Temporary plugging fiber group as well as preparation method, use method and application thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a temporary plugging fiber group and a preparation method, a use method and application thereof. The temporary plugging fiber mass provided by the invention comprises degradable fiber lines and a degradation accelerant, wherein the degradable fiber line is wound on the outer side of the degradation accelerant. The temporary plugging fiber mass has the advantages of being small in density, deformable, controllable in degradation time, degradable at low temperature, high in plugging strength, non-toxic, environmentally friendly and the like, and can meet the temporary plugging fracturing construction requirements of fracturing acidizing perforation holes at different formation temperatures.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction, and in particular relates to a temporary plugging fiber group and a preparation method, a use method and an application thereof. Background Art

[0002] Low-permeability oil and gas reservoirs are abundant worldwide, and low-permeability oil and gas reservoirs generally need to be transformed through fracturing to form industrial production capacity. The success or failure of fracturing measures directly determines the effect of increased production after fracturing of oil and gas wells.

[0003] At present, perforation fracturing is generally used in low permeability oil and gas reservoirs in the industry. In order to increase the permeability and recovery rate of the reservoir, a large number of perforation operations are usually performed. However, too many perforation holes may cause some holes to be unable to be effectively used. The rock structure of low permeability oil and gas reservoirs such as shale gas reservoirs is usually complex, and the reservoir permeability is uneven. This complexity will also cause some perforation holes to be unable to be effectively used, reducing the effect of fracturing transformation. Under certain geological conditions, such as complex structures and low formation pressure, the difficulty of mobilizing all perforation holes may increase. These restrictions may make some perforation holes unable to be effectively used.

[0004] In response to these problems, the industry has also developed a wide variety of products, such as steel balls, nylon balls, wax balls, temporary plugging balls, knotted temporary plugging, etc. Different types of products have different mechanisms of action and scope of application, but they all have their own limitations. For example, due to the irregularity of the perforated holes, the holes cannot be completely blocked with ball materials, and they are easy to fall off; non-degradable materials remain in the wellbore or holes after fracturing, affecting the reservoir, the production of oil and gas wells and subsequent construction; knotted temporary plugging is a new type of plugging hole developed in recent years, which can be used to plug irregular holes, but the knots are easily entangled during the addition process, resulting in plugging failure. At the same time, the knots degrade slowly in the holes, affecting the post-fracturing flowback. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a temporary plugging fiber group and a preparation method, a use method and an application thereof.

[0006] Specifically, the temporary plugging fiber group provided by the present invention comprises: a degradable fiber line and a degradation promoter; wherein the degradable fiber line is wound around the outside of the degradation promoter.

[0007] The temporary plugging fiber group mentioned above further includes a coating layer; the coating layer is arranged between the degradable fiber line and the degradation accelerator.

[0008] In the temporary plugging fiber group, the degradable fiber line is 70 to 95 parts by weight, and the degradation accelerator is 5 to 30 parts by weight.

[0009] In the temporary plugging fiber group, the degradable fiber line accounts for 70 to 80 parts by weight, and the degradation accelerator accounts for 20 to 30 parts by weight.

[0010] In the above-mentioned temporary plugging fiber group, the material of the degradable fiber line is polyester material.

[0011] In the above-mentioned temporary plugging fiber group, the polyester material includes at least one of polylactic acid, polyglycolic acid, polyethylene terephthalate, polycaprolactone, polyhydroxyalkanoate and polybutylene succinate.

[0012] In the above-mentioned temporary plugging fiber cluster, the degradation accelerator includes at least one of metal oxides, metal hydroxides and metal carbonates.

[0013] In the temporary plugging fiber cluster, 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.

[0014] In the above-mentioned temporary plugging fiber group, the material of the coating layer includes polyvinyl alcohol.

[0015] In the above-mentioned temporary plugging fiber group, the degradable fiber line is composed of 10 to 30 fiber filaments.

[0016] In the above-mentioned temporary plugging fiber cluster, the diameter of the cross section of the fiber filament is 10-100 μm.

[0017] On the other hand, the present invention also provides a method for preparing the temporary plugging fiber cluster, comprising:

[0018] S1: making the degradation promoter into a core;

[0019] S2: Winding the degradable fiber thread on the inner core to obtain a temporary plugging fiber mass.

[0020] The above-mentioned method for preparing temporary plugging fiber clusters, between S1 and S2, further comprises: coating molten polyvinyl alcohol on the inner core.

[0021] In the above-mentioned method for preparing the temporary plugging fiber cluster, the shape of the inner core is an ellipsoid.

[0022] In another aspect, the present invention further provides a method for using the temporary plugging fiber mass, comprising:

[0023] S11: Pumping part of the total material into the fracturing well according to the first displacement;

[0024] S12: adding the temporary plugging fiber mass mentioned above;

[0025] S13: pumping the delivery liquid according to the second displacement to deliver the temporary plugging fiber group to the reservoir position;

[0026] S14: Inject the remaining total material into the fracturing well according to the first displacement, and complete the construction.

[0027] In the above-mentioned method for using the temporary plugging fiber group, the second displacement is smaller than the first displacement, and the second displacement is 1 to 3 m 3 / min.

[0028] In the above-mentioned method for using the temporary plugging fiber group, the number of the temporary plugging fiber group is:

[0029] N 暂堵纤维团 =N 射孔孔眼数 ×50%×η

[0030] Among them, N 暂堵纤维团 is the number of temporary plugging fiber clusters, pieces;

[0031] N 射孔孔眼数 is the number of perforation holes, pcs;

[0032] η is the safety factor, dimensionless, and ranges from 1 to 2.

[0033] In the method for using the temporary plugging fiber group mentioned above, the diameter of the temporary plugging fiber group is 1 to 4 times the diameter of the perforation hole.

[0034] In another aspect, the present invention also provides the use of the temporary plugging fiber group in oil production.

[0035] Compared with the prior art, the temporary plugging fiber group of the present invention has the following beneficial effects:

[0036] (1) The temporary plugging fiber group of the present invention has the advantages of low density, deformation, controllable degradation time, degradability at low temperature, high plugging strength, non-toxicity and environmental protection, and can meet the temporary plugging and fracturing construction requirements of fracturing acidification perforations at different formation temperatures;

[0037] (2) The temporary plugging fiber group of the present invention has fewer types of raw materials and a simple preparation method, which effectively reduces its production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the following detailed description of the preferred embodiment.The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the invention.

[0039] Figure 1 Schematic diagram of the structure of the temporary plugging fiber group of the present invention;

[0040] Figure 2 This is a physical picture of the temporary plugging fiber group of the present invention;

[0041] Figure 3 This is the mechanism of action of the temporary plugging fiber group of the present invention;

[0042] Figure 4 This is the fracturing operation curve diagram of Well X in Application Example 1;

[0043] Figure 5 This is the high-frequency fluid inlet point position analysis diagram for the X-well fracturing operation in Application Example 1;

[0044] Figure 6 This is the simulation diagram of Well X after pressure reduction in Application Example 1. DETAILED DESCRIPTION

[0045] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments. Except for the following contents, the process method of the present invention adopts conventional methods or devices in the art. Unless otherwise specified, the following terms have the meanings commonly understood by those skilled in the art.

[0046] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0047] First, as Figure 1 and Figure 2 As shown, the present invention provides a temporary plugging fiber group, comprising: a degradable fiber line 1 and a degradation promoter 2; wherein the degradable fiber line 1 is wound around the outside of the degradation promoter 2.

[0048] In the temporary plugging fiber group of the present invention, the density of the degradable fiber lines is low and there are certain gaps between the lines, so that the density of the temporary plugging micro-group is maintained at 1.0-1.3 g / cm 3 Therefore, compared with the conventional temporary plugging agent in the prior art, the temporary plugging fiber group of the present invention has the advantage of low density. Furthermore, under high pressure, the pores between the degradable fiber lines will be compressed, and the entangled degradable fiber lines will also be twisted. Therefore, the temporary plugging fiber group of the present invention can change its shape according to the shape of the perforation hole, showing good deformability.

[0049] In the present invention, the degradation time of the temporary plugged fiber group can be adjusted by adjusting the type of degradable fiber material, the type of degradation accelerator and the ratio of the two. As a principle, low-temperature degradation materials and a large amount of strong alkaline accelerators are generally used at low and medium temperatures to increase the degradation rate, while high-temperature degradation materials, a small amount of weak alkaline accelerators and accelerator surface coating materials are used at high temperatures to reduce the degradation rate.

[0050] In some preferred embodiments, the degradable fiber line is 70-95 parts by weight, and the degradation accelerator is 5-30 parts by weight. More preferably, the degradable fiber line is 70-80 parts by weight, and the degradation accelerator is 20-30 parts by weight.

[0051] In some preferred embodiments, the material of the degradable fiber line is a polyester material. Further preferably, the polyester material includes at least one of polylactic acid, polyglycolic acid, polyethylene terephthalate, polycaprolactone, polyhydroxyalkanoate and polybutylene succinate.

[0052] Further preferably, the molecular weight range of polylactic acid is 20,000 to 300,000, the molecular weight range of polyglycolic acid is 20,000 to 150,000, the molecular weight range of polyethylene terephthalate is 10,000 to 30,000, the molecular weight range of polycaprolactone is 0.5 to 100,000, the molecular weight range of polyhydroxyalkanoate is 400,000 to 600,000 and the molecular weight range of polybutylene succinate is 30,000 to 70,000.

[0053] The polyester used in the present invention has stronger blocking strength than water-soluble materials such as polyvinyl alcohol. Moreover, the polyester material is non-toxic and environmentally friendly, and only produces carbon dioxide and water after degradation, ensuring that it will not have a negative impact on the environment during use.

[0054] In some preferred embodiments, the degradable fiber thread of the present invention is composed of 10 to 30 fiber filaments, wherein the diameter of the cross section of the fiber filament is 10 to 100 μm.

[0055] Wherein, the fiber filaments are all commercially available products or produced according to existing methods, and the present invention does not specifically limit this. In some preferred embodiments, the degradation accelerator includes at least one of metal oxides, metal hydroxides, and metal carbonates. Further 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; the metal carbonate includes at least one of calcium carbonate and magnesium carbonate.

[0056] In current applications, the degradability of temporary plugging agents at low temperatures is very important. The degradation promoter used in the present invention slowly releases hydroxide in the formation environment, promoting the degradation of the degradable fiber line, so that the temporary plugging fiber group can be quickly degraded even at low temperatures. According to tests, the temporary plugging fiber group of the present invention can play a good temporary plugging effect at 40-200°C, greatly expanding its scope of use.

[0057] In some preferred embodiments, Figure 1 As shown, the temporary plugging fiber group of the present invention further includes a coating layer 3; the coating layer 3 is arranged between the degradable fiber line 1 and the degradation accelerator 2.

[0058] The present invention can effectively delay the release rate of the degradation accelerator by coating the inner core degradation accelerator with a coating layer. Further preferably, the coating layer is made of polyvinyl alcohol with a molecular weight of 50,000 to 100,000.

[0059] In a second aspect, the present invention also provides a method for preparing the temporary plugging fiber cluster, comprising:

[0060] S1: making the degradation promoter into a core;

[0061] S2: Winding the degradable fiber thread on the inner core to obtain a temporary plugging fiber mass.

[0062] In some preferred embodiments, the inner core is ellipsoidal in shape.

[0063] In order to delay the release rate of the degradation accelerator, in some preferred embodiments, the present invention further comprises coating molten polyvinyl alcohol on the core.

[0064] The coating amount of the polyvinyl alcohol can be adjusted according to the weight of the degradable fiber material and the degradation accelerator, the degradation time, the temperature and other process parameters. In some optional embodiments, the thickness of the coated polyvinyl alcohol film is 40 to 150 microns.

[0065] The parameters such as raw materials and proportions used in preparing the temporary plugging fiber cluster are the same as those in the temporary plugging fiber cluster disclosed in the first method of the present invention, and the present invention does not make repeated limitations here.

[0066] In a third aspect, the present invention further provides a method for using the temporary plugging fiber mass, comprising:

[0067] S11: Pumping part of the total material into the fracturing well according to the first displacement;

[0068] S12: adding the temporary plugging fiber mass;

[0069] S13: pumping the delivery liquid according to the second displacement to deliver the temporary plugging fiber group to the reservoir position;

[0070] S14: Inject the remaining total material into the fracturing well according to the first displacement, and complete the construction.

[0071] Figure 3 The mechanism of action of the temporary plugging fiber group of the present invention is shown. Figure 3 It can be seen that the fiber mass is pumped to the perforation through the fracturing fluid. As the pumping pressure increases, the fiber part of the fiber mass deforms under the action of pressure, completely blocking the irregular perforations, forcing the fracturing fluid to turn to other unused perforations and press open the unused perforations. Under the formation temperature and pressure, the degradation accelerator is released to promote the rapid degradation of the fiber. Finally, the fiber mass is completely degraded, restoring the flow channel that blocks the perforations.

[0072] In some optional embodiments, the total material includes: fracturing fluid, proppant; the transport fluid includes fracturing fluid base fluid, that is: uncrosslinked fracturing fluid. Among them, fracturing fluid, proppant, fracturing fluid base fluid, etc. are all well known in the prior art, and the present invention does not specifically limit them.

[0073] In some preferred embodiments, the second displacement is smaller than the first displacement, and the second displacement is 1 to 3 m 3 / min.

[0074] In some preferred embodiments, the number of the temporary plugging fiber clusters is:

[0075] N 暂堵纤维团 =N 射孔孔眼数 ×50%×η

[0076] Among them, N 暂堵纤维团 is the number of temporary plugging fiber clusters, pieces;

[0077] N 射孔孔眼数 is the number of perforation holes, pcs;

[0078] η is the safety factor, dimensionless, and ranges from 1 to 2.

[0079] Further preferably, the safety factor is between 1.2 and 1.5.

[0080] In some preferred embodiments, the diameter of the temporary plugging fiber group is 1 to 4 times the diameter of the perforation hole.

[0081] In some preferred embodiments, the temporary plugging fiber mass is introduced by a stopcock, directly introduced into a high-pressure pipeline, or directly introduced through a wellhead.

[0082] In a fourth aspect, the present invention also provides the use of the temporary plugging fiber group in oil production.

[0083] The temporary plugging fiber group of the present invention has the advantages of low density, deformation, controllable degradation time, degradability at low temperature, high plugging strength, non-toxicity and environmental protection, and can meet the temporary plugging fracturing construction requirements of fracturing acidizing perforations at different formation temperatures.

[0084] Example

[0085] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods without specific conditions in the following examples are based on conventional methods and conditions. The raw materials used in the following examples are all commercially available.

[0086] The raw material molecular weights used in each embodiment are summarized as follows:

[0087] Polyvinyl alcohol, the product molecular weight is about 75,000; polylactic acid fiber filament, the product molecular weight is about 60,000; polyglycolic acid fiber filament, the product molecular weight is about 60,000; polyethylene terephthalate fiber filament, the product molecular weight is about 20,000.

[0088] Example 1

[0089] 3.4g of calcium oxide was made into an ellipsoidal degradation promoter core, and molten polyvinyl alcohol was coated on its surface, and the thickness of the polyvinyl alcohol film was 80±5μm. 30 polylactic acid fiber filaments with a cross-sectional diameter of 12μm were used to form a fiber line, and 13.5g of polylactic acid fiber line was weighed to wrap the degradation promoter core into a ball, forming a temporary plugging fiber ball with a diameter of 30-32mm.

[0090] Example 2

[0091] 2.5g of a mixture of calcium oxide and calcium hydroxide in a mass ratio of 1:1 was made into an ellipsoidal degradation promoter core, and molten polyvinyl alcohol was coated on its surface, and the thickness of the polyvinyl alcohol film was 50±5μm. Five polylactic acid fiber filaments with a cross-sectional diameter of 15μm and 20 polyglycolic acid fiber filaments with a cross-sectional diameter of 15μm were used to form a fiber line. 15g of fiber line was weighed, and the core was wound into a ball to form a temporary plugging fiber ball with a diameter of 29-31mm.

[0092] Example 3

[0093] 2.5g of a mixture of calcium oxide and calcium carbonate with a mass ratio of 1:3 was made into an ellipsoidal degradation promoter core, and molten polyvinyl alcohol was coated on its surface, and the thickness of the polyvinyl alcohol film was 120±5μm. Ten polylactic acid fiber filaments with a cross-sectional diameter of 15μm and five polyethylene terephthalate fiber filaments with a cross-sectional diameter of 15μm were used to form a fiber line. 18g of fiber line was weighed, and the degradation promoter core was wound into a ball to form a temporary plugging fiber ball with a diameter of 32-34mm.

[0094] Example 4

[0095] 1.5g of sodium hydroxide was made into an ellipsoidal degradation promoter core. 30 polylactic acid fiber filaments with a cross-sectional diameter of 14 μm were used to form a fiber line, and 3.8g of polylactic acid fiber line was weighed to wrap the degradation promoter core into a ball, forming a temporary plugging fiber ball with a diameter of 19 to 21 mm.

[0096] Performance Testing

[0097] The performance of the temporary plugging fiber cluster prepared in the above embodiment was tested. The specific test method is as follows, and the test results are shown in Table 1.

[0098] 1. Degradation time test

[0099] Take a 100mL centrifuge tube and place it in a 105℃ constant temperature drying oven to keep constant weight (accurate to 0.01g), record its mass as m 1 Take a clean sealed container (a hydrothermal synthesis reactor is used for the samples of Examples 1 and 3, and a temperature-resistant reagent bottle is used for the samples of Examples 2 and 4), and put 100 mL of the test liquid in each container. The test liquid is distilled water.

[0100] Weigh the temporary plugging fiber mass sample to an accuracy of 0.01 g and record the mass as m 2 , put it into a sealed container filled with distilled water to disperse the sample evenly in the test liquid. Seal the sealed container and put it into a water bath or drying oven that has been heated to a constant temperature (a constant temperature water bath is used for the samples of Examples 2 and 4, and a constant temperature drying oven is used for the samples of Examples 1 and 3), take it out after degradation, and record the degradation time.

[0101] 2. Compression strength test

[0102] The pressure strength test system is mainly composed of an injection pump, a high-pressure chamber, a ball rack, a constant temperature device (oven or electric heating jacket), etc.

[0103] a) According to the diameter of the fiber cluster, select a ball rack with a ball-aperture ratio of 1.4 to 1.6;

[0104] b) Adhere the fiber mass to the hole of the ball rack on the ball rack with glass glue;

[0105] c) After the glass glue solidifies, install the ball rack into the outlet of the high-pressure cavity, and tighten the ball rack and the high-pressure cavity thread through the tetrafluoroethylene pad at the end of the ball rack to ensure the sealing of the test mold;

[0106] d) Connect the system according to the process;

[0107] e) Sealing test: Connect the injection pump to the injection end of the high-pressure chamber, set the pressure to 0.5MPa, open the valve and adjust the displacement to 10mL / min. If liquid flows out of the outlet, stop the injection and take another fiber ball for testing;

[0108] f) Set the heating rate to 5°C / min, heat the system to the test temperature, and keep the temperature constant for 5 minutes;

[0109] g) Set the maximum injection pressure to 40MPa. Adjust the displacement to 5mL / min, hold the pressure, and observe the pressure.

[0110] h) When the pressure rises and reaches 40MPa, the constant pressure is maintained at 40±0.5MPa without pressure drop, then the test is terminated and the pressure difference is recorded as 40MPa. If the test pressure reaches 40MPa but the constant pressure time is less than 60min, or the test pressure does not reach 40MPa, then the test is stopped. The pressure difference is recorded as less than 40MPa.

[0111] Table 1 Summary of temporary plugging fiber group performance of Examples 1 to 4

[0112] Serial number sample Dissolving temperature, °C Degradation time, h Compression strength, MPa 1 Example 1 120 96 40 2 Example 2 90 132 40 3 Example 3 200 72 40 4 Example 4 40 156 40

[0113] It can be seen from Table 1 that the temporary plugging fiber group of the present invention can be degraded at 40-200° C. and has a compressive strength of up to 40 MPa.

[0114] Application Example 1

[0115] The temporary plugging fiber mass prepared in Example 1 was used for fracturing construction in Well X, where the perforation diameter was 11.7 mm, and 5 clusters of perforations were used, with a total of 120 holes. The construction steps were as follows:

[0116] S1: 5m 3 / min pump a portion of the predetermined total material into the fracturing well and perform construction (main ① fracturing);

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

[0118] S3: Reduce the displacement to 2.2-2.7 m3 / min, use the conveying fluid to deliver the fiber mass to the reservoir position, when the injection fluid volume is 43 m3, the wellhead pressure increases from 33.2 MPa to 37.14 MPa, and the temporary plugging is obvious;

[0119] S4: The remaining part of the predetermined total material is pumped into the fracturing well to complete the construction (main ② fracturing).

[0120] Figure 4This is the fracturing operation curve of Well X. Among them, main ① fracturing (S1): operation displacement 5.0m3 / min, maximum operation pressure 47.32MPa, sand ratio 5%-8%-12%-16%-20%-24%-28%-32%-36%, cumulative sand-carrying liquid volume 290.3m3, cumulative sand volume 25.1m3, stop pumping for 21min and the surface pressure drops from 28.85MPa to 15.51MPa; put in 73 temporary plugging fiber groups (S2), displacement 2.2~2.7m3 / min, injection volume 43 m3, the wellhead pressure increased from 33.2MPa to 37.14MPa, temporary plugging was obvious, and the main fracturing construction (S3) stage was switched; main fracturing (S3): construction displacement 5.0m3 / min, maximum construction pressure 46.18MPa, sand ratio 5%-9%-13%-18%-23%-28%-32%-36%, cumulative sand-carrying liquid volume 268.3m3, cumulative sand volume 25.0m3, and the surface pressure dropped from 22.59MPa to 0MPa after the pump was stopped for 54min.

[0121] The overall construction parameters are consistent with the process design, and the overall construction pressure is stable, indicating the normal extension of the cracks and the smooth migration of the proppant. At the same time, the temporary plugging is obvious, indicating that the temporary plugging has achieved the purpose of opening new cracks and balanced fracturing.

[0122] Figure 5 This is an analysis diagram of the high-frequency inlet point position of the X-well fracturing operation. High-frequency pressure monitoring shows that the main inlet points of the main ① fracturing are 3988m, 4008m, and 4020m. After the temporary plugging of the fiber group, the main inlet points of the main ② fracturing are 4002m and 4026m. The diversion effect is obvious, which is consistent with the temporary plugging pressure response, indicating that this technology has achieved the purpose of improving the vertical transformation degree of the reservoir section in the large-span thin interlayer.

[0123] Figure 6 This is a simulation diagram after fracturing of Well X. From the post-fracturing fitting fracture morphology, it can be seen that the fractures formed in this well are longer and higher, and the fiber ball temporary plugging and flow control fracturing technology has achieved the purpose of balanced reservoir transformation and large-scale fracture creation.

[0124] The present invention has been disclosed above with preferred embodiments, but those skilled in the art should understand that these embodiments are only used to describe the present invention and should not be understood as limiting the scope of the present invention. It should be noted that all changes and substitutions equivalent to these embodiments should be deemed to be included in the scope of the claims of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined in the claims.

Claims

1. A temporary plugging fiber group, characterized in that: include: A degradable fiber line and a degradation accelerator; wherein the degradable fiber line is wound around the outside of the degradation accelerator.

2. The temporary plugging fiber group according to claim 1, characterized in that: It also includes a coating layer; the coating layer is arranged between the degradable fiber line and the degradation accelerator.

3. The temporary plugging fiber cluster according to claim 1, characterized in that: In terms of weight, the degradable fiber line is 70 to 95 parts by weight, and the degradation accelerator is 5 to 30 parts by weight.

4. The temporary plugging fiber cluster according to claim 1, characterized in that: In terms of weight, the degradable fiber line is 70 to 80 parts by weight, and the degradation accelerator is 20 to 30 parts by weight.

5. The temporary plugging fiber cluster according to claim 1, characterized in that: The material of the degradable fiber line is polyester material.

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

7. The temporary plugging fiber cluster according to claim 1, characterized in that: The degradation accelerator includes at least one of metal oxides, metal hydroxides and metal carbonates.

8. The temporary 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 temporary plugging fiber cluster according to claim 2, characterized in that: The material of the coating layer includes polyvinyl alcohol.

10. The temporary plugging fiber cluster according to claim 1, characterized in that: The degradable fiber line consists of 10 to 30 fiber filaments.

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

12. The method for preparing the temporary plugging fiber cluster according to any one of claims 1 to 11, characterized in that: include: S1: making the degradation promoter into a core; S2: Winding the degradable fiber thread on the inner core to obtain a temporary plugging fiber mass.

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

14. The preparation method according to claim 12, characterized in that: The inner core is in the shape of an ellipsoid.

15. A method for using a temporary plugging fiber group, characterized in that: include: S11: Pumping part of the total material into the fracturing well according to the first displacement; S12: adding the temporary plugging fiber mass according to any one of claims 1 to 11; S13: pumping the delivery liquid according to the second displacement to deliver the temporary plugging fiber group to the reservoir position; S14: Inject the remaining total material into the fracturing well according to the first displacement, and 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 1 to 3 m 3 / min.

17. The method of use according to claim 15, characterized in that: The number of the temporary plugging fiber clusters is: N 暂堵纤维团 =N 射孔孔眼数 ×50%×η Among them, N 暂堵纤维团 is the number of temporary plugging fiber clusters, pieces; N 射孔孔眼数 is the number of perforation holes, pcs; η is the safety factor, 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 group is 1 to 4 times the diameter of the perforation hole.

19. Use of the temporary plugging fiber mass according to any one of claims 1 to 11 in oil extraction.

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