High-temperature-resistant high-strength resin blocking agent and preparation method thereof

Abstract

The invention relates to the technical field of resin plugging, and discloses a high-temperature-resistant high-strength resin plugging agent and a preparation method thereof.The resin plugging agent is prepared from, by weight, 40-70 parts of epoxy resin, 5-15 parts of diluent, 5-10 parts of modified filler, 0.5-1 part of emulsifier, 1-1.5 parts of coupling agent, 6-20 parts of composite curing agent and 0.5-1.5 parts of imidazole microcapsule; the modified filler is prepared by firstly preparing nano cellulose loaded with metal ions and then modifying the nano cellulose loaded with the metal ions with tannic acid; the composite curing agent comprises POSS (Polyhedral Oligomeric Silsesquioxane) and 4, 4-diaminodiphenyl ether; the imidazole microcapsule takes 2-methylimidazole as a core material and polyvinyl alcohol as a shell material. According to the high-temperature-resistant high-strength resin blocking agent provided by the invention, through the synergistic effect of all the components, the obtained blocking agent is good in fluidity, high in toughness, high in strength, good in heat resistance, good in sealing performance and good in blocking effect.

Description

Technical Field

[0001] The invention relates to the technical field of resin plugging, in particular to a high-temperature resistant and high-strength resin plugging agent and a preparation method thereof. Background Art

[0002] In the process of oil extraction, wellbore plugging is one of the key technologies, the purpose of which is to prevent unplanned flow of formation fluids, repair damaged well walls, and deal with underground accidents. At the same time, the effectiveness of plugging technology directly affects the safety and production efficiency of the wellbore.

[0003] Traditional wellbore plugging methods mainly include cement slurry plugging, mechanical packer plugging, and chemical plugging. Cement slurry plugging has the advantages of low cost and simple construction. However, the strength and stability of cement slurry are poor, resulting in poor high temperature resistance. The cement slurry takes a long time to solidify, which affects the construction efficiency. At the same time, in corrosive formations, cement slurry is easily corroded, resulting in poor plugging effect. Mechanical packer plugging has the advantage of simple operation, but it is only suitable for short-distance plugging. When applied to long-distance or multi-stage plugging, the effect is poor. It is easy to be damaged under high temperature and high pressure, which affects the plugging effect. Chemical plugging can form a stable plugging layer and is suitable for complex formations. Among them, resin plugging technology has been widely used in modern wellbore plugging due to its unique advantages. For example, it can be applied to complex wellbore environments, such as high temperature, high pressure and corrosive formations. It has good fluidity and pumpability. It can be solidified in a short time, shortening the construction period. It has high strength and toughness and can be effectively plugged.

[0004] However, although resin sealing has the above advantages, its performance will decrease at high temperature and high pressure environment, so that the strength and toughness of resin sealing cannot meet the requirements of sealing, resulting in cracking or failure. Summary of the invention

[0005] Technical problems solved by the present invention: The invention is used to solve the problems of poor high temperature resistance and mechanical properties of resin plugging agents in the prior art, which lead to poor plugging effect.

[0006] The technical solution adopted by the present invention is: In view of the above technical problems, the object of the present invention is to provide a high-temperature resistant and high-strength resin plugging agent and a preparation method thereof.

[0007] Based on this, the specific implementation plan is: First, the present invention provides a high-temperature resistant and high-strength resin plugging agent, wherein the raw material components are measured by weight and include 40-70 parts of epoxy resin, 5-15 parts of diluent, 5-10 parts of modified filler, 0.5-1 part of emulsifier, 1-1.5 parts of coupling agent, 6-20 parts of composite curing agent, and 0.5-1.5 parts of imidazole microcapsules; wherein the modified filler is prepared by first preparing nanocellulose loaded with metal ions, and then modifying the nanocellulose loaded with metal ions with tannic acid; wherein the composite curing agent includes POSS and 4,4-diaminodiphenyl ether; wherein the imidazole microcapsules are made of 2-methylimidazole as a core material and polyvinyl alcohol as a shell material, and the ratio of the core material to the shell material is 1:0.5-1.

[0008] Specifically, the preparation method of the modified filler comprises the following steps: In the first step, nanocellulose is dispersed in distilled water, and then TEMPO and sodium bromide are added, stirring is maintained, and then 10% sodium hypochlorite solution is added dropwise. After the addition is completed, the pH value is adjusted to 10.5, and stirring is maintained for 2 hours. Then, the oxidation reaction is terminated with an ethanol solution to obtain oxidized nanocellulose. In the above, the specific amount of each substance is: based on the amount of nanocellulose added, TEMPO accounts for 0.2~1%, sodium bromide accounts for 10~20%, and sodium hypochlorite accounts for 5%.

[0009] In the second step, the oxidized nanocellulose is dispersed in a 1-10 wt% metal salt solution and soaked at room temperature for 4-10 hours to obtain nanocellulose loaded with metal ions. The metal salt is chloride, and the metal ions include Fe 3+ , Cu 2+ 、Zn 2+ .

[0010] In the third step, the nanocellulose loaded with metal ions is placed in anhydrous ethanol for ultrasonic treatment for 2 hours, taken out, rinsed with deionized water, and dried; then the nanocellulose is immersed in 1.5g / L~2.5g / L tannic acid solution, and the pH value is adjusted to 8.5. After shaking on a shaker at room temperature for 15~20 hours, it is taken out, rinsed with deionized water, and dried to obtain the modified filler.

[0011] Specifically, the preparation method of imidazole microcapsules comprises the following steps: In the first step, 2-methylimidazole is dissolved in a solvent, heated to 100-130°C, and then phenyl glycidyl ether is added dropwise, reacted for 2 hours, and modified imidazole is obtained by vacuum distillation; the mass ratio of 2-methylimidazole, solvent xylene, and phenyl glycidyl ether is 10:100:20-30.

[0012] In the second step, the modified imidazole and polyvinyl alcohol are dissolved in ethanol, heated and stirred evenly, and then a 5wt% sodium dodecyl sulfate aqueous solution is added dropwise under the action of a homogenizer to obtain an emulsion, and then the emulsion is spray-dried to obtain imidazole microcapsules. The mass ratio of modified imidazole to polyvinyl alcohol is 1-3:1.

[0013] In the above, the epoxy resin includes bisphenol A epoxy resin and hydantoin epoxy resin, and the ratio of the two is 1:1.

[0014] In the above, the diluent includes at least one of butyl glycidyl ether, ethylene glycol glycidyl ether, ethyl acetate, and dibutyl phthalate.

[0015] In the above, the emulsifier includes at least one of glycerol fatty acid ester, octylphenol polyoxyethylene ether, polyoxyethylene sorbitan trioleate, and sodium lauryl sulfate.

[0016] In the above, the coupling agent includes at least one of silane coupling agent KH550 and silane coupling agent KH570.

[0017] Second, the present invention provides a method for preparing the aforementioned high-temperature resistant high-strength resin plugging agent, comprising the following steps: The first step is to blend epoxy resin, diluent, coupling agent and emulsifier to obtain a first treated product; The second step is to blend the modified filler, the composite curing agent and the imidazole microcapsules to obtain a second treated product; The third step is to blend the first treated material with the second treated material to obtain a high-temperature resistant and high-strength resin plugging agent.

[0018] In the above, in the first step to the third step, blending is performed by stirring.

[0019] In the above, the first step of blending is: 500~1000r / min, 10~30min.

[0020] In the above, the second step of blending: 500~1000r / min, 10~30min.

[0021] In the above, the third step of blending: 800~1000r / min, 5~15min.

[0022] The technical mechanism and beneficial effects adopted by the present invention are as follows: (1) The high-temperature resistant and high-strength resin plugging agent provided by the present invention is added in the form of a composite epoxy resin, specifically including bisphenol A epoxy resin and hydantoin epoxy resin. The combination of the two can make the epoxy value of the resin appropriate and avoid thermal runaway during high-temperature curing.

[0023] (2) The high-temperature resistant and high-strength resin plugging agent provided by the present invention comprises a modified filler including nanocellulose, tannic acid and metal ions, which are loaded in one body: nanocellulose is dispersed in the resin matrix to provide the resin with a heat-resistant skeleton, and the multi-hydroxyl groups of the nanofibers themselves are used to form non-covalent bonds with the resin, and can be interwoven and entangled in the resin network, thereby improving the strength of the resin; metal ions are added to the resin system, and the metal ions can form non-covalent bonds with the epoxy resin molecular chains, and when deformed by external force, the non-covalent bonds break to dissipate the fracture energy, and after the external force disappears, the non-covalent bonds are reconstructed in the resin network; however, if the metal ions are directly added to the system, it will cause the problem of incompatibility with the resin system; based on this, by loading the metal ions in the nanocellulose, the above-mentioned disadvantages can be solved, and then the nanocellulose is modified by tannic acid, and the tannic acid can play a bridging role between the nanocellulose and the resin system, thereby improving the toughness and impact strength.

[0024] (3) The high-temperature resistant and high-strength resin plugging agent provided by the present invention, the composite curing agent includes POSS and 4,4-diaminodiphenyl ether. By introducing POSS, the heat resistance and mechanical properties of the resin can be improved. However, if only POSS is added for cross-linking and curing, due to the high cross-linking density of POSS, the resin will become hard and brittle. Therefore, 4,4-diaminodiphenyl ether is added to ensure heat resistance while reducing the cross-linking density of the resin. In addition, we also enhance the toughness of the resin by adding nanocellulose as mentioned above.

[0025] (4) The high-temperature resistant and high-strength resin plugging agent provided by the present invention, the imidazole microcapsules include 2-methylimidazole and polyvinyl alcohol, and the imidazole curing agent is used as a potential curing agent, which can be further cured under high temperature conditions, thereby playing a self-repairing role. Adding it in the form of microcapsules can ensure the stability of imidazole, so that it can play a role at high temperatures. Here, polyvinyl alcohol is used as a coating layer, and the excellent film-forming property of polyvinyl alcohol, good compatibility with resin, easy water absorption and swelling at high temperature and release of imidazole are utilized to achieve the purpose of self-repair. In addition, the silane coupling agent in the system can also be used to further improve the compatibility of polyvinyl alcohol with the resin.

[0026] (5) The high-temperature resistant and high-strength resin plugging agent provided by the present invention comprises epoxy resin, diluent, modified filler, emulsifier, coupling agent, composite curing agent and imidazole microcapsule. Through the synergistic effect of the aforementioned components, the obtained plugging agent has good fluidity, strong toughness, high strength, good heat resistance, good sealing and good plugging effect. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0028] Example 1 A high-temperature resistant and high-strength resin plugging agent, the raw materials include: 30 parts of bisphenol A epoxy resin 30 parts of hyaluronic acid epoxy resin 10 parts of butyl glycidyl ether 0.5 parts of sodium lauryl sulfate KH5501 copy Modified filler 8 parts Octa-vinyl POSS 2.5 parts 2.5 parts of 4,4-diaminodiphenyl ether Imidazole microcapsules 1 part The preparation method of the modified filler is: In the first step, 1 g of nanocellulose is dispersed in distilled water, and then 0.01 g of TEMPO and 0.1 g of sodium bromide are added, while stirring is maintained, and then 10% sodium hypochlorite solution is added dropwise to make the sodium hypochlorite account for 5%. After the addition is completed, the pH value is adjusted to 10.5, while stirring is maintained for 2 hours, and then the oxidation reaction is terminated with an ethanol solution to obtain oxidized nanocellulose.

[0029] In the second step, the oxidized nanocellulose prepared in step 1 was dispersed in 5 wt% FeCl 3 The Fe-loaded 3+ of nanocellulose.

[0030] The third step is to prepare the Fe-loaded 3+ The nanocellulose was placed in anhydrous ethanol for ultrasonic treatment for 2 hours, taken out, rinsed with deionized water, and dried; then the nanocellulose was immersed in a 2g / L tannic acid solution, and the pH value was adjusted to 8.5. After shaking on a shaker at room temperature for 15 hours, it was taken out, rinsed with deionized water, and dried to obtain a modified filler.

[0031] The preparation method of imidazole microcapsules is as follows: In the first step, 10 g of 2-methylimidazole was dissolved in 100 g of xylene, heated to 120° C., and then 20 g of phenyl glycidyl ether was added dropwise, reacted for 2 h, and the modified imidazole was obtained by vacuum distillation.

[0032] In the second step, the modified imidazole and polyvinyl alcohol are dissolved in ethanol, heated and stirred evenly, and then a 5wt% aqueous solution of sodium dodecyl sulfate is dropped under the action of a homogenizer to obtain an emulsion, and the emulsion is then spray-dried to obtain imidazole microcapsules. The mass ratio of the modified imidazole to the polyvinyl alcohol is 2:1, and the sodium dodecyl sulfate accounts for 0.3% of the amount of modified imidazole added.

[0033] The preparation method of the high temperature resistant and high strength plugging agent is as follows: The first step is to weigh the aforementioned raw material components in proportion; The second step is to blend bisphenol A epoxy resin, hydantoin epoxy resin, butyl glycidyl ether, KH550 and sodium lauryl sulfate at 550 r / min for 20 min to obtain a first treated product; The third step is to blend the modified filler, octavinyl POSS, 4,4-diaminodiphenyl ether and imidazole microcapsules at 550 r / min for 20 min to obtain a second treated product; The fourth step is to mix the first treated product and the second treated product at 800 r / min for 10 minutes to obtain a high-temperature resistant and high-strength resin plugging agent.

[0034] Comparative Example 1 The difference between this comparative example and Example 1 is that the nanocellulose is modified by a conventional silane coupling agent and then reacted with FeCl 3 The two are added together into the raw material system to obtain a plugging agent.

[0035] Comparative Example 2 The difference between this comparative example and Example 1 is that imidazole microcapsules are not added.

[0036] Comparative Example 3 The difference between this comparative example and Example 1 is that octavinyl POSS and 4,4-diaminodiphenyl ether are all replaced by 4,4-diaminodiphenyl ether.

[0037] Comparative Example 4 The difference between this comparative example and Example 1 is that the addition ratio of octavinyl POSS and 4,4-diaminodiphenyl ether is 4:1.

[0038] Test example The plugging agents prepared in Example 1 and Comparative Examples 1-4 were used as samples for testing, and the performance was measured according to the standard of GB-T 19139-2012. The results are shown in Table 1.

[0039] Table 1 Measurement results of each sample (Example-E, Comparative Example-D)

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-temperature resistant and high-strength resin plugging agent, characterized in that: The raw material components are calculated by weight, including 40-70 parts of epoxy resin, 5-15 parts of diluent, 5-10 parts of modified filler, 0.5-1 part of emulsifier, 1-1.5 parts of coupling agent, 6-20 parts of composite curing agent, and 0.5-1.5 parts of imidazole microcapsule; In the above, the modified filler is prepared by first preparing nanocellulose loaded with metal ions, and then modifying the nanocellulose loaded with metal ions with tannic acid; In the aforementioned, the composite curing agent includes POSS and 4,4-diaminodiphenyl ether; In the above, the imidazole microcapsules are made of 2-methylimidazole as the core material and polyvinyl alcohol as the shell material.

2. The high temperature resistant and high strength resin plugging agent according to claim 1, characterized in that: The epoxy resin includes bisphenol A epoxy resin and hydantoin epoxy resin, and the mass ratio of the two is 1:

1.

3. The high temperature resistant and high strength resin plugging agent according to claim 1, characterized in that: The mass ratio of POSS to 4,4-diaminodiphenyl ether is 0.5~1:0.5~1.

4. The high temperature resistant and high strength resin plugging agent according to claim 1, characterized in that: Each component of the raw material includes at least one of the characteristics (A) to (C): (A) the diluent comprises at least one of butyl glycidyl ether, ethylene glycol glycidyl ether, ethyl acetate, and dibutyl phthalate; (B) the emulsifier includes at least one of glycerol fatty acid ester, octylphenol polyoxyethylene ether, polyoxyethylene sorbitan trioleate, and sodium lauryl sulfate; (C) The coupling agent includes at least one of silane coupling agent KH550 and silane coupling agent KH570.

5. The high temperature resistant and high strength resin plugging agent according to any one of claims 1 to 4, characterized in that: The preparation method of the modified filler comprises the following steps: In the first step, nanocellulose is dispersed in distilled water, and then TEMPO and sodium bromide are added, stirring is maintained, and then sodium hypochlorite solution is added dropwise. After the addition is completed, the pH value is adjusted to 10.5, stirring is maintained, and then the oxidation reaction is terminated with an ethanol solution to obtain oxidized nanocellulose; The second step is to disperse the oxidized nanocellulose in a metal salt solution and soak it at room temperature to obtain nanocellulose loaded with metal ions; In the third step, the nanocellulose loaded with metal ions is placed in anhydrous ethanol for ultrasonic treatment, and then washed with deionized water and dried. The nanocellulose is then immersed in a tannic acid solution and the pH value is adjusted to 8.

5. The nanocellulose is shaken on a shaker at room temperature, and then washed with deionized water and dried to obtain a modified filler.

6. The high-temperature resistant and high-strength resin plugging agent according to claim 5, characterized in that: The modified filler includes at least one of the features (1-1) to (1-2): (1-1) Based on the amount of nanocellulose added, TEMPO accounts for 0.2~1%, sodium bromide accounts for 10~20%, and sodium hypochlorite accounts for 5%; (1-2) The metal salt is a chloride salt, and the metal ions include Fe 3+ , Cu 2+ 、Zn 2+ At least one of .

7. The high temperature resistant and high strength resin plugging agent according to any one of claims 1 to 4, characterized in that: The preparation method of imidazole microcapsules comprises the following steps: The first step is to dissolve 2-methylimidazole in a solvent, heat it, and then drop phenyl glycidyl ether to react, and obtain modified imidazole by vacuum distillation; In the second step, the modified imidazole and polyvinyl alcohol are dissolved in ethanol, heated and stirred evenly, and then dripped with sodium dodecyl sulfate aqueous solution under the action of a homogenizer to obtain an emulsion, and then the emulsion is spray-dried to obtain imidazole microcapsules.

8. The high-temperature resistant and high-strength resin plugging agent according to claim 7, characterized in that: The imidazole microcapsules include at least one of the features (2-1) to (2-2): (2-1) The mass ratio of 2-methylimidazole, solvent xylene, and phenyl glycidyl ether is 10:100:20-30; (2-2) The mass ratio of modified imidazole to polyvinyl alcohol is 1~3:

1.

9. A method for preparing the high temperature resistant and high strength resin plugging agent according to any one of claims 1 to 8, characterized in that: The steps include: The first step is to blend epoxy resin, diluent, coupling agent and emulsifier to obtain a first treated product; The second step is to blend the modified filler, the composite curing agent and the imidazole microcapsules to obtain a second treated product; The third step is to blend the first treated material with the second treated material to obtain a high-temperature resistant and high-strength resin plugging agent.

10. The method for preparing the high temperature resistant and high strength resin plugging agent according to claim 9, characterized in that: In the first step to the third step, the blending is performed by stirring. In the above, the first step of blending: 500~1000r / min, 10~30min; In the above, the second step of blending: 500~1000r / min, 10~30min; In the above, the third step of blending: 800~1000r / min, 5~15min.

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