Temporary plugging fiber cluster, and preparation method therefor, usage method therefor and use thereof

Abstract

The present disclosure belongs to the technical field of oil exploitation, and specifically relates to a temporary plugging fiber cluster, and a preparation method therefor, a usage method therefor and the use thereof. The temporary plugging fiber cluster provided by the present disclosure comprises degradable fiber filaments and a degradation promoter, wherein the degradable fiber filaments are wound around the outside of the degradation promoter.

Description

Temporarily plugging fiber clusters, their preparation methods, usage methods and applications

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202411194487.1, filed on August 28, 2024, entitled "A Temporarily Plugging Fiber Cluster and Its Preparation Method, Use Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure belongs to the field of petroleum extraction technology, specifically relating to a temporary plugging fiber cluster and its preparation method, usage method and application. Background Technology

[0004] The world is rich in low-permeability oil and gas reservoirs, but these reservoirs generally need to be fracturing to achieve industrial production capacity. The success or failure of fracturing directly determines the post-fracturing production enhancement effect of oil and gas wells.

[0005] Currently, perforation fracturing is commonly used for low-permeability oil and gas reservoirs in the industry. To increase reservoir permeability and recovery, a large number of perforations are typically performed. However, an excessive number of perforations may render some ineffective. Shale gas reservoirs and other low-permeability oil and gas reservoirs often have complex rock structures and uneven reservoir permeability. This complexity can also lead to some perforations remaining unused, reducing the effectiveness of fracturing. Under certain geological conditions, such as complex geological structures and low formation pressure, utilizing all perforations may become more difficult. These limitations may prevent some perforations from being effectively utilized.

[0006] To address these issues, the industry has developed a wide variety of products, such as steel balls, nylon balls, wax balls, temporary plugging balls, and rope knot temporary plugs. Different types of products have different mechanisms of action and applicable ranges, but each has its own limitations. For example, due to the irregularity of perforation holes, spherical materials cannot completely seal them and are prone to detachment; non-degradable materials remain in the wellbore or perforation after fracturing, affecting the reservoir, oil and gas well production, and subsequent construction; rope knot temporary plugs are a new type of perforation plugging developed in recent years, capable of sealing irregular holes, but the knots easily become entangled during addition, leading to plugging failure. Furthermore, the degradation time of the knots in the perforation is slow, affecting post-fracturing flowback. Summary of the Invention

[0007] To address the aforementioned technical problems, this disclosure provides a temporary plugging fiber cluster, its preparation method, usage method, and application.

[0008] Specifically, the temporary plugging fiber bundle provided in this disclosure includes: a biodegradable fiber thread and a degradation promoter; wherein the biodegradable fiber thread is wrapped around the outside of the degradation promoter.

[0009] The aforementioned temporarily blocked fiber cluster also includes a coating layer; the coating layer is disposed between the biodegradable fiber thread and the degradation promoter.

[0010] The aforementioned temporary plugging fiber clusters, by weight, consist of 70-95 parts by weight of biodegradable fiber thread and 5-30 parts by weight of degradation promoter.

[0011] The aforementioned temporary plugging fiber clusters, by weight, consist of 70-80 parts by weight of biodegradable fiber thread and 20-30 parts by weight of degradation accelerator.

[0012] The aforementioned temporarily plugging fiber clusters and biodegradable fiber threads are made of polyester materials.

[0013] The aforementioned temporary plugging fiber bundles include polyester materials such as at least one of polylactic acid, polyglycolic acid, polyethylene terephthalate, polycaprolactone, polyhydroxyalkanoates, and polybutylene succinate.

[0014] The degradation promoters for the aforementioned temporarily blocked fiber clusters include at least one of metal oxides, metal hydroxides, and metal carbonates.

[0015] The aforementioned temporary plugging fiber clusters include metal oxides such as calcium oxide, magnesium oxide, and zinc oxide; metal hydroxides such as calcium hydroxide, sodium hydroxide, and magnesium hydroxide; and metal carbonates such as calcium carbonate and magnesium carbonate.

[0016] The aforementioned temporary plugging fiber clusters have a coating material including polyvinyl alcohol.

[0017] The aforementioned temporary plugging fiber clusters and biodegradable fiber threads consist of 10 to 30 fiber filaments.

[0018] The aforementioned temporary plugging fiber clusters have a cross-sectional diameter of 10μm to 100μm for the fiber filaments.

[0019] On the other hand, this disclosure also provides a method for preparing the aforementioned temporarily plugging fiber clusters, including:

[0020] S1: The degradation accelerator is made into the core;

[0021] S2: The biodegradable fiber thread is wound around the core to obtain a temporarily blocked fiber cluster.

[0022] The above-mentioned method for preparing the temporarily plugged fiber clusters further includes, between S1 and S2: coating the core with molten polyvinyl alcohol.

[0023] In the above-mentioned method for preparing temporary plugging fiber clusters, the core shape is ellipsoidal.

[0024] Furthermore, this disclosure also provides a method for using the aforementioned temporary plugging fiber clumps, including:

[0025] S11: Inject a portion of the total material into the fracturing well according to the first displacement;

[0026] S12: Add the aforementioned temporary plugging fiber cluster;

[0027] S13: Pump the delivery fluid according to the second displacement to deliver the temporarily plugging fiber clump to the reservoir location;

[0028] S14: Pump the remaining material into the fracturing well according to the first displacement to complete the construction.

[0029] The above-mentioned method for temporarily plugging fiber clumps involves a second discharge volume that is less than the first discharge volume, with the second discharge volume being 1m. 3 / min~3m 3 / min.

[0030] The above method of temporarily plugging fiber clumps is used, where the number of temporarily plugged fiber clumps is: N 暂堵纤维团 =N 射孔孔眼数 ×50%×η

[0031] Where, N 暂堵纤维团 The number of temporarily blocked fiber clusters;

[0032] N 射孔孔眼数 The number of perforations;

[0033] η is the safety factor, which is dimensionless and ranges from 1 to 2.

[0034] The above-mentioned method of using temporary plugging fiber clumps involves using fiber clumps with a diameter that is 1 to 4 times the diameter of the perforation hole.

[0035] Furthermore, this disclosure also provides the application of the aforementioned temporary plugging fiber clusters in oil extraction.

[0036] Compared with the prior art, the temporary plugging fiber cluster of this disclosure has the following beneficial effects:

[0037] (1) The temporary plugging fiber clump disclosed herein has the advantages of low density, deformability, controllable degradation time, low temperature degradation, high plugging strength, non-toxic and environmentally friendly, and can meet the requirements of temporary plugging fracturing construction of fracturing and acidizing perforation holes at different formation temperatures.

[0038] (2) The temporary plugging fiber clusters disclosed herein have fewer types of raw materials and a simple preparation method, which effectively reduces their production costs.

[0039] Overview of the attached figures

[0040] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0041] Figure 1 is a schematic diagram of the structure of the temporary plugging fiber mass of this invention;

[0042] Figure 2 is a physical image of the temporary plugging fiber cluster of this invention;

[0043] Figure 3 illustrates the mechanism of action of the temporarily blocked fiber clusters in this disclosure;

[0044] Figure 4 shows the fracturing operation curve of Well X in Application Example 1;

[0045] Figure 5 is an analysis diagram of the high-frequency fluid inlet location during fracturing of Well X in Application Example 1;

[0046] Figure 6 is a post-pressure simulation diagram of well X in application example 1.

[0047] Preferred embodiments of this disclosure

[0048] To fully understand the purpose, features, and effects of this disclosure, the following specific embodiments are provided for detailed explanation. Except as described below, the processes and methods of this disclosure employ conventional methods or apparatus in the art. Unless otherwise stated, the terms and phrases used below have the meanings commonly understood by those skilled in the art.

[0049] When a range of values ​​is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0050] In a first aspect, as shown in Figures 1 and 2, this disclosure provides a temporary plugging fiber bundle, comprising: a biodegradable fiber thread 1 and a degradation promoter 2; wherein the biodegradable fiber thread 1 is wound around the outside of the degradation promoter 2.

[0051] In the temporarily plugging fiber clusters disclosed herein, the density of the biodegradable fiber threads is low and there are certain gaps between the threads, so that the density of the temporarily plugging micro-clusters is maintained at 1.0–1.3 g / cm³. 3Within a certain range. Therefore, compared to conventional plugging agents in the prior art, the plugging fiber clusters of this disclosure have the advantage of low density. Furthermore, under high pressure, the pores between the biodegradable fiber threads will be compressed, and the wound biodegradable fiber threads will also be twisted. Therefore, the plugging fiber clusters of this disclosure can change their shape according to the shape of the perforation orifice, exhibiting good deformability.

[0052] In this disclosure, the degradation time of temporarily blocked fiber clusters can be adjusted by regulating parameters such as the type of biodegradable fiber material, the type of degradation accelerator, and their ratio. As a general rule, low-temperature degradation materials and a large amount of strongly alkaline accelerators are used to increase the degradation rate at medium and low temperatures, while high-temperature degradation materials, a small amount of weakly alkaline accelerators, and accelerator surface coating materials are used to reduce the degradation rate at high temperatures.

[0053] In some preferred embodiments, the biodegradable fiber yarn comprises 70-95 parts by weight, and the degradation accelerator comprises 5-30 parts by weight. More preferably, the biodegradable fiber yarn comprises 70-80 parts by weight, and the degradation accelerator comprises 20-30 parts by weight.

[0054] In some preferred embodiments, the biodegradable fiber yarn is made of polyester. More preferably, the polyester material includes at least one selected from polylactic acid, polyglycolic acid, polyethylene terephthalate, polycaprolactone, polyhydroxyalkanoates, and polybutylene succinate.

[0055] More preferably, the molecular weight ranges of polylactic acid (PLA) from 20,000 to 300,000, polyglycolic acid (PGA) from 20,000 to 150,000, polyethylene terephthalate (PET) from 10,000 to 30,000, polycaprolactone (PCL) from 5,000 to 100,000, polyhydroxyalkanoates (PHA) from 400,000 to 600,000, and polybutylene succinate (PBS) from 30,000 to 70,000.

[0056] The polyester materials used in this disclosure have stronger sealing strength compared to water-soluble materials such as polyvinyl alcohol. Furthermore, polyester materials are non-toxic and environmentally friendly, producing only carbon dioxide and water after degradation, ensuring that they will not have a negative impact on the environment during use.

[0057] In some preferred embodiments, the biodegradable fiber yarn of this disclosure is composed of 10 to 30 fiber filaments, wherein the diameter of the cross-section of the fiber filaments is 10 μm to 100 μm.

[0058] The fiber filaments used are all commercially available products or produced using existing methods, and this disclosure does not specifically limit their use. In some preferred embodiments, the degradation promoter includes at least one of a metal oxide, a metal hydroxide, and a metal carbonate. More preferably, the metal oxide includes at least one of calcium oxide, magnesium oxide, and zinc oxide; the metal hydroxide includes at least one of calcium hydroxide, sodium hydroxide, and magnesium hydroxide; and the metal carbonate includes at least one of calcium carbonate and magnesium carbonate.

[0059] In current applications, the degradability of temporary plugging agents at low temperatures is crucial. The degradation promoter used in this disclosure slowly releases hydroxyl groups in the formation environment, promoting the degradation of the degradable fiber strands, enabling the temporary plugging fiber clusters to degrade rapidly even at low temperatures. Testing has shown that the temporary plugging fiber clusters of this disclosure exhibit good plugging effects at temperatures ranging from 40℃ to 200℃, significantly expanding their application range.

[0060] In some preferred embodiments, as shown in FIG1, the temporarily plugging fiber cluster of the present disclosure further includes a coating layer 3; the coating layer 3 is disposed between the biodegradable fiber thread 1 and the degradation promoter 2.

[0061] This disclosure effectively slows down the release rate of the degradation accelerator by coating the core with a coating layer. More preferably, the coating layer is made of polyvinyl alcohol with a molecular weight of 50,000 to 100,000.

[0062] Secondly, this disclosure also provides a method for preparing the aforementioned temporarily plugging fiber clusters, including:

[0063] S1: The degradation accelerator is made into the core;

[0064] S2: The biodegradable fiber thread is wound around the core to obtain a temporarily blocked fiber cluster.

[0065] In some preferred embodiments, the kernel is ellipsoidal in shape.

[0066] In order to slow down the release rate of the degradation promoter, in some preferred embodiments, this disclosure also includes coating the core with molten polyvinyl alcohol.

[0067] The amount of polyvinyl alcohol (PVA) coating can be adjusted based on the weight of the degradable fiber material and degradation accelerator, as well as process parameters such as degradation time and temperature. In some optional embodiments, the thickness of the coated PVA film is 40 μm to 150 μm.

[0068] The raw materials and proportions used in preparing the temporarily plugged fiber clusters are the same as those in the temporarily plugged fiber clusters disclosed in the first method of this disclosure, and this disclosure will not repeat the limitation here.

[0069] Thirdly, this disclosure also provides a method for temporarily plugging fiber clumps, including:

[0070] S11: Inject a portion of the total material into the fracturing well according to the first displacement;

[0071] S12: Temporarily plugging fiber clusters;

[0072] S13: Pump the delivery fluid according to the second displacement to deliver the temporarily plugging fiber clump to the reservoir location;

[0073] S14: Pump the remaining material into the fracturing well according to the first displacement to complete the construction.

[0074] Figure 3 illustrates the mechanism of action of the temporary plugging fiber clusters disclosed in this invention. As shown in Figure 3, the fiber clusters are pumped to the perforation by fracturing fluid. As the pumping pressure increases, the fiber portion of the fiber cluster deforms under pressure, completely blocking the irregular perforation orifice. This forces the fracturing fluid to redirect to other unused orifices, opening them up. Under formation temperature and pressure, degradation promoters are released, promoting rapid fiber degradation. Ultimately, the fiber clusters are completely degraded, restoring the flow channel that blocked the perforation orifice.

[0075] In some optional embodiments, the total materials include fracturing fluid and proppant; the delivery fluid includes fracturing fluid base fluid, i.e., uncrosslinked fracturing fluid. The fracturing fluid, proppant, and fracturing fluid base fluid are all known in the prior art, and this disclosure does not specifically limit them.

[0076] In some preferred embodiments, the second displacement is smaller than the first displacement, and the second displacement is 1m. 3 / min~3m 3 / min.

[0077] In some preferred embodiments, the number of temporarily plugged fiber clusters is: N 暂堵纤维团 =N 射孔孔眼数 ×50%×η

[0078] Where, N 暂堵纤维团 The number of temporarily blocked fiber clusters;

[0079] N 射孔孔眼数 The number of perforations;

[0080] η is the safety factor, which is dimensionless and ranges from 1 to 2.

[0081] More preferably, the safety factor is between 1.2 and 1.5.

[0082] In some preferred embodiments, the diameter of the temporary plugging fiber cluster is 1 to 4 times the diameter of the perforation aperture.

[0083] In some preferred embodiments, the temporary plugging fiber clump is introduced by one of the following methods: injection via a plug valve, direct injection into the high-pressure pipeline, or direct injection through the wellhead.

[0084] Fourthly, this disclosure also provides the application of the aforementioned temporary plugging fiber clusters in oil extraction.

[0085] The temporary plugging fiber clump disclosed herein has advantages such as low density, deformability, controllable degradation time, low-temperature degradation, high plugging strength, and non-toxicity and environmental friendliness, and can meet the requirements of temporary plugging fracturing construction for fracturing and acidizing perforation holes at different formation temperatures. Example

[0086] The present disclosure is further illustrated below by way of examples, but these examples are not intended to limit the scope of the present disclosure to the specific embodiments. Experimental methods not specifically described in the following examples are performed using conventional methods and conditions. All raw materials used in the following examples were commercially available.

[0087] The molecular weights of the raw materials used in each embodiment are summarized below:

[0088] Polyvinyl alcohol, with a molecular weight of approximately 75,000; polylactic acid fiber filament, with a molecular weight of approximately 60,000; polyglycolic acid fiber filament, with a molecular weight of approximately 60,000; polyethylene terephthalate fiber filament, with a molecular weight of approximately 20,000.

[0089] Example 1

[0090] 3.4g of calcium oxide was used to prepare an ellipsoidal degradation promoter core, and molten polyvinyl alcohol was coated on its surface, with a polyvinyl alcohol film thickness of 80±5μm. Thirty polylactic acid (PLA) filaments with a cross-sectional diameter of 12μm were used to form a fiber thread. 13.5g of PLA fiber thread was weighed and wound around the degradation promoter core into a ball, forming a temporary plugging fiber ball with a diameter of 30mm–32mm.

[0091] Example 2

[0092] An ellipsoidal degradation promoter core was prepared by mixing 2.5g of calcium oxide and calcium hydroxide in a 1:1 mass ratio, and molten polyvinyl alcohol was coated on its surface, with a polyvinyl alcohol film thickness of 50±5μm. A fiber filament was composed of 5 polylactic acid filaments with a cross-sectional diameter of 15μm and 20 polyglycolic acid filaments with a cross-sectional diameter of 15μm. 15g of the fiber filament was weighed and wound around the core to form a temporary plugging fiber clump with a diameter of 29mm–31mm.

[0093] Example 3

[0094] An ellipsoidal degradation accelerator core was prepared by mixing 2.5g of calcium oxide and calcium carbonate in a 1:3 mass ratio, and then coated with molten polyvinyl alcohol (PVC) to form a PVC film with a thickness of 120±5μm. A fiber filament was composed of 10 polylactic acid (PLA) filaments with a cross-sectional diameter of 15μm and 5 polyethylene terephthalate (PET) filaments with a cross-sectional diameter of 15μm. 18g of the fiber filament was weighed and used to wind the degradation accelerator core into a ball, forming a temporary plugging fiber ball with a diameter of 32mm–34mm.

[0095] Example 4

[0096] 1.5g of sodium hydroxide was used to prepare an ellipsoidal degradation promoter core. 30 polylactic acid (PLA) fiber filaments with a cross-sectional diameter of 14μm were used to form a fiber thread. 3.8g of PLA fiber thread was weighed and wound around the degradation promoter core to form a temporary plugging fiber cluster with a diameter of 19mm to 21mm.

[0097] Performance testing

[0098] The performance of the temporarily plugging fiber clusters prepared in the above embodiments was tested. The specific test methods are as follows, and the test results are shown in Table 1.

[0099] 1. Degradation time test

[0100] Take a 100mL centrifuge tube and weigh it in a constant temperature drying oven at 105℃ (accurate to 0.01g), and record its mass as m1. Take a clean, sealed container (a hydrothermal synthesis reactor was used for samples in Examples 1 and 3, and a heat-resistant reagent bottle was used for samples in Examples 2 and 4), and put 100mL of the test liquid into each container. The test liquid is distilled water.

[0101] Weigh the temporarily blocked fiber cluster sample to an accuracy of 0.01 g, record the mass as m2, and place it in a sealed container filled with distilled water to ensure uniform dispersion of the sample in the test liquid. Seal the sealed container and place it in a heated constant-temperature water bath or drying oven (a constant-temperature water bath was used for samples in Examples 2 and 4, and a constant-temperature drying oven was used for samples in Examples 1 and 3). After degradation, remove the sample and record the degradation time.

[0102] 2. Compressive strength test

[0103] The pressure strength testing system mainly consists of an injection pump, a high-pressure chamber, a ball frame, and a constant temperature device (oven or heating mantle).

[0104] a) Select a ball frame with a ball aperture ratio of 1.4 to 1.6 according to the diameter of the fiber cluster;

[0105] b) Adhere the fiber bundle to the holes of the ball frame using glass glue;

[0106] c) After the glass glue has solidified, insert the ball frame into the outlet end of the high-pressure chamber, and tighten the ball frame and the high-pressure chamber thread through the PTFE gasket at the end of the ball frame to ensure the test mold is sealed.

[0107] d) Connect the system according to the process;

[0108] e) Sealing test: Connect the injection pump to the injection end of the high-pressure chamber, set the pressure to 0.5 MPa, open the valve and adjust the flow rate to 10 mL / min. If liquid flows out of the outlet, stop the injection and test another fiber bundle;

[0109] f) Set the heating rate to 5℃ / min, heat the system to the test temperature, and hold the temperature for 5 minutes;

[0110] g) Set the maximum injection pressure to 40 MPa. Adjust the flow rate to 5 mL / min to achieve pressure buildup and observe the pressure.

[0111] h) When the pressure rises and reaches 40 MPa, maintain a constant pressure of 40 ± 0.5 MPa without any pressure drop, then end the test and record the pressure difference as 40 MPa. If the test pressure reaches 40 MPa but the constant pressure time is less than 60 min, or if the test pressure does not reach 40 MPa, then stop the test and record the pressure difference as less than 40 MPa.

[0112] Table 1 Summary of the performance of the temporarily plugged fiber clusters in Examples 1-4

[0113] As can be seen from Table 1, the temporary plugging fiber clusters disclosed herein are degradable at temperatures ranging from 40°C to 200°C and have a compressive strength as high as 40 MPa.

[0114] Application Example 1

[0115] The temporary plugging fiber clusters prepared in Example 1 were used in the fracturing operation of Well X. The perforation diameter of this well is 11.7 mm, with 5 clusters of perforations totaling 120 holes. The construction steps are as follows:

[0116] S1: at 5m 3 A displacement of / min will pump a portion of the predetermined total material into the fracturing well and carry out the operation (main ① fracturing);

[0117] S2: 73 temporary plugging fiber clusters prepared in Example 1 were added;

[0118] S3: Reduce displacement to 2.2m 3 / min~2.7m 3 The fiber clumps are delivered to the reservoir location using a transport fluid at a rate of 43 m³ / min. 3 At that time, the wellhead pressure increased from 33.2 MPa to 37.14 MPa, indicating a clear temporary plugging effect;

[0119] S4: Pump the remaining portion of the predetermined total material into the fracturing well to complete the construction (main ② fracturing).

[0120] Figure 4 shows the fracturing operation curve for Well X. Specifically, the main fracturing operation (S1) had a displacement of 5.0 m³ / s. 3 / min, maximum construction pressure 47.32MPa, sand ratio 5%-8%-12%-16%-20%-24%-28%-32%-36%, cumulative sand-carrying liquid volume 290.3m 3 The total sand volume is 25.1m. 3 After 21 minutes of pump shutdown, the ground pressure decreased from 28.85 MPa to 15.51 MPa; 73 temporary plugging fiber clumps (S2) were introduced, with a discharge volume of 2.2 m³. 3 / min~2.7m 3 / min, injection volume 43m 3 At that time, the wellhead pressure increased from 33.2 MPa to 37.14 MPa, and the temporary plugging showed obvious signs, transitioning to the main fracturing stage (S3); Main fracturing (S3): Fracturing displacement 5.0 m³ / s. 3 / min, maximum construction pressure 46.18MPa, sand ratio 5%-9%-13%-18%-23%-28%-32%-36%, cumulative sand-carrying liquid volume 268.3m 3 The total sand volume is 25.0 m³. 3 After the pump was stopped, the ground pressure dropped from 22.59 MPa to 0 MPa in 54 minutes.

[0121] The construction parameters were generally consistent with the process design, and the overall construction pressure was stable, indicating normal crack extension and smooth propagation. At the same time, the temporary plugging was obvious, indicating that the temporary plugging achieved the purpose of opening new cracks and equalizing crack initiation.

[0122] Figure 5 shows the location analysis of high-frequency fluid inlet points during fracturing operations in Well X. High-frequency pressure monitoring revealed that the main fluid inlet points for fracturing operation ① were 3988m, 4008m, and 4020m. After temporary plugging with fiber clusters, the main fluid inlet points for fracturing operation ② were 4002m and 4026m, showing a significant diversion effect. This is consistent with the pressure response of the temporary plugging, indicating that this technology effectively enhances the vertical modification of reservoir sections in large-span thin interbedded reservoirs.

[0123] Figure 6 shows the post-fracturing simulation of Well X. The simulated fracture morphology after fracturing indicates that the well formed longer and higher fractures. The fiber-bubble temporary plugging and flow-controlled fracturing technology effectively achieved balanced reservoir modification and large-scale fracture creation.

[0124] This disclosure has been described above with reference to preferred embodiments. However, those skilled in the art should understand that these embodiments are for illustrative purposes only and should not be construed as limiting the scope of this disclosure. It should be noted that any variations and substitutions equivalent to these embodiments should be considered to be covered within the scope of the claims of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A method for temporarily blocking fiber clusters, characterized in that, include: A biodegradable fiber thread and a degradation promoter; wherein the biodegradable fiber thread is wound around the outside of the degradation promoter.

2. The temporarily plugging fiber mass according to claim 1, characterized in that, It also includes a coating layer; the coating layer is disposed between the biodegradable fiber thread and the degradation promoter.

3. The temporarily blocked fiber mass according to claim 1, characterized in that, The biodegradable fiber yarn comprises 70-95 parts by weight, and the degradation promoter comprises 5-30 parts by weight.

4. The temporarily plugging fiber mass according to claim 1, characterized in that, The biodegradable fiber yarn comprises 70-80 parts by weight, and the degradation promoter comprises 20-30 parts by weight.

5. The temporarily plugging fiber mass according to claim 1, characterized in that, The biodegradable fiber yarn is made of polyester.

6. The temporarily plugging fiber mass according to claim 5, characterized in that, The polyester material includes at least one of polylactic acid, polyglycolic acid, polyethylene terephthalate, polycaprolactone, polyhydroxyalkanoates, and polybutylene succinate.

7. The temporarily plugging fiber mass according to claim 1, characterized in that, The degradation promoter includes at least one of metal oxides, metal hydroxides, and metal carbonates.

8. The temporarily plugging fiber mass according to claim 7, characterized in that, The metal oxide includes at least one of calcium oxide, magnesium oxide, and zinc oxide; the metal hydroxide includes at least one of calcium hydroxide, sodium hydroxide, and magnesium hydroxide; and the metal carbonate includes at least one of calcium carbonate and magnesium carbonate.

9. The temporarily plugging fiber mass according to claim 2, characterized in that, The material of the coating layer includes polyvinyl alcohol.

10. The temporarily plugging fiber mass according to claim 1, characterized in that, The biodegradable fiber yarn consists of 10 to 30 fiber filaments.

11. The temporarily plugging fiber mass according to claim 10, characterized in that, The cross-sectional diameter of the fiber filament is 10μm to 100μm.

12. The method for preparing the temporarily plugging fiber cluster according to any one of claims 1 to 11, characterized in that, include: S1: The degradation accelerator is made into the core; S2: The biodegradable fiber thread is wound around the core to obtain a temporarily blocked fiber bundle.

13. The preparation method according to claim 12, characterized in that, Between S1 and S2, the process also includes coating the core with molten polyvinyl alcohol.

14. The preparation method according to claim 12, characterized in that, The core is ellipsoidal in shape.

15. A method for temporarily blocking fiber clumps, characterized in that, include: S11: Inject a portion of the total material into the fracturing well according to the first displacement; S12: Inject the temporary plugging fiber cluster as described in any one of claims 1 to 11; S13: The temporarily plugging fiber clump is delivered to the reservoir location by pumping the delivery fluid according to the second displacement. S14: Pump the remaining material into the fracturing well according to the first displacement to complete the construction.

16. The method of use according to claim 15, characterized in that, The second displacement is smaller than the first displacement, and the second displacement is 1m. 3 / min~3m 3 / min.

17. The method of use according to claim 15, characterized in that, The number of the temporarily plugging fiber clusters is: N 暂堵纤维团 =N 射孔孔眼数 ×50%×η Where, N 暂堵纤维团 The number of temporarily blocked fiber clusters; N 射孔孔眼数 The number of perforations; η is the safety factor, which is dimensionless and ranges from 1 to 2.

18. The method of use according to claim 15, characterized in that, The diameter of the temporary plugging fiber cluster is 1 to 4 times the diameter of the perforation hole.

19. The application of the temporary plugging fiber clusters according to any one of claims 1 to 11 in oil extraction.

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