients and bearing properties of materials in Examples 1-4 using different formulations (140 DEG C)

[0090] Formulation Expansion coefficient, 10 -6 / K]] 50 mm wellbore pressure, MPa Example 1 63 33.5 Example 2 71 32.1 Example 3 135 11.4 Example 4 173 12.3 Comparative Example 1 285 0.2 Comparative Example 2 223 2.5

[0091] Table 4 Comparison of expansion coefficients and bearing properties of materials in Examples and Comparative Examples using different formulations (160 DEG C)

[0092]

[0093]

[0094] As can be seen from Tables 3 and 4, with the increase of the test temperature, the expansion coefficients of the materials in Examples have a tendency to increase at 160 DEG C, however, the expansion coefficients are still smaller than those of the current sealing materials, and the bearing pressure has a tendency to decrease but is still obviously higher than that of the current sealing materials. The materials obtained in Comparative Examples 1 and 2 have larger expansion coefficients and almost 0 bearing capacity.

[0095] The present application has the following advantages:

[0096] 1. The present application successfully reduces the volume shrinkage of the material during solidification by modifying the solidified monomer and doping the thermal expansion particles, and significantly improves the stability of the material.

[0097] 2. The present application improves the bonding performance of the material: the use of the modified solidified monomer greatly improves the bonding performance of the material and enhances the adhesion of the material to the wall surface of the wellbore or lost circulation channel.

[0098] 3、The application widens the application range: the anti-shrinkage liquid bridge plug material is suitable for complex environment of high temperature and high pressure, can effectively deal with the challenge in fracturing and plugging construction, and has obvious advantages in complex fracture plugging and serious casing deformation well borehole temporary plugging.

[0099] 4、The application provides a new solution: for the problems of well leakage and casing deformation well fracturing, the application provides an effective temporary plugging method, and provides a new idea and means for engineering technology in the related field.

[0100] The above specific embodiments further specifically describe the purposes, technical solutions and beneficial effects of the application, and it should be understood that the above is only a specific embodiment of the application, and is not used to limit the protection scope of the application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. An anti- shrinkage liquid bridging plug material, characterized in that, The glue hardener, the bonding enhancer and the thermal expansion particles are mixed and stirred according to the ratio, and then cured in an oven to obtain the liquid bridge plug material.

2. The anti-contraction liquid bridging plug material of claim 1, wherein, The glue hardener is phenol novolac, and the epoxy equivalent weight of the phenol novolac is 110-150 g / eq.

3. The anti-contraction liquid bridging plug material of claim 1, wherein, The bonding enhancer is one or a combination of bisphenol A epoxy resin and triethoxysilyl-functionalized bisphenol A novolac epoxy resin. The triethoxysilyl-functionalized bisphenol A novolac epoxy resin is prepared from hydroxylated phenolic epoxy resin, isocyanate coupling agent, N,N-diisopropylethylamine and toluene, and the mass ratio of the hydroxylated phenolic epoxy resin, the isocyanate coupling agent, the N,N-diisopropylethylamine and the toluene is (25-35):(5-15):(3-8):(45-55).

4. The anti-contraction liquid bridging plug material of claim 3, wherein, The hydroxylated phenolic epoxy resin is prepared from bisphenol A novolac epoxy resin, phenol, toluene and triphenylphosphine, and the mass ratio of the bisphenol A novolac epoxy resin, the phenol, the toluene and the triphenylphosphine is (45-60):(3-8):(40-50):(0.2-0.8).

5. An anti-contraction liquid bridging plug material according to claim 4, wherein, The epoxy equivalent weight of the bisphenol A epoxy resin is 150-220 g / eq.

6. The anti-contraction liquid bridging plug material of claim 3, wherein, The hydroxylated phenolic epoxy resin is a substance having any one of the following structural formulae or a combination of substances having any one of the following structural formulae:

7. The anti-contraction liquid bridging plug material of claim 3, wherein, The isocyanate coupling agent includes one or a combination of several of stearic acid, isophorone diisocyanate, 3-(triethoxysilyl)propyl isocyanate and isocyanate silane coupling agent.

8. An anti-shrinkage liquid bridging plug material according to any one of claims 1 to 7, characterized in that, The thermal expansion particles are any one or a combination of several of silicon dioxide, oil-soluble modified expanded graphite, Al2O3 and MgO.

9. An anti-contraction liquid bridging plug material according to claim 8, wherein, The particle size of the silicon dioxide is 50-200 nm. The preparation process of the oil-soluble modified expanded graphite is as follows: the air-dried graphene oxide powder is added to n-octanol and stirred; The insoluble substance is centrifugally separated and dispersed in vinyl acetate monomer containing an initiator azobisisobutyronitrile under stirring; After centrifugal separation of the insoluble intermediate, the obtained powder is heated and dried under a nitrogen atmosphere, and then stirred in n-hexane solution to remove residual vinyl acetate, and then centrifuged and dried to obtain the oil-soluble modified expanded graphite.

10. The method of preparing an anti-shrinkage liquid bridging plug material according to any one of claims 1 to 9, characterized in that, The glue hardener, the bonding enhancer and the thermal expansion particles are mixed and stirred according to the ratio, and then cured in an oven to obtain the liquid bridge plug material.

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