A two-dimensional flexible temporary plugging agent for fracturing and preparation method thereof

Abstract

The present invention discloses a two-dimensional flexible temporary plugging agent for fracturing and a preparation method thereof, wherein step S1, a toughening agent is melt-blended with a biodegradable material to toughen and modify the biodegradable material, and the mixture is cooled to obtain a particle masterbatch; the toughening agent is selected from at least one of polycaprolactone PCL, a copolymer of butylene adipate and butylene terephthalate PBAT, polybutylene succinate PBS, and polyhydroxyalkanoate PHA; the biodegradable material is polylactic acid or polyglycolide or a mixture of the two; S2, the particle masterbatch is uniformly dispersed in a polyvinyl alcohol solution to obtain a mixed solution; S3, the mixed solution is spun to obtain fibers, the fibers are processed into cloth, and the woven cloth is cut into different shapes to obtain a two-dimensional flexible temporary plugging agent. The two-dimensional flexible temporary plugging agent, when in contact with water and reaching a certain temperature, can be flexibly deformed to wrap the temporary plugging agent particles and powder to form a composite temporary plugging steering, which significantly improves the temporary plugging effect.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field chemicals, in particular to a soluble and degradable two-dimensional flexible temporary plugging agent for fracturing and a preparation method thereof. Background Art

[0002] Temporary plugging in fracturing means that during the fracturing process, temporary plugging agents are pumped into the well to selectively and temporarily block the advantageous fluid inlet channels, so that the fracturing fluid is diverted and new fractures are opened to increase the complexity of fractures, thereby achieving the purpose of reservoir volume transformation and increasing oil and gas seepage channels. It is required that during the fracturing construction process, the temporary plugging agents are concentrated and block the seam openings or seams, and do not dissolve or dissolve slowly during the construction period, so as to facilitate the generation of new fractures; within a period of time after the completion of the fracturing construction, the temporary plugging agents are dissolved or degraded, so that the temporarily blocked fractures can resume their diversion function, thereby achieving the purpose of increasing oil and gas production as a whole.

[0003] The temporary plugging agent widely used at present is a composite modified polymer. The temporary plugging agent particles and powder are injected into the reservoir through the working fluid, and then the large particles are bridged and the powder is filled to form a filter cake to achieve the temporary plugging effect. However, this technical solution has the following problems: (1) Since the filter cake formed by bridging filling depends on the matching relationship between the particle size and the pore, throat or crack width. However, the distribution of reservoir fractures is relatively complex, the scale is unknown, and the bridging ability of particles of different sizes is limited, making it difficult to fully apply; (2) Limited by the sand mixing truck filling process, the particle size of traditional hard temporary plugging agents is less than 5mm, and particles with a particle size of more than 5mm require special equipment and special manifolds for construction. The process is complicated, the filling is inconvenient, and the dosage is limited. (3) According to the 1 / 3 bridging principle, traditional temporary plugging agents are more suitable for bridging and plugging cracks with an opening of 1 to 15mm. When the crack opening is greater than 15mm under the conditions of a reservoir with relatively developed natural fractures, conventional temporary plugging agents cannot effectively bridge and plug, and even temporary plugging is ineffective. (4) During the filling process, the density of traditional temporary plugging particles and powders is greater than that of the working fluid, and they are easily dispersed during the pumping process, resulting in a large loss of temporary plugging agents along the way. It is difficult for temporary plugging particles to reach the target position at the same time, resulting in a relatively large amount of chemical particle temporary plugging agents used and high costs.

[0004] In order to solve the above problems, the applicant has developed a fiber composite temporary plugging technology in the early stage, which uses soluble or degradable fibers mixed with temporary plugging agents and injected simultaneously. Its purpose is to use the fiber to entangle the temporary plugging agent to reduce the loss along the way, and at the same time use the clusters formed by the fiber and temporary plugging agent to improve the adaptability to different openings during temporary plugging. However, the fiber length is limited by the injection conditions, generally 3-12mm. If the fiber is too long, it will affect the pumping and tool construction, and it cannot be injected smoothly. The adaptability of the cluster plugging formed by it can theoretically be increased to about 30mm. Summary of the invention

[0005] In view of the problem of matching the temporary plugging agent shape with the crack width, as well as the contradiction between the plugging time and the plugging pressure bearing strength and the dissolution time existing in the above-mentioned existing polymer particle / powder temporary plugging agents, the present invention provides a soluble and degradable two-dimensional flexible temporary plugging agent for fracturing.

[0006] The present invention prepares a two-dimensional flexible temporary plugging agent suitable for reservoirs at different temperatures by melt blending and modification of raw materials - spinning to form fibers - weaving fibers - cutting into different shapes, so as to achieve matching of the temporary plugging material shape with the reservoir crack width, and the dissolution (degradation) temperature of the two-dimensional flexible temporary plugging agent with the reservoir depth.

[0007] The preparation method of the two-dimensional flexible temporary plugging agent for fracturing comprises the following steps:

[0008] S1. A toughening agent is melt-blended with a biodegradable material to toughen and modify the biodegradable material, and then cooled to obtain a granular masterbatch; the toughening agent is selected from at least one of polycaprolactone PCL, a copolymer of butylene adipate and butylene terephthalate PBAT, polybutylene succinate PBS, and polyhydroxyalkanoate PHA; the biodegradable material is polylactic acid or polyglycolide or a mixture of the two. The mass ratio of the toughening agent to the biodegradable material is 1:(2-5).

[0009] During the toughening modification process, small molecule toughening agents react with large molecular weight PLA and (or) PGA molecular chains to produce flexible groups such as -COOCH2-, -CONH-, and -OCO-, thereby improving the fiber spinning performance of PLA and (or) PGA, and further making the fiber textile processed into sheet materials have flexible and deformable properties under the action of water and temperature.

[0010] S2, at 60-90° C., uniformly dispersing the particle masterbatch obtained in step S1 in a polyvinyl alcohol solution to obtain a mixed solution;

[0011] S3, spinning the mixed solution of step S2, obtaining fibers after drying, and then processing the fibers into cloth through a weaving process or a non-woven process, and then cutting the woven cloth into different shapes and sizes to obtain a two-dimensional flexible temporary plugging agent.

[0012] Preferably, in step S1, the melt blending temperature is 170-200°C and the time is 2-5 minutes.

[0013] Preferably, step S2 specifically comprises: adding the particle masterbatch obtained in step S1 to the polyvinyl alcohol solution, stirring at a high speed of 800 to 1000 rpm for 30 to 60 min at a temperature of 60 to 90° C., and then stirring at a low speed of 200 to 300 rpm for 2 to 5 h to obtain a mixed solution.

[0014] Preferably, the mass concentration of the polyvinyl alcohol solution is 20-40%, the alcoholysis degree is 88%, the polymerization degree is 1700 or 580, and the weight ratio of the polyvinyl alcohol solution to the particle masterbatch is (1-3):(2-4).

[0015] Preferably, the number of spinneret holes in step S3 is 800-1200, the hole diameter is 70-90 μm, and the fiber diameter is 30-70 D. The woven cloth is cut into any shape of triangle, quadrilateral, polygon, or circle; different size specifications include side length or diameter 1-150 mm, thickness 0.1-2.0 mm.

[0016] Compared with the prior art, the present invention is beneficial in that:

[0017] (1) The two-dimensional flexible temporary plugging agent prepared by the present invention improves the toughness of PLA and PGA and the dissolution (degradation) performance at different temperatures by adjusting the proportion of the toughening agent, thereby solving the problems of conventional PLA fibers and PGA fibers being brittle and having poor flexibility and deformation, as well as the problems of a single component having a long high-temperature dissolution time and poor dispersibility.

[0018] (2) The two-dimensional flexible temporary plugging agent of the present invention is suitable for use with a granular temporary plugging agent and a powder temporary plugging agent. The two-dimensional flexible temporary plugging agent does not dissolve or degrade under low temperature conditions. During the filling process, the two-dimensional flexible temporary plugging agent becomes flexible and deforms when it encounters water at a certain formation temperature, and will wrap the granular temporary plugging agent and the powder temporary plugging agent to form a composite temporary plugging agent. It has strong adaptability to reservoir cracks and a simple filling process. The composite temporary plugging formed by wrapping is not easy to be dispersed during the pumping process, which reduces the loss along the way. The cracks with an opening greater than 15mm can also smoothly reach the reservoir cracks. The two-dimensional flexible temporary plugging agent that reaches the formation will heat up slowly when the fracturing fluid is continuously replenished, so that the two-dimensional flexible temporary plugging agent has sufficient time to play a plugging role and ensure the formation of new cracks. When the fracturing construction is completed, there is no replenishment of low-temperature fracturing fluid, and the reservoir temperature quickly rises to the ambient temperature. The two-dimensional flexible temporary plugging agent begins to dissolve or degrade rapidly. Finally, the two-dimensional flexible temporary plugging agent dissolves or degrades within 24 to 48 hours after the construction is completed, giving full play to the fracturing production increase effect.

[0019] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of different shapes of the two-dimensional flexible temporary plugging agent of the present invention.

[0021] Figure 2 This is a field application construction curve diagram of Application Case 1 using the two-dimensional flexible temporary plugging agent prepared in Example 1.

[0022] Figure 3 This is a field application construction curve diagram of Application Case 1 without using the two-dimensional flexible temporary plugging agent prepared in Example 1.

[0023] Figure 4 This is a field application construction curve diagram of Application Case 2 using the two-dimensional flexible temporary plugging agent prepared in Example 2.

[0024] Figure 5 This is a field application construction curve diagram of Application Case 2 where the two-dimensional flexible temporary plugging agent prepared in Example 2 is not used.

[0025] Figure 6 This is a field application construction curve diagram of Application Case 3 using the two-dimensional flexible temporary plugging agent prepared in Example 3.

[0026] Figure 7 This is a field application construction curve diagram of Application Case 3 where the two-dimensional flexible temporary plugging agent prepared in Example 3 is not used.

[0027] Figure 8 This is a temporary plugging status diagram with and without the use of two-dimensional flexible temporary plugging agent. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] The two-dimensional flexible temporary plugging agent of the present invention can be cut into Figure 1 The various shapes shown have dimensions controlled within a side length or diameter of 2 to 5 cm, and a thickness of preferably 0.3 to 0.4 mm.

[0030] Example 1

[0031] A preparation method of a two-dimensional flexible temporary plugging agent:

[0032] Step 1. According to the construction technical index requirements of a well fracturing temporary plugging construction temperature of 120-150°C, dissolution time of 24-48h, and dissolution rate ≥90%, two toughening agents, PBAT and PBS, are used to toughen and modify the PGA polymer. The mass ratio of PBAT:PBS:PGA is 0.5:0.5:2. The specific method is to melt blend at 180°C for 5min, and then cool to prepare a toughened modified PGA particle masterbatch.

[0033] Step 2: At 80°C, add 200 kg of the toughened modified PGA particle masterbatch obtained in step 1 to a PVA solution with a mass concentration of 40%, a mass of 500 kg, and a model of 1799. The temperature is controlled to 80°C, and stirred at high speed (speed 800-1000 rpm) for 60 minutes to evenly disperse the toughened modified PGA particles in the polyvinyl alcohol solution. Then, stir and degas at low speed (speed 200-300 rpm) for 5 hours to obtain a mixed solution.

[0034] Step 3: The mixed solution obtained in step 2 is spun and then dried, the spinneret hole number is 800, the hole diameter is 90 μm, and the fiber diameter is 70D; the fiber is then woven into cloth, and the woven cloth is cut into triangles with a side length of 20 mm and a thickness of 0.33 mm, thus obtaining a 120-150°C soluble (degradable) two-dimensional flexible temporary plugging agent.

[0035] The performance indicators of the two-dimensional flexible temporary plugging agent are shown in Table 1.

[0036] Table 1 Performance indexes of two-dimensional flexible temporary plugging agent prepared in Example 1

[0037]

[0038] Example 2

[0039] A preparation method of a two-dimensional flexible temporary plugging agent:

[0040] Step 1. According to the construction technical index requirements of a well fracturing temporary plugging construction temperature of 90-120°C, dissolution time of 24-48h, and dissolution rate ≥90%, two toughening agents, PCL and PHA, are used to toughen and modify the PLA polymer, and the mass ratio of PBAT:PBS:PLA is 1:0.5:3. The specific method is to melt blend at 170°C for 5min, and then cool to prepare a toughened modified PLA particle masterbatch.

[0041] Step 2: At 80°C, add 100 kg of the toughened modified PLA particle masterbatch obtained in step 1 to a PVA solution with a mass concentration of 30%, a mass of 600 kg, and a model of 1788. The temperature is controlled to 80°C, and stirred at high speed (speed 800-1000 rpm) for 30 minutes to make the toughened modified PLA particles evenly dispersed in the polyvinyl alcohol solution. Then, stir and degas at low speed (speed 200-300 rpm) for 4 hours to obtain a mixed solution.

[0042] Step 3: The mixed solution obtained in step 2 is spun and then dried, the spinneret hole number is 800, the hole diameter is 90 μm, and the fiber diameter is 70D; the fiber is then woven into cloth, and the woven cloth is cut into squares with a side length of 20 mm and a thickness of 0.33 mm, thus obtaining a 90-120°C soluble (degradable) two-dimensional flexible temporary plugging agent.

[0043] The performance indicators of the two-dimensional flexible temporary plugging agent are shown in Table 2.

[0044] Table 2 Performance indicators of two-dimensional flexible temporary plugging agent prepared in Example 2

[0045]

[0046] Example 3

[0047] A preparation method of a two-dimensional flexible temporary plugging agent:

[0048] Step 1. According to the construction technical index requirements of a well fracturing temporary plugging construction temperature of 60-90°C, dissolution time of 24-48h, and dissolution rate ≥90%, PCL is used to toughen and modify the PLA polymer, and the mass ratio of PCL:PLA is 1:2. The specific method is to melt blend at 170°C for 2min, and then cool to prepare a toughened and modified PLA particle masterbatch.

[0049] Step 2: At 80°C, add 50 kg of the toughened modified PLA particle masterbatch obtained in step 1 to a PVA solution with a mass concentration of 20%, a mass of 650 kg, and a model of 0588, control the temperature to 80°C, stir at high speed (speed 800-1000 rpm) for 30 minutes to evenly disperse the toughened modified PLA particles in the polyvinyl alcohol solution, and then stir and degas at low speed (speed 200-300 rpm) for 4 hours to obtain a mixed solution.

[0050] Step 3: The mixed solution obtained in step 2 is spun and then dried, the spinneret hole number is 800, the hole diameter is 90 μm, and the fiber diameter is 70D; the fiber is then spun into cloth, and the woven cloth is cut into circles with a diameter of 20 mm and a thickness of 0.33 mm, thus obtaining a 60-90°C soluble (degradable) two-dimensional flexible temporary plugging agent.

[0051] The performance indicators of the two-dimensional flexible temporary plugging agent are shown in Table 3.

[0052] Table 3 Performance indicators of two-dimensional flexible temporary plugging agent prepared in Example 3

[0053]

[0054] The temporary plugging agent particles and temporary plugging agent powder used in the following application cases 1-3 are made of polyvinyl alcohol. The particle size is 1-3mm, and the powder size is 20-140 mesh.

[0055] Application Case 1:

[0056] Application in the second-level temporary plugging construction of a well:

[0057] The design dosage of the single-stage triangular two-dimensional flexible temporary plugging agent (prepared in Example 1) is 3kg, and the design dosage of the temporary plugging agent particles and temporary plugging agent powder are 20kg and 10kg respectively. During the construction process, the two-dimensional flexible temporary plugging agent, temporary plugging agent particles and temporary plugging agent powder are added from the sand mixing vehicle, and the dosage displacement is 1m 3 / min, delivery volume 6m 3 / min, the two-dimensional flexible temporary plugging agent was completely injected within 1 minute, and the two-dimensional flexible temporary plugging agent + temporary plugging agent (granules + powder) were pumped to the temporary plugging layer section. The construction pressure increased from 61.0MPa to 67.3MPa, and the pressure increased by 6.3MPa. Figure 2 shown.

[0058] In the third-level temporary plugging construction of a certain well, temporary plugging agent particles and powder were directly used. The designed dosage of temporary plugging agent particles and temporary plugging agent powder was 20kg and 10kg respectively. The two-dimensional flexible temporary plugging agent of Example 1 was not used. During the construction process, the temporary plugging agent (particles + powder) was added from the sand mixing truck, and the dosage was 1m 3 / min, delivery volume 6m 3 / min, the construction pressure increased from 49.1MPa to 51.7MPa, and the pressure increased by 2.6MPa. Figure 3 shown.

[0059] By comparison, it can be concluded that the combined use of two-dimensional flexible temporary plugging agent, temporary plugging agent particles and temporary plugging agent powder during the construction process can significantly improve the temporary plugging effect. This is because the two-dimensional flexible temporary plugging agent becomes flexible and deforms when it encounters water at a certain formation temperature, and will wrap the granular temporary plugging agent and powder temporary plugging agent to form a composite temporary plugging, thereby achieving the plugging and diversion of reservoir fractures, thereby improving the temporary plugging effect.

[0060] Application Case 2:

[0061] Application in the 4th level temporary plugging construction of a well:

[0062] The design dosage of the single-stage quadrilateral two-dimensional flexible temporary plugging agent (prepared in Example 2) is 5kg, and the design dosage of the temporary plugging agent granules and temporary plugging agent powder is 30kg and 20kg respectively. During the construction process, the two-dimensional flexible temporary plugging agent + temporary plugging agent (granules + powder) are added from the sand mixing vehicle, and the dosage displacement is 1m 3 / min, delivery volume 6m 3 / min, the two-dimensional flexible temporary plugging agent was completely injected within 1 minute, and the two-dimensional flexible temporary plugging agent + temporary plugging agent (granules + powder) were pumped to the temporary plugging layer section. The construction pressure increased from 47.2MPa to 53.3MPa, and the pressure increased by 6.1MPa. Figure 4 shown.

[0063] Two-dimensional flexible temporary plugging agent was not used in the fifth-level temporary plugging construction of a certain well:

[0064] During the construction process, temporary plugging agent (granules + powder) is added from the sand mixing truck. The designed dosage of temporary plugging agent granules and temporary plugging agent powder is 30kg and 20kg respectively. The dosage displacement is 1m 3 / min, delivery volume 6m 3 / min, the construction pressure increased from 49.8MPa to 52.6MPa, and the pressure increased by 2.8MPa. Figure 5 shown.

[0065] By comparison, it can be concluded that the composite use of two-dimensional flexible temporary plugging agent, temporary plugging agent particles and temporary plugging agent powder during construction can significantly improve the temporary plugging effect. This is also because the two-dimensional flexible temporary plugging agent becomes flexible and deforms when it encounters water at a certain formation temperature, wrapping the particle temporary plugging agent and the powder temporary plugging agent to form a composite temporary plugging, thereby improving the temporary plugging effect and achieving the plugging and diversion of reservoir fractures.

[0066] Application Case 3:

[0067] Application in the 10th level temporary plugging construction of a well:

[0068] The design dosage of the single-stage circular two-dimensional flexible temporary plugging agent (prepared in Example 3) is 8kg, and the design dosage of the temporary plugging agent granules and temporary plugging agent powder is 50kg and 30kg respectively. During the construction process, the two-dimensional flexible temporary plugging agent + temporary plugging agent (granules + powder) are added from the sand mixing vehicle, and the dosage displacement is 1m 3 / min, delivery volume 6m 3 / min, the two-dimensional flexible temporary plugging agent was completely injected within 1 minute, and the two-dimensional flexible temporary plugging agent + temporary plugging agent (granules + powder) were pumped to the temporary plugging layer section. The construction pressure increased from 50.2MPa to 53.5MPa, and the pressure increased by 3.3MPa. Figure 6 shown.

[0069] Two-dimensional flexible temporary plugging agent was not used in the 11th temporary plugging construction of a certain well:

[0070] During the construction process, temporary plugging agent (granules + powder) is added from the sand mixing truck. The designed dosage of temporary plugging agent granules and temporary plugging agent powder is 50kg and 30kg respectively. The dosage displacement is 1m 3 / min, delivery volume 6m 3 / min, the construction pressure increases from 52.4MPa to 52.9MPa, and the pressure rises by 0.5MPa. Figure 7 shown.

[0071] By comparison, it can be concluded that the composite use of two-dimensional flexible temporary plugging agent, temporary plugging agent particles and temporary plugging agent powder can significantly improve the temporary plugging effect. Under a certain formation temperature, the two-dimensional flexible temporary plugging agent becomes flexible and deforms when it encounters water, and will wrap the particle temporary plugging agent and the powder temporary plugging agent to form a composite temporary plugging, thereby improving the temporary plugging effect.

[0072] The laboratory test plan for the pressure-bearing performance of the composite temporary plugging agent (granules + powder) of two-dimensional flexible temporary plugging agent is as follows:

[0073] (1) In the preparation method of Example 2, in step 3, the woven cloth is cut into squares with side lengths of 10 mm, 20 mm, 30 mm, and a thickness of 0.33 mm, respectively, to obtain two-dimensional flexible temporary plugging agents of different shapes.

[0074] (2) Prepare fracturing fluid (thickener mass percentage concentration 0.4%), add granular and powder temporary plugging agents with a total concentration of 20%, the amount of two-dimensional flexible temporary plugging agent accounts for 1%, 2% and 4% of the total amount of granular and powder temporary plugging agents, the side lengths of the two-dimensional flexible temporary plugging agent are 10mm, 20mm, and 30mm respectively, and the experimental seam width is 4mm. Filling method: Use segment plugging to add two-dimensional flexible temporary plugging agent and temporary plugging agent (granular + powder) in sections to evaluate their plugging pressure bearing performance. Test the plugging pressure bearing performance of two-dimensional flexible temporary plugging agents with different side lengths under different dosage conditions.

[0075] The experimental results show that: for a two-dimensional flexible temporary plugging agent with a side length of 30 mm and a concentration of 1%, the temporary plugging agent (granules + powder) is wrapped in flexible deformation. For the same crack (4 mm), the temporary plugging pressure is as high as 40.00 MPa, and the plugging pressure speed is fast. The state of the two-dimensional flexible temporary plugging agent after composite temporary plugging is as follows: Figure 8 (a) shown. Figure 8 (b) is the state after plugging in the comparative experiment, where no two-dimensional flexible temporary plugging agent was used, and only granular temporary plugging agent and powder temporary plugging agent were used.

[0076] In summary, for reservoir conditions with relatively developed natural fractures, conventional temporary plugging agents and temporary plugging fiber construction cannot bridge and plug, and the temporary plugging construction is ineffective or inefficient. The two-dimensional flexible temporary plugging agent provided by the present invention is used in combination with granular and powdery temporary plugging agents. The two-dimensional flexible temporary plugging agent absorbs water and deforms flexibly at a certain temperature, and the temporary plugging agent (granules + powder) is wrapped to form a composite temporary plugging diversion, which can plug blastholes, even deformed blastholes, reduce the amount of bridge plugs and temporary plugging agents used, and reduce costs; and the dissolution (degradation) performance of the two-dimensional flexible temporary plugging agent is flexible and controllable.

[0077] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a two-dimensional flexible temporary plugging agent for fracturing, characterized in that: Here are the steps: S1. A toughening agent is melt-blended with a biodegradable material at a temperature of 170 to 200° C. for 2 to 5 minutes to toughen and modify the biodegradable material, and then cooled to obtain a granular masterbatch; the toughening agent is selected from at least one of polycaprolactone PCL, a copolymer of butylene adipate and butylene terephthalate PBAT, polybutylene succinate PBS, and polyhydroxyalkanoate PHA; the biodegradable material is polylactic acid or polyglycolide or a mixture of the two; the mass ratio of the toughening agent to the biodegradable material is 1:(2 to 5); S2, at 60-90° C., uniformly dispersing the particle masterbatch obtained in step S1 in a polyvinyl alcohol solution to obtain a mixed solution; S3, spinning the mixed solution of step S2, obtaining fibers after drying, and then processing the fibers into cloth, and then cutting the woven cloth into different shapes and sizes to obtain a two-dimensional flexible temporary plugging agent.

2. The method for preparing the two-dimensional flexible temporary plugging agent for fracturing according to claim 1, characterized in that: Step S2 specifically includes: adding the particle masterbatch obtained in step S1 into the polyvinyl alcohol solution, stirring at a temperature of 60 to 90° C. at a rotation speed of 800 to 1000 rpm for 30 to 60 minutes, and then stirring at a rotation speed of 200 to 300 rpm for 2 to 5 hours to obtain a mixed solution.

3. The method for preparing the two-dimensional flexible temporary plugging agent for fracturing according to claim 2, characterized in that: The mass concentration of the polyvinyl alcohol solution is 20-40%, the alcoholysis degree is 88%, the polymerization degree is 1700 or 580, and the weight ratio of the polyvinyl alcohol solution to the particle masterbatch is (1-3):(2-4).

4. The method for preparing the two-dimensional flexible temporary plugging agent for fracturing according to claim 1, characterized in that: In step S3, the number of spinneret holes for spinning is 800-1200, the hole diameter is 70-90 μm, and the fiber diameter is 30-70D.

5. The method for preparing the two-dimensional flexible temporary plugging agent for fracturing according to claim 4, characterized in that: In step S3, the woven cloth is cut into any shape of a triangle, a quadrilateral, a polygon, or a circle; different sizes include side length or diameter of 1 to 150 mm and thickness of 0.1 to 2.0 mm.

6. A two-dimensional flexible temporary plugging agent for fracturing, characterized in that: The two-dimensional flexible temporary plugging agent for fracturing is prepared by the preparation method of any one of claims 1 to 5.

7. The two-dimensional flexible temporary plugging agent for fracturing according to claim 6, characterized in that: The two-dimensional flexible temporary plugging agent is used in combination with a granular temporary plugging agent and a powder temporary plugging agent.

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