High-strength elastic flaky plugging agent and preparation method thereof

Abstract

The invention discloses a high-strength elastic flaky plugging agent. Comprising the following components in parts by weight: 30-40 parts of clear water, 0.03-0.05 part of sodium carbonate, 1-3 parts of soil powder, 0.025-0.075 part of carboxymethyl cellulose, 1-4 parts of single seal, 40-50 parts of saw timber, 1-3 parts of lignin fibers, 1-3 parts of apricot shell powder, 1-3 parts of shell powder, 0.5-1 part of modified phenolic resin particles, 0.25-0.5 part of polyimide resin particles, 0.25-0.5 part of epoxy resin particles, 0.5-1 part of sodium carboxymethyl cellulose and 10-15 parts of cottonseed hulls. The preparation method comprises the following steps: S1, mixing clear water with sodium carbonate to obtain an alkaline aqueous solution; s2, adding carboxymethyl cellulose into an alkaline aqueous solution to form a uniform solution; s3, adding soil powder, stirring, adding saw timber, apricot shell powder and cotton seed hulls, stirring, adding single seal and lignin fibers, stirring, sequentially adding shell powder, a resin material and sodium carboxymethyl cellulose, and stirring and mixing; and S4, tabletting by using a flat tablet press, drying, crushing in a crusher, and screening by using a standard sieve to obtain the flaky plugging agent with different particle sizes.

Description

Technical Field

[0001] This invention relates to the field of drilling plugging agent technology, specifically to a high-strength elastic sheet plugging agent and its preparation method. Background Technology

[0002] Severe leakage is prevalent at the bottom of Liujiagou in Zizhou and Mizhi areas. The strata at the bottom of Liujiagou in Zizhou and Mizhi areas are the main leakage strata in the region. It is characterized by multi-level leakage, complex fracture types, coexistence of primary and induced fractures, and coexistence of longitudinal and transverse fractures. The strata have low bearing capacity and generally have pressure differential leakage problems. At the same time, the strata fractures are well developed, with strong fracture penetration and large capacity space, which greatly increases the difficulty of plugging the leakage.

[0003] Traditional methods of plugging leaks have low success rates, frequent recurrence of leaks, and numerous downhole accidents during the plugging process. This makes it difficult to control drilling fluid costs for single wells, and drilling cycles often exceed the planned construction time, severely impacting the speed and efficiency of well operations in the region. Furthermore, conventional plugging materials such as walnut shells and mica exhibit significant deformation coefficients due to temperature, pressure, and soaking time within the wellbore, easily leading to plugging failures and subsequent repeated leaks. Therefore, improving regional leak prevention and plugging technologies to reduce leakage has become a critical issue that urgently needs to be addressed. The situation is very serious, requiring more innovative and effective solutions to improve overall operational efficiency and safety. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength elastic sheet-like sealing agent and its preparation method, so as to solve the problems mentioned in the background art.

[0005] In a first aspect, the present invention provides a high-strength elastic sheet-like sealant, comprising the following components in parts by weight: 30-40 parts water, 0.03-0.05 parts soda ash, 1-3 parts clay powder, 0.025-0.075 parts carboxymethyl cellulose, 1-4 parts single sealant, 40-50 parts sawdust, 1-3 parts lignin fiber, 1-3 parts apricot shell powder, 1-3 parts shell powder, 0.5-1 part modified phenolic resin particles, 0.25-0.5 parts polyimide resin particles, 0.25-0.5 parts epoxy resin particles, 0.5-1 part sodium carboxymethyl cellulose, and 10-15 parts cottonseed hulls.

[0006] Secondly, the present invention also provides a method for preparing a high-strength elastic sheet-like sealing agent, comprising the following steps:

[0007] S1. Weigh out water, add soda ash, stir at low speed to dissolve, and obtain an alkaline aqueous solution;

[0008] S2. While maintaining low-speed stirring, slowly add carboxymethyl cellulose to the alkaline aqueous solution, then stir at high speed for 10-15 minutes to form a homogeneous solution;

[0009] S3. Maintain a high-speed stirring speed and slowly add the soil powder to the above uniform solution. Stir until there are no lumps, then add sawdust, apricot shell powder, and cottonseed hulls. Continue stirring for 15-20 minutes. Then add monosaccharide and lignin fiber and continue stirring for 5-8 minutes. Adjust the stirring speed to 300-400 rpm, and then add shell powder, modified phenolic resin particles, polyimide resin particles, epoxy resin particles, and sodium carboxymethyl cellulose in sequence. Continue stirring for 8-10 minutes to obtain a mixed slurry.

[0010] S4. Place the mixed slurry into a flat plate press and press it into a sheet-like preform with a thickness of 0.5~1cm. Place the sheet-like preform into a hot air circulating drying oven for drying. Add the dried sheet-like preform into a pulverizer for pulverization. After sieving with a multi-layer standard sieve, obtain sheet-like sealing agents of different particle sizes.

[0011] As a preferred technical solution of the present invention, the method for preparing the modified phenolic resin particles is as follows: phenol is heated to a molten state, and 0.15-0.3% (by weight of phenol) of an alkaline catalyst sodium hydroxide is added. The stirring speed is set to 300-400 rpm, and the mixture is stirred evenly. Then, formaldehyde solution and phenol are slowly added dropwise at a molar ratio of 1:1.5-1.7. The mixture is reacted at 60-80°C for 2-4 hours, and the temperature is raised to 90-100°C. Tung oil (by weight of phenol) is added, and the polycondensation reaction is continued for 1-2 hours to obtain modified phenolic resin. The modified phenolic resin is heated to 120-150°C to melt, and sprayed into a cooling medium of water through a nozzle to form spherical particles. The particles are screened and dried at 60-70°C for 1-2 hours to obtain modified phenolic resin particles.

[0012] As a preferred embodiment of the present invention, the particle size of the sheet-like sealing agent is available in three sizes: 1mm~3mm, 3mm~5mm, and 5mm~8mm.

[0013] As a preferred embodiment of the present invention, the low-speed stirring in S1 is performed at a speed of 300-350 rpm for 5-10 minutes; the high-speed stirring in S2 is performed at a speed of 500-600 rpm.

[0014] As a preferred embodiment of the present invention, the flatbed tablet press is set to a pressure of 8~12MPa and held for 5~10s.

[0015] As a preferred embodiment of the present invention, the drying temperature is 60~70℃, the wind speed is 2~3m / s, the drying time is 4~6 hours, and the surface is turned over every two hours to ensure uniform drying.

[0016] As a preferred embodiment of the present invention, the pulverizer speed is 40~75 rpm.

[0017] As a preferred embodiment of the present invention, the mesh sizes of the multi-layer standard sieve from top to bottom are 8mm, 5mm, 3mm and 1mm respectively.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The preparation method of this invention is simple. By introducing high-strength elastic components, the material can withstand greater pressure and temperature changes. Sawdust, cottonseed hulls and other fibrous components form a three-dimensional fiber network, which improves the tensile strength of the material through physical interweaving, giving the product good elasticity and toughness. Soil powder, carboxymethyl cellulose and other colloidal components enhance the structural strength. Moreover, the natural organic components used, such as sawdust, cottonseed hulls and apricot shell powder, can be slowly degraded in complex geological environments, avoiding the permanent pollution of the formation by traditional synthetic polymer plugging agents. The amount of soda ash used is extremely low, replacing traditional heavy metal catalysts, reducing the content of harmful elements such as lead and cadmium, while having little impact on the pH value of drilling fluid, reducing interference with subsequent drilling processes.

[0020] 2. In this invention, by adding a series of additives, fine-particle rigid material shell powder, resin materials such as modified phenolic resin particles, polyimide resin particles, and epoxy resin particles, and plant fiber additives such as lignin fiber and sodium carboxymethyl cellulose form a multi-dimensional synergistic enhancement effect. Among them, fine-particle rigid shell powder can fill micro-cracks, build a physical sealing foundation, and improve overall rigidity. Modified phenolic resin particles, polyimide resin particles, and epoxy resin particles have both temperature resistance and salt resistance. After curing, they form a dense cross-linked structure, which strengthens the sealing performance and erosion resistance, making it suitable for high-temperature and high-salt strata. Lignin fiber can build a three-dimensional bridging structure, enhance the toughness of the plug, and reduce cracking. Sodium carboxymethyl cellulose can thicken and retain water, prevent material sedimentation and stratification, and improve construction fluidity and stability. This solves the contradiction of traditional plugging agents having high strength but low elasticity or high elasticity but easy breakage, forming a "rigid and flexible" skeleton structure that can maintain a good elastic deformation recovery rate even under high pressure.

[0021] 3. The three particle sizes and sheet-like structure design of this invention can be specifically matched to cracks of different widths. Small-diameter particles fill micro-cracks, medium-diameter particles form bridging supports, and large-diameter particles quickly seal wider leakage channels, achieving graded sealing and step-by-step reinforcement. Compared with single-diameter products, the success rate of leak sealing is significantly improved, and the adaptability of leak sealing is wider. Therefore, the high-strength elastic sheet-like leak sealant of this invention has characteristics such as high temperature resistance, high strength, high elasticity, and irregularity. It can play a good bridging and embedding role in the treatment of large crack leakage, and its good elasticity makes it effective in leak sealing under pressure. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the preparation method of the high-strength elastic sheet-like sealing agent of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] By introducing high-strength elastic components, the material can withstand greater pressure and temperature changes, resolving the contradiction between high strength and high elasticity in traditional plugging agents. Fibrous components such as sawdust and cottonseed hulls form a three-dimensional fiber network, physically interwoven to enhance the material's tensile strength, elasticity, and toughness; colloidal components such as clay powder and carboxymethyl cellulose improve structural strength. These natural organic components (such as sawdust, cottonseed hulls, and apricot shells) can slowly degrade in complex geological environments, thus avoiding permanent formation pollution caused by traditional synthetic polymer plugging agents. The use of soda ash is extremely low, replacing traditional heavy metal catalysts and significantly reducing the content of harmful elements such as lead and cadmium, while having minimal impact on the pH of the drilling fluid, reducing interference with subsequent drilling processes.

[0025] By adding a series of additives, fine-particle rigid materials such as shell powder, resin materials such as modified phenolic resin particles, polyimide resin particles, and epoxy resin particles, along with plant fiber additives such as lignin fiber and sodium carboxymethyl cellulose, form a multi-dimensional synergistic enhancement effect. Among them, fine-particle rigid shell powder can fill micro-cracks, construct a physical sealing foundation, and improve overall rigidity. Modified phenolic resin particles, polyimide resin particles, and epoxy resin particles have both temperature and salt resistance, and form a dense cross-linked structure after curing, which strengthens the sealing performance and erosion resistance, making it suitable for high-temperature and high-salt strata. Lignin fiber can construct a three-dimensional bridging structure, enhance the toughness of the plug, and reduce cracking. Sodium carboxymethyl cellulose can thicken and retain water, prevent material sedimentation and stratification, and improve construction fluidity and stability. This solves the contradiction of traditional plugging agents having high strength but low elasticity or high elasticity but easy breakage, forming a "rigid and flexible" skeleton structure that can maintain a good elastic deformation recovery rate even under high pressure. Thus, through a "rigid-flexible" skeleton structure that combines high strength and high elasticity, the sealant of this invention can effectively solve the problem of uneven performance of traditional sealants, and improve the success rate and stability of sealant application.

[0026] By employing a three-particle-size sheet structure design, this sealant addresses the need for sealing leaks of varying crack widths. Small-diameter particles fill micro-cracks, medium-diameter particles provide bridging support, and large-diameter particles quickly seal wider leakage channels, achieving tiered sealing and progressive reinforcement. This design significantly improves the sealant's adaptability, enabling it to handle more complex leakage environments. Overall, the high-strength, elastic sheet sealant effectively bridges and embeds leaks in large cracks, while its excellent elasticity and high strength ensure superior sealing performance under pressure.

[0027] like Figure 1 As shown, a method for preparing a high-strength elastic sheet-like sealing agent includes the following steps:

[0028] S1. Weigh out water, add soda ash, stir at low speed to dissolve, and obtain an alkaline aqueous solution;

[0029] S2. While maintaining low-speed stirring, slowly add carboxymethyl cellulose to the alkaline aqueous solution, and stir at high speed for 10-15 minutes to form a homogeneous solution;

[0030] S3. Maintain a high-speed stirring speed and slowly add the soil powder to the above uniform solution. Stir until there are no lumps, then add sawdust, apricot shell powder, and cottonseed hulls. Continue stirring for 15-20 minutes to ensure uniform dispersion. Then add monosaccharide and lignin fiber, and stir for 5-8 minutes until uniformly distributed. Then adjust the stirring speed to 300-400 rpm, and then add shell powder, modified phenolic resin particles, polyimide resin particles, epoxy resin particles, and sodium carboxymethyl cellulose in sequence. Continue stirring for 8-10 minutes to obtain a mixed slurry.

[0031] S4. Place the mixed slurry into a flat plate press and press it into a sheet-like preform with a thickness of 0.5~1cm. Place the sheet-like preform into a hot air circulating drying oven for drying. Add the dried sheet-like preform into a pulverizer for pulverization. After sieving with a multi-layer standard sieve, obtain sheet-like sealing agents of different particle sizes.

[0032] All raw materials used in this invention are commercially available.

[0033] Example 1:

[0034] A method for preparing a high-strength elastic sheet-like sealing agent includes the following steps:

[0035] S1. Weigh 30 parts by weight of water, add 0.03 parts by weight of soda ash, stir at low speed (300 rpm) for 5 minutes to dissolve, and obtain an alkaline aqueous solution;

[0036] S2. While maintaining a low stirring speed of 300 rpm, slowly add 0.025 parts by weight of carboxymethyl cellulose to the alkaline aqueous solution, increase the stirring speed to 500 rpm and continue stirring for 10 minutes to form a homogeneous solution;

[0037] S3. Maintaining a speed of 500 rpm, slowly add 1 part by weight of soil powder to the above uniform solution and stir until there are no lumps. Then add 40 parts by weight of sawdust, 1 part by weight of apricot shell powder, and 10 parts by weight of cottonseed hulls. Continue stirring for 15 minutes to ensure uniform dispersion. Then add 1 part by weight of monosaccharide and 1 part by weight of lignin fiber and stir for 5 minutes until uniformly distributed. Adjust the stirring speed to 300 rpm and add 1 part by weight of shell powder, 0.5 parts by weight of modified phenolic resin particles, 0.25 parts by weight of polyimide resin particles, 0.25 parts by weight of epoxy resin particles, and 0.5 parts by weight of sodium carboxymethyl cellulose in sequence. Continue stirring for 8 minutes to obtain a mixed slurry.

[0038] S4. Place the mixed slurry into a flatbed tablet press, set the pressure to 8MPa, hold the pressure for 5 seconds, and press it into a sheet-like preform with a thickness of 1cm. Place the sheet-like preform into a hot air circulating drying oven for drying at a temperature of 60℃, a wind speed of 2 m / s, and a time of 4 hours. Turn the preform over every two hours. Add the dried sheet-like preform to a pulverizer for pulverization at a speed of 40rpm. After sieving using a multi-layer standard sieve (with mesh sizes of 8mm, 5mm, 3mm, and 1mm from top to bottom), obtain sheet-like sealing agents of different particle sizes.

[0039] Example 2:

[0040] A method for preparing a high-strength elastic sheet-like sealing agent includes the following steps:

[0041] S1. Weigh 40 parts by weight of water, add 0.05 parts by weight of soda ash, stir at low speed (350 rpm) for 10 minutes to dissolve, and obtain an alkaline aqueous solution.

[0042] S2. While maintaining a low stirring speed of 350 rpm, slowly add 0.075 parts by weight of carboxymethyl cellulose to the alkaline aqueous solution, increase the stirring speed to 600 rpm and continue stirring for 15 minutes to form a homogeneous solution;

[0043] S3. Maintaining a speed of 600 rpm, slowly add 3 parts by weight of soil powder to the above uniform solution and stir until there are no lumps. Then add 50 parts by weight of sawdust, 3 parts by weight of apricot shell powder, and 15 parts by weight of cottonseed hulls. Continue stirring for 20 minutes to ensure uniform dispersion. Then add 4 parts by weight of monosaccharide and 3 parts by weight of lignin fiber and stir for 8 minutes until uniformly distributed. Adjust the stirring speed to 400 rpm and add 3 parts by weight of shell powder, 1 part by weight of modified phenolic resin particles, 0.5 parts by weight of polyimide resin particles, 0.5 parts by weight of epoxy resin particles, and 1 part by weight of sodium carboxymethyl cellulose in sequence. Continue stirring for 10 minutes to obtain a mixed slurry.

[0044] S4. Place the mixed slurry into a flatbed tablet press, set the pressure to 12MPa, hold the pressure for 10 seconds, and press it into a sheet-like preform with a thickness of 0.5cm. Place the sheet-like preform into a hot air circulating drying oven for drying at a temperature of 70℃, a wind speed of 3m / s, and a time of 6 hours, turning it over every two hours. Add the dried sheet-like preform to a pulverizer for pulverization at a speed of 75rpm. After sieving using a multi-layer standard sieve (with mesh sizes of 8mm, 5mm, 3mm, and 1mm from top to bottom), obtain sheet-like sealing agents of different particle sizes.

[0045] Example 3:

[0046] A method for preparing a high-strength elastic sheet-like sealing agent includes the following steps:

[0047] S1. Weigh 35 parts by weight of water, add 0.04 parts by weight of soda ash, stir at low speed (325 rpm) for 8 minutes to dissolve, and obtain an alkaline aqueous solution.

[0048] S2. While maintaining a low stirring speed of 325 rpm, slowly add 0.05 parts by weight of carboxymethyl cellulose to the alkaline aqueous solution, increase the stirring speed to 550 rpm and continue stirring for 13 minutes to form a homogeneous solution;

[0049] S3. Maintaining a speed of 550 rpm, slowly add 2 parts by weight of soil powder to the above uniform solution and stir until there are no lumps. Then add 45 parts by weight of sawdust, 2 parts by weight of apricot shell powder, and 13 parts by weight of cottonseed hulls. Continue stirring for 18 minutes to ensure uniform dispersion. Then add 2 parts by weight of monosaccharide and 2 parts by weight of lignin fiber and stir for 7 minutes until uniformly distributed. Adjust the stirring speed to 350 rpm and add 2 parts by weight of shell powder, 0.8 parts by weight of modified phenolic resin particles, 0.4 parts by weight of polyimide resin particles, 0.4 parts by weight of epoxy resin particles, and 0.8 parts by weight of sodium carboxymethyl cellulose in sequence. Continue stirring for 9 minutes to obtain a mixed slurry.

[0050] S4. Place the mixed slurry into a flatbed tablet press, set the pressure to 10MPa, hold the pressure for 8 seconds, and press it into a sheet-like preform with a thickness of 0.8cm. Place the sheet-like preform into a hot air circulating drying oven for drying at a temperature of 65℃, an air velocity of 2.5m / s, and a time of 5 hours, turning it over every two hours. Add the dried sheet-like preform to a pulverizer for pulverization at a speed of 55rpm. After sieving using a multi-layer standard sieve (with screen apertures of 8mm, 5mm, 3mm, and 1mm from top to bottom), obtain sheet-like sealing agents of different particle sizes.

[0051] Example 4:

[0052] A method for preparing a high-strength elastic sheet-like sealing agent includes the following steps:

[0053] S1. Weigh 38 parts by weight of water, add 0.04 parts by weight of soda ash, stir at low speed (340 rpm) for 8 minutes to dissolve, and obtain an alkaline aqueous solution;

[0054] S2. While maintaining a low stirring speed of 340 rpm, slowly add 0.07 parts by weight of carboxymethyl cellulose to the alkaline aqueous solution, increase the stirring speed to 580 rpm and continue stirring for 13 minutes to form a homogeneous solution;

[0055] S3. Maintaining a speed of 580 rpm, slowly add 2 parts by weight of soil powder to the above uniform solution and stir until there are no lumps. Then add 48 parts by weight of sawdust, 2 parts by weight of apricot shell powder, and 14 parts by weight of cottonseed hulls. Continue stirring for 18 minutes to ensure uniform dispersion. Then add 3 parts by weight of monosaccharide and 2 parts by weight of lignin fiber and stir for 7 minutes until uniformly distributed. Adjust the stirring speed to 380 rpm and add 2 parts by weight of shell powder, 0.8 parts by weight of modified phenolic resin particles, 0.4 parts by weight of polyimide resin particles, 0.4 parts by weight of epoxy resin particles, and 0.8 parts by weight of sodium carboxymethyl cellulose in sequence. Continue stirring for 9 minutes to obtain a mixed slurry.

[0056] S4. Place the mixed slurry into a flatbed tablet press, set the pressure to 10MPa, hold the pressure for 8 seconds, and press it into a sheet-like preform with a thickness of 0.8cm. Place the sheet-like preform into a hot air circulating drying oven for drying at a temperature of 67℃, an air velocity of 2.8m / s, and a time of 5 hours, turning it over every two hours. Add the dried sheet-like preform to a pulverizer for pulverization at a speed of 70rpm. After sieving using a multi-layer standard sieve (with screen apertures of 8mm, 5mm, 3mm, and 1mm from top to bottom), obtain sheet-like sealing agents of different particle sizes.

[0057] Comparative Example 1:

[0058] The difference from Example 1 is that the additive-modified phenolic resin particles, polyimide resin particles, and epoxy resin particles are removed.

[0059] Comparative Example 2:

[0060] The difference from Example 1 is that the additives lignin fiber and sodium carboxymethyl cellulose are removed.

[0061] The plugging agents produced in Examples 1, 2, 3, and 4, and Comparative Examples 1 and 2 were subjected to relevant performance tests. The pressure bearing capacity, leakage amount, and time to form a sealing layer were tested in 3-5 mm cracks in accordance with SY / T5840-2007 "Indoor Test Method for Bridging and Plugging Materials for Drilling Fluids" at a temperature of 150℃. The test results are shown in Table 1.

[0062] Table 1: Test results of pressure bearing capacity and sealing performance, etc.

[0063]

[0064] As shown in Table 1, the sheet-like sealing agents prepared in Examples 1, 2, 3, and 4 have good performance and can effectively seal 3-5mm cracks. The leakage under 3-5mm cracks is significantly reduced, and the pressure-bearing capacity is high. In contrast, the pressure-bearing capacity of Comparative Examples 1 and 2 is significantly reduced compared to Examples 1, 2, 3, and 4, and the leakage under cracks is also significantly increased. The effect is not as good as that of Examples 1, 2, 3, and 4.

[0065] By introducing high-strength and high-elasticity components, a three-dimensional fiber network formed by interwoven sawdust, cottonseed hulls, and other fibrous materials significantly enhances the material's tensile strength and toughness, making it less prone to breakage under high pressure and maintaining its elastic deformation recovery rate under high stress, ensuring the continuity of the leak-sealing effect. Simultaneously, by employing a sheet-like structure with three different particle sizes, small-diameter particles can fill tiny cracks, medium-diameter particles provide support bridging, and large-diameter particles quickly seal wider leakage channels. This tiered sealing design can precisely match cracks of different widths, avoiding the incomplete or excessive sealing problems that may occur when using materials of a single particle size, thus reducing unnecessary sealing volume. Furthermore, the synergistic effect of resin material additives and plant fiber-based auxiliaries improves the high-temperature and salt resistance of the sealant, enabling it to respond quickly and form an effective seal even under extreme conditions. This ensures that the sealing time can still be effectively controlled even in complex and harsh environments. In summary, the sealant of this invention, through its structural design and ingredient ratio, not only enhances the stability of the sealant under pressure, but also effectively reduces the amount of sealant needed and shortens the sealing time by providing precise sealing, rapid response, and reduced overuse, thereby improving overall construction efficiency.

[0066] Implementation Case 1:

[0067] 8:00-13:30 Drilling proceeded normally, with two sand sinkers. 13:30-19:00 Two reaming holes were drilled. 19:00-20:00 Loss occurred at a depth of 2606 meters, with a loss rate of 30 cubic meters per hour. 6 cubic meters of grout were injected using a single-valve method, but no grout returned. 20:00-23:30 Drilling was pulled out to 1320 meters. A reading was obtained between 2480-2510 meters, with the well being pulled out with some movement. 23:30-3:00 35 cubic meters of plugging agent were prepared according to Example 2, 12 cubic meters were injected, and 1 cubic meter returned. 20 cubic meters were used for shut-in plugging. No pressure was maintained throughout the process. 3:00-7:00 Stop plugging was performed. The fluid level in the wellbore continued to drop. By 4:00, the fluid level was no longer visible. 7:00-8:00 Drilling was pulled out. Preparations were made to run the drill pipe. Total loss for the day: 45 cubic meters, cumulative loss: 508 cubic meters.

[0068] Implementation Case 2:

[0069] 8:00-12:00 Drilling commenced. 12:00-13:00 Site rectification. 13:00-17:00 Drill rod lowered to 1700 meters. 17:00-20:00 16 cubic meters of plugging agent prepared according to Example 1 was injected, 11 cubic meters were squeezed out of the well, pressure was increased to 3.5 MPa, and stabilized at 2.5 MPa after 20 minutes. 20:00-22:00 10 cubic meters were squeezed out of the well, pressure was increased to 4 MPa, and stabilized at 3.5 MPa after 30 minutes. 1 cubic meter was returned to the well upon opening. 22:00-2:00 Pluging slurry was circulated, with normal discharge rate. 2:00-6:00 Drilling commenced. 6:00-8:00 Instrument screw drilling was tested. Total loss for the day: 20 cubic meters; cumulative loss: 528 cubic meters.

[0070] In summary, the preparation method of this invention is simple, and the resulting sheet-like sealing agent has the characteristics of high temperature resistance, high strength, high elasticity, and irregularity. It can play a good bridging and embedding role in the treatment of large crack-type leakage, and its good elasticity can make it effective in sealing leaks under pressure.

[0071] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A high-strength elastic sheet-like sealant, characterized in that, The product comprises the following components in parts by weight: 30-40 parts water, 0.03-0.05 parts soda ash, 1-3 parts clay powder, 0.025-0.075 parts carboxymethyl cellulose, 1-4 parts monosodium glutamate, 40-50 parts sawdust, 1-3 parts lignin fiber, 1-3 parts apricot shell powder, 1-3 parts shell powder, 0.5-1 part modified phenolic resin granules, 0.25-0.5 parts polyimide resin granules, 0.25-0.5 parts epoxy resin granules, 0.5-1 part sodium carboxymethyl cellulose, and 10-15 parts cottonseed hulls.

2. The high-strength elastic sheet-like sealant according to claim 1, characterized in that, The method for preparing the modified phenolic resin particles is as follows: Phenol is heated to a molten state, and 0.15-0.3% (by weight of phenol) of an alkaline catalyst, sodium hydroxide, is added. The stirring speed is set to 300-400 rpm, and the mixture is stirred until homogeneous. Then, formaldehyde solution and phenol are slowly added dropwise at a molar ratio of 1:1.5-1.

7. The mixture is reacted at 60-80°C for 2-4 hours, and then heated to 90-100°C. Tung oil (by weight of phenol) is added, and the polycondensation reaction is continued for 1-2 hours to obtain modified phenolic resin. The modified phenolic resin is heated to 120-150°C to melt, and then sprayed into a cooling medium of water through a nozzle to form spherical particles. The particles are screened and dried at 60-70°C for 1-2 hours to obtain modified phenolic resin particles.

3. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 1, characterized in that, Includes the following steps: S1. Weigh out water, add soda ash, stir at low speed to dissolve, and obtain an alkaline aqueous solution; S2. While maintaining low-speed stirring, slowly add carboxymethyl cellulose to the alkaline aqueous solution, then stir at high speed for 10-15 minutes to form a homogeneous solution; S3. Maintain a high-speed stirring speed and slowly add the soil powder to the above uniform solution. Stir until there are no lumps, then add sawdust, apricot shell powder, and cottonseed hulls. Continue stirring for 15-20 minutes. Then add monosaccharide and lignin fiber and continue stirring for 5-8 minutes. Adjust the stirring speed to 300-400 rpm, and then add shell powder, modified phenolic resin particles, polyimide resin particles, epoxy resin particles, and sodium carboxymethyl cellulose in sequence. Continue stirring for 8-10 minutes to obtain a mixed slurry. S4. Place the mixed slurry into a flat plate press and press it into a sheet-like preform with a thickness of 0.5~1cm. Place the sheet-like preform into a hot air circulating drying oven for drying. Add the dried sheet-like preform into a pulverizer for pulverization. After sieving with a multi-layer standard sieve, obtain sheet-like sealing agents of different particle sizes.

4. The high-strength elastic sheet-like sealant according to claim 1, characterized in that, The sheet-like sealing agent has three particle sizes: 1mm~3mm, 3mm~5mm, and 5mm~8mm.

5. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 3, characterized in that, The low-speed stirring in S1 is performed at a speed of 300-350 rpm for 5-10 minutes; the high-speed stirring in S2 is performed at a speed of 500-600 rpm.

6. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 3, characterized in that, The flatbed tablet press is set to a pressure of 8~12MPa and held for 5~10s.

7. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 3, characterized in that, The drying temperature is 60~70℃, the wind speed is 2~3m / s, and the drying time is 4~6 hours. The surface is turned over every two hours to ensure uniform drying.

8. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 3, characterized in that, The crusher speed is 40~75 rpm.

9. The method for preparing a high-strength elastic sheet-like sealing agent according to claim 3, characterized in that, The multi-layer standard sieve has mesh sizes of 8mm, 5mm, 3mm, and 1mm from top to bottom.

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