High-temperature-resistant expanded fiber resin plugging material, preparation method thereof and application thereof in leakage-proofing and plugging of cement slurry

Abstract

The application discloses a high-temperature-resistant expanded fiber resin plugging material and a preparation method and application thereof in leakage prevention and plugging of well cement slurry. The preparation method of the high-temperature-resistant expanded fiber resin plugging material comprises the following steps: S1, adding sodium hydroxide into an acrylic acid solution, and then adding a chitosan solution, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and fibers into the acrylic acid solution in sequence; and then adding an initiator and a crosslinking agent into the acrylic acid solution in sequence, and obtaining a polymer gel through polymerization; the chitosan solution adopts glacial acetic acid solution as a solvent; and the polymer gel is dried and then crushed to obtain a granular resin. Through use of the high-temperature-resistant expanded fiber resin plugging material, the problem of cement slurry leakage in a fractured formation can be effectively solved, the treatment time and cost of cement slurry leakage in the fractured formation are greatly reduced, and the cementing quality of the fractured formation is improved, thereby opening up a new way for solving the problem of cement slurry leakage in the fractured formation.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant expandable fiber resin plugging material, its preparation method, and its application in well cementing slurry for leak prevention and plugging, belonging to the field of oil and gas field drilling and cementing technology. Background Technology

[0002] As oil and gas exploration and development expands into deeper, ultra-deep, and deep-sea formations, severe leakage in fractured formations has become one of the major engineering challenges in oil and gas wells. Nearly a quarter of oil and gas wells worldwide experience severe leakage during drilling, significantly impacting exploration and development. Fractured formation leakage can be categorized into microfracture leakage, extended fracture leakage, and induced fracture leakage. In actual drilling, leakage typically involves a combination of these three types. The degree of fractured formation leakage depends primarily on the pressure difference between the wellbore and formation pore pressure, the development and connectivity of the leakage channels, the width and length of the fractures, and the size of the space within the leakage channels.

[0003] During cementing operations, the density of cement slurry far exceeds that of drilling fluid, exacerbating the problem of severe well leakage. In fractured formations, severe leakage often leads to insufficient cement slurry return, making it difficult to effectively seal the upper well sections. Furthermore, due to leakage in fractured formations, both drilling fluid circulation and cementing displacement are limited, resulting in low displacement efficiency, difficulty in timely removal of drilling cuttings, and poor mud cake cleaning by flushing fluid—all of which seriously affect cementing quality.

[0004] Currently, both domestically and internationally, appropriate plugging techniques are generally employed to enhance the formation's pressure-bearing capacity, thereby meeting the requirements of cementing operations. Various plugging materials, including bridging materials, high-fluid-loss materials, fluid-absorbing and expanding materials, flexible gel materials, curable materials, and smart materials, are commonly used for plugging severe well losses in fractured formations. Expandable resin plugging materials, compared to other materials, offer advantages such as good adaptability to fracture channels and excellent filling and pressure-bearing effects.

[0005] Currently, significant progress has been made in leakage prevention and plugging technologies for fractured formations both domestically and internationally. Furthermore, field practice results indicate that fluid-absorbing and expanding plugging materials have a high success rate in addressing drilling fluid loss in fractured formations. However, they still have limitations in addressing cement slurry loss in fractured formations. Cement slurry has a higher density than drilling fluid, thus posing a greater risk of leakage in fractured formations. Therefore, there is an urgent need to develop new plugging materials applicable to cement slurry leakage prevention and plugging in fractured formations. Summary of the Invention

[0006] The purpose of this invention is to provide a pressure-bearing anti-leakage and plugging material for cement slurry used in cementing in fractured formations, which can ensure the smooth progress of cementing operations in fractured formations and solve the problem of anti-leakage and plugging of cement slurry in cementing in fractured formations.

[0007] The method for preparing the high-temperature resistant expandable fiber resin sealing material provided by the present invention includes the following steps:

[0008] S1. Add sodium hydroxide to an acrylic acid solution, then add chitosan solution, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and fiber in sequence; then add initiator and crosslinking agent in sequence, and obtain polymer gel through polymerization reaction;

[0009] The chitosan solution uses glacial acetic acid solution as the solvent;

[0010] S2. The polymer gel is dried and then pulverized to obtain granular resin, which is the high-temperature resistant expanding fiber resin sealing material.

[0011] In the above preparation method, sodium hydroxide reacts with acrylic acid to form sodium carboxylate, which creates internal and external osmotic pressure in the three-dimensional network structure of the resin, and is the main reason for the resin's liquid absorption and swelling.

[0012] In the above preparation method, the added chitosan has the ability to complex metal ions, which can bind with heavy metal ions in the formation, thereby reducing the heavy metal content in the formation, improving the formation environment quality, and protecting oil and gas reservoirs. Chitosan-grafted water-absorbing resin has superior thermal stability and exhibits a loose and porous surface structure. Combined with the original expandable properties of the resin, it helps to improve the liquid absorption, temperature resistance, mechanical strength, and tensile properties of the expanded resin, which is of great significance for the application of expanded resin in the prevention and plugging of leaks in cement grout in fractured formations.

[0013] In addition, chitosan has a large number of active groups in its molecular structure, which can undergo graft copolymerization with various monomers. Chitosan grafted expanded resin mainly grafts hydrophilic monomers onto the chitosan backbone through a free radical-initiated graft copolymerization reaction. The persulfate initiator decomposes under heating conditions to generate sulfate anion free radicals. These free radicals extract hydrogen from the active groups on chitosan, thereby forming alkoxy free radicals on the chitosan backbone. The alkoxy group acts as an active center, initiating the graft copolymerization reaction.

[0014] In the above preparation method, in step S1, the mass concentration of the glacial acetic acid solution is 1-3%, preferably 2%;

[0015] The fibers are basalt fibers, glass fibers, etc., with a single filament diameter of 11-15 μm and a length of 2-6 mm;

[0016] The basalt fiber has a variety of excellent properties such as high strength, corrosion resistance, and high temperature resistance, making it suitable for plugging leaks in fractured formations.

[0017] The fibers can physically cross-link with the expanded resin, with the fibers, in irregular needle-like shapes, embedded in the expanded resin gel, filling some of the pores. The addition of fibers to the expanded resin gel enhances the formation of a three-dimensional network structure of polymer molecules, strengthens the interaction between the fibers and polymer molecules, and improves the strength and toughness of the resin, making it less prone to breakage under pressure. Simultaneously, the fibers can be compressed into the fracture channels along with the expanded resin. The fibers can bridge within the fracture channels, and after the resin expands, it fills the smaller pores created by the fiber bridging. The particles are compressed and stacked, compacting and filling the entire fracture channel, meeting the requirements of cementing slurry plugging technology for various complex fractured formations.

[0018] In the above preparation method, in step S1, based on 100 parts by weight of water in the polymerization reaction system, the amounts of each raw material are as follows:

[0019] The composition includes 0.5–3 parts by weight of fiber, 1–5 parts by weight of chitosan, 0.6–3 parts by weight of glacial acetic acid, 10–15 parts by weight of acrylic acid, 1.5–2.0 parts by weight of acrylamide, 6–10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 4–8 parts by weight of NaOH, 0.6–0.8 parts by weight of initiator, and 0.05–0.08 parts by weight of crosslinking agent.

[0020] Because sulfonic acid groups have excellent hydrophilic properties and good salt tolerance, they react with vinyl monomers containing sulfonic acid groups that are prone to copolymerization. In this invention, 2-acrylamido-2-methylpropanesulfonic acid is used as a comonomer to introduce sulfonic acid groups into the high-temperature resistant expandable fiber resin sealing material, thereby improving the expansion and salt resistance of the high-temperature resistant expandable fiber resin sealing material.

[0021] Furthermore, the -CONH2 and -COOH hydrophilic groups on the acrylamide (AM) molecular chain exhibit better water absorption and swelling properties compared to a single hydrophilic group. However, experiments revealed that with further increases in the amount of acrylamide (AM), the polymer's expansion ratio decreased. This is because increasing the crosslinking density of the expanding resin reduces the pores in the polymer's three-dimensional network structure, causing the molecular chains to coil, thus decreasing the expansion ratio, but increasing the strength, making it more suitable for inclusion in cementing slurry systems. Therefore, appropriately increasing the amount of acrylamide (AM) will yield better results, leading to a more stable structure, higher strength, and better expansion properties in the prepared high-temperature resistant expanding fiber resin plugging material. It is also less prone to deformation under high temperature and high pressure environments, making it suitable for cementing slurry plugging in fractured formations.

[0022] In the above preparation method, the initiator is a redox system, wherein the oxidant is ammonium persulfate and the reducing agent is sodium bisulfite or sodium sulfite;

[0023] The mass ratio of the oxidant to the reducing agent is 1:1;

[0024] The crosslinking agent is N,N-methylenebisacrylamide.

[0025] In the above preparation method, in step S1, the polymerization reaction temperature is 60-70°C, and the reaction is carried out for 3-5 hours under the condition of stirring speed of 500-1000 rpm, that is, the reaction is stopped when the polymer gel is formed;

[0026] In step S2, the polymer gel is soaked in ethanol and water in sequence, and then dried at 80-90°C to constant weight to obtain a solid product.

[0027] The high-temperature resistant expandable fiber resin sealing material provided by this invention has a maximum expansion ratio of 10 to 21 times, an expansion time of 49 to 55 minutes, a salt resistance of 69 to 80%, a water retention rate of 80 to 93%, and a strength of 351 to 448 g / cm² when reaching the maximum expansion ratio. 2 .

[0028] The high-temperature resistant expandable fiber resin plugging material of this invention forms gel particles after absorbing liquid and expanding. These particles have high temperature resistance and elasticity. Under certain external force, they can be squeezed into the fracture channel together with the bridging plugging fiber, compacted and filled. As the gel particles continue to absorb liquid and expand, they are squeezed and accumulated between the particles, eventually forming an accumulation that fills the entire fracture channel, thereby solving the problem of severe loss of cement slurry in fractured formations.

[0029] Based on the aforementioned high-temperature resistant expandable fiber resin plugging material, the present invention further provides a cementing slurry, the composition of which is as follows:

[0030] 100 parts oil well cement, 15-20 parts coarse silica sand, 10-15 parts fine silica sand, 0.5-3 parts high-temperature resistant expanding fiber resin plugging material of this invention, 2-5 parts nano silica, 1-10 parts calcium carbonate, 0-5 parts water loss reducer, 0-5 parts drag reducer, 0.5-2 parts retarder, 0.2-0.8 parts defoamer, and 30-100 parts water;

[0031] The particle size of the high-temperature resistant expandable fiber resin sealing material is 0.01 to 0.2 mm.

[0032] The oil well cement is API Grade G cement for oil wells;

[0033] The coarse silica sand has a particle size of 50-150 μm, is an amorphous white solid powder, and has a silica mass content of >99%.

[0034] The fine silica sand has a particle size of 5-15 μm, is an amorphous white solid powder, and has a silica mass content of >99%.

[0035] The nano-silica is a nano-silica hydrosol, which is a transparent liquid, wherein the mass content of silica is 20% to 50%.

[0036] The calcium carbonate has a particle size of 0.1–0.3 mm and is a white hexagonal crystalline solid particle.

[0037] The water loss reducing agent is a butadiene-styrene latex water loss reducing agent;

[0038] The drag-reducing agent is a sulfonated formaldehyde-acetone condensate or a polynaphthalene sulfonate drag-reducing agent;

[0039] The defoamer is a silicone ether copolymer defoamer, an organosiloxane defoamer, or a polyether defoamer;

[0040] The retarder is at least one of lignosulfonate retarder, hydroxycarboxylic acid retarder, and AMPS polymer retarder;

[0041] The cement slurry is suitable for plugging leaks in fractured formations of 0-3mm under temperature conditions of 120-180℃.

[0042] The high-temperature resistant expanding fiber resin plugging material or the cementing slurry has a pressure resistance of more than 3.5 MPa for 0-3 mm cracks, a pressure resistance time of more than 10 minutes, and a maximum leakage rate of less than 86 mL.

[0043] By using the high-temperature resistant expanding fiber resin plugging material of this invention, the problem of severe leakage of cement slurry in cementing of fractured formations can be effectively solved. This method is simple to implement, low in cost, and can meet the requirements of modern cementing pressure-bearing technology. It significantly reduces the treatment time and cost of cement slurry leakage in fractured formations and improves the cementing quality of fractured formations, opening up a new way to solve the problem of cement slurry plugging in cementing of fractured formations. Attached Figure Description

[0044] Figure 1 The graph shows a comparison of the compressive strength of cement slurries prepared in Examples 1-6 for cracks of different widths under 150℃ conditions. Detailed Implementation

[0045] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0046] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0047] The first aspect of this invention provides a high-temperature resistant, expandable fiber resin sealing material, the raw materials for which are prepared are as follows:

[0048] Based on 100 parts by weight of deionized water, the following components are included: 0.5-3 parts by weight of fiber, 1-5 parts by weight of chitosan, 0.6-3 parts by weight of glacial acetic acid, 10-15 parts by weight of acrylic acid, 1.5-2.0 parts by weight of acrylamide, 6-10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 4-8 parts by weight of NaOH, 0.6-0.8 parts by weight of initiator, and 0.05-0.08 parts by weight of crosslinking agent.

[0049] The fiber is preferably basalt fiber, which has many excellent properties such as high strength, corrosion resistance and high temperature resistance. It is suitable for plugging leaks in fractured formations. The diameter of a single filament is 11-15 μm and the length is 2-6 mm.

[0050] Furthermore, the initiator includes an oxidant and a reducing agent, wherein the oxidant is ammonium persulfate and the reducing agent is either sodium bisulfite or sodium sulfite; the mass ratio of the oxidant to the reducing agent is 1:1.

[0051] Furthermore, the glacial acetic acid needs to be prepared into a 2% dilute solution to dissolve chitosan, and 30 mL of 2% glacial acetic acid is required to dissolve each gram of chitosan.

[0052] Furthermore, the crosslinking agent is N,N-methylenebisacrylamide.

[0053] The second aspect of this invention provides a method for preparing the high-temperature resistant expansion fiber resin sealing material, which is prepared by aqueous solution copolymerization reaction. The specific preparation method is as follows:

[0054] (1) Weigh a certain amount of chitosan and add it to a beaker. Add a certain amount of 2% glacial acetic acid solution to the beaker and start stirring until the chitosan is completely dissolved.

[0055] (2) Add a certain amount of deionized water to a three-necked flask, start stirring, purge with nitrogen, add a certain amount of acrylic acid (AA) and stir until homogeneous.

[0056] (3) Dissolve a certain amount of NaOH particles in the solution of step 2 in small amounts several times. After the solution cools down, add a certain amount of the solution in step 1, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and fiber in sequence and stir evenly. Add the solution containing appropriate amounts of initiator and crosslinking agent to a three-necked flask through a dropping funnel. Place the three-necked flask in a constant temperature water bath and stir. After the reaction is complete, a polymer gel is obtained.

[0057] (4) The polymer gel reaction product is transferred to a beaker, and then soaked and washed with ethanol and pure water. After being chopped and dried, a solid product is obtained. The granular resin obtained after further pulverization is the high-temperature resistant expanding fiber resin sealing material.

[0058] The reaction conditions are as follows: water bath heating at 60-70°C, stirring speed of 500-1000 rpm, stirring is stopped when polymer gel is formed, and reaction time is 3-5 hours.

[0059] Furthermore, after the polymer gel cools, it is repeatedly washed by soaking in ethanol and pure water. The synthesized product can be cut into blocks using scissors or knives, placed in a drying oven, and continuously dried to constant weight at 80-90℃. After being pulverized using a powder mill, the resulting granular resin is the high-temperature resistant expandable fiber resin plugging material, suitable for plugging 0-3mm fractured formations at temperatures of 120-180℃.

[0060] The third aspect of the present invention provides a cement slurry system for preventing and plugging leaks in cementing wells. The high-temperature resistant expanding fiber resin plugging material can be used in the cement slurry system and is suitable for preventing and plugging leaks in 0-3mm fractured formations at temperatures of 120-180℃.

[0061] The high-temperature resistant expanding fiber resin plugging material can be used in cementing slurry systems. The specific components and weight ratios of the cementing slurry system are as follows: 100 parts oil well cement, 15-20 parts coarse silica sand, 10-15 parts fine silica sand, 0.5-3 parts high-temperature resistant expanding fiber resin plugging material, 2-5 parts nano silica, 1-10 parts calcium carbonate, 0-5 parts fluid loss reducer, 0-5 parts drag reducer, 0.5-2 parts retarder, 0.2-0.8 parts defoamer, and 30-100 parts water.

[0062] The particle size of the high-temperature resistant expanding fiber resin sealing material is 0.01 to 0.2 mm.

[0063] Furthermore, the coarse silica sand is an amorphous white solid powder with a silica content >99% and a particle size of 50-150 μm; the fine silica sand is an amorphous white solid powder with a silica content >99% and a particle size of 5-15 μm.

[0064] Furthermore, the well cement is API Grade G cement for wells.

[0065] Furthermore, the defoamer is one of the following: silicone ether copolymer defoamer, organosiloxane defoamer, or polyether defoamer.

[0066] Furthermore, the nano-silica is a nano-silica hydrosol, which is a transparent liquid with a silica mass content of 20% to 50%.

[0067] Furthermore, the calcium carbonate is a white hexagonal crystalline solid particle with a particle size of 0.1–0.3 mm.

[0068] Furthermore, the drag-reducing agent is one of sulfonated formaldehyde-acetone condensate or polynaphthalene sulfonate drag-reducing agent.

[0069] Furthermore, the water loss reducing agent is a butadiene-styrene latex water loss reducing agent.

[0070] Furthermore, the retarder is one or a mixture of two or more of the following: lignosulfonate retarder, hydroxycarboxylic acid retarder, and AMPS polymer retarder.

[0071] The specific sources of the raw materials used in the following examples and comparative examples are as follows:

[0072] Acrylic acid (AA) (grade, analytical grade), acrylamide (AM) (grade, analytical grade), N,N-methylenebisacrylamide (grade, analytical grade), ammonium persulfate (grade, analytical grade), glacial acetic acid (grade, analytical grade), chitosan (grade, analytical grade), sodium bisulfite (grade, analytical grade), and sodium hydroxide (NaOH) (grade, analytical grade) were all purchased from Sinopharm Chemical Reagent Co., Ltd.

[0073] 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) (grade, analytical grade) and anhydrous ethanol (grade, analytical grade) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0074] Coarse and fine silica sand: purchased from Kasong Quartz Sand Factory in Jianping County, Liaoning Province.

[0075] Basalt fiber: purchased from Wuxi Simude Engineering Materials Co., Ltd.

[0076] Calcium carbonate: Purchased from Guangzhou Tuoyi Trading Co., Ltd.

[0077] Defoamer: Purchased from Chengdu Omeke Petroleum Technology Co., Ltd., model number DF-E (polyether defoamer).

[0078] Drag reducer: Purchased from Chengdu Omeke Petroleum Technology Co., Ltd., model HX-21L (sulfonated formaldehyde-acetone condensate).

[0079] Water loss reducer: Purchased from Chengdu Omeke Petroleum Technology Co., Ltd., model HX-11L (butadiene-styrene latex water loss reducer).

[0080] Retarder: Purchased from Chengdu Omeke Petroleum Technology Co., Ltd., model HX-31L (AMPS polymer retarder).

[0081] Nano-silica: Purchased from Beijing Deco Island Gold Technology Co., Ltd.

[0082] Grade G oil well cement: Grade G oil well cement purchased from Shandong Linqu Shengwei Special Cement Co., Ltd.

[0083] Performance testing of high-temperature resistant expandable fiber resin sealing material:

[0084] 1. Maximum expansion ratio test:

[0085] Take a 500mL beaker and place approximately 0.3g (M0) of high-temperature resistant expandable fiber resin sealing material into it. Add 200mL of deionized water at room temperature. After the material absorbs liquid and expands to its maximum value, filter out the excess water through a 100-mesh sieve. Let it stand and drain for 10 minutes, then wipe off the surface moisture. Weigh the expanded high-temperature resistant expandable fiber resin sealing material as M1. The formula for the maximum expansion ratio of the high-temperature resistant expandable fiber resin sealing material is:

[0086] Q s =(M1-M0) / M0 (1)

[0087] In the formula Q s This represents the maximum expansion factor, and its unit is g / g.

[0088] 2. Expansion time test:

[0089] The time required for the high-temperature resistant expandable fiber resin sealing material to reach its maximum expansion ratio per unit time. Weigh approximately 0.3g of the high-temperature resistant expandable fiber resin sealing material granules (M0) into a 500mL beaker, add 200mL of deionized water at room temperature, filter out excess water using a sieve at regular intervals, wipe off surface moisture, and weigh the expanded gel. The absorption time T is defined as the time when the mass remains stable. s The unit is min.

[0090] 3. Salt resistance test:

[0091] Salt resistance refers to the ability of high-temperature resistant expandable fiber resin plugging materials to expand in oilfield saline water or in salt water of different concentrations of NaCl and CaCl2. Generally, it is believed that high-temperature resistant expandable fiber resin plugging materials with an expansion capacity of 50 times or more have good salt resistance.

[0092] Weigh approximately 1g of high-temperature resistant expandable fiber resin sealing material particles (M0) into a 500mL beaker. Add 200mL of a 1000mg / L NaCl solution at room temperature. After periodic intervals, filter out excess water using a sieve and wipe off surface moisture. Weigh the mass of the expanded gel. When the mass remains stable, the mass of the expanded high-temperature resistant expandable fiber resin sealing material is M1. The formula for the salt resistance of the high-temperature resistant expandable fiber resin sealing material is:

[0093] K = (M1 - M0) / (M0 + Q) s (2) × 100%

[0094] In the formula, K represents the salt resistance, %.

[0095] 4. Water retention rate test:

[0096] Weigh a certain amount of high-temperature resistant expandable fiber resin sealing material that has reached its maximum expansion ratio. Under the same environmental conditions, measure the mass of the high-temperature resistant expandable fiber resin sealing material over a certain period of time. The formula for the water retention rate of the high-temperature resistant expandable fiber resin sealing material is:

[0097] B = (M1 / M2) × 100% (3)

[0098] Where: B—water retention rate of high-temperature resistant expandable fiber resin sealing material, %; M1—mass of high-temperature resistant expandable fiber resin sealing material under the same environmental conditions within a certain time, g; M2—mass of high-temperature resistant expandable fiber resin sealing material reaching the maximum expansion ratio, g.

[0099] 5. Strength test:

[0100] After the high-temperature resistant expandable fiber resin sealing material fully absorbs liquid and expands, a rectangular gel sample with an upper surface area of ​​S and a height of 0.9–1.1 cm is placed on an electronic balance. An appropriately sized glass slide is placed on the sample, and weights are added to the slide to apply uniform pressure until the gel ruptures. The mass M of the weights at the time of gel rupture is recorded in grams. The larger the E value, the greater the gel strength of the high-temperature resistant expandable fiber resin sealing material.

[0101] E = M / S, (4)

[0102] In the formula: E is the gel strength, g / cm³ 2 M represents the mass of the weight, in grams; S represents the surface area of ​​the gel, in centimeters. 2 .

[0103] Example 1: Preparation of high-temperature resistant expandable fiber resin sealing material

[0104] (1) Weigh 2g of chitosan and add it to a beaker. Add 60mL of 2% glacial acetic acid solution to the beaker and start stirring until the chitosan is completely dissolved.

[0105] (2) Add 90g of deionized water to a three-necked flask, start stirring, purge with nitrogen, add 18g of acrylic acid (AA) and stir until homogeneous.

[0106] (3) Dissolve 8 g of NaOH particles in the solution of step 2 in small amounts several times. After the solution cools, add the solution from step 1. Then add 2.2 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid and 1.5 g of fiber and stir evenly. Add the solution containing 1 g of initiator (ammonium persulfate as oxidant and sodium bisulfite as reducing agent) and 0.12 g of crosslinking agent (N,N-methylenebisacrylamide) slowly dropwise into a three-necked flask through a dropping funnel. Place the three-necked flask in a 60°C constant temperature water bath and stir. After the reaction is complete, a polymer gel is obtained.

[0107] (4) The polymer gel reaction product is transferred to a beaker, and then soaked and washed with ethanol and pure water. After being chopped and dried at 90°C, a solid product is obtained. The granular resin obtained after further pulverization is the high-temperature resistant expanding fiber resin sealing material P1 (particle size is 0.01-0.2 mm).

[0108] The properties of the high-temperature resistant expanding fiber resin sealing material P1 are shown in Table 1.

[0109] Example 2: Preparation of high-temperature resistant expandable fiber resin sealing material

[0110] (1) Weigh 3g of chitosan and add it to a beaker. Add 90mL of 2% glacial acetic acid solution to the beaker and start stirring until the chitosan is completely dissolved.

[0111] (2) Add 60g of deionized water to a three-necked flask, start stirring, purge with nitrogen, add 18g of acrylic acid (AA) and stir until homogeneous.

[0112] (3) Dissolve 8 g of NaOH particles in the solution of step 2 in small amounts several times. After the solution cools, add the solution from step 1. Then add 2.2 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid and 1.5 g of fiber and stir evenly. Add the solution containing 1 g of initiator (ammonium persulfate as oxidant and sodium bisulfite as reducing agent) and 0.12 g of crosslinking agent (N,N-methylenebisacrylamide) slowly dropwise into a three-necked flask through a dropping funnel. Place the three-necked flask in a 60°C constant temperature water bath and stir. After the reaction is complete, a polymer gel is obtained.

[0113] (4) The polymer gel reaction product is transferred to a beaker, and then soaked and washed with ethanol and pure water. After being chopped and dried at 90°C, a solid product is obtained. The granular resin obtained after further pulverization is the high-temperature resistant expanding fiber resin sealing material P2 (particle size is 0.01-0.2 mm).

[0114] The properties of the high-temperature resistant expanding fiber resin sealing material P2 are shown in Table 1.

[0115] Example 3: Preparation of high-temperature resistant expandable fiber resin sealing material

[0116] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that 20 grams of acrylic acid were added in step (2) and 9 grams of NaOH particles were added in step (3). The properties of the obtained high-temperature resistant expandable fiber resin sealing material P3 are shown in Table 1 (particle size 0.01-0.2 mm).

[0117] Example 4: Preparation of high-temperature resistant expansion fiber resin sealing material

[0118] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that 2.5 g of acrylamide and 15 g of 2-acrylamido-2-methylpropanesulfonic acid were added in step (3). The properties of the obtained high-temperature resistant expandable fiber resin sealing material P4 are shown in Table 1.

[0119] Example 5: Preparation of high-temperature resistant expandable fiber resin sealing material

[0120] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that 2.5 grams of basalt fiber were added in step (3). The properties of the obtained high-temperature resistant expandable fiber resin sealing material P5 are shown in Table 1 (particle size 0.01-0.2 mm).

[0121] Example 6: Preparation of high-temperature resistant expandable fiber resin sealing material

[0122] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that 0.075 g of crosslinking agent was added in step (3). The properties of the obtained high-temperature resistant expandable fiber resin sealing material P6 are shown in Table 1 (particle size 0.01-0.2 mm).

[0123] Comparative Example 1

[0124] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that chitosan and glacial acetic acid solution were not added in step (1), and 150 grams of deionized water were used in step (2). The properties of the obtained high-temperature resistant expandable fiber resin sealing material DP1 are shown in Table 1.

[0125] Comparative Example 2

[0126] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that no acrylamide (AM) was added. The properties of the prepared high-temperature resistant expandable fiber resin sealing material DP2 are shown in Table 1.

[0127] Comparative Example 3

[0128] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was not added. The properties of the prepared high-temperature resistant expandable fiber resin sealing material DP3 are shown in Table 1.

[0129] Comparative Example 4

[0130] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that acrylamide (AM) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were not added. The properties of the prepared high-temperature resistant expandable fiber resin sealing material DX4 are shown in Table 1.

[0131] Comparative Example 5

[0132] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 2, except that basalt fibers were not added. The properties of the prepared high-temperature resistant expandable fiber resin sealing material DX5 are shown in Table 1.

[0133] Comparative Example 6

[0134] The high-temperature resistant expandable fiber resin sealing material was prepared using the same method as in Example 1, except that the polymerization reaction water bath temperature was 70°C. The properties of the obtained high-temperature resistant expandable fiber resin sealing material DX6 are shown in Table 1.

[0135] Table 1 shows the performance of different high-temperature resistant expandable fiber resin sealing materials:

[0136]

[0137]

[0138] As shown in Table 1, the high-temperature resistant expandable fiber resin sealing materials of Examples P1-P5 of the present invention have a maximum expansion ratio of 10-21 times, an expansion time of 49-55 minutes, a salt resistance of 69-80%, a water retention rate of 80-93%, and a strength of 351-448 g / cm³ when reaching the maximum expansion ratio. 2 In a sodium chloride solution with a mineralization of 1000 mg / L, its swelling capacity decreases, but its strength increases, with the maximum swelling ratio reaching over 62% of that in deionized water. The gel strength of the sealing material is 351 g / cm³. 2 The above demonstrates that the plugging material described in this invention possesses excellent liquid absorption and swelling capacity, liquid retention capacity, and good salt resistance, while also exhibiting high strength, making it suitable for plugging leaks in fractured formations using cement slurry. Comparative Examples 1-6 show that the addition of chitosan slightly reduces the resin's swelling capacity, while the addition of basalt fiber significantly improves the resin's strength and toughness. The amide groups in acrylamide (AM) enhance the resin's swelling capacity, and the sulfonic acid groups in 2-acrylamido-2-methylpropanesulfonic acid (AMPS) improve the resin's salt resistance. The liquid absorption and swelling capacity is even better when the polymerization temperature is 60°C.

[0139] Cement grout sealing performance test:

[0140] A fracture mold with an inlet fracture width of 0–3 mm was installed and fixed in the core dynamic simulation experimental device. Formation confining pressure was applied using a pressurized pump. Cement slurry was filled into a 2000 mL slurry cylinder, the cap was tightened and sealed, and the agitator was turned on at 200 rpm. The temperature was set and the heating switch was turned on. After sealing, the pressure was increased to 7.5 MPa at a rate of 0.10 MPa / s until all the cement slurry in the container had leaked out. The volume of leaked cement slurry and the maximum pressure reached were recorded at pressures of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, and 7.5 MPa. If the sealing was successful, the pressure was maintained for 10 minutes, and the leakage was recorded.

[0141] The following application examples and comparative examples further illustrate the plugging performance of the high-temperature resistant expandable fiber resin plugging material of the present invention in cementing slurry, but are not limited thereto.

[0142] Experimental methods: Cement slurry was prepared according to standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells", and the performance of the cement slurry system was tested according to standard SY / T 6544-2017 "Performance Requirements for Cement Slurry in Oil Wells".

[0143] In the application examples and comparative examples, "parts" refers to "parts by mass".

[0144] Application Example 1: Preparation of Cement Slurry for Well Cementing and Pouring

[0145] The significance of this application example is to illustrate the application of the high-temperature resistant fiber water-absorbing resin plugging material in well cement slurry leak prevention and plugging.

[0146] The cement slurry for plugging leaks in this embodiment is prepared from the following raw material components in parts by weight: 100 parts of oil well cement (API G-grade oil well cement), 15 parts of coarse silica sand (particle size 50-150μm, amorphous white solid powder, silica content >99%), 15 parts of fine silica sand (particle size 5-15μm, amorphous white solid powder, silica content >99%), 1 part of high-temperature resistant expanding fiber resin plugging material (particle size 0.01-0.2mm), and nano silica (nano silica water sol, which is permeable). A clear liquid containing 3 parts silica (20%–50% by mass), 4 parts calcium carbonate (0.1–0.3 mm particle size, white hexagonal crystalline solid particles), 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer is prepared with a water-cement ratio of 0.38 to form a cement slurry. The solid phase material is continuously and evenly poured into the mixing cup at a speed of 4000 rpm within 15 seconds to mix with the liquid phase material. Then, the speed is adjusted to 12000 rpm and stirred for 35 seconds to obtain the well-sealing cement slurry, thus producing well-sealing cement slurry G1.

[0147] Application Example 2: Preparation of Cement Slurry for Well Cementing and Pouring

[0148] The cement slurry for well cementing and plugging in this embodiment is prepared from the following raw material components in parts by weight: 100 parts oil well cement, 15 parts coarse silica sand, 15 parts fine silica sand, 2 parts high-temperature resistant expanding fiber resin plugging material, 3 parts nano silica, 4 parts calcium carbonate, 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer. The cement slurry is prepared with a water-cement ratio of 0.38 to obtain cement slurry G2 for well cementing and plugging.

[0149] The preparation method is the same as in Application Example 1.

[0150] Application Example 3: Preparation of Cement Slurry for Well Cementing and Pouring

[0151] The cement slurry for well cementing and plugging in this embodiment is prepared from the following raw material components in parts by weight: 100 parts oil well cement, 15 parts coarse silica sand, 15 parts fine silica sand, 3 parts high-temperature resistant expanding fiber resin plugging material, 3 parts nano silica, 4 parts calcium carbonate, 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer. The cement slurry is prepared with a water-cement ratio of 0.38 to obtain cement slurry G3 for well cementing and plugging.

[0152] The preparation method is the same as in Application Example 1.

[0153] Application Example 4: Preparation of Cement Slurry for Well Cementing and Pouring

[0154] The cement slurry for well cementing and plugging in this embodiment is prepared from the following raw material components in parts by weight: 100 parts oil well cement, 15 parts coarse silica sand, 15 parts fine silica sand, 2 parts high-temperature resistant expanding fiber resin plugging material, 3 parts nano silica, 8 parts calcium carbonate, 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer. The cement slurry is prepared with a water-cement ratio of 0.38 to obtain cement slurry G4 for well cementing and plugging.

[0155] The preparation method is the same as in Application Example 1.

[0156] Application Example 5: Preparation of Cement Slurry for Well Cementing and Pouring

[0157] The cement slurry for well cementing and plugging in this embodiment is prepared from the following raw material components in parts by weight: 100 parts oil well cement, 20 parts coarse silica sand, 10 parts fine silica sand, 2 parts high-temperature resistant expanding fiber resin plugging material, 3 parts nano silica, 4 parts calcium carbonate, 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer. The cement slurry is prepared with a water-cement ratio of 0.38 to obtain cement slurry G5 for well cementing and plugging.

[0158] The preparation method is the same as in Application Example 1.

[0159] Application Example 6: Preparation of Cement Slurry for Well Cementing and Pouring

[0160] The cement slurry for well cementing and plugging in this embodiment is prepared from the following raw material components in parts by weight: 100 parts oil well cement, 15 parts coarse silica sand, 15 parts fine silica sand, 2 parts high-temperature resistant expanding fiber resin plugging material, 5 parts nano silica, 4 parts calcium carbonate, 1 part fluid loss reducer, 2 parts drag reducer, 1 part retarder, and 0.3 parts defoamer. The cement slurry is prepared with a water-cement ratio of 0.38 to obtain cement slurry G6 for well cementing and plugging.

[0161] The preparation method is the same as in Application Example 1.

[0162] Application Comparative Example 1

[0163] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, except that high-temperature resistant expanding fiber resin plugging material was not used. This resulted in cementing and plugging slurry DG1.

[0164] Application Comparative Example 2

[0165] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, except that calcium carbonate was not used. This resulted in cementing and plugging slurry DG2.

[0166] Application Comparative Example 3

[0167] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, the difference being that no coarse or fine silica sand was added. This resulted in cementing and plugging slurry DG3.

[0168] Application Comparative Example 4

[0169] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, the difference being that nano-silica was not added. This resulted in cementing and plugging slurry DG4.

[0170] Application Comparative Example 5

[0171] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, the difference being that 5 parts of a fluid loss reducing agent were used. This resulted in cementing and plugging slurry DG5.

[0172] Application Comparative Example 6

[0173] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, the difference being that 5 parts of drag-reducing agent were used. This resulted in cementing and plugging slurry DG6.

[0174] Application Comparative Example 7

[0175] In this case, cement slurry systems for plugging leaks were prepared according to the method corresponding to Application Example 2, the difference being the addition of 2 parts of retarder. This resulted in cement slurry DG7 for plugging leaks.

[0176] Application Comparative Example 8

[0177] In this case, cementing and plugging slurry systems were prepared according to the method corresponding to Application Example 2, the difference being that 0.8 parts of defoamer were used. This resulted in cementing and plugging slurry DG8.

[0178] Test Example 1

[0179] The plugging performance of the above-mentioned cement slurries G1~G6 and DG1~DG8 on 0.25mm cracks at 150℃ and their compressive strength and elastic modulus after 5 days of curing were measured. The results are shown in Table 2.

[0180] Table 2. Plugging performance and cement slurry properties of different cementing slurries on 0.25mm cracks at 150℃

[0181]

[0182] According to the data in Table 2, at 150℃, the addition of high-temperature resistant expanding fiber resin sealing material (G1-G3 and DG1) improves the sealing performance of cement grout for 0.25mm cracks. However, excessive addition reduces the compressive strength and elastic modulus of cement stone after 5 days of curing. Comparing G4-G6 and DG2-DG4, calcium carbonate improves the sealing performance and compressive strength of cement grout while reducing the elastic modulus of cement stone. Nano-silica effectively improves both the compressive strength and elastic modulus of cement stone, slightly enhancing sealing performance. Adding silica sand to the cement grout system further optimizes the compressive strength and toughness of cement stone, improving the sealing performance. DG5-DG8 show that the dosage of various additives significantly affects the performance of cement grout; appropriate dosages do not significantly impact its sealing performance. In summary, the addition of high-temperature resistant expandable fiber resin sealing material can enable cement slurry to withstand pressure of more than 7MPa on a 0.25mm crack at 150℃, with a pressure-bearing time of more than 10min and a leakage of less than 26mL, demonstrating excellent sealing performance.

[0183] Test Example 2

[0184] The sealing performance of the above-mentioned cement slurries G1 to G6 on 1.5mm cracks under temperature conditions of 120℃ to 180℃, as well as their compressive strength and elastic modulus after 5 days of curing, are measured. The results are shown in Table 3.

[0185] Table 3. Plugging performance and cement slurry properties of different cementing slurries for 1.5mm cracks at 120℃~180℃.

[0186]

[0187] According to the data in Table 3, cement slurries G1 to G6 can effectively seal 1.5mm cracks at temperatures ranging from 120℃ to 180℃, with a pressure-bearing capacity exceeding 5.0MPa, leakage controlled within 56mL, and a pressure-bearing time exceeding 10 minutes. As the temperature increases, the pressure-bearing capacity initially rises to 180℃ and then slightly decreases. This is because as the temperature rises, the increased molecular thermal motion leads to a higher resin absorption rate and capacity. However, at 180℃, the expanded gel strength decreases, reducing the maximum pressure-bearing capacity of the gel particle accumulation sealing layer. Comparison shows that as the temperature increases, the compressive strength of the cement stone gradually increases, while the elastic modulus gradually decreases, indicating that the above-mentioned cement slurry system has good high-temperature resistance. This test example demonstrates that the addition of high-temperature resistant expanding fiber resin sealing material enables the cement slurry to exhibit good sealing performance for 1.5mm cracks at temperatures ranging from 120℃ to 180℃.

[0188] Test Example 3

[0189] The sealing performance of the above-mentioned cement slurries G1 to G6 on 3mm cracks under temperature conditions of 120℃ to 180℃ is shown in Table 4.

[0190] Table 4. Plugging performance of different cement slurries for 3mm cracks at 120℃~180℃.

[0191] Cement grout for sealing leaks Crack width / mm Temperature / °C Pressure bearing capacity / MPa Pressure bearing time / min Leakage / mL G1 3 120 3.5 >10 86 G2 3 120 4.5 >10 64 G3 3 120 5.0 >10 54 G4 3 120 5.0 >10 57 G5 3 120 4.5 >10 67 G6 3 120 4.5 >10 68 G1 3 150 4.0 >10 73 G2 3 150 5.5 >10 47 G3 3 150 5.5 >10 44 G4 3 150 6.0 >10 38 G5 3 150 5.0 >10 55 G6 3 150 5.5 >10 45 G1 3 180 4.0 >10 71 G2 3 180 5.5 >10 48 G3 3 180 5.0 >10 58 G4 3 180 5.5 >10 49 G5 3 180 5.0 >10 59 G6 3 180 5.5 >10 47

[0192] According to the data in Table 4, cement slurries G1 to G6 can effectively seal 3mm cracks at temperatures ranging from 120℃ to 180℃, with a pressure-bearing capacity exceeding 3.5MPa, leakage controlled within 86mL, and a pressure-bearing time exceeding 10 minutes. Compared to 1.5mm cracks, the pressure-bearing capacity decreases, but it can still withstand pressure for more than 10 minutes. This test example demonstrates that the high-temperature resistant expandable fiber resin plugging material provided by this invention, when added to the cement slurry system, still exhibits good plugging performance for 3mm cracks at temperatures ranging from 120℃ to 180℃.

[0193] Figure 1 The chart shows a comparison of the compressive strength of cement slurries used in Examples 1-6 for sealing cracks of different widths at 150℃. The comparison charts show that cement slurries with added high-temperature resistant expanding fiber resin sealing material can effectively seal cracks of 0-3mm, exhibiting good stability and strong compressive strength, indicating that the present invention has good practical application effects.

[0194] Test Example 4: Effect of the Dosage of High-Temperature Expansive Fiber Resin Sealing Material on the Performance of Cement Grout

[0195] Using the cement slurry in Application Example 1 as the test object, the slurry was prepared according to the standard GB / T19139-2012 "Test Method for Cement in Oil Wells". The high-temperature resistant expanding fiber resin plugging material and cement slurry were mixed evenly at different mixing ratios. The rheological properties of the mixture were measured using a ZNN-D6 rotational viscometer, and the thickening time of the mixture was measured using a high-temperature and high-pressure thickening instrument.

[0196] Table 5. Compatibility Test of High-Temperature Expansive Fiber Resin Plugging Material with Cement Slurry

[0197]

[0198] According to the data in Table 5, the rheological modes of cement slurry with added high-temperature resistant expanding fiber resin plugging material all conform to the power law mode, which has little impact on the rheological properties of cement slurry. The thickening time and compressive strength can meet the relevant requirements of on-site cementing construction.

[0199] In summary, the high-temperature resistant expanding fiber resin plugging material provided by this invention can effectively solve the current problem of leakage prevention and plugging of cement slurry in fractured formations, and can effectively improve the cementing quality of fractured formations, showing good application prospects.

Claims

1. A method for preparing a high-temperature resistant expandable fiber resin sealing material, comprising the following steps: S1. Add sodium hydroxide to an acrylic acid solution, then add chitosan solution, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and fiber in sequence; then add initiator and crosslinking agent in sequence, and obtain polymer gel through polymerization reaction; The chitosan solution uses glacial acetic acid solution as the solvent; The mass concentration of the glacial acetic acid solution is 1%~3%; The fiber is basalt fiber or glass fiber, with a single filament diameter of 11-15 μm and a length of 2-6 mm; The initiator is a redox system, wherein, The oxidizing agent is ammonium persulfate, and the reducing agent is sodium bisulfite or sodium sulfite; In step S1, based on 100 parts by weight of water in the polymerization reaction system, the amounts of each raw material are as follows: The ingredients are: 0.5-3 parts by weight of fiber, 1-5 parts by weight of chitosan, 0.6-3 parts by weight of glacial acetic acid, 10-15 parts by weight of acrylic acid, 1.5-2.0 parts by weight of acrylamide, 6-10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 4-8 parts by weight of NaOH, 0.6-0.8 parts by weight of initiator, and 0.05-0.08 parts by weight of crosslinking agent. In step S1, the polymerization reaction is carried out at a temperature of 60°C. S2. The polymer gel is dried and then pulverized to obtain granular resin, which is the high-temperature resistant expanding fiber resin sealing material.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the oxidant to the reducing agent is 1:1; The crosslinking agent is N,N-methylenebisacrylamide.

3. The preparation method according to claim 1 or 2, characterized in that: In step S1, the polymerization reaction is carried out for 3 to 5 hours under a stirring rate of 500 to 1000 rpm; In step S2, the polymer gel is soaked in ethanol and water in sequence, and then dried at 80-90°C to constant weight to obtain a solid product.

4. The high-temperature resistant expandable fiber resin sealing material obtained by the preparation method according to any one of claims 1-3; The high-temperature resistant expandable fiber resin sealing material has a maximum expansion ratio of 10–21 times, an expansion time of 49–55 minutes, a salt resistance of 69–80%, a water retention rate of 80–93%, and a strength of 351–448 g / cm² when reaching its maximum expansion ratio. 2 .

5. A cementing slurry, the composition of which is as follows: 100 parts oil well cement, 15-20 parts coarse silica sand, 10-15 parts fine silica sand, 0.5-3 parts of the high-temperature resistant expanding fiber resin plugging material as described in claim 4, 2-5 parts nano silica, 1-10 parts calcium carbonate, 0-5 parts water loss reducer, 0-5 parts drag reducer, 0.5-2 parts retarder, 0.2-0.8 parts defoamer, and 30-100 parts water; The particle size of the high-temperature resistant expandable fiber resin sealing material is 0.01 to 0.2 mm.

6. The cementing slurry according to claim 5, characterized in that: The oil well cement is API Grade G cement for oil wells; The coarse silica sand has a particle size of 50~150μm; The particle size of the fine silica sand is 5~15μm; The nano-silica is a nano-silica hydrosol, wherein the mass content of silica is 20% to 50%. The calcium carbonate has a particle size of 0.1–0.3 mm; The water loss reducing agent is a butadiene-styrene latex water loss reducing agent; The drag-reducing agent is a sulfonated formaldehyde-acetone condensate or a polynaphthalene sulfonate drag-reducing agent; The defoamer is a silicone ether copolymer defoamer, an organosiloxane defoamer, or a polyether defoamer; The retarder is at least one of lignosulfonate retarder, hydroxycarboxylic acid retarder, and AMPS polymer retarder.

7. The application of the high-temperature resistant expanding fiber resin plugging material of claim 4 or the cementing slurry of claim 5 or 6 in the cementing slurry for leak prevention and plugging in fractured formations.

8. The application according to claim 7, characterized in that: The high-temperature resistant expanding fiber resin plugging material or the cementing slurry is suitable for plugging 0-3mm fractured formations at temperatures of 120-180℃. The high-temperature resistant expanding fiber resin plugging material or the cementing slurry has a pressure resistance of more than 3.5 MPa for 0-3 mm cracks, a pressure resistance time of more than 10 minutes, and a maximum leakage rate of less than 86 mL.

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