Degradable biological material, preparation method and application

Abstract

The invention relates to a degradable biological material as well as a preparation method and application thereof. The degradable biological material comprises a polymeric monomer sodium alginate, large-particle-size water-swelling biological particles, medium-particle-size water-swelling biological particles and small-particle-size water-swelling biological particles. The degradable biological material is combined with the sodium alginate gel and the water-swelling biological particles, and rapid swelling and tight filling of stratum fractures are achieved through the synergistic effect of the sodium alginate gel and the water-swelling biological particles. The water swelling biological particles are fixed by the sodium alginate gel, so that the stability of the plugging layer is enhanced; the water swelling biological particles are used as a framework support, so that the plugging layer has high self-adaptability and pressure bearing capacity, the construction process is simplified, the plugging layer has the advantages of being environmentally friendly and easy to degrade, and a more efficient and more environment-friendly solution is provided for stratum fracture plugging.

Description

Technical Field

[0001] The invention belongs to the technical field of degradable biomaterials for rapid plugging of formation fissures, and in particular relates to a degradable biomaterial, a preparation method and an application thereof. Background Art

[0002] During pipe jacking construction, groundwater flow in faults and fracture zones will wash away the drag-reducing mud, weaken the grouting effect, reduce the pipe jacking rate and increase friction. Traditional plugging methods are ineffective, costly and may cause environmental pollution. Traditional plugging methods are powerless in the face of this challenge and have many defects: they are often not tightly sealed and easily damaged by groundwater flow and mechanical stress, resulting in high and frequent maintenance costs; at the same time, these materials may cause environmental pollution and pose a potential threat to the ecological environment; in addition, traditional methods have poor adaptability and are difficult to flexibly adjust according to complex and changeable geological conditions, with obvious technical limitations; coupled with the difficulty of construction, not only are technical requirements high, but they are also prone to safety hazards. Therefore, there is an urgent need to provide a degradable biomaterial that can quickly plug stratum fissures. Summary of the invention

[0003] In order to overcome the problems existing in the prior art, the present invention provides a degradable biomaterial, a preparation method and an application thereof.

[0004] A degradable biomaterial for rapid plugging of formation fissures, comprising the following components by weight:

[0005] 5% to 20% of polymerized monomer A;

[0006] 0% to 36% large-size water-swollen biogranules;

[0007] 0% to 27% medium-sized water-swollen biogranules;

[0008] 54% to 63% of small-size water-swollen bioparticles;

[0009] Wherein, the polymerizable monomer A is sodium alginate, and its molecular formula is: Where n represents the degree of polymerization, that is, the number of repeating units in the sodium alginate molecule; β indicates that the connection between the sugar rings is 1,4-β-connection, that is, the two sugar rings are connected by a β-bond between C1 and C4.

[0010] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the particle size of the large-size water-swelling biological particles is [12, 13] mm; the particle size of the medium-size water-swelling biological particles is [10, 11] mm; and the particle size of the small-size water-swelling biological particles is [5, 7] mm.

[0011] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the mass ratio of the sodium alginate to all the water-swelling biological particles is 1:19 to 1:4.

[0012] According to the above aspects and any possible implementation, an implementation is further provided, wherein the particle size gradation of the large-size water-swelling biological particles, the medium-size water-swelling biological particles and the small-size water-swelling biological particles is 0-3:0-3:4-10.

[0013] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the particle size gradation of the large-size water-swelling biological particles, the medium-size water-swelling biological particles and the small-size water-swelling biological particles is 0:3:7.

[0014] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the degradable biomaterial forms a gel having a three-dimensional network structure after absorbing water, and the pressure bearing capacity is greater than 3.0 MPa.

[0015] The present invention also provides a method for preparing a degradable biomaterial, the method being used for preparing the degradable biomaterial, comprising the following steps: Step 1. first preparing three water-swollen bioparticles of different particle sizes and a sufficient amount of sodium alginate;

[0016] Step 2. Place water-swelling biological particles of different particle sizes into the container in the order of large, medium and small according to the corresponding particle grading;

[0017] Step 3. After closing the container, shake it at a constant speed for a first set time to evenly disperse the biological particles;

[0018] Step 4. Open the container, stir and add sodium alginate, close the container again after adding, and shake at a constant speed for a second set time to allow the sodium alginate to be evenly adsorbed on the biological particles;

[0019] Step 5. After taking out, seal and store, thus obtaining a degradable biomaterial for rapid plugging of formation fissures.

[0020] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the first set time is 15 minutes and the second set time is 10 minutes.

[0021] According to the above aspects and any possible implementation, an implementation is further provided, wherein the prepared biological particles rapidly expand and plug the leaking formation after entering the cracks of the water-bearing formation, and after plugging, the biological particles rot and degrade to produce Escherichia coli, and under the action of Escherichia coli, the sodium alginate reacts with water and degrades, and the reaction formula is (C6H7O6Na) n+H2O→CO2+NaOH+HPO3, where n represents the degree of polymerization, that is, the number of repeating units in the sodium alginate molecule.

[0022] The invention provides an application of a degradable biomaterial in rapid plugging of formation fissures.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The degradable biomaterial of the present invention comprises sodium alginate polymer monomers of different components and water-swelling biological particles of different particle sizes. Compared with the traditional method, the plugging mechanism of the degradable biomaterial for temporary plugging of formation fissures of the present invention is significantly different. The traditional method relies on chemical grouting solidification, physical barriers or structural reinforcement, while the present invention combines sodium alginate gel and water-swelling biological particles to achieve rapid expansion and tight filling of formation fissures through the synergistic effect of the two. The sodium alginate gel fixes the water-swelling biological particles to enhance the stability of the plugging layer; the water-swelling biological particles serve as a skeleton support, so that the plugging layer has high adaptability and pressure bearing capacity, which not only simplifies the construction process, but also has the advantages of being environmentally friendly and easy to degrade, providing a more efficient and environmentally friendly solution for plugging formation fissures. Sodium alginate has the advantage of being able to quickly form a gel with a three-dimensional network structure, and form a composite material with high stability and high adhesion with the water-swelling biological particles. The biomaterial proposed in the present invention expands rapidly after absorbing water, tightly filling the formation cracks, and can form an efficient rapid plugging layer with a pressure bearing capacity of 3.0MPa, which meets the pressure bearing requirements of pipe jacking construction. As a natural biomaterial, the water-swelling bioparticles are relatively cheap and environmentally friendly. In some rapid plugging requirements, the use of water-swelling bioparticles will not cause long-term pollution problems to the environment, and is easy to clean and degrade. Therefore, it is feasible to use water-swelling bioparticles as biomaterials to plug broken zones and faults. It has the following significant advantages:

[0025] (1). Highly efficient and rapid plugging performance. Compared with traditional methods, the plugging mechanism of the degradable biomaterials for temporary plugging of formation fissures in the present invention is significantly different. Traditional methods rely on chemical grouting solidification, physical barriers or structural reinforcement, while the present invention innovatively combines sodium alginate gel and water-swelling biological particles to achieve rapid expansion and tight filling of formation fissures through the synergistic effect of the two. Sodium alginate gel fixes the water-swelling biological particles to enhance the stability of the plugging layer; the water-swelling biological particles serve as a skeleton support, giving the plugging layer high adaptability and pressure-bearing capacity, and its pressure-bearing capacity can reach more than 3.0MPa, effectively solving the problems of mud loss and reduced jacking rate caused by formation fissures during pipe jacking construction.

[0026] (2) Environmental protection and sustainability. The degradable biomaterial of the present invention is a natural bio-based material, which is non-toxic and harmless and easily degraded. The water-swollen bioparticles swell and rot and breed microorganisms such as Escherichia coli. Sodium alginate dissolves in water to form a gel substance that is decomposed by microorganisms such as Escherichia coli, which is environmentally friendly and pollution-free.

[0027] (3) Significant economic benefits. Compared with traditional plugging materials, the biodegradable biomaterials of the present invention have a great cost advantage. Water-swelling bioparticles are widely available and inexpensive. The preparation and construction process of the materials are simple and do not require special equipment and technology, which helps to reduce the overall cost of the project.

[0028] (4) Wide applicability. The degradable biomaterial of the present invention is not only suitable for plugging stratum fissures in pipe jacking construction, but can also be widely used in other occasions that require rapid plugging of stratum fissures, such as tunnel construction, groundwater engineering, etc., and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of plugging leakage of formation cracks in pipe jacking construction of the present invention;

[0030] Figure 2 It is a schematic diagram of the whole process of expansion plugging and degradation of the degradable biomaterial of the present invention;

[0031] Figure 3 It is a stratum fissure plugging and conveying system for pipe jacking construction of the present invention;

[0032] Figure 4 It is a schematic diagram of the gas-solid separation equipment of the present invention;

[0033] Figure 5 It is a schematic diagram of the interior of the top pipe wall of the present invention. DETAILED DESCRIPTION

[0034] In order to better understand the technical solution of the present invention, the content of the present invention includes but is not limited to the specific implementation methods described below, and similar technologies and methods should be considered to be within the scope of protection of the present invention. In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] It should be clear that the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0037] The present invention provides a degradable biomaterial for rapid plugging of formation fissures, which comprises the following components by weight:

[0038] 5% to 20% of polymerized monomer A, as the main gel-forming substance, can ensure the rapid formation of a stable three-dimensional network structure gel within this range. At a lower concentration, the gel formation speed is moderate, which is convenient for construction operation; at a higher concentration, the gel strength increases, improving the stability and pressure bearing capacity of the plugging layer. This range is selected to balance the gel formation speed, strength and construction convenience, ensuring the plugging effect while optimizing the construction efficiency.

[0039] 0% to 36% of large-size water-swelling biological particles. Large-size particles serve as the skeleton support of the plugging layer, which can significantly improve the pressure-bearing capacity and stability of the plugging layer. Its large volume can effectively fill large cracks in the formation, while providing attachment points for the gel to enhance the firmness of the overall structure. Adjusting the content within this range can be flexibly adjusted according to the actual crack size and plugging requirements to achieve the best plugging effect and pressure-bearing performance;

[0040] 0% to 27% of medium-sized water-swelling bioparticles. The medium-sized particles act as a transition layer, filling the gaps between large-sized particles and working in synergy with small-sized particles to form a denser and more uniform plugging layer. They enhance the adaptability and sealing of the plugging layer and reduce the risk of leakage;

[0041] 54% to 63% of small-size water-swelling biological particles. Small-size particles are the most delicate part of the plugging layer. They can penetrate into the tiny space of the formation cracks to achieve tight filling, further improving the sealing and pressure-bearing capacity of the plugging layer. The high proportion of its use ensures comprehensive coverage of the plugging layer and efficient plugging;

[0042] Wherein, the polymerizable monomer A is sodium alginate, and its molecular formula is: Where n represents the degree of polymerization, that is, the number of repeating units in the sodium alginate molecule; β represents that the connection between the sugar rings is 1,4-β-connection, that is, the two sugar rings are connected by the β-bond between C1 and C4. Sodium alginate contains a large number of -COO- groups, which can show polyanionic behavior in aqueous solution and has a certain degree of adhesion. This adhesion enables the sodium alginate gel to adhere tightly to the wall of the formation fracture, enhancing the stability of the plugging layer.

[0043] The water-swelling biological particles are preferably made of soybeans. Specifically, the large-diameter water-swelling biological particles are soybeans with a particle size of [12, 13] mm; the medium-diameter water-swelling biological particles are soybeans with a particle size of [10, 11] mm; and the small-diameter water-swelling biological particles are soybeans with a particle size of [5, 7] mm. Water-swelling biological particles (soybeans) of different particle sizes each play an important role in the material. Large-diameter ([12, 13] mm) particles enhance the stability of the structure by providing strong support and slowing down the expansion rate; medium-diameter ([10, 11] mm) particles optimize the pore distribution and balance the expansion performance, ensuring that the material will not rupture due to excessive expansion while maintaining efficient water absorption; small-diameter ([5, 7] mm) particles further improve the density and overall strength of the material by increasing the water absorption rate and filling tiny pores. The reasonable combination of these particle sizes jointly optimizes the material performance. Preferably, the particle size of the large-diameter water-swelling biological particles is 12.59mm The particle size of the medium-sized water-swollen biological particles is 10.22mm The particle size of the small-size water-swollen biological particles is 6.44mm

[0044] The mass ratio of sodium alginate to water-swelling biological particles is 1:19 to 1:4, and the preferred mass ratio is 1:9, which finds a good balance between performance and cost. At this ratio, sodium alginate is sufficient to form a stable gel network to fix the water-swelling biological particles and enhance the stability of the plugging layer; at the same time, the content of the water-swelling biological particles is relatively high, which can provide sufficient filling and support, thus ensuring the plugging effect and controlling the material cost.

[0045] When the particles are of a single size, the packing density is usually low because large gaps are formed between the particles. In this case, the packing density is affected by factors such as particle shape and surface roughness. When three particles of different sizes are mixed, small particles can fill the gaps between large particles, thereby increasing the overall packing density. This effect is called the "filling effect", which makes the density of the mixed packing higher than that of a single particle size. There is an optimal particle size ratio that maximizes the packing density. This ratio depends on the shape, size distribution and packing conditions of the particles.

[0046] The preferred ratios of the water-swelling bioparticles of different particle sizes are 3:0:7, 0:3:7, 4:0:6, 3:1:6, and 2:2:6, and the most preferred bioparticle grading is 0:3:7. In the grading of 0:3:7, large-size particles are removed, and the ratio of medium-size particles to small-size particles is carefully optimized to maximize the filling effect. With medium-size particles as the skeleton, small-size particles fill the pores to form an extremely dense plugging layer. This grading reduces the complexity of particle types and simplifies the construction process.

[0047] As a disclosed embodiment of the present invention, the present invention provides a method for preparing a degradable biomaterial suitable for rapid plugging of formation fissures, comprising the following steps:

[0048] Step 1: Prepare three water-swellable bioparticles of different particle sizes and sufficient amount of sodium alginate;

[0049] Step 2: Put water-swollen biological particles of different particle sizes into the container in the order of large, medium and small according to the corresponding most preferred particle size distribution;

[0050] Step 3: After the container is sealed, the container is placed in a shaker for shaking to promote the dispersion of water-swollen biological particles of different particle sizes in the container until the water-swollen biological particles are evenly dispersed, and the shaking is stopped;

[0051] Step 4: Open the container and slowly add sodium alginate while stirring. After adding, close the container again and put the container into the shaker for shaking to allow the sodium alginate molecules to fully interact with the surface of the water-swollen biological particles to ensure that the sodium alginate is evenly adsorbed on the water-swollen biological particles. Stop shaking after a stable adsorption layer is formed.

[0052] Step 5: Take out the mixture in the container and seal it for storage, and you can get a degradable biomaterial suitable for rapid plugging of formation fissures.

[0053] The prepared degradable biomaterial can form a gel with a three-dimensional network structure after absorbing water, and cooperate with the water-swollen bioparticles to quickly block the water flow and form a stable blocking layer with a pressure bearing capacity of more than 3.0 MPa.

[0054] The degradable biomaterial obtained by the above preparation method belongs to natural bio-based materials, which are non-toxic, harmless and easy to degrade. After the degradable biomaterial enters the cracks of the water-bearing stratum, it expands and seals the stratum. After the construction is completed, the water-swollen biological particles rot and breed microorganisms such as Escherichia coli, while the sodium alginate therein dissolves in water to form a gel substance that is decomposed by microorganisms such as Escherichia coli. The reaction formula is (C6H7O6Na) n +H2O→CO2+NaOH+HPO3, where (C6H7O6Na) n is the molecular formula of sodium alginate, n represents the degree of polymerization, which means the chain length of sodium alginate molecule, ranging from several hundred to several thousand. Therefore, the use of degradable biomaterials for leak plugging is in line with the concept of green building and sustainable development.

[0055] Compared with traditional methods, the plugging mechanism of the degradable biomaterials for temporary plugging of formation fissures in the present invention is significantly different. Traditional methods rely on chemical grouting solidification, physical barriers or structural reinforcement, while the present invention combines sodium alginate gel with water-swelling biological particles to achieve rapid expansion and tight filling of formation fissures through the synergistic effect of the two. Sodium alginate gel fixes the water-swelling biological particles to enhance the stability of the plugging layer; the water-swelling biological particles serve as a skeleton support, giving the plugging layer high adaptability and pressure-bearing capacity. This method not only simplifies the construction process, but also has the advantages of being environmentally friendly and easy to degrade, providing a more efficient and environmentally friendly solution for plugging formation fissures.

[0056] As an embodiment disclosed in the present invention, the present invention provides an application of a degradable biomaterial in rapid plugging of formation fissures. The present invention is further described in detail below in conjunction with the accompanying drawings.

[0057] like Figure 1 The figure shows the situation of plugging formation cracks during pipe jacking construction. During the process of pipe jacking, the pipe jacking head 3 enters the formation fracture zone under the jacking of the hydraulic jack 9. At this time, the drag reduction mud is seriously lost and the jacking force is increased. The biomaterial particle plugging operation is started. The degradable biomaterial particles are transported to the gas-solid separation equipment 4 through the plugging conveying system 1 and the conveying pipeline 2. The designated area is plugged by the equipment to reduce the pipeline air pressure and the movement speed of the plugging biomaterial particles. The biomaterial particles in the gas-solid separation equipment 4 are transported to the formation through the grouting port 5 reserved by the grouting pipeline 10 on the pipe wall 12 of the pipe jacking. The biomaterial particles 6 are brought into the formation cracks by the flow of formation water. After entering the cracks, the biomaterial particles quickly absorb water and expand to form a formation plugging structure 7, thereby plugging the formation cracks.

[0058] like Figure 2 The figure shows the whole process of swelling plugging and degradation of degradable biomaterials, wherein after the degradable biomaterial particles 13 enter the formation fissures, the sodium alginate powder 14 attached to the surface of the water-swelling biological particles 13 quickly dissolves in water to form a gel 15 with a three-dimensional network structure, and the water-swelling biological particles 13 continue to absorb water and swell in the gel structure to squeeze the formation to plug the fissures. After a certain period of time, the water-swelling organisms rot and degrade to produce a microbial decomposition gel structure 16, until the plugging structure is completely degraded and the formation recovers.

[0059] like Figure 3The figure shows a conveying system for plugging formation fissures in pipe jacking construction, in which pre-configured degradable biomaterial particles are stored in a biomaterial particle storage tank 109 through a feed port 108. Before the operation begins, the normal functions of all sensors and pressure gauges should be checked, the initial mass of the storage tank 109 should be recorded using a mass sensor 105, and the solid particle conveying hose 114 should be connected to a preset grouting port 5 on the pipe wall of the pipe jacking. After the operation begins, the air pressure pump 101 and valve 104 are turned on, and the air flow closing pipeline is sent into the biomaterial particle storage tank 109, and the granular biomaterial is pressed into the conveying pipeline. When the biomaterial can enter the conveying pipeline by itself, valve 104 is closed, and valves 110 and 111 are opened to blow and convey the granular biomaterial through the pipeline airflow. When the material reaches the designated plugging area, the particles enter the gas-solid separation device 4, and the air pressure regulating valve 2 112 is opened to reduce the air pressure in the pipeline to prevent the granular biomaterial from being conveyed too fast. The biomaterial particles are injected through two solid particle conveying hoses, and the biomaterial particles enter the cracks with the formation water. The output pressure of the air pressure pump is monitored by the pressure gauge 102, and the pressure gauge 107 monitors the internal pressure of the storage box. If the pressure in the box is abnormal, the air pressure regulating valve 106 is opened to adjust the air pressure. The pressure gauge 113 monitors the injection pressure of the grouting port. The pressure gauge connects the gauge head to the pipeline through the flange. After the operation is completed, the air pressure pump is stopped first, and then the relevant valves are closed, and the final quality of the storage box is recorded. All pressure gauges and sensors are transmitted to the data processing terminal 115 through the data network to achieve real-time monitoring. If abnormal data is found, construction should be stopped in time and the problem should be checked. This method effectively implements the rapid plugging of stratum fissures and ensures construction safety and efficiency.

[0060] like Figure 4 Shown Figure 3 The internal situation of the gas-solid separation device 4 in the figure, the biological material particles 6 enter the gas-solid separation device through the conveying pipeline along the gas-solid mixture entry direction 401, the gas follows the air flow pressure relief direction 402, and the gas is released after the air pressure regulating valve 112 is opened, thereby reducing the air pressure in the gas-solid separation device 4 and the movement speed of the biological particles. At the same time, a screen 403 with a pore size of 2 mm is provided in the gas-solid separation device 4 to separate gas and solid.

[0061] like Figure 5 The figure shows the internal structure of the top pipe wall. The grouting pipe 10 is arranged inside the top pipe wall 12, and a reserved grouting port 5 is provided on it. The granular biomaterial can pass through the top pipe wall 12 into the formation rock mass 11 through the reserved grouting port 5 to perform flexible grouting and plugging operations.

[0062] The plugging process in the above application process is simple, does not require complicated pretreatment, has a fast construction process, and is easy to promote and apply.

[0063] The present invention is further illustrated below by specific preparation examples and performance tests.

[0064] Example 1

[0065] The most preferred biological particle grading is selected as large: medium: small 0:3:7, and the optimal ratio of sodium alginate to biological particles is 1:9. Weigh 20g of sodium alginate; 0g of large-size water-swelling biological particles; 54g of medium-size water-swelling biological particles; and 126g of small-size water-swelling biological particles, and prepare the leak-proof biological material according to the following steps.

[0066] Step 1: Prepare three water-swellable bioparticles of different sizes and sufficient amount of sodium alginate;

[0067] Step 2: Put water-swollen biological particles of different particle sizes into the container in the order of large, medium and small according to the corresponding most preferred particle size distribution;

[0068] Step 3: After closing the container, shake it at a constant speed for 15 minutes until the biological particles are evenly dispersed;

[0069] Step 4: Open the container and slowly add sodium alginate while stirring. After adding, close the container again; shake at a constant speed for 10 minutes to ensure that the sodium alginate is evenly adsorbed on the biological particles, and a degradable biomaterial suitable for rapid plugging of formation fissures can be obtained.

[0070] Example 2

[0071] Weigh 20 g of sodium alginate, 54 g of large-size water-swelling bioparticles, 0 g of medium-size water-swelling bioparticles, and 126 g of small-size water-swelling bioparticles, and prepare the leak-proof biomaterial according to the above steps. A higher proportion of large-size water-swelling bioparticles (54 g) and a lower proportion of small-size water-swelling bioparticles (126 g) were selected in the secondary ratio, while the sodium alginate content remained unchanged (20 g). In this case, the influence of large-size particles on the material properties is shown, especially its ability to serve as a skeleton support and its possible influence on the expansion rate and pressure bearing capacity.

[0072] Example 3

[0073] Weigh 20 g of sodium alginate, 72 g of large-size water-swelling bioparticles, 0 g of medium-size water-swelling bioparticles, and 108 g of small-size water-swelling bioparticles, and prepare the leak-proof biomaterial according to the above steps. This ratio shows that when there are too many large-size particles, the generated material can still maintain good expansion and pressure-bearing capacity.

[0074] Example 4

[0075] Weigh 20 g of sodium alginate, 54 g of large-size water-swelling bioparticles, 18 g of medium-size water-swelling bioparticles, and 108 g of small-size water-swelling bioparticles, and prepare plugging biomaterials according to the above steps. This ratio shows the role of medium-size particles in filling the gaps between large-size particles and improving the density of the plugging layer.

[0076] Example 5

[0077] Weigh 20 g of sodium alginate, 36 g of large-size water-swelling bioparticles, 36 g of medium-size water-swelling bioparticles, and 108 g of small-size water-swelling bioparticles, and prepare plugging biomaterials according to the above steps. This ratio uses equal proportions of large-size and medium-size water-swelling bioparticles to demonstrate the interaction between particles of different sizes and their comprehensive impact on material properties.

[0078] Example 6

[0079] Weigh sodium alginate: 0g; large-size water-swelling biological particles: 0g; medium-size water-swelling biological particles: 54g; small-size water-swelling biological particles: 126g, and prepare plugging biomaterials according to the above steps. This ratio removes sodium alginate and uses the same biological particle size ratio as in Example 1 to demonstrate the key role of sodium alginate in forming gel and enhancing the stability of the plugging layer.

[0080] The following tests are conducted to evaluate the product performance of the degradable biomaterial for rapid plugging of formation fissures in the above-mentioned embodiments.

[0081] Room temperature water absorption performance test: Example: According to the respective sodium alginate and water-swelling biological particles, the particle size ratio is configured, and 200 cm 3 The weight change of each sample was measured after being immersed in clean water for 24 hours at room temperature (26°C). The weight change is shown in Table 1.

[0082] Table 1 Water absorption of samples prepared in all embodiments at room temperature

[0083]

[0084]

[0085] As can be seen from Table 1, the water absorption rates of the six ratios of degradable biomaterials are between 110% and 135%. Example 1 uses a designed particle size distribution and a combination of 30% medium-sized and 70% small-sized water-swollen bioparticles, which significantly optimizes the internal structure of the particles, increases the number of micropores and microcracks, and provides more penetration channels for water. This unique design enables Example 1 to exhibit the highest water absorption rate compared to Examples 2-6, reaching 134.8%, which is significantly better than the other groups, fully demonstrating its superior water absorption performance. After removing sodium alginate, the water absorption of Example 6 decreased significantly, which is mainly due to the weakening of the synergistic effect between sodium alginate and water-swollen bioparticles.

[0086] Changes in volume expansion rate at room temperature: The above examples are configured according to the respective sodium alginate and water-swelling biological particles, and 30 cm 3 The sample of volume was put into clean water and then placed in a constant temperature box for 6h, 12h, 18h and 24h. The volume change of the sample under 26℃ was measured. The changes of the test volume expansion rate and expansion rate are shown in Table 2.

[0087] Table 2 Expansion ratio and expansion rate of the sample prepared in all embodiments at room temperature

[0088]

[0089]

[0090] It can be seen from Table 2 that the change trend of the degradable biomaterial is mainly divided into three stages: the initial expansion period (0-6h), the intermediate transition period (6-12h), and the final stagnation period (12-24h). In the initial expansion period, Example 1 exhibited an extremely fast expansion rate, achieving a high expansion rate of 76.67% within 6 hours. This excellent performance shows that the formula or structural design adopted in Example 1 greatly promotes the rapid penetration and absorption of water, allowing the material to reach a higher expansion state in a short time. This fast-response expansion characteristic is extremely beneficial for application scenarios that require rapid water absorption and expansion to function. Therefore, Example 1 shows significant advantages and potential in rapid water absorption and expansion.

[0091] Test of water permeability under pressure at room temperature: The above embodiments are configured according to the respective particle size ratios of sodium alginate and water-swelling biological particles. 200 g of water-swelling biological particle samples with different ratios are taken and put into the variable pressure simulation plugging device. Sufficient clean water is injected to soak for 24 hours. The valve of the variable pressure simulation plugging device is opened to discharge excess clean water. The valve is closed to adjust the valve of the nitrogen bottle to slowly increase the pressure in the kettle of the plugging device to 3 MPa. After stabilizing the pressure for 10 minutes, 200 ml of clean water is injected into it. The pressurization cycle is repeated twice, and the leakage amount is recorded.

[0092] Table 3 Water permeability of samples prepared in all examples at room temperature

[0093]

[0094] As can be seen from Table 3, the degradable biomaterial of Example 1 can effectively block flowing water, with a pressure bearing capacity of more than 3.0Mpa, and has the characteristics of continuous expansion and delayed expansion performance, which can achieve that under the action of formation water flow, the material can gradually expand and reach the formation fissures, achieving a more accurate and lasting plugging effect. Compared with Example 2, Example 3, Example 4, and Example 5, Example 1 achieves the optimal particle size ratio by preferably mixing water-swelling bioparticles of different particle sizes (large-size water-swelling bioparticles, medium-size water-swelling bioparticles, and small-size water-swelling bioparticles). Compared with Example 6, Example 1 combines sodium alginate and water-swelling bioparticles, and the three-dimensional network structure gel formed after sodium alginate is dissolved in water can quickly block water flow, while the water-swelling bioparticles serve as the skeleton structure of the gel, providing a strong support force, significantly enhancing the material's pressure resistance and water plugging performance.

[0095] Degradability test: The above-mentioned Example 1 and each example are prepared according to their respective sodium alginate and water-swollen bioparticle size ratios, and 200g of the water-swollen bioparticle sample mass (m0) of different ratios is placed in a beaker (mass m1), and sufficient water is added, and placed in a constant temperature and humidity chamber, with the temperature controlled at 26°C and the humidity controlled at 99%. On the 7th day, the morphology was observed, and its mass m2 was weighed, and its degradation rate was calculated, degradation rate (%) = (m2-m1-m0) / m0 Table 4 Degradation rate of samples prepared in all examples at room temperature

[0096]

[0097] As can be seen from the above table, the degradable biomaterial prepared in Example 1 of the present invention has better degradability than Examples 1 and 2-6. The water-swollen biological granular soybean used in the present invention is the skeleton part of the gel formed after sodium alginate is dissolved in water. Although the gel is formed by connecting β-D-mannuronic acid and α-L-guluronic acid by (1→4) bonds, this structure makes sodium alginate have good stability and is not easy to degrade naturally. Moreover, the water-swollen biological granular soybean as its skeleton is easily moldy and rancid after being soaked in water, and is contaminated and decomposed by microorganisms, resulting in the destruction of the gel structure, reducing its pressure bearing performance, and being washed away by the flowing water in the stratum fissures, restoring its original appearance, so that the degradable biomaterial achieves the purpose of degradability.

[0098] Therefore, the degradable biomaterial for rapid plugging of formation fissures of the present invention utilizes the characteristics of sodium alginate and water-swelling biological particles that absorb water and swell. Sodium alginate quickly forms a gel with a three-dimensional network structure, and forms a composite material with high stability and high adhesion with the water-swelling biological particles. The degradable biomaterial rapidly swells after absorbing water, tightly fills the formation fissures, and can form an efficient rapid plugging layer with a pressure bearing capacity of 3.0MPa, which meets the pressure bearing requirements of pipe jacking construction plugging. The degradable water-swelling biological particles are a natural biomaterial that is relatively cheap and environmentally friendly. In some rapid plugging requirements, the above embodiments show that the use of water-swelling biological particles will not cause long-term pollution problems to the environment, and are easy to clean and degrade. Therefore, it is feasible to use water-swelling biological particles as biomaterials to plug broken zones and faults.

[0099] The degradable biomaterial prepared by the method of the present invention is used as a plugging layer like natural biomaterials. It is not only relatively cheap and environmentally friendly, but its use will not cause long-term pollution problems to the environment. In the demand for rapid plugging, this material is easy to clean and degrade, which greatly reduces the environmental burden after construction. Compared with traditional plugging methods, the degradable biomaterial of the present invention significantly improves environmental protection performance while maintaining an efficient plugging effect, reduces construction costs and maintenance difficulties, and demonstrates a high feasibility of plugging broken zones and faults.

[0100] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not depart from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A degradable biomaterial for rapid plugging of formation fissures, characterized in that: The components include the following by weight: 5% to 20% of polymerized monomer A; 0% to 36% large-size water-swollen biogranules; 0% to 27% medium-sized water-swollen biogranules; 54% to 63% of small-size water-swollen bioparticles; Wherein, the polymerizable monomer A is sodium alginate, and its molecular formula is: Where n represents the degree of polymerization, that is, the number of repeating units in the sodium alginate molecule; β indicates that the connection between the sugar rings is 1-4-β-connection, that is, the two sugar rings are connected by a β-bond between C1 and C4.

2. The degradable biomaterial according to claim 1, characterized in that: The particle size of the large-size water-swelling biological particles is [12, 13] mm; the particle size of the medium-size water-swelling biological particles is [10, 11] mm; and the particle size of the small-size water-swelling biological particles is [5, 7] mm.

3. The degradable biomaterial according to claim 1 or 2, characterized in that: The mass ratio of the sodium alginate to all the water-swelling biological particles is 1:19 to 1:

4.

4. The degradable biomaterial according to claim 2, characterized in that: The particle size distribution of the large-size water-swelling biological particles, the medium-size water-swelling biological particles and the small-size water-swelling biological particles is 0-3:0-3:4-10.

5. The degradable biomaterial according to claim 4, characterized in that: The particle size distribution of the large-size water-swelling biological particles, the medium-size water-swelling biological particles and the small-size water-swelling biological particles is 0:3:

7.

6. The degradable biomaterial according to claim 1, characterized in that: The degradable biomaterial forms a gel with a three-dimensional network structure after absorbing water, and the pressure bearing capacity is greater than 3.0 MPa.

7. A method for preparing a degradable biomaterial, characterized in that: The method is used to prepare the degradable biomaterial according to any one of claims 1 to 6, comprising the following steps: Step 1. Firstly, prepare three water-swollen bioparticles with different particle sizes and a sufficient amount of sodium alginate; Step 2. Place water-swelling biological particles of different particle sizes into the container in the order of large, medium and small according to the corresponding particle grading; Step 3. After closing the container, shake it at a constant speed for a first set time to evenly disperse the biological particles; Step 4. Open the container, stir and add sodium alginate, close the container again after adding, and shake at a constant speed for a second set time to allow the sodium alginate to be evenly adsorbed on the biological particles; Step 5. After taking out, seal and store, thus obtaining a degradable biomaterial for rapid plugging of formation fissures.

8. The preparation method according to claim 7, characterized in that: The first set time is 15 minutes, and the second set time is 10 minutes.

9. The preparation method according to claim 7, characterized in that: The reaction formula of sodium alginate and water during the preparation process is (C6H7O6Na) n +H2O→CO2+NaOH+HPO3.

10. Use of the degradable biomaterial according to any one of claims 1 to 6 in rapid plugging of formation fissures.

Images