Expanding pressure-bearing leak-stopper, its preparation method and application

Abstract

This invention provides an intumescent pressure-bearing sealing agent, its preparation method, and its application. The intumescent pressure-bearing sealing agent, based on 100 wt%, comprises 10–35 wt% intumescent pressure-resistant material, 40–75 wt% rigid particulate material, 0.1–10 wt% fiber material, and 0.5–15 wt% flexible sealing material. The intumescent pressure-resistant material comprises a porous structure formed by thermosetting resin curing and water sealed within the porous structure. The pore size of the porous structure is 60 μm–400 μm, and the porosity of the intumescent pressure-resistant material is 8–30%. Using DSC measurement, the intumescent pressure-resistant material exhibits a first weight loss peak within 100°C–300°C, a second weight loss peak within 320–380°C, and a third weight loss peak within 400–500°C. The weight loss rate of the intumescent pressure-resistant material at the first weight loss peak is <4%; the weight loss rate at the second weight loss peak is 4%–20%; and the weight loss rate at the third weight loss peak is 21%–55%. In this invention, the expansion and pressure-resistant material in the sealing agent works in conjunction with rigid particulate material, fiber material and flexible sealing material to form a high pressure-resistant and high elasticity sealing system.

Description

Technical Field

[0001] This invention relates to the field of oil well leakage prevention and plugging materials, specifically to an expandable pressure-bearing plugging agent and its preparation method and application. Background Technology

[0002] Bridging plugging technology is one of the most widely used plugging technologies both domestically and internationally. It is simple to prepare, has a rapid onset of action, does not affect drilling fluid rheology, has low negative effects on downhole tools, and is highly adaptable to formations with different lithologies. With proper gradation, it can mitigate or seal leakage in shallow wells, deep wells, fractures, caverns, and pores. Bridging plugging technology heavily relies on understanding the formation leakage channels, requiring prior knowledge of their conditions, including their size, pressure, and temperature. However, effective online detection technologies for natural and induced leakage channels are lacking, and leakage channels generally exhibit multi-scale characteristics. Therefore, precise guidance on particle size selection for plugging materials is not possible, leading to plugging failures or frequent recurrence of leaks.

[0003] Chinese patent CN114702722B discloses "A High-Temperature Shape Memory Foam Composite Material and Its Preparation Method and Leak-Plugging Application." The preparation method of the composite material includes the following steps: S1, mixing an aqueous dispersion of nanoparticles with epoxy monomers and stirring to obtain a water-in-oil Pickering emulsion; adding a curing agent to the Pickering emulsion to form a reactive emulsion; S2, pouring the reactive emulsion into a mold and heating to cure to obtain a shape memory epoxy foam composite material. This invention utilizes a Pickering emulsion template for the polymerization of epoxy monomers and curing agents, and combines foaming and filler particle reinforcement technologies to prepare a shape memory epoxy foam composite material with high transition temperature, high strength and toughness, and high compressibility. This patent enables the production of shape memory materials with activation temperatures above 100℃. Dynamic thermomechanical analysis (DMA) shows a rubber-state storage modulus of 10–30 MPa at 170–200℃. After heating in an oil bath, bending the material into a U-shape at a temperature 20–30℃ higher than the glass transition temperature of the foam composite material, and fixing it at room temperature, followed by heating in an oil bath, the shape recovery temperature is tested at 80–170℃, with a shape recovery rate of 95–100% and a linear expansion rate of 50%–350%. Specifically, the rubber-state storage modulus is 10 MPa; the linear expansion rate is 350% at a shape memory transition temperature of 100℃ and 50% at a shape memory transition temperature of 170℃. When compounded with other sealing materials, the sealing liquid can withstand a pressure of 20 MPa when sealing cracks.

[0004] The high-temperature shape memory foam composite materials provided in the aforementioned patent documents have complex preparation processes and can only achieve linear expansion by hot pressing near the phase transition temperature after the filler has foamed and cured, resulting in low industrialization levels. Therefore, there is an urgent need to develop an expansion-resistant pressure-bearing leak-sealing agent with stable mechanical properties at high temperatures and a simple preparation process. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of complex preparation process and low industrialization of high temperature shape memory composite materials in the prior art, and to provide an expandable pressure-bearing sealing agent, its preparation method and application. The expandable pressure-bearing material of this sealing agent has a high proportion of volume expansion, which has strong adaptability to filling and sealing space. Under high temperature conditions, the mechanical strength of the above-mentioned sealing agent is significantly improved and the leakage is significantly reduced.

[0006] To achieve the above objectives, the first aspect of the present invention provides an intumescent pressure-bearing sealing agent, which, based on 100 wt% of the intumescent pressure-bearing sealing agent, comprises 10-35 wt% intumescent pressure-resistant material, 40-75 wt% in rigid particulate material, 0.1-10 wt% in fiber material, and 0.5-15 wt% in flexible sealing material.

[0007] The expansion and pressure-resistant material comprises a porous structure formed by the curing of thermosetting resin and water sealed within the porous structure;

[0008] The porous structure has a pore size of 60μm to 400μm, and the expansion and compressive strength material has a porosity of 8 to 30%.

[0009] DSC measurements showed that the expandable compressive-resistant material exhibits a first weight loss peak within the range of 100℃ to 300℃, a second weight loss peak within the range of 320℃ to 380℃, and a third weight loss peak within the range of 400℃ to 500℃. The weight loss rate of the expandable compressive-resistant material at the first weight loss peak is <4%; the weight loss rate at the second weight loss peak is 4% to 20%; and the weight loss rate at the third weight loss peak is 21% to 55%.

[0010] It is believed that the relatively flat first weight loss peak at 100℃ to 300℃ may be obtained by the evaporation of water adsorbed on the surface of the expansion and compression-resistant material; the second weight loss peak at 320℃ to 380℃ may be obtained by the rapid evaporation of water sealed in the material after the structure of the expansion and compression-resistant material is destroyed by high temperature heating; and the third weight loss peak at more than 400℃ may be the decomposition and vaporization of the non-aqueous components of the expansion and compression-resistant material.

[0011] The thermosetting resin of the expansion and pressure-resistant material in the plugging agent of this invention is cured to form a porous structure. This porous structure seals water within the expansion and pressure-resistant material. By controlling the pore size of the porous structure and the porosity of the expansion and pressure-resistant material, an expansion and pressure-resistant material with both rigidity and flexibility is formed. In a wellbore environment with a temperature of 100°C or higher, the water in this expansion and pressure-resistant material reaches its boiling point and boils, causing it to expand in volume. The expansion and pressure-resistant material in the plugging agent works in conjunction with rigid particulate materials, fiber materials, and flexible sealing materials. The rigid particulate materials can stably bridge in the fractures, forming the basic framework for sealing. The fiber materials form a network to provide the initial retention performance of the plugging agent. At high temperatures, the surface viscosity of the expansion and pressure-resistant material is activated, firmly adhering to the wellbore while bonding the rigid particulate materials, fiber materials, and flexible sealing materials to form a dense plugging wall. The above four components work together to form a high-pressure-resistant and high-elasticity plugging system.

[0012] In some embodiments of the present invention, the expanding pressure-bearing sealing agent comprises, at 100 wt%, 15-30 wt% expanding pressure-resistant material, 50-70 wt% rigid particulate material, 0.1-8 wt% fiber material, and 1-12 wt% flexible sealing material.

[0013] In some embodiments of the present invention, the thermosetting resin comprises one or more of epoxy resin, phenolic resin, polyetherketone resin, and polyimide resin.

[0014] In some embodiments of the present invention, the pore size of the porous structure is 100 μm to 320 μm, and the porosity of the expansion and compressive strength material is 10 to 25%.

[0015] In some embodiments of the present invention, the method for preparing the expansion-resistant compressive material includes the following steps:

[0016] Preparation of the first mixture S1: The thermosetting resin is mixed with the first curing agent to obtain the first mixture;

[0017] Preparation of the second mixture S2: Mix the second curing agent with water to obtain the second mixture;

[0018] Preparation of the third mixture S3: Mix the first mixture and the second mixture evenly, add the accelerator and foaming agent, and stir for ≥10 minutes at 60℃~85℃ with the speed adjusted to 700rpm~3000rpm to obtain the third mixture;

[0019] S4 Curing: Curing the third mixture to obtain the expansion and compression resistant material.

[0020] In some embodiments of the present invention, the first curing agent and the second curing agent may be the same or different, and each is independently selected from one or more of acid anhydride curing agents, phenolic curing agents, and aromatic polyamine curing agents.

[0021] In step S1, the thermosetting resin undergoes a crosslinking reaction with the first curing agent to obtain a pre-crosslinked body. In step S3, the second curing agent is added to the pre-crosslinked body, mixed evenly, and then an accelerator and a foaming agent are added before curing. Adding the first and second curing agents in steps, with the thermosetting resin and the first curing agent forming the pre-crosslinked body first, allows for easier control of the crosslinking reaction rate and direction compared to adding both simultaneously. Furthermore, the resulting pre-crosslinked body and the second curing agent are more evenly distributed, resulting in a high-temperature mechanical strength and strong sealing ability for functional water in the prepared intumescent and pressure-resistant material.

[0022] In some embodiments of the present invention, in step S1, the thermosetting resin is heated to 60°C to 85°C, the first curing agent is added, the temperature is adjusted to 5°C to 30°C above the melting point of the first curing agent, and after the first curing agent is completely dissolved, it is stirred at a stirring speed of 200 to 400 rpm for 20 to 60 minutes, and then adjusted to 60°C to 85°C to obtain the first mixture.

[0023] In some embodiments of the present invention, step S2 includes step S2-1, step S2-2 or step S2-3;

[0024] Step S2-1: The second curing agent is a solid with a melting point ≥90℃. Add the second curing agent to the solution and adjust the temperature to 5℃~30℃ above the melting point of the second curing agent. After the second curing agent is completely dissolved, adjust the temperature to 60℃~85℃, add water, and stir at a stirring speed of 200~400rpm for 20~60min to obtain the second mixture.

[0025] Step S2-2: The second curing agent is a solid with a melting point <90℃. Add the second curing agent to water and heat it to 5℃~10℃ above the melting point of the second curing agent. After the second curing agent is completely dissolved, adjust the temperature to 60℃~85℃ and stir at a stirring speed of 200~400rpm for 20~60min to obtain the second mixture.

[0026] Step S2-3: The second curing agent is a liquid. Adjust the temperature to 60℃~85℃, add water to the second curing agent, and stir at a stirring speed of 200~400rpm for 20~60min to obtain the second mixture.

[0027] In some embodiments of the present invention, in step S3, the second mixture is added to the first mixture, an accelerator and a foaming agent are added, and the mixture is stirred for 10-30 minutes to obtain a third mixture.

[0028] In some embodiments of the present invention, in step S4, the curing includes two or all three of the following: first curing, second curing, and third curing; the first curing is carried out at a constant temperature of 100℃~110℃ for 2h~8h; the second curing is carried out at a constant temperature of 120℃~130℃ for 0.5h~4h; and the third curing is carried out at a constant temperature of 140℃~160℃ for 0.5h~4h.

[0029] In some embodiments of the present invention, the amount of the solvent is 10 to 20 parts by weight; the solvent contains at least one of a liquid resin curing agent and a liquid resin toughening agent.

[0030] In some embodiments of the present invention, the solution comprises at least one of a modified aromatic amine liquid curing agent, a modified phenolic high-temperature curing agent, and an alkenyl succinic anhydride.

[0031] In some embodiments of the present invention, the mass ratio of the first curing agent to the second curing agent is (0.75-3):1.

[0032] In some embodiments of the present invention, the amount of thermosetting resin is 100 parts by weight, the total amount of the first curing agent and the second curing agent is 50 to 100 parts by weight, the amount of accelerator is 0 to 2 parts by weight, the amount of water is 10 to 50 parts by weight, and the amount of foaming agent is 0.1 to 3 parts by weight.

[0033] In this invention, by further adjusting the dosage of each component in the expanding and pressure-resistant material of the sealing agent, the expanding and pressure-resistant material in the sealing agent has a stronger self-adaptive ability, changing the linear expansion of the resin to a high proportion of volumetric expansion, which significantly improves the expansion rate of the sealing agent; and significantly improves the mechanical properties of the sealing agent after expansion, changing the defects of the previous material expansion, which was loose in structure and decreased in mechanical properties, so that the expanding and pressure-resistant material still has high compressive and shear resistance after expansion at high temperature, combining the advantages of rigid and flexible sealing.

[0034] In some embodiments of the present invention, the epoxy resin in the expanding and compressive material comprises one or more of glycidyl ether epoxy resin, glycidyl amine epoxy resin, glycidyl ester epoxy resin, imide-modified epoxy resin, and phenolic-modified epoxy resin.

[0035] In some embodiments of the present invention, the epoxy resin comprises one or more of bisphenol A diglycidyl ether, phenolic epoxy resin, and imide epoxy resin.

[0036] In some embodiments of the present invention, the epoxy resin comprises one or both of bisphenol A diglycidyl ether E51 and phenolic epoxy resin F51.

[0037] In some embodiments of the present invention, the anhydride curing agent comprises one or more of maleic anhydride, alkenyl succinic anhydride, phthalic anhydride, cyclopentetrate dianhydride, and methyl hexahydrophthalic anhydride.

[0038] In some embodiments of the present invention, the curing agent comprises one or two of the following: modified phenolic high-temperature curing agent F-52B or F-51A, and modified aromatic amine liquid curing agent VT5327.

[0039] In some embodiments of the present invention, the accelerator comprises one or more of triethanolamine, dimethylaniline, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0040] In some embodiments of the present invention, the water is fresh water or salt water.

[0041] In some embodiments of the present invention, a foam enhancer is added to the water.

[0042] In some embodiments of the present invention, the foam enhancer comprises one or both of a surfactant or a thickening and shearing agent; the mass content of the foam enhancer is 0.1% to 1% based on the weight of the water.

[0043] In some embodiments of the present invention, the surfactant-based foam enhancer comprises one or more of polysorbate, sorbitan monooleate, oleyl alcohol polyoxyethylene ether, and dodecyl oleate.

[0044] In some embodiments of the present invention, the thickening and cutting agent-type foam reinforcing agent comprises one or more of hydroxyethyl methyl cellulose, polyacrylamide, and sodium carboxymethyl starch.

[0045] In some embodiments of the present invention, the foaming agent comprises one or more of anionic foaming agents, cationic foaming agents, and nonionic foaming agents.

[0046] In some embodiments of the present invention, the foaming agent is an anionic foaming agent, preferably comprising one or more of sodium dodecylbenzenesulfonate, fatty alcohol glyceryl ether sulfonate, or α-olefin sulfonate.

[0047] The rigid particulate material in the sealant of the present invention is mainly used to improve the pressure-bearing capacity of the sealant, especially in projects with greater depth, where the sealant needs to provide greater pressure-bearing capacity. The rigid particulate material bridges at the crack to provide pressure-bearing capacity.

[0048] In some embodiments of the present invention, the rigid particulate material comprises at least one of vermiculite, quartz, calcite, calcium carbonate, and mica.

[0049] In some embodiments of the present invention, the particle size of the rigid particulate material is selected from at least three gradations selected from 1-2 mm, 3-5 mm, 6-10 mesh, 10-20 mesh, 20-40 mesh, 40-80 mesh, 100-150 mesh, 200-400 mesh, and 400-800 mesh.

[0050] The role of the fiber material in the sealant of the present invention is as follows: 1) It enhances the friction between the sealant components; 2) It can be stacked into a network structure to improve the retention performance of the sealant, especially in the early stage of sealant application when the expansion and pressure-resistant material has not yet reached a certain expansion rate, the sealant can easily move in a larger leakage space and is not easy to remain; 3) The network structure formed by the fibers can work together with the rigid particulate material to improve the overall pressure-bearing effect of the composition.

[0051] In some embodiments of the present invention, the fiber material comprises at least one of aromatic polyamide fiber, polytetrafluoroethylene fiber, polysilicon fiber, glass fiber, polyimide fiber, sepiolite fiber, ceramic fiber, and polyvinyl alcohol fiber.

[0052] In some embodiments of the present invention, the fiber material is a porous mesh fiber.

[0053] In some embodiments of the present invention, the pore size of the mesh fiber is 1 mm to 3 mm; the fiber length is selected from at least one of 1 to 2 mm, 3 to 5 mm, 7 to 10 mm, and 12 to 15 mm.

[0054] In some embodiments of the present invention, the flexible sealing material comprises at least one of silicone rubber, polystyrene, bitumen, and silicone-modified acrylate.

[0055] In some embodiments of the present invention, the flexible sealing material comprises at least one of polydisperse polystyrene microspheres, thermoplastic silicone rubber particles, and asphalt powder.

[0056] In some embodiments of the present invention, the flexible sealing material is micron-sized particles with a particle size range of 4μm to 100μm.

[0057] The flexible sealing material in the sealant of this invention improves the pressure-resistant buffering effect. It can fill the fine pores by compression, which helps to form a denser sealing layer. Furthermore, after the surface viscosity of the expanding pressure-resistant material is activated at high temperature, it adheres to the flexible sealing material, forming a dense sealing wall. The selected flexible sealing material has a better pressure-resistant buffering effect, can be better dispersed in the fine pores, and the selection of an appropriate particle size range further facilitates the dispersion effect of the flexible particles. By compressing the flexible sealing material, the fine pores can be fully filled.

[0058] The second aspect of the present invention provides a method for preparing an intumescent pressure-bearing sealing agent, comprising the following steps: mixing an intumescent pressure-resistant material, a rigid particulate material, a fiber material, and a flexible sealing material to obtain the intumescent pressure-bearing sealing agent.

[0059] In some embodiments of the present invention, the stirring rate is 300-1000 r / min; the stirring time is 5-20 min; and the mixing temperature is 10-70℃.

[0060] A third aspect of the present invention provides a method for sealing leaks using the above-described expanding pressure-bearing sealing agent or the expanding pressure-bearing sealing agent prepared by the above-described method, comprising the following steps:

[0061] In water-based leak sealing, the leak-sealing agent is added at a temperature of 100-240℃ and a density of 1.2-2.4 g / cm³. 3 In the drilling fluid, the amount of the plugging agent is 10% to 50% (w / v).

[0062] The technical solution provided by this invention has the following beneficial effects:

[0063] 1. The thermosetting resin of the expanding and pressure-resistant material in the plugging agent of the present invention is cured to form a porous structure. This porous structure seals water within the expanding and pressure-resistant material. By controlling the pore size of the porous structure and the porosity of the expanding and pressure-resistant material, an expanding and pressure-resistant material with both rigidity and flexibility is formed. In a wellbore environment with a temperature of 100°C or higher, the water in this expanding and pressure-resistant material reaches its boiling point and boils, causing it to expand in volume. The expanding and pressure-resistant material in the plugging agent works in conjunction with rigid particulate material, fiber material, and flexible sealing material. The rigid particulate material can stably bridge the fractures, forming the basic framework for sealing. The fiber material forms a network to provide the initial retention performance of the plugging agent. At high temperatures, the surface viscosity of the expanding and pressure-resistant material is activated, firmly adhering to the wellbore while bonding the rigid particulate material, fiber material, and flexible sealing material to form a dense plugging wall. The above four components work together to form a high-pressure-resistant and high-elasticity plugging system.

[0064] 2. Expansive and pressure-resistant materials can also improve the mechanical properties of sealants after high-temperature expansion, overcoming the shortcomings of previous materials that had a loose structure and decreased mechanical properties after expansion. This allows the sealant to retain high compressive and shear strength even after expansion at high temperatures, combining the advantages of both rigid and flexible sealants. Rigid granular materials are mainly used to enhance the pressure-bearing capacity of sealants, especially in deep projects, enabling the sealant to provide greater pressure resistance.

[0065] 3. The role of fiber materials in the sealing agent: 1) Enhance the friction between the sealing components in the sealing agent; 2) They can be overlapped into a network structure to improve the retention performance of the sealing agent, especially in the early stage of sealing, when the expansion and pressure-resistant material has not yet reached a certain expansion rate, the sealing agent is easy to move in a larger leakage space and is not easy to stay; 3) The network structure formed by the fibers can work together with the rigid particulate materials to improve the overall pressure resistance of the sealing agent.

[0066] 4. Compared with other sealing agents, the sealing agent provided by the present invention achieves high pressure resistance and tight sealing with low concentration. The sealing agent formed can achieve a pressure resistance of 33.5 MPa for cracks with different openings, and the leakage is reduced by more than 59%. Detailed Implementation

[0067] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Unless otherwise specified, specific conditions in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the materials used in the embodiments are commercially available products or conventional products that can be synthesized by known methods.

[0068] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0069] The main reagents used in this invention are as follows:

[0070] Bisphenol A diglycidyl ether E51 was purchased from Hubei Dongcao Chemical Technology Co., Ltd., CAS No. 1675-54-3.

[0071] The phenolic epoxy resin F51 was purchased from Nantong Xingchen Synthetic Materials Co., Ltd.

[0072] Maleic anhydride was purchased from Sinopharm Group, CAS number 108-31-6.

[0073] The alkenyl succinic anhydride (ASA) was purchased from Guangzhou Haoyi New Material Technology Co., Ltd., CAS No. 26544-38-7.

[0074] Phthalic anhydride (PA) was purchased from Shandong Sanju Chemical Technology Co., Ltd., CAS No. 85-44-9.

[0075] The modified phenolic high-temperature curing agent F-52B was purchased from Bengbu Tianyu High-Temperature Resin Materials Co., Ltd.

[0076] The modified aromatic amine liquid curing agent VT5327 was purchased from Shenzhen Huite Chemical Co., Ltd.

[0077] VT5327 is a liquid modified aromatic amine curing agent, a yellow to brown viscous liquid, mainly used as a high-temperature curing agent for epoxy resins.

[0078] Sodium dodecylbenzenesulfonate (SDBS) was purchased from Shandong Yongwang Chemical Co., Ltd., CAS No. 25155-30-0.

[0079] Sodium α-olefin sulfonate (AOS) was purchased from China National Light Industry Chemical Co., Ltd., CAS No. 68439-57-6.

[0080] The glass mesh fiber was purchased from Hangzhou Mingyi Decoration Materials Co., Ltd.

[0081] Polyvinyl alcohol fiber was purchased from Shandong Taicheng Fiber Co., Ltd.

[0082] The thermoplastic silicone rubber granules TPSiV were purchased from Shandong Tairuifeng New Material Co., Ltd.

[0083] The polystyrene microspheres were purchased from Zhongke Leiming Technology Co., Ltd., CAS No. 9003-53-6.

[0084] The preparation method of thermosensitive shape memory polymer particles is as follows: The thermosensitive shape memory polymer (styrene-butyl acrylate copolymer with a shape memory deformation temperature of 50–110℃, purchased from Texas Continental Shelf Petroleum Engineering Technology Co., Ltd.) is cryogenically frozen with liquid nitrogen at a temperature of -10℃ to -20℃. The fibers are polypropylene fibers (polypropylene fiber) and polyvinyl chloride fibers (chlorofiber) in a weight ratio of 50% each. The fibers and thermosensitive shape memory polymer powder in a 1:1 weight ratio are mixed uniformly using a high-speed mixer. The uniformly mixed material is then granulated using an extrusion granulator, with the extrusion granulation temperature set at 55–75℃.

[0085] The testing method used in this invention:

[0086] 1. Test methods for pore size and porosity

[0087] The expansion and compressive strength materials prepared in the examples and comparative examples were made into test samples according to a mold with specifications of 60mm×60mm×30mm. The samples were subjected to liquid nitrogen brittle fracture, and the surface morphology of the samples was observed using a Hitachi S4800 field emission scanning electron microscope to obtain their pore size and porosity.

[0088] 2. Test method for weightlessness rate

[0089] The mass of the expansion and compressive strength material prepared in the test examples and comparative examples is recorded as m1. The expansion and compressive strength material is heated to 100-300℃ at a rate of 5℃ / min, maintained at the high temperature for 4-5 hours, removed and cooled to room temperature, and its mass is recorded as m2. The first weight loss rate is calculated according to the formula: First weight loss rate = 100(m1-m2) / m1. The expansion and compressive strength material is heated to 320-380℃ at a rate of 5℃ / min, maintained at the high temperature for 4-5 hours, removed and cooled to room temperature, and its mass is recorded as m3. The second weight loss rate is calculated according to the formula: Second weight loss rate = 100(m2-m3) / m2. The expansion and compressive strength material is heated to 400-500℃ at a rate of 5℃ / min, maintained at the high temperature for 3-4 hours, removed and cooled to room temperature, and its mass is recorded as m4. The third weight loss rate is calculated according to the formula: Third weight loss rate = 100(m4-m3) / m3.

[0090] Preparation Example 1

[0091] Preparation Example 1 provides a method for preparing an expansion-resistant compressive material.

[0092] Preparation of the first mixture S1: Heat 100g of bisphenol A diglycidyl ether E51 to 60℃ and maintain the temperature for 10min. After the bisphenol A diglycidyl ether E51 becomes thin, add 25g of maleic anhydride while stirring at 300rpm. Adjust the temperature to 85℃. After the maleic anhydride dissolves, add 15g of alkenyl succinic anhydride. Continue stirring for 40min and adjust the temperature to 60℃ to obtain the first mixture.

[0093] Preparation of the second mixture S2: Add 20g of maleic anhydride to 40mL of water, adjust the temperature to 85℃, and keep stirring at 200rpm until the maleic anhydride is completely dissolved. Then add 16g of alkenyl succinic anhydride and adjust the temperature to 60℃ to obtain the second mixture.

[0094] Preparation of the third mixture S3: Add the second mixture to the first mixture, mix well, then add 1.2g of dimethylaniline and 0.25g of sodium dodecylbenzenesulfonate. Stir at 60℃ for 10 minutes at 1000 rpm to obtain the third mixture.

[0095] S4 Curing: Brush silicone oil on the mold surface, put the third mixture into the mold, put the mold into a preheated constant temperature box, keep it at 100℃ for 4 hours, then raise the temperature to 120℃ and keep it at 2 hours, then raise the temperature to 150℃ and keep it at 2 hours to complete the curing; after the cured body cools down, the cured body board is obtained, and after demolding, it is crushed into different particle sizes to obtain the expansion and compression resistant material.

[0096] The intumescent compressive strength material prepared in Example 1 comprises a porous structure formed by the curing of a thermosetting resin and water sealed within the porous structure; the pore size of the porous structure is 250–300 μm, and the porosity of the intumescent compressive strength material is 20.1%; using DSC measurement, at 200–270 °C, the weight loss rate of the intumescent compressive strength material at the first weight loss peak is 1.7%; at 360–370 °C, the weight loss rate of the intumescent compressive strength material at the second weight loss peak is 15.0%; above 450 °C, the weight loss rate of the intumescent compressive strength material at the third weight loss peak is 50.2%.

[0097] Preparation Example 2

[0098] Preparation Example 2 provides a method for preparing an expansion-resistant compressive material.

[0099] Preparation of the first mixture S1: Heat 60g of bisphenol A diglycidyl ether E51 to 60℃ and add 40g of phenolic epoxy resin F51. After maintaining the temperature for 10min, wait until the bisphenol A diglycidyl ether E51 and phenolic epoxy resin F51 become thin. Then, while stirring at 300rpm, add 25g of alkenyl succinic anhydride and 15g of modified phenolic high-temperature curing agent F-52B. Adjust the temperature to 85℃ and continue stirring for 40min. Adjust the temperature to 60℃ to obtain the first mixture.

[0100] Preparation of the second mixture S2: Mix 20g of alkenyl succinic anhydride and 16g of modified phenolic high-temperature curing agent F-52B evenly, adjust the temperature to 85℃, maintain a stirring speed of 200rpm, add 30mL of water while stirring, and adjust the temperature to 60℃ to obtain the second mixture.

[0101] Preparation of the third mixture S3: Add the second mixture to the first mixture, mix well, then add 1.2g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.25g of sodium dodecylbenzenesulfonate. Stir at 60℃ for 10 minutes at 1000 rpm to obtain the third mixture.

[0102] S4 Curing: Brush silicone oil on the mold surface, put the third mixture into the mold, put the mold into a preheated constant temperature box, keep it at 100℃ for 4 hours, then raise the temperature to 120℃ and keep it at 2 hours, then raise the temperature to 150℃ and keep it at 1 hour to complete the curing; after the cured body cools down, the cured body board is obtained, and after demolding, it is crushed into different particle sizes to obtain the expansion and compression resistant material.

[0103] Preparation Example 2 prepared an intumescent compressive material comprising a porous structure formed by the curing of a thermosetting resin and water sealed within the porous structure; the pore size of the porous structure is 230–280 μm, and the porosity of the intumescent compressive material is 15.48%; using DSC measurement, at 200–270 °C, the weight loss of the intumescent compressive material at the first weight loss peak is 1.7%; at 360–370 °C, the weight loss of the intumescent compressive material at the second weight loss peak is 12.8%; above 420 °C, the weight loss of the intumescent compressive material at the third weight loss peak is 46.8%.

[0104] Preparation Example 3

[0105] Preparation Example 3 provides a method for preparing an expansion-resistant compressive material.

[0106] Preparation of the first mixture S1: Heat 100g of bisphenol A diglycidyl ether E51 to 85℃ and maintain the temperature for 10min. After the bisphenol A diglycidyl ether E51 becomes thin, add 25g of phthalic anhydride PA while stirring at 300rpm. Adjust the temperature to 135℃ and add 15g of modified aromatic amine liquid curing agent VT5327. After the phthalic anhydride PA is completely dissolved, continue stirring for 20min and adjust the temperature to 85℃ to obtain the first mixture.

[0107] Preparation of the second mixture S2: Add 20g of phthalic anhydride PA to 16g of modified aromatic amine liquid curing agent VT5327, adjust the temperature to 135℃, maintain a stirring speed of 200rpm until the phthalic anhydride PA is completely dissolved, adjust the temperature to 85℃, and then add 40mL of water while stirring to obtain the second mixture.

[0108] Preparation of the third mixture S3: Add the second mixture to the first mixture, mix well, then add 1.2g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.50g of sodium α-olefin sulfonate. Stir at 85℃ for 10 minutes at 1000 rpm to obtain the third mixture.

[0109] S4 Curing: Brush silicone oil on the mold surface, put the third mixture into the mold, put the mold into a preheated constant temperature box, then raise the temperature to 120℃ and hold for 4 hours, then raise the temperature to 150℃ and hold for 4 hours to complete the curing; after the cured body cools down, the cured body board is obtained, and after demolding, it is crushed into different particle sizes to obtain the expansion and compressive strength material.

[0110] Preparation Example 3 prepared an intumescent compressive material comprising a porous structure formed by the curing of a thermosetting resin and water sealed within the porous structure; the pore size of the porous structure is 230–280 μm, and the porosity of the intumescent compressive material is 20.18%; using DSC measurement, at 200–270 °C, the weight loss of the intumescent compressive material at the first weight loss peak is 1.3%; at 360–370 °C, the weight loss of the intumescent compressive material at the second weight loss peak is 14.9%; above 400 °C, the weight loss of the intumescent compressive material at the third weight loss peak is 39.0%.

[0111] Example 1

[0112] 1. Preparation method of expansion pressure-bearing sealing agent

[0113] The expansion and compressive strength material prepared in Example 1 was pulverized and sieved to obtain particulate material with a particle size of 30-50 mesh.

[0114] The expansion pressure-resistant sealant is obtained by mixing 3 parts by weight of intumescent pressure-resistant material (30-50 mesh), 5 parts by weight of calcite (1-2 mm), 4 parts by weight of calcium carbonate (10-20 mesh), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.3 parts by weight of glass mesh fiber (1-3 mm), 0.2 parts by weight of polyvinyl alcohol fiber (1-3 mm), and 2 parts by weight of thermoplastic silicone rubber TPSiV (50-100 μm). The stirring rate is 400 r / min, the stirring time is 5-10 min, and the mixing temperature is 25℃.

[0115] 2. Application method of expansion pressure sealing agent

[0116] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3 At 25℃, an expansion pressure-bearing sealant was added at a ratio of 21.5% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 3×2mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0117] Example 2

[0118] 1. Preparation method of expansion pressure-bearing sealing agent

[0119] The expansion and compressive strength material prepared in Example 2 was pulverized and sieved to obtain particulate material with a particle size of 30-50 mesh.

[0120] The expansion pressure-resistant sealant is obtained by mixing 5 parts by weight of intumescent pressure-resistant material (30-50 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (10-20 mesh), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.3 parts by weight of glass mesh fiber (1-3 mm), 0.2 parts by weight of polyvinyl alcohol fiber (1-3 mm), and 2 parts by weight of thermoplastic silicone rubber TPSiV (50-100 μm). The stirring rate is 400 r / min, the stirring time is 5-10 min, and the mixing temperature is 25℃.

[0121] 2. Application method of expansion pressure sealing agent

[0122] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3 At 25℃, an expansion pressure-bearing sealant was added at a ratio of 19.5% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 3×2mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0123] Example 3

[0124] 1. Preparation method of expansion pressure-bearing sealing agent

[0125] The expansion and compressive strength material prepared in Example 3 was pulverized and sieved to obtain particulate materials with particle sizes of 10-20 mesh and 30-50 mesh.

[0126] The expansion pressure-resistant sealant is obtained by mixing 2 parts by weight of expansion pressure-resistant material (10-20 mesh), 3 parts by weight of expansion pressure-resistant material (30-50 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.3 parts by weight of glass mesh fiber (3-5 mm), 0.3 parts by weight of polyvinyl alcohol fiber (1-3 mm), and 2 parts by weight of thermoplastic silicone rubber TPSiV (50-100 μm). The stirring rate is 500 r / min, the stirring time is 10-15 min, and the mixing temperature is 30℃.

[0127] 2. Application method of expansion pressure sealing agent

[0128] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3At 30℃, an expansion pressure-bearing sealant was added at a ratio of 18.5% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 4×3mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0129] Example 4

[0130] 1. Preparation method of expansion pressure-bearing sealing agent

[0131] The expansion and compressive strength material prepared in Preparation Example 1 was pulverized and sieved to obtain particulate materials with particle sizes of 10-20 mesh, 30-50 mesh and 100-150 mesh;

[0132] The expansion pressure-resistant sealant is obtained by mixing 2 parts by weight of expansion pressure-resistant material (10-20 mesh), 3 parts by weight of expansion pressure-resistant material (30-50 mesh), 1 part by weight of expansion pressure-resistant material (100-150 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 0.3 parts by weight of glass mesh fiber (3-5 mm), 0.3 parts by weight of polyvinyl alcohol fiber (1-3 mm), and 2 parts by weight of thermoplastic silicone rubber TPSiV (50-100 μm). The stirring rate is 500 r / min, the stirring time is 10-15 min, and the mixing temperature is 30℃.

[0133] 2. Application method of expansion pressure sealing agent

[0134] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3 At 30℃, an expansion pressure-bearing sealant was added at a ratio of 18.5% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 4×3mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0135] Example 5

[0136] 1. Preparation method of expansion pressure-bearing sealing agent

[0137] The expansion and compressive strength material prepared in Example 1 was pulverized and sieved to obtain particulate materials with particle sizes of 10-20 mesh and 30-50 mesh.

[0138] The following ingredients are mixed by stirring: 2 parts by weight of intumescent compressive strength material (10-20 mesh), 3 parts by weight of intumescent compressive strength material (30-50 mesh), 5 parts by weight of quartz (6-10 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.5 parts by weight of glass mesh fiber (3-5 mm), 0.2 parts by weight of polyvinyl alcohol fiber (7-10 mm), and 2 parts by weight of polystyrene microspheres (20-100 μm) to obtain the intumescent pressure-bearing sealing agent; the stirring rate is 700 r / min; the stirring time is 10-15 min; and the mixing temperature is 50℃.

[0139] 2. Application method of expansion pressure sealing agent

[0140] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3 At 50℃, an expansion pressure-bearing sealant was added at a ratio of 23.7% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 5×4mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0141] Example 6

[0142] 1. Preparation method of expansion pressure-bearing sealing agent

[0143] The expansion and compressive strength material prepared in Preparation Example 1 was pulverized and sieved to obtain particulate materials with particle sizes of 10-20 mesh, 30-50 mesh and 100-800 mesh;

[0144] The following ingredients are mixed: 2 parts by weight of intumescent pressure-resistant material (10-20 mesh), 3 parts by weight of intumescent pressure-resistant material (30-50 mesh), 1 part by weight of intumescent pressure-resistant material (100-800 mesh), 5 parts by weight of quartz (6-10 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.5 parts by weight of glass mesh fiber (3-5 mm), 0.2 parts by weight of polyvinyl alcohol fiber (7-10 mm), and 2 parts by weight of thermoplastic silicone rubber TPSiV (50-100 μm) to obtain the intumescent pressure-bearing sealing agent; the stirring rate is 700 r / min; the stirring time is 10-15 min; and the mixing temperature is 50℃.

[0145] 2. Application method of expansion pressure sealing agent

[0146] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3At 50℃, an expansion pressure-bearing sealant was added at a ratio of 22.7% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 5×4mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0147] Example 7

[0148] 1. Preparation method of expansion pressure-bearing sealing agent

[0149] The expansion and compressive strength material prepared in Example 1 was pulverized and sieved to obtain particulate materials with particle sizes of 10-20 mesh and 30-50 mesh.

[0150] The following ingredients are mixed by stirring: 2 parts by weight of intumescent compressive strength material (10-20 mesh), 3 parts by weight of intumescent compressive strength material (30-50 mesh), 5 parts of quartz (6-10 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), 2 parts by weight of calcium carbonate (100-150 mesh), 0.5 parts by weight of glass mesh fiber (3-5 mm), 0.2 parts by weight of polyvinyl alcohol fiber (7-10 mm), and 2 parts by weight of polystyrene microspheres (20-100 μm) to obtain the intumescent pressure-bearing sealing agent; the stirring rate is 700 r / min; the stirring time is 10-15 min; and the mixing temperature is 50℃.

[0151] 2. Application method of expansion pressure sealing agent

[0152] Accurately measure 2000 mL of water-based drilling fluid (2.0 g / cm³). 3 At 50℃, an expansion pressure-bearing sealant was added at a ratio of 23.7% (w / v). After stirring evenly, the pressure-bearing sealing capacity (pressure strength and leakage) of a 6×5mm joint plate was tested at 180℃ using a DL-3A high-temperature and high-pressure sealant evaluation instrument. See Table 3 for the results.

[0153] Comparative Example 1

[0154] The expansion pressure-bearing sealing agent was prepared according to the method described in Example 5, except that 2 parts by weight of temperature-sensitive shape memory polymer particles (10-20 mesh) were used instead of 2 parts by weight of expansion pressure-resistant material (10-20 mesh).

[0155] Comparative Example 2

[0156] The expansion pressure-bearing sealant was prepared according to the method described in Example 5, except that 5 parts by weight of quartz (6-10 mesh), 4 parts by weight of calcite (1-2 mm), 2 parts by weight of calcium carbonate (20-40 mesh), 3 parts by weight of calcium carbonate (40-80 mesh), and 2 parts by weight of calcium carbonate (100-150 mesh) were not added.

[0157] Comparative Example 3

[0158] The expansion pressure-bearing sealant was prepared according to the method described in Example 5, except that 0.5 parts by weight of glass mesh fiber (3-5 mm) and 0.2 parts by weight of polyvinyl alcohol fiber (7-10 mm) were not added.

[0159] Comparative Example 4

[0160] The expansion pressure-bearing sealing agent was prepared according to the method described in Example 7, except that 2 parts by weight of thermosensitive shape memory polymer particles (10-20 mesh) and 3 parts by weight of thermosensitive shape memory polymer particles (30-50 mesh) were used to replace 2 parts by weight of expansion pressure-resistant material (10-20 mesh) and 3 parts by weight of expansion pressure-resistant material (30-50 mesh), respectively.

[0161] Test example:

[0162] The testing method of this invention is as follows:

[0163] 1. Test method for curing rate

[0164] Let the total mass of the expanded compressive strength material after curing be m1, and the total mass of all components before curing be m0. Calculate the curing rate T of the expanded compressive strength material. m :

[0165]

[0166] 2. Density testing methods

[0167] The expansion and compression-resistant material prepared in the preparation example was made into a test sample according to a mold with specifications of 60mm×60mm×30mm. The original volume (denoted as V0) and the volume after expansion at 150℃ (denoted as V1) were tested by the displacement method. The density was calculated according to the mass-volume formula.

[0168] Using the test method of the present invention patent described above, the curing rate and density of preparation examples 1 to 3 were tested, and the test results are shown in Table 1 below.

[0169] Table 1. Curing rate and density tests of preparation examples 1-3

[0170]

[0171] The curing rates of Preparation Examples 1-3 were relatively high, generally remaining at 98.9% or above. At 150°C, Preparation Examples 1-3 exhibited lower densities and better expansion effects.

[0172] 3. Compressive strength test method

[0173] The expansion and compressive strength material prepared in the preparation example was made into test samples according to a mold with a specification of 60mm×60mm×30mm. The high temperature universal testing machine was used to test the compressive strength of the samples at room temperature, high temperature of 90℃ and 180℃ respectively. (Note: Before the high temperature test, silicone oil was applied to the inner cavity of the test to prevent the high temperature expansion and compressive strength material from sticking to the instrument.)

[0174] 4. Tensile strength test method

[0175] The expansion and compression resistant material prepared in the preparation example was made into a test sample according to a dumbbell mold with a length of 30cm. The tensile strength of the sample was tested at room temperature, 90℃ and 180℃ using a high-temperature universal testing machine with a test speed of 5mm / min and an arbitration test speed of 2mm / min.

[0176] Using the test method of the present invention described above, the compressive strength and tensile strength of preparation examples 1 to 3 were tested, and the test results are shown in Table 2 below.

[0177] Table 2 Mechanical property tests of preparation examples 1-3

[0178]

[0179] As shown in Table 2, the mechanical strength (including compressive strength and tensile strength) of Preparation Examples 1-3 at 90℃ and 180℃ was relatively small, especially the mechanical strength loss at high temperature (180℃). The compressive strength retention rate was all above 30%, and the tensile strength retention rate was all above 25%.

[0180] 5. High-Temperature Pressure Leakage Prevention and Sealing Performance Test Method

[0181] A DL-3A high-temperature and high-pressure plugging test apparatus (working pressure 40 MPa, temperature 260℃) was used to simulate downhole high-temperature and high-pressure conditions to evaluate the pressure-bearing capacity of the plugging material for sealing fractures. Using sealing plates of different fracture widths, the pressure-bearing capacity of the plugging fluid at 180℃ was tested. It was noted that after reaching the predetermined temperature, the temperature was maintained for 3 hours before gradually increasing the pressure at a rate of 0.5 MPa / 5 min until the breakthrough pressure was reached. The highest pressure value and cumulative leakage before reaching the breakthrough pressure were recorded as the pressure-bearing capacity and leakage rate of the plugging agent.

[0182] The high-temperature pressure-resistant leak-proofing performance of the sealing agents prepared in Examples 1-7 and Comparative Examples 1-4 was tested, and the test results are shown in the table below.

[0183] Table 3 Test performance of the plugging agents prepared in Examples 1-7 and Comparative Examples 1-4

[0184] Test case seam width / mm Compressive strength / MPa Leakage volume (mL) Example 1 3×2 16.7 45 Example 2 3×2 23.2 26 Example 3 4×3 25.4 24 Example 4 4×3 28.6 20 Example 5 5×4 29.9 32 Example 6 5×4 33.5 7 Example 7 6×5 31.1 46 Comparative Example 1 5×4 8.0 380 Comparative Example 2 5×4 3.2 176 Comparative Example 3 5×4 26.1 78 Comparative Example 4 6×5 2.0 880

[0185] As shown in Table 1, the plugging agents prepared in Examples 1-7 exhibit good pressure-bearing sealing capabilities for cracks approximately 5 mm in diameter. This is mainly manifested in high pressure-bearing strength (up to 33.5 MPa) and low leakage, with a minimum reduction of over 59% in leakage. In Comparative Example 1, compared to Example 5, using the same size and quantity of existing intumescent pressure-resistant material instead of the original material resulted in a plugging agent that did not undergo steam-driven expansion, leading to a significant decrease in pressure-bearing strength and a large leakage. In Comparative Example 2, compared to Example 5, the plugging agent without the addition of rigid particulate material could not provide high pressure-bearing capacity; its pressure-bearing strength was significantly reduced, and the leakage was large. In Comparative Example 3, compared to Example 5, the plugging agent without the addition of fiber material exhibited reduced retention capacity upon reaching the lost formation, resulting in a larger leakage; the lack of a fiber network structure also slightly reduced its pressure-bearing strength. Compared with Example 7, Comparative Example 4 uses the same size and quantity of existing intumescent pressure-resistant material instead of the intumescent pressure-resistant material. The resulting sealing agent does not undergo steam-driven expansion, and when the crack is large, its pressure-bearing capacity is extremely poor, resulting in a large amount of leakage.

[0186] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An expansion-pressure sealing agent, characterized in that, The expansion pressure-bearing sealing agent, at a weight of 100 wt%, comprises 10-35 wt% expansion pressure-resistant material, 40-75 wt% rigid particulate material, 0.1-10 wt% fiber material, and 0.5-15 wt% flexible sealing material. The expansion and pressure-resistant material comprises a porous structure formed by the curing of thermosetting resin and water sealed within the porous structure; The porous structure has a pore size of 60μm to 400μm, and the expansion and compressive strength material has a porosity of 8 to 30%. DSC measurements showed that the expandable compressive-resistant material exhibits a first weight loss peak within the range of 100℃ to 300℃, a second weight loss peak within the range of 320℃ to 380℃, and a third weight loss peak within the range of 400℃ to 500℃. The weight loss rate of the expandable compressive-resistant material at the first weight loss peak is <4%; the weight loss rate at the second weight loss peak is 4% to 20%; and the weight loss rate at the third weight loss peak is 21% to 55%.

2. The expanding pressure-bearing leak-sealing agent according to claim 1, characterized in that, The expansion pressure-bearing sealing agent, at 100 wt%, comprises 15-30 wt% expansion pressure-resistant material, 50-70 wt% rigid particulate material, 0.1-8 wt% fiber material, and 1-12 wt% flexible sealing material. And / or, the thermosetting resin comprises one or more of epoxy resin, phenolic resin, polyetherketone resin, and polyimide resin; And / or, the pore size of the porous structure is 100μm to 320μm, and the porosity of the expansion and compressive strength material is 10% to 25%.

3. The expanding pressure-bearing leak-sealing agent according to claim 1 or 2, characterized in that, The preparation method of the expansion-resistant material includes the following steps: Preparation of the first mixture S1: The thermosetting resin is mixed with the first curing agent to obtain the first mixture; Preparation of the second mixture S2: Mix the second curing agent with water to obtain the second mixture; Preparation of the third mixture S3: Mix the first mixture and the second mixture evenly, add the accelerator and foaming agent, and stir for ≥10 minutes at 60℃~85℃ with the speed adjusted to 700rpm~3000rpm to obtain the third mixture; S4 curing: Curing the third mixture to obtain the expansion and compression resistant material; Preferably, the first curing agent and the second curing agent are the same or different, and each is independently selected from one or more of acid anhydride curing agents, phenolic curing agents, and aromatic polyamine curing agents.

4. The expandable pressure-bearing sealant according to any one of claims 1-3, characterized in that, Based on 100 parts by weight of thermosetting resin, the total amount of the first curing agent and the second curing agent is 50 to 100 parts by weight, the amount of accelerator is 0 to 2 parts by weight, the amount of water is 10 to 50 parts by weight, and the amount of foaming agent is 0.1 to 3 parts by weight.

5. The expanding pressure-bearing leak-sealing agent according to claim 4, characterized in that, In the expansion and compression resistant material, the epoxy resin comprises one or more of glycidyl ether epoxy resin, glycidyl amine epoxy resin, glycidyl ester epoxy resin, imide modified epoxy resin, and phenolic modified epoxy resin. Preferably, the epoxy resin comprises one or more of bisphenol A diglycidyl ether, phenolic epoxy resin, and imide epoxy resin; And / or, the anhydride curing agent comprises one or more of maleic anhydride, alkenyl succinic anhydride, phthalic anhydride, cyclopentadienoic dianhydride, and methyl hexahydrophthalic anhydride; And / or, the accelerator comprises one or more of triethanolamine, dimethylaniline, and 2,4,6-tris(dimethylaminomethyl)phenol; And / or, the water is fresh water or salt water, preferably, the water contains a foam enhancer; More preferably, the foam enhancer comprises one or both of a surfactant or a thickening and shearing agent; the mass content of the foam enhancer is 0.1% to 1% based on the weight of the water; Most preferably, the surfactant-based foam enhancer comprises one or more of polysorbate, sorbitan monooleate, oleyl alcohol polyoxyethylene ether, and dodecyl oleate; And / or, the thickening and cutting agent-type foam reinforcing agent comprises one or more of hydroxyethyl methyl cellulose, polyacrylamide, and sodium carboxymethyl starch; And / or, the foaming agent comprises one or more of anionic foaming agents, cationic foaming agents, and nonionic foaming agents; Preferably, the foaming agent is an anionic foaming agent, and preferably includes one or more of sodium dodecylbenzene sulfonate, fatty alcohol glyceryl ether sulfonate, or α-olefin sulfonate.

6. The expanding pressure-bearing sealant according to any one of claims 1-5, characterized in that, The rigid particulate material includes at least one of vermiculite, quartz, calcite, calcium carbonate, and mica; And / or, the particle size of the rigid particulate material is selected from at least three gradations selected from 1-2 mm, 3-5 mm, 6-10 mesh, 10-20 mesh, 20-40 mesh, 40-80 mesh, 100-150 mesh, 200-400 mesh, and 400-800 mesh.

7. The expandable pressure-bearing sealant according to any one of claims 1-6, characterized in that, The fiber material comprises at least one of aromatic polyamide fiber, polytetrafluoroethylene fiber, polysilicon fiber, glass fiber, polyimide fiber, sepiolite fiber, ceramic fiber, and polyvinyl alcohol fiber; Preferably, the fiber material is a porous mesh fiber; more preferably, the pore size of the porous mesh fiber is 1 mm to 3 mm; the fiber length is selected from at least one of 1 to 3 mm, 3 to 5 mm, 7 to 10 mm, and 12 to 15 mm.

8. The expandable pressure-bearing sealant according to any one of claims 1-7, characterized in that, The flexible sealing material comprises at least one of silicone rubber, polystyrene, asphalt, and silicone-modified acrylate; Preferably, the flexible sealing material comprises at least one of polydisperse polystyrene microspheres, thermoplastic silicone rubber particles, and asphalt powder; And / or, the flexible sealing material is micron-sized particles with a particle size range of 4μm to 100μm.

9. The method for preparing the expansion pressure-bearing sealing agent according to any one of claims 1-8, characterized in that, Includes the following steps: The expansion pressure-resistant material, rigid granular material, fiber material, and flexible sealing material are mixed together to obtain the expansion pressure-bearing leak-sealing agent; Preferably, the stirring rate is 300-1000 r / min; the stirring time is 5-20 min; and the mixing temperature is 10-70℃.

10. A method for sealing leaks using the expandable pressure-bearing leak-sealing agent according to any one of claims 1-8 or the expandable pressure-bearing leak-sealing agent prepared by the preparation method according to claim 9, characterized in that, Includes the following steps: In water-based leak sealing, the leak-sealing agent is added at a temperature of 100-240℃ and a density of 1.2-2.4 g / cm³. 3 In the drilling fluid, the amount of the plugging agent is 10% to 50% (w / v).

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