High-temperature-resistant water-borne epoxy resin cement paste for plugging and preparation method thereof

Abstract

The invention relates to the technical field of cement paste materials, in particular to high-temperature-resistant water-borne epoxy resin cement paste for plugging and a preparation method thereof.The high-temperature-resistant water-borne epoxy resin cement paste for plugging is obtained through the following steps that firstly, cement, silica fume and quartz sand are mixed, and a solid-phase material is obtained; the preparation method comprises the following steps: sequentially adding a fluid loss agent, a dispersing agent, a retarder, a defoaming agent, water-borne epoxy resin, a curing agent and a thickening time control agent into water, stirring to obtain slurry preparation water, and finally, adding a solid-phase material into the slurry preparation water. The high-temperature-resistant water-borne epoxy resin cement paste for plugging, which is prepared by taking the water-borne epoxy resin with adjustable setting time and excellent mechanical property as a raw material, has the advantages of adjustable thickening time at 130 DEG C, high compressive strength, low Young modulus and low permeability, and the comprehensive performance meets the requirements of workover treatment.

Description

Technical Field

[0001] The invention relates to the technical field of cement slurry materials, in particular to high temperature resistant waterborne epoxy resin cement slurry for plugging and a preparation method thereof. Background Art

[0002] Epoxy resin has good compatibility with cement-based materials, and epoxy resin and cement paste have similar curing characteristics. Its liquid state has good fluidity and has excellent mechanical properties after hardening. After curing, epoxy resin can effectively fill the pores of cement paste to form a continuous reinforcement phase, which can combine the high elasticity of resin with the high strength of cement-based materials, significantly improve the mechanical properties of resin-cement paste, and has attracted the attention of scholars.

[0003] For example, the literature (Mai YW, Cotterell B. Pergamon. Porosity and mechanical properties of epoxy-resin modified cement mortar [J]. Cement and Concrete Research, 1986, 16 (5): 646–652.) reported that 10% epoxy resin can increase the flexural strength and specific fracture work of cement paste by 65% ​​and 85% respectively; the literature (Zheng Z, Li Y, He S, Ma X, Zhu X, Li S. High density and high strength cement-based mortar by modification with epoxy resin emulsion [J]. Construction and Building Materials, 2019, 197: 319–330.) found that epoxy resin can enhance the bonding strength of the interface between cement paste and other materials. At the same time, scholars have also studied the interaction between resin and cement paste matrix. The literature (Dai Y, Yang R, Xu C, Al-MansourA, Lan Y, Peng Y, Li L, Zeng Q, Li K. In-situ μ-XCT characterization of cement-waterborne epoxy resin coalescence[J]. Construction and Building Materials, 2023, 377: 131161.) dispersed cement particles in waterborne epoxy resin and found that the cement hydration and resin hardening process would form an aggregation area at the interface; the literature (LiuW, SunY, Meng X, Qin Y. Experimental analysis of Nano-SiO2modified waterborne epoxyresin on the properties and microstructure of cement-based grouting materials[J]. Energy, 2023, 268: 126669.) used nano-SiO2 to modify waterborne epoxy resin and found that the modified waterborne epoxy resin could reduce the Ca2+ between the resin and the cement matrix. 2+The concentration of epoxy resin can accelerate cement hydration, and nano-SiO2 plays a bridging role at the interface, which can further improve the compressive strength, stiffness and toughness of cement paste. From the above analysis, it can be seen that epoxy resin has a good strengthening and toughening effect on cement paste.

[0004] In oil and gas well repair projects, chemical plugging for casing damage well management has always been the focus of downhole operation research in major oil and gas fields, and has attracted much attention in recent years. Cement squeeze operation has the advantages of good operation effect and low cost, and is widely used in casing damage well management in oil fields. However, conventional cement stone has low strength, poor toughness, poor retention performance, and a volume shrinkage of 4% to 6% after solidification. The bonding quality is poor, and the pressure bearing capacity of the wellbore after plugging is limited. At present, the wellhead pressure test of conventional cement stone plugging blastholes in the industry is generally ≤15MPa, and the wellhead pressure test of the leaking well after cementing and plugging the annulus with cement squeeze is generally ≤8MPa.

[0005] Epoxy resin-cement paste can take into account the high elasticity of resin and the high strength of cement paste, thereby effectively improving the strength and toughness of cement paste and improving the effect of cement squeeze treatment operations in casing damaged wells. At the same time, water-based epoxy resin modified by epoxy resin can be directly added to the slurry mixing water and directly mixed with cement ash on site, and the operation process is simple. Xinjiang Oilfield uses resin cement slurry to plug the blasthole wellhead pressure test of 45MPa. After the annulus of the lost well was plugged by squeezing resin cement after cementing, the wellhead pressure reached 20MPa. In the well repair operation, the resin cement slurry has the advantages of high pressure bearing capacity and high plugging efficiency, but the use temperature is ≤100℃.

[0006] As oil and gas exploration and development move towards deeper layers, the number of well depths has increased significantly. The existing resin cement slurry generally has insufficient temperature resistance. The reason is that after the water-based epoxy resin is mixed with the conventional curing agent, the setting time of the epoxy resin and curing agent mixture is difficult to control at a temperature exceeding 100°C, which causes the resin cement slurry system to gel abnormally and the thickening time is difficult to control, resulting in the comprehensive performance of the resin cement slurry system being difficult to meet the requirements of high temperature and high pressure cementing operations.

[0007] Chinese patent document with publication number CN106519572A discloses a water-based epoxy resin emulsion and a preparation method thereof. The water-based epoxy resin disclosed therein mainly solves the problem of poor compatibility between traditional epoxy resin and cement, but it still has the problems of insufficient high temperature resistance and coagulation performance. Summary of the invention

[0008] The present invention provides a high temperature resistant waterborne epoxy resin cement slurry for plugging and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problem of poor mechanical properties of the existing conventional cement slurry.

[0009] One of the technical solutions of the present invention is achieved through the following measures: a high-temperature resistant water-based epoxy resin cement slurry for plugging, wherein the raw materials, by weight, include 100 parts of cement, 2 to 10 parts of microsilica powder, 30 to 60 parts of quartz sand, 1 to 6 parts of fluid loss reducer, 0 to 3 parts of dispersant, 0.2 to 3.0 parts of retarder, 0.2 to 1.0 parts of defoaming agent, 5 to 30 parts of water-based epoxy resin, 0.5 to 6 parts of curing agent, 0.2 to 2.0 parts of setting regulator and 30 to 60 parts of water.

[0010] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above cement is a highly sulfate-resistant G-grade oil well cement.

[0011] The mesh number of the above-mentioned quartz sand is 200 mesh to 1200 mesh.

[0012] The fluid loss additive is prepared by copolymerization of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid.

[0013] The above dispersant is a sulfonated acetone formaldehyde condensation product.

[0014] The retarder mentioned above is hydroxycarboxylic acid retarder GH-9.

[0015] The above defoaming agent is an organosilicon defoaming agent.

[0016] The curing agent is one or more of ethylimidazole, 2-ethylimidazole, 1,3-diazacyclopentadiene, 1,3-diazolylazole and 2-ethyl-4-methylimidazole.

[0017] The above-mentioned setting agent is 1,2-propylene glycol.

[0018] The above waterborne epoxy resin is obtained by the following method: The first step is to completely melt 100 parts by weight of epoxy resin and 8 parts by weight of nonionic polyether at 70° C. and stir them uniformly at a stirring speed of 100 r / min to 200 r / min to obtain an epoxy resin phase; In the second step, deionized water is added to the epoxy resin phase at a stirring speed of 800 r / min to 1000 r / min and a temperature of 70°C to 80°C until the epoxy resin phase completely turns milky white. At a stirring speed of 400 r / min, deionized water is continued to be added to obtain a water-based epoxy resin with a mass concentration of 20% to 80%.

[0019] In the first step, the epoxy resin is bisphenol A type epoxy resin.

[0020] In the first step, the nonionic polyether is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene polyoxypropylene ether, alkylamine polyoxyethylene ether and fatty amide polyoxyethylene ether.

[0021] The above-mentioned high temperature resistant water-based epoxy resin cement slurry for plugging is obtained according to the following method: S1, mixing required amounts of cement, microsilica powder and quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min to 4500 r / min, add the required amount of fluid loss reducer, dispersant, retarder, defoamer, waterborne epoxy resin, curing agent and setting regulator to the required amount of water in sequence and stir for 5s to 10s to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 to 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0022] The second technical solution of the present invention is achieved by the following measures: A method for preparing high temperature resistant water-based epoxy resin cement slurry for plugging is carried out according to the following method: S1, mixing required amounts of cement, microsilica powder and quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min to 4500 r / min, add the required amount of fluid loss reducer, dispersant, retarder, defoamer, waterborne epoxy resin, curing agent and setting regulator to the required amount of water in sequence and stir for 5s to 10s to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 to 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0023] The high-temperature resistant water-based epoxy resin cement slurry for plugging prepared by the present invention using water-based epoxy resin with adjustable setting time and excellent mechanical properties as raw material has the advantages of adjustable thickening time at 130° C., high compressive strength, low Young's modulus and low permeability, and its comprehensive performance meets the requirements of well repair operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The thickening time curve of the high temperature resistant waterborne epoxy resin cement slurry for plugging of the present invention obtained by adding different amounts of raw material retarders is shown. DETAILED DESCRIPTION

[0025] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0026] The present invention will be further described below in conjunction with embodiments: Example 1: The high-temperature resistant water-based epoxy resin cement slurry for plugging includes, by weight, 100 parts of cement, 2 to 10 parts of microsilica powder, 30 to 60 parts of quartz sand, 1 to 6 parts of fluid loss reducer, 0 to 3 parts of dispersant, 0.2 to 3.0 parts of retarder, 0.2 to 1.0 parts of defoaming agent, 5 to 30 parts of water-based epoxy resin, 0.5 to 6 parts of curing agent, 0.2 to 2.0 parts of setting regulator and 30 to 60 parts of water.

[0027] Example 2: As an optimization of the above example, the cement is a high sulfate-resistant G-grade oil well cement.

[0028] Embodiment 3: As an optimization of the above embodiment, the mesh size of the quartz sand is 200 to 1200 mesh.

[0029] Embodiment 4: As an optimization of the above embodiment, the fluid loss additive is prepared by copolymerization of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid.

[0030] Example 5: As an optimization of the above example, the dispersant is sulfonated acetone formaldehyde condensation product.

[0031] Example 6: As an optimization of the above example, the retarder is a hydroxycarboxylic acid retarder GH-9.

[0032] Embodiment 7: As an optimization of the above embodiment, the defoaming agent is a silicone defoaming agent.

[0033] Embodiment 8: As an optimization of the above embodiment, the curing agent is one or more of ethylimidazole, 2-ethylimidazole, 1,3-diazacyclopentadiene, 1,3-diazolylazole and 2-ethyl-4-methylimidazole.

[0034] Example 9: As an optimization of the above example, the setting agent is 1,2-propylene glycol.

[0035] Embodiment 10: As an optimization of the above embodiment, the water-based epoxy resin is obtained by the following method: The first step is to completely melt 100 parts by weight of epoxy resin and 8 parts by weight of nonionic polyether at 70° C. and stir them uniformly at a stirring speed of 100 r / min to 200 r / min to obtain an epoxy resin phase; In the second step, deionized water is added to the epoxy resin phase at a stirring speed of 800 r / min to 1000 r / min and a temperature of 70°C to 80°C until the epoxy resin phase completely turns milky white. At a stirring speed of 400 r / min, deionized water is continued to be added to obtain a water-based epoxy resin with a mass concentration of 20% to 80%.

[0036] Example 11: As an optimization of the above example, in the first step, the epoxy resin is bisphenol A epoxy resin.

[0037] Example 12: As an optimization of the above example, in the first step, the nonionic polyether is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene polyoxypropylene ether, alkylamine polyoxyethylene ether and fatty amide polyoxyethylene ether.

[0038] Example 13: As an optimization of the above example, the high temperature resistant water-based epoxy resin cement slurry for plugging is obtained by the following method: S1, mixing required amounts of cement, microsilica powder and quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min to 4500 r / min, add the required amount of fluid loss reducer, dispersant, retarder, defoamer, waterborne epoxy resin, curing agent and setting regulator to the required amount of water in sequence and stir for 5s to 10s to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 to 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0039] Embodiment 14: The waterborne epoxy resin is obtained by the following method: In the first step, 100 parts by weight of bisphenol A epoxy resin and 8 parts by weight of nonionic polyether (fatty alcohol polyoxyethylene ether) are completely melted and stirred at 70° C. at a stirring speed of 100 r / min to obtain an epoxy resin phase; In the second step, deionized water was added to the epoxy resin phase at a stirring speed of 800 r / min and a temperature of 70°C until the epoxy resin phase completely turned milky white. Deionized water was continued to be added at a stirring speed of 400 r / min to obtain a water-based epoxy resin with a mass concentration of 20%.

[0040] The high temperature resistant water-based epoxy resin cement slurry for plugging is obtained according to the following method: S1, mixing 100 parts of high sulfate resistance G grade oil well cement, 2 parts of microsilica powder and 30 parts of quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min, 1 part of a fluid loss reducer (copolymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid), 0.2 parts of a hydroxycarboxylic acid retarder GH-9, 0.2 parts of a silicone defoamer, 5 parts of a waterborne epoxy resin, 0.5 parts of a curing agent (ethylimidazole) and 0.2 parts of 1,2-propylene glycol were added to 30 parts of water in sequence and stirred for 5 seconds to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0041] Embodiment 15: The waterborne epoxy resin is obtained by the following method: In the first step, 100 parts by weight of bisphenol A epoxy resin and 15 parts by weight of nonionic polyether (alkylphenol polyoxyethylene polyoxypropylene ether) are completely melted and stirred at 70° C. at a stirring speed of 200 r / min to obtain an epoxy resin phase; In the second step, deionized water is added to the epoxy resin phase at a stirring speed of 1000 r / min and a temperature of 80°C until the epoxy resin phase completely turns milky white. At a stirring speed of 400 r / min, deionized water is continued to be added to obtain a water-based epoxy resin with a mass concentration of 80%.

[0042] The high temperature resistant water-based epoxy resin cement slurry for plugging is obtained according to the following method: S1, mixing 100 parts of high sulfate resistance G grade oil well cement, 10 parts of microsilica powder and 60 parts of quartz sand to obtain a solid phase material; S2, at a stirring speed of 4500 r / min, 6 parts of fluid loss reducer (copolymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid), 3 parts of sulfonated acetone formaldehyde polycondensate, 3.0 parts of hydroxycarboxylic acid retarder GH-9, 1.0 part of silicone defoamer, 30 parts of water-based epoxy resin, 6 parts of curing agent (2-ethylimidazole) and 2.0 parts of 1,2-propylene glycol were added to 60 parts of water in sequence, and stirred for 10 seconds to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0043] Embodiment 16: The waterborne epoxy resin is obtained by the following method: The first step is to completely melt 100 parts by weight of bisphenol A epoxy resin and 10 parts by weight of nonionic polyether (fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene polyoxypropylene ether, alkylamine polyoxyethylene ether and fatty amide polyoxyethylene ether) at 70° C. and stir them uniformly at a stirring speed of 150 r / min to obtain an epoxy resin phase; In the second step, deionized water was added to the epoxy resin phase at a stirring speed of 900 r / min and a temperature of 75°C until the epoxy resin phase completely turned milky white. Deionized water was continued to be added at a stirring speed of 400 r / min to obtain a water-based epoxy resin with a mass concentration of 60%.

[0044] The high temperature resistant water-based epoxy resin cement slurry for plugging is obtained according to the following method: S1, mixing 100 parts of high sulfate resistance G grade oil well cement, 6 parts of microsilica powder and 45 parts of quartz sand to obtain a solid phase material; S2, at a stirring speed of 4000 r / min, 3 parts of fluid loss reducer (copolymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid), 2 parts of sulfonated acetone formaldehyde polycondensate, 1.5 parts of hydroxycarboxylic acid retarder GH-9, 0.6 parts of silicone defoamer, 20 parts of water-based epoxy resin, 3 parts of curing agent (1,3-diazacyclopentadiene) and 1.0 part of 1,2-propylene glycol were added to 45 parts of water in sequence, and stirred for 8 seconds to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 35 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0045] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses high temperature resistant nonionic polyether to emulsify epoxy resin at 70°C to obtain water-based epoxy resin, and then uses high temperature resistant imidazole polymer as a curing agent and 1,2-propylene glycol as a setting agent to obtain high temperature resistant water-based epoxy resin cement slurry for plugging with strong heat resistance.

[0046] The high temperature resistant water-based epoxy resin cement slurry for plugging prepared by using water-based epoxy resin with adjustable setting time and excellent mechanical properties as one of the raw materials has the advantages of adjustable thickening time at 130°C, high compressive strength, low Young's modulus and low permeability, and the comprehensive performance meets the requirements of well repair operations. It effectively solves the problems of poor temperature resistance, abnormal gelation at high temperature, difficult to control thickening time, high temperature brittleness and poor toughness of cement stone after curing in the existing cement slurry system.

[0047] In the preparation process of the present invention, a setting regulator is used to control the setting process of the waterborne epoxy resin, and a retarder is used to regulate the hydration rate of the cement, so as to effectively solve the problem that the conventional cement slurry gels abnormally at high temperature, resulting in the difficulty in regulating the thickening time.

[0048] The resin cement paste obtained after curing the high temperature resistant water-based epoxy resin cement slurry for plugging of the present invention has a low Young's modulus and exhibits high strength and toughness compared to pure cement paste. The main reason is that in the high temperature resistant water-based epoxy resin cement slurry system for plugging of the present invention, the cured epoxy resin can form a three-dimensional network interpenetrating structure through cross-linking and curing, so that the mechanical properties of the formed solid phase are excellent.

[0049] Embodiment 17: The waterborne epoxy resin is obtained by the following method: In the first step, 100 g of bisphenol A epoxy resin and 10 g of fatty alcohol polyoxyethylene ether are placed in a stainless steel barrel of a high-speed disperser at a stirring speed of 150 r / min, and the barrel is placed in an oil bath at 70° C. to melt the materials in the barrel and stir for 10 minutes to obtain an epoxy resin phase; In the second step, deionized water was added dropwise into the barrel containing the epoxy resin phase at a stirring speed of 800 r / min and a temperature of 70°C and stirred evenly. Deionized water was continued to be added at a stirring speed of 400 r / min to obtain a water-based epoxy resin with a mass concentration of 65%.

[0050] The high temperature resistant water-based epoxy resin cement slurry for plugging is obtained according to the following method: S1, mixing 100 g of high sulfate resistance G grade oil well cement, 7 g of microsilica powder and 35 g of quartz sand to obtain a solid phase material; S2, at a stirring speed of 4000 r / min, 2.9 g of a fluid loss reducer (copolymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid), 0.8 g of a sulfonated acetone formaldehyde polycondensate, 0.2 g of a hydroxycarboxylic acid retarder GH-9, 0.22 g of a silicone defoamer, 16 g of a water-based epoxy resin, 3 g of a curing agent (2-ethyl-4-methylimidazole) and 0.42 g of 1,2-propylene glycol were added to 50 g of water in sequence, and the mixture was stirred for 10 seconds to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 35 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

[0051] In the present invention, the dispersant, the fluid loss additive and the retarder were all purchased from Weihui Chemical Co., Ltd.

[0052] Example 18: The difference from Example 17 of the present invention is that the amount of retarder (hydroxycarboxylic acid retarder GH-9) is changed from 0.2 g to 0.3 g, and the other steps are the same.

[0053] Example 19: The difference from Example 17 of the present invention is that the amount of retarder (hydroxycarboxylic acid retarder GH-9) is changed from 0.2 g to 0.4 g, and the other steps are the same.

[0054] Example 20: The difference from Example 17 of the present invention is that the amount of retarder (hydroxycarboxylic acid retarder GH-9) is changed from 0.2 g to 0.5 g, and the other steps are the same.

[0055] Example 21: The difference from Example 17 of the present invention is that the raw materials of water-based epoxy resin, curing agent (2-ethyl-4-methylimidazole) and setting agent (1,2-propylene glycol) are not added, and the remaining steps are the same.

[0056] Example 22: The difference from Example 18 of the present invention is that the raw materials of water-based epoxy resin, curing agent (2-ethyl-4-methylimidazole) and setting agent (1,2-propylene glycol) are not added, and the remaining steps are the same.

[0057] Example 23: The difference from Example 19 of the present invention is that the raw materials of water-based epoxy resin, curing agent (2-ethyl-4-methylimidazole) and setting agent (1,2-propylene glycol) are not added, and the remaining steps are the same.

[0058] Example 24: The difference from Example 20 of the present invention is that the raw materials of water-based epoxy resin, curing agent (2-ethyl-4-methylimidazole) and setting agent (1,2-propylene glycol) are not added, and the remaining steps are the same.

[0059] Example 25: The mechanical properties of the waterborne epoxy resin prepared by the present invention after curing were examined.

[0060] Test method: Weigh 500g of the waterborne epoxy resin prepared in Example 17 of the present invention, 100g of the curing agent ((2-ethyl-4-methylimidazole)) and 25g of the setting agent (1,2-propylene glycol), mix them evenly at a stirring speed of 1000r / min, pour them into a cubic mold with a side length of 50.8mm, and cure them at 130°C and 20.7MPa for 2 days and 7 days to obtain a waterborne epoxy resin cured body, and examine the compressive strength and Young's modulus of the waterborne epoxy resin cured body.

[0061] Test results: The compressive strength and Young's modulus of the waterborne epoxy resin cured body of the present invention are shown in Table 1. It can be seen from Table 1 that the waterborne epoxy resin with a mass concentration of 65% prepared in Example 17 of the present invention still has a high compressive strength and a low Young's modulus after curing.

[0062] Example 26: The thickening time of the high temperature resistant water-based epoxy resin cement slurry for plugging of the present invention obtained by adding different amounts of the raw material retarder was investigated.

[0063] Test method: The raw material water-based epoxy resin improves the mechanical properties of cement paste by cross-linking and curing. However, the curing of the raw material water-based epoxy resin is after the cement paste solidifies, and it cannot affect the normal thickening process of the cement paste. Only in this way can the thickening time of the cement paste be adjustable to ensure the safety of on-site construction. The thickening time of the high-temperature resistant water-based epoxy resin cement paste for plugging of the present invention obtained by adding different amounts of the raw material retarder was investigated, and it was also to prove that the curing of the water-based epoxy resin does not affect the normal thickening process of the high-temperature resistant water-based epoxy resin cement paste for plugging. The high-temperature resistant water-based epoxy resin cement paste for plugging prepared in Examples 17 to 20 of the present invention was subjected to a thickening test.

[0064] The evaluation method is that if there is a linear relationship between the different addition amounts of the raw material retarder and the thickening time of the high-temperature resistant water-based epoxy resin cement slurry for plugging, it proves that the raw material water-based epoxy resin has no effect on the thickening of the high-temperature resistant water-based epoxy resin cement slurry for plugging.

[0065] Test results: See the test results. Figure 1 As shown, Figure 1 It can be seen that there is a linear relationship between the different addition amounts of the raw material retarder and the thickening time of the high-temperature resistant water-based epoxy resin cement slurry for plugging, and the curing of the water-based epoxy resin does not affect the normal thickening process of the high-temperature resistant water-based epoxy resin cement slurry for plugging, indicating that the thickening time of the high-temperature resistant water-based epoxy resin cement slurry for plugging of the present invention is adjustable, and the raw material water-based epoxy resin has no effect on the thickening of the high-temperature resistant water-based epoxy resin cement slurry for plugging.

[0066] Example 27: The mechanical properties of the high temperature resistant water-based epoxy resin cement slurry for plugging of the present invention were investigated.

[0067] Test method: The high temperature resistant water-based epoxy resin cement slurry for plugging prepared in Examples 17 to 20 of the present invention was poured into a cubic mold with a side length of 50.8 mm, and cured for 2 days and 7 days in a pressurized curing kettle at a temperature of 130° C. and a pressure of 20.4 MPa to obtain cement paste, and the mechanical properties and permeability of the cement paste were tested. At the same time, conventional cement slurry obtained without adding water-based epoxy resin, curing agent and setting regulator in Examples 21 to 24 of the present invention was used as a control.

[0068] Test results: The raw material formula of the high temperature resistant water-based epoxy resin cement slurry for plugging of the present invention is shown in Table 1, and the mechanical properties and permeability results of the high temperature resistant water-based epoxy resin cement slurry for plugging of the present invention are shown in Table 2. It can be seen from Table 2 that, compared with the conventional cement slurry prepared in Examples 21 to 24 of the present invention, the high temperature resistant water-based epoxy resin cement slurry for plugging prepared in Examples 17 to 20 of the present invention has the characteristics of higher compressive strength, lower Young's modulus and low permeability after curing. It also shows that adding the raw water-based epoxy resin to the cement slurry can effectively enhance the compressive strength of the cement stone and improve the toughness of the cement stone.

[0069] In summary, the high-temperature resistant water-based epoxy resin cement slurry for plugging prepared by the present invention using a water-based epoxy resin with adjustable setting time and excellent mechanical properties as one of the raw materials has the advantages of adjustable thickening time at 130°C, high compressive strength, low Young's modulus and low permeability, and its comprehensive performance meets the requirements of well repair operations.

[0070] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A high temperature resistant water-based epoxy resin cement slurry for plugging, characterized in that The raw materials, measured by weight, include 100 parts of cement, 2 to 10 parts of microsilica powder, 30 to 60 parts of quartz sand, 1 to 6 parts of fluid loss reducer, 0 to 3 parts of dispersant, 0.2 to 3.0 parts of retarder, 0.2 to 1.0 parts of defoaming agent, 5 to 30 parts of water-based epoxy resin, 0.5 to 6 parts of curing agent, 0.2 to 2.0 parts of setting regulator and 30 to 60 parts of water.

2. The high temperature resistant water-based epoxy resin cement slurry for plugging according to claim 1, characterized in that The cement is high sulfate-resistant G-grade oil well cement; or / and the mesh number of the quartz sand is 200 mesh to 1200 mesh.

3. The high temperature resistant water-based epoxy resin cement slurry for plugging according to claim 1 or 2, characterized in that The fluid loss additive is copolymerized by acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid; or / and the dispersant is sulfonated acetone formaldehyde condensate.

4. The high temperature resistant water-based epoxy resin cement slurry for plugging according to claim 1, 2 or 3, characterized in that The retarder is a hydroxycarboxylic acid retarder GH-9; or / and, the defoamer is an organic silicon defoamer.

5. The high temperature resistant water-based epoxy resin cement slurry for plugging according to any one of claims 1 to 4, characterized in that The curing agent is one or more of ethylimidazole, 2-ethylimidazole, 1,3-diazacyclopentadiene, 1,3-diazodiazepine and 2-ethyl-4-methylimidazole; or / and the setting regulator is 1,2-propylene glycol.

6. The high temperature resistant water-based epoxy resin cement slurry for plugging according to any one of claims 1 to 5, characterized in that Waterborne epoxy resin is obtained as follows: The first step is to completely melt 100 parts by weight of epoxy resin and 8 parts by weight of nonionic polyether at 70° C. and stir them uniformly at a stirring speed of 100 r / min to 200 r / min to obtain an epoxy resin phase; In the second step, deionized water is added to the epoxy resin phase at a stirring speed of 800 r / min to 1000 r / min and a temperature of 70°C to 80°C until the epoxy resin phase completely turns milky white. At a stirring speed of 400 r / min, deionized water is continued to be added to obtain a water-based epoxy resin with a mass concentration of 20% to 80%.

7. The high temperature resistant waterborne epoxy resin cement slurry for plugging according to claim 6, characterized in that In the first step, the epoxy resin is a bisphenol A epoxy resin; or / and, in the first step, the nonionic polyether is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene polyoxypropylene ether, alkylamine polyoxyethylene ether and fatty amide polyoxyethylene ether.

8. The high temperature resistant water-based epoxy resin cement slurry for plugging according to any one of claims 1 to 7, characterized in that Obtained as follows: S1, mixing required amounts of cement, microsilica powder and quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min to 4500 r / min, add the required amount of fluid loss reducer, dispersant, retarder, defoamer, waterborne epoxy resin, curing agent and setting regulator to the required amount of water in sequence and stir for 5s to 10s to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 to 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

9. A method for preparing the high temperature resistant waterborne epoxy resin cement slurry for plugging according to any one of claims 1 to 7, characterized in that Proceed as follows: S1, mixing required amounts of cement, microsilica powder and quartz sand to obtain a solid phase material; S2, at a stirring speed of 3500 r / min to 4500 r / min, add the required amount of fluid loss reducer, dispersant, retarder, defoamer, waterborne epoxy resin, curing agent and setting regulator to the required amount of water in sequence and stir for 5s to 10s to obtain slurry water; S3, adding solid materials into the slurry water and stirring for 30 to 40 seconds under stirring at 12000 r / min to obtain high temperature resistant water-based epoxy resin cement slurry for plugging.

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