A degradable soft diverter knot for temporary plugging of blasthole and preparation method thereof

Abstract

The present invention particularly relates to a degradable soft diverter knot for temporary plugging of blastholes and a preparation method thereof, which belongs to the technical field of petroleum extraction. The diverter knot is made by compounding several degradable fibers with different solubility properties and different strengths in a certain proportion and twisting them into rope segments, which are then knotted. The diverter knot can achieve efficient plugging of irregular blastholes, and can be completely degraded within the time range required for fracturing, so as to restore production in time. The diverter knot has the advantages of strong pressure bearing capacity, good plugging performance, controllable degradation, and complete degradation without residue.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum exploitation, and particularly relates to a degradable soft diverter knot for temporary plugging of blastholes and a preparation method thereof. Background Art

[0002] With the depletion of conventional oil and gas resources, low-permeability or ultra-low-permeability unconventional oil and gas resources have gradually become the focus of exploration and development, and hydraulic fracturing and acid fracturing technology are the key means of exploration and development of unconventional reservoirs. However, due to the large span of unconventional reservoirs, such as coalbed methane, tight gas, and shale gas reservoirs, the diversity and complexity of geological structures, and the presence of many carbonate rock reservoirs, there are strong heterogeneity and large differences in formation opening pressure. During the hydraulic fracturing or acid fracturing construction process, it is often encountered that the reservoir transformation working fluid is unevenly distributed, and some perforated layers cannot be fully transformed.

[0003] To solve this problem, mechanical sealing tools, chemical fiber or granular temporary plugging agents and temporary plugging balls have been used on site to seal blastholes.

[0004] Although these technologies have certain applicability, they still expose certain problems: 1) The tool strings required for mechanical isolation technology are complex, and subsequent operations are difficult, making it difficult to simply and efficiently achieve the diversion of the production-increasing working fluid; 2) The temporary plugging strength of fiber and granular temporary plugging agents is insufficient, and it is easy to cause pump blockage or pipe blockage during the pumping process. At the same time, due to their material performance defects, it is difficult to achieve complete degradation, and there is still the possibility of secondary damage; 3) The temporary plugging balls have a high degree of sphericity, and most blastholes are irregular in shape. Therefore, conventional temporary plugging balls cannot completely plug irregular blastholes. At the same time, the degradation performance of temporary plugging ball materials is generally poor, which can easily cause downhole tools to get stuck. Summary of the invention

[0005] The purpose of the present application is to provide a degradable soft diverter knot for temporary plugging of blastholes and a preparation method thereof, so as to solve the problem of poor degradation performance of current temporary plugging agents.

[0006] The embodiment of the present invention provides a degradable soft diverter knot for temporary plugging of a blasthole, wherein the diverter knot comprises a soluble fiber A, and the polymer chemical structure of the soluble fiber A is:

[0007]

[0008] Wherein, x, y, z, m, n and p are all positive integers.

[0009] Optionally, the diverter junction further comprises soluble fiber B, and the polymer chemical structure of the soluble fiber B is:

[0010]

[0011] Wherein, x, y, z, m and p are all positive integers.

[0012] Optionally, the diverter junction further comprises polyester fiber, and the polymer chemical structure of the polyester fiber is:

[0013]

[0014] Wherein, m and n are both positive integers.

[0015] Optionally, the diverter knot includes soluble fiber A, soluble fiber B and polyester fiber; the specification model of the diverter knot is 800D~1200D; the diameter of the diverter knot is preferably 13~18mm; the length of the diverter knot is preferably 50~80mm; in terms of mass, the ratio of the soluble fiber A, soluble fiber B and polyester fiber is 2~4:0.5~6:2~5.

[0016] Based on the same inventive concept, an embodiment of the present invention further provides a method for preparing the above-mentioned degradable soft diverter knot for temporary plugging of blastholes, the method comprising:

[0017] Get soluble fiber A;

[0018] Get soluble fiber B;

[0019] Obtaining polyester fiber;

[0020] The soluble fiber A, the soluble fiber B and the polyester fiber are twisted to obtain a rope segment;

[0021] The rope segment is subjected to a knotting process to obtain a diverter knot.

[0022] Optionally, the step of obtaining soluble fiber A specifically includes:

[0023] acrylamide, acrylic acid, methyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are prepared into a solution to obtain a first mixed solution;

[0024] The first mixed solution is mixed with PEG-400 and a first initiator, and then reacted to obtain soluble fiber A.

[0025] Optionally, the first initiator includes ammonium persulfate and ethylenediamine.

[0026] Optionally, the step of obtaining soluble fiber B specifically includes:

[0027] acrylamide, acrylic acid and vinyl pyrrolidone are prepared into a solution to obtain a second mixed solution;

[0028] The second mixed liquid is mixed with N,N'-methylenebisacrylamide and a second initiator, and then reacted to obtain soluble fiber B.

[0029] Optionally, the second initiator includes ammonium persulfate and sodium bisulfite.

[0030] Optionally, the polyester fiber is obtained, specifically comprising:

[0031] 1,3-propylene glycol, 1,4-succinic acid, terephthalic acid and a solvent are mixed and reacted to obtain polyester;

[0032] The polyester is melted and then mixed with ferric chloride to obtain a first intermediate product;

[0033] The first intermediate product is reacted with paraformaldehyde to obtain polyester fiber.

[0034] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0035] The degradable soft diverter knot for temporary plugging of blastholes provided in the embodiments of the present invention is made of degradable fibers, can be degraded within the required time range of fracturing, can restore production status in time, can achieve efficient plugging of irregular blastholes, and has the advantages of strong pressure bearing capacity, good plugging performance, controllable degradation, and complete degradation without residue.

[0036] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 is a flow chart of a method provided by an embodiment of the present invention;

[0039] Figure 2 is a graph of the expansion rate of the soluble fiber A provided by an embodiment of the present invention at different temperatures;

[0040] Figure 3 is a graph showing the degradation rate of soluble fiber A at different temperatures provided by an embodiment of the present invention;

[0041] Figure 4 is a graph of the expansion rate of the soluble fiber B provided in an embodiment of the present invention at different temperatures;

[0042] Figure 5 is a graph showing the degradation rate of soluble fiber B at different temperatures provided by an embodiment of the present invention;

[0043] Figure 6 is a graph showing the degradation rate of polyester fiber at different temperatures provided by an embodiment of the present invention;

[0044] Figure 7 It is a graph showing the relationship between the degradation rate of the diverter junction provided in Example 1 of the present invention in the slippery water, guar gum system and the thickened acid solution system with an acid concentration of 20% and time;

[0045] Figure 8 is a diagram of the pressure bearing capacity of the shunt junction provided in Example 1 of the present invention;

[0046] Fig. 9 is a graph showing the relationship between the degradation rate of the diverter junction provided in Example 2 of the present invention in the slippery water, guar gum system and the thickened acid solution system with an acid concentration of 20% and time;

[0047] Fig.10 This is a diagram of the pressure bearing capacity of the shunt junction provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0049] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0050] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0051] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0052] According to a typical embodiment of the present invention, a degradable soft diverter knot for temporary plugging of a blasthole is provided, wherein the diverter knot comprises a soluble fiber A, and the polymer chemical structure of the soluble fiber A is:

[0053]

[0054] Wherein, x, y, z, m, n and p are all positive integers.

[0055] In some embodiments, the diverter junction further comprises soluble fiber B, and the polymer chemical structure of the soluble fiber B is:

[0056]

[0057] Wherein, x, y, z, m and p are all positive integers.

[0058] In some embodiments, the diverter junction further comprises polyester fiber, and the polymer chemical structure of the polyester fiber is:

[0059]

[0060] Wherein, m and n are both positive integers.

[0061] It should be noted that x, y, z, m, n and p in each chemical structural formula all represent positive integers, and x, y, z, m, n and p in each chemical structural formula are not related to each other.

[0062] The principle of the temporary plugging of blastholes by the degradable soft diverter knot is as follows: after the diverter knot is pumped into the wellbore, it flows in the direction of least resistance, first along the already opened blasthole layer, embedded in the blasthole, and then the temporary plugging agent absorbs water and expands to completely plug the irregular blasthole, forcing the subsequent fracturing fluid or acid to enter the unconverted reservoir, realizing the transition to acid fracturing or fracturing. At the same time, the flexible blasthole temporary plugging agent is made of degradable fiber, and after the construction is completed, it can be degraded within the required time range of fracturing, and the production state can be restored in time. The high-strength degradable flexible blasthole temporary plugging agent provided by the present invention has the following characteristics: the flexible knot-shaped temporary plugging agent that absorbs water and expands can achieve efficient plugging of irregular blastholes, strong pressure bearing capacity, good plugging performance, controllable degradation, and can be completely degraded without residue.

[0063] According to another typical embodiment of the present invention, a method for preparing the above-mentioned degradable soft diverter knot for temporary plugging of blastholes is provided, the method comprising:

[0064] S1. Obtain soluble fiber A;

[0065] In some embodiments, acrylamide, acrylic acid, methyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are prepared into a solution to obtain a first mixed solution;

[0066] The first mixed solution is mixed with PEG-400 (polyethylene glycol 400) and a first initiator, and then reacted to obtain soluble fiber A.

[0067] In some embodiments, the first initiator includes ammonium persulfate and ethylenediamine.

[0068] In this embodiment, the preparation method of soluble fiber A is as follows: a 30wt% aqueous solution prepared by acrylamide (AM), acrylic acid (AA), methyl methacrylate (MMA), and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) in a molar ratio of 1:2:3:1, 0.06wt% PEG-400 is added, and an initiator concentration of 0.1%-0.15wt% is formed by using ammonium persulfate and ethylenediamine in a molar ratio of 2:1.5, and the reaction temperature is controlled at 45°C and the reaction is carried out for 6 hours. After the reaction is completed, the formed rubber block is dehydrated with ethanol and acetone and then dried to obtain soluble fiber A. In other embodiments, those skilled in the art can prepare soluble fiber A in other ways according to actual conditions.

[0069] S2. Obtain soluble fiber B;

[0070] In some embodiments, soluble fiber B is obtained, specifically comprising:

[0071] acrylamide, acrylic acid and vinyl pyrrolidone are prepared into a solution to obtain a second mixed solution;

[0072] The second mixed liquid is mixed with N,N'-methylenebisacrylamide and a second initiator, and then reacted to obtain soluble fiber B.

[0073] In some embodiments, the second initiator includes ammonium persulfate and sodium bisulfite.

[0074] In this embodiment, the preparation method of soluble fiber B is specifically as follows: a 35wt% aqueous solution is prepared from acrylamide (AM), acrylic acid (AA), and vinylpyrrolidone (VP) in a molar ratio of 2:3:5, and 0.03wt% of the cross-linking monomer N,N'-methylenebisacrylamide (MBA) is added, and ammonium persulfate and sodium bisulfite are used in a molar ratio of 2:1.5 to form an initiator concentration of 0.2wt%, the reaction temperature is controlled at 50°C, the polymerization reaction time is 6 hours, and the rubber block formed after the reaction is completed is dehydrated with ethanol and acetone and then dried to obtain soluble fiber B.

[0075] S3. Obtaining polyester fiber;

[0076] In some embodiments, polyester fibers are obtained, specifically comprising:

[0077] 1,3-propylene glycol, 1,4-succinic acid, terephthalic acid and a solvent are mixed and reacted to obtain polyester;

[0078] The polyester is melted and then mixed with ferric chloride to obtain a first intermediate product;

[0079] The first intermediate product is reacted with paraformaldehyde to obtain polyester fiber.

[0080] In this embodiment, the preparation method of the polyester fiber is specifically as follows: water, 1,3-propylene glycol, 1,4-butanediol, and terephthalic acid are added into a high temperature and high pressure reactor in a molar ratio of 5:22:11:13, and reacted at a pressure of 250, 150 MPa for 4 hours to form polyester, the polyester material is fully melted at 200°C, 7wt% ferric chloride is added, and after 30 minutes, 5wt% of paraformaldehyde (degree of polymerization: 80) is added and reacted for 3 hours.

[0081] S4. The soluble fiber A, the soluble fiber B and the polyester fiber are twisted to obtain a rope segment;

[0082] S5. knotting the rope segment to obtain a diverter knot.

[0083] The expansion rate and degradation rate of the soluble fiber A prepared in the embodiment of the present application were tested at different temperatures. The results are as follows: Figure 2 and Figure 3 shown.

[0084] The test method of expansion rate is to put soluble fiber A into clean water, heat it at a specific temperature, filter it with a funnel after a certain period of time, absorb the residual water on its surface with filter paper, and measure its mass after absorbing liquid. The calculation formula of expansion rate Q is Q = (M2-M1) / M1, where M2 and M1 represent the mass g of soluble fiber A after and before absorbing liquid, respectively.

[0085] like Figure 2 As shown in the figure, it is the expansion rate of soluble fiber A at different temperatures. It can be seen from the figure that soluble fiber A has a faster expansion process in the first 2 hours, and tends to be slow after 2 hours. The temperature has a certain influence on the expansion of soluble fiber A. The higher the temperature, the higher the expansion multiple. At 120°C, soluble fiber A can expand 14 times in 8 hours. Therefore, the high expansion performance of the material is beneficial to the manufactured diverter junction to plug the irregular blasthole structure.

[0086] The test method of degradation rate is to put soluble fiber A with a mass of m1 into clean water, heat it at a specific temperature, filter it with a funnel after a certain period of time, dry it, and weigh the mass m2 of soluble fiber A after drying. The calculation formula of degradation rate N is N = (m1-m2) / m1, where m2 and m1 represent the mass g of soluble fiber A after degradation and before degradation respectively.

[0087] like Figure 3As shown, it is the degradation rate of soluble fiber A at different temperatures. It can be seen from the figure that soluble fiber A is almost completely degraded after 24 hours, which can ensure that the diverter junction is completely degraded after the construction is completed, so that the oil and gas well can resume production capacity.

[0088] The expansion rate and degradation rate of the soluble fiber B prepared in the embodiment of the present application at different temperatures were tested, and the results were as follows: Figure 4 and Figure 5 shown.

[0089] Similarly, the testing method is the same as that for soluble fiber A.

[0090] like Figure 4 As shown in the figure, it is the expansion rate of soluble fiber B at different temperatures. It can be seen from the figure that soluble fiber B has a faster expansion process in the first hour, and the temperature has a certain influence on the expansion of soluble fiber B. The higher the temperature, the higher the expansion multiple. Although the expansion multiple is lower than that of soluble fiber A, it can also meet the requirements of the manufactured diverter knot to seal the irregular blasthole structure.

[0091] like Figure 5 As shown, it is the degradation rate of soluble fiber B at different temperatures. It can be seen from the figure that soluble fiber B is almost completely degraded after 24 hours, which can ensure that the diverter junction is completely degraded after the construction is completed, so that the oil and gas well can resume production capacity.

[0092] The degradation rate of the polyester fiber prepared in the embodiment of the present application at different temperatures was tested, and the results were as follows: Figure 6 shown.

[0093] like Figure 6 As shown, it is the degradation rate of polyester fiber at different temperatures. It can be seen from the figure that the polyester fiber is almost completely degraded after 12 hours, allowing the oil and gas well to quickly restore its production capacity.

[0094] The degradable soft diverter knot for temporary plugging of blastholes and the preparation method thereof of the present application will be described in detail below in combination with embodiments, comparative examples and experimental data.

[0095] Example 1

[0096] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0097] Soluble fiber A, soluble fiber B and polyester fiber with a specification of 800D were selected and made into rope segments with a diameter of 13 mm and a length of 50 mm according to a mass ratio of 2:1:2. The rope segments were knotted with a force of 800 kg to make a degradable soft diversion knot suitable for low temperature environments.

[0098] Example 2

[0099] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0100] Soluble fiber A, soluble fiber B and polyester fiber with a specification of 1000D were selected and made into rope segments with a diameter of 15 mm and a length of 60 mm according to a mass ratio of 3:5:3. The rope segments were knotted with a force of 900 kg to make a degradable soft diversion knot suitable for high temperature environment.

[0101] Example 3

[0102] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0103] Soluble fiber A, soluble fiber B and polyester fiber with a specification of 1200D were selected and made into rope segments with a diameter of 18 mm and a length of 80 mm according to a mass ratio of 4:6:5. The rope segments were knotted with a force of 1000 kg to make a degradable soft diversion knot suitable for high temperature environment.

[0104] Comparative Example 1

[0105] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0106] Soluble fiber A and polyester fiber with a specification of 800D were selected and made into rope segments with a diameter of 13 mm and a length of 50 mm at a mass ratio of 1:1. The rope segments were knotted with a force of 800 kg to make degradable soft diversion knots suitable for low-temperature environments.

[0107] Comparative Example 2

[0108] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0109] Soluble fiber B and polyester fiber with a specification of 800D were selected and made into rope segments with a diameter of 13 mm and a length of 50 mm at a mass ratio of 1:2. The rope segments were knotted with a force of 800 kg to make degradable soft diversion knots suitable for low-temperature environments.

[0110] Comparative Example 3

[0111] A method for preparing a degradable soft diverter junction for temporary plugging of a blasthole, comprising the following steps:

[0112] Soluble fiber A and soluble fiber B were selected with a specification of 800D, and were made into rope segments with a diameter of 13 mm and a length of 50 mm at a mass ratio of 2:1. The rope segments were knotted with a force of 800 kg to make a degradable soft diversion knot suitable for low-temperature environments.

[0113] Experimental example

[0114] The diverter junctions prepared in Example 1 and Comparative Examples 1-3 were tested. The tests included: testing the relationship between the degradation rate of each diverter junction in slippery water and time under low temperature environment (60°C); and testing the pressure bearing capacity of the soft diverter junction under the same conditions. After sealing the simulated blasthole with the soft diverter junction, pressure was applied and the change of pressure over time was recorded. The test results are shown in the following table and Figure 7 , Figure 8 shown.

[0115] Group Degradation rate (%), 12h Degradation rate (%), 24h Pressure bearing time (h) Maximum pressure bearing capacity (MPa) Example 1 77 100 4 35 Comparative Example 1 83 95 3.5 32 Comparative Example 2 89.0 98 3.0 30 Comparative Example 3 61.3 92 4 26

[0116] Figure 7 The figure shows the relationship between the degradation rate of different diverter junctions provided in Example 1 in slippery water and time. Figure 8 The shunt junction provided in Example 1 is shown to test the pressure bearing capacity of different soft shunt junctions under the same conditions.

[0117] From the comparison of experimental data and curves, it can be seen that in terms of degradation rate, Example 1 has a lower degradation rate at 12h, while the degradation rate reaches 100% at 24h, which not only ensures good integrity during the plugging period, but also can be completely degraded after plugging. The degradation rate of the shunt junction also indirectly reflects its pressure bearing performance. Figure 7 and Figure 8 From the comprehensive analysis of the comparison curves, it can be seen that although the polyester component is also present, the dissolution rate of Example 1 within 4 hours is significantly lower than that of Comparative Examples 1-N1 and 1-N2, so Example 1 has the best pressure-bearing time and maximum pressure-bearing capacity; while although the degradation rate of Comparative Example 1-N3 is low, the pressure-bearing capacity is obviously insufficient, which is also largely related to the lack of polyester component.

[0118] It can also be seen from the comparison of the two groups of experiments that the degradation performance and pressure-bearing performance of the degradable soft diverter junction of the present invention are inseparable from the three components. If any component is missing, the performance of the resulting diverter junction will be weakened or even fail to meet the standards. This is exactly what is expected by the molecular design and experimental optimization of the present invention.

[0119] The diverter junction prepared in Example 3 was tested. The test included: testing the relationship between the degradation rate and time in a slippery water system, a guar gum system and a 20% thickened acid solution system under a high temperature environment (120° C.); and testing the pressure bearing capacity of the soft diverter junction under the same conditions. After sealing the simulated blasthole with the soft diverter junction, pressure was applied and the change of pressure over time was recorded. The test results are shown in FIG. Fig. 9 and Fig.10 shown.

[0120] like Fig. 9As shown in FIG. 1 , the degradation rate of the diverter provided in Example 3 in the slick water, guar gum system and 20% acid concentration thickened acid solution system is related to time. It can be seen from the figure that at 120°C, after the diverter prepared in Example 3 was dissolved for 12 hours, the degradation rate was almost 100%, indicating that the material has good degradation performance in several liquids and can be used for temporary plugging of blastholes in construction such as fracturing and acidizing. Fig.10 As shown, the pressure bearing capacity diagram of the diverter provided in Example 3 under the same conditions for testing the soft diverter, from which it can be obtained that the 120°C temperature-resistant diverter prepared in Example 3 can withstand pressure for 4 hours in the slippery water and guar gum system, with a maximum pressure of about 46 MPa, which can fully meet the temporary plugging requirements of long-term fracturing construction, and the diverter can withstand pressure for 3 hours in the 20% thickened acid system, which is also sufficient for acidification construction. The comprehensive performance test of Example 3 also confirms that the degradable soft diverter provided by the present invention has excellent performance, providing an experimental basis for on-site construction.

[0121] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0122] (1) The diverter knot provided in the embodiment of the present invention is prepared by a series of processing techniques using two kinds of flexible, degradable and water-swellable polymer fibers and one kind of high-strength degradable polyester fiber. The flexibility and water-swelling characteristics of the degradable soft diverter knot enable it to effectively block blastholes with irregular shapes and sizes, thereby achieving efficient diversion fracturing or acidizing.

[0123] (2) The diverter knot provided in the embodiment of the present invention is made of degradable fibers, and after the acid fracturing operation is completed, it can be self-degraded in various working fluid systems, thereby removing the blasthole blockage and resuming production;

[0124] (3) The diverter knot provided in the embodiment of the present invention can achieve efficient plugging of irregular blastholes, strong pressure bearing capacity, good plugging performance, controllable degradation, and can be completely degraded without residue.

[0125] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0126] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0127] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A degradable soft diverter knot for temporary plugging of blastholes, characterized in that: The diverter node comprises soluble fiber A, soluble fiber B and polyester fiber, and the ratio of the soluble fiber A, soluble fiber B and polyester fiber is 2-4:0.5-6:2-5 by mass; The preparation method of the degradable soft diverter knot for temporary plugging of blastholes comprises: Get soluble fiber A; Get soluble fiber B; Obtaining polyester fiber; The soluble fiber A, the soluble fiber B and the polyester fiber are twisted to obtain a rope segment; The rope segment is subjected to knotting processing to obtain a diverter knot; The preparation method of the soluble fiber A comprises: acrylamide, acrylic acid, methyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are prepared into a solution to obtain a first mixed solution; The first mixed solution is mixed with PEG-400 and a first initiator, and then reacted to obtain soluble fiber A; The preparation method of the soluble fiber B comprises: acrylamide, acrylic acid and vinyl pyrrolidone are prepared into a solution to obtain a second mixed solution; The second mixed liquid is mixed with N,N'-methylenebisacrylamide and a second initiator, and then reacted to obtain soluble fiber B; The preparation method of the polyester fiber comprises: 1,3-propylene glycol, 1,4-succinic acid, terephthalic acid and a solvent are mixed and reacted to obtain polyester; The polyester is melted and then mixed with ferric chloride to obtain a first intermediate product; The first intermediate product is reacted with paraformaldehyde to obtain polyester fiber.

2. The degradable soft diverter knot for temporary plugging of blastholes according to claim 1 is characterized in that: The first initiator includes ammonium persulfate and ethylenediamine.

3. The degradable soft diverter knot for temporary plugging of blasthole according to claim 1, characterized in that: The second initiator includes ammonium persulfate and sodium bisulfite.

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