A method for adding temporary plugging agent in dynamic temporary plugging of tight gas horizontal wells

Abstract

The present invention discloses a method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well, comprising the following steps: S1. establishing a single-cluster hole abrasion model using Ansys finite element analysis software; S2. calibrating the model through an indoor hole abrasion experiment; S3. simulating the fracturing process using the model in S1 and obtaining the hole friction resistance P. perf , hole diameter after pressing D ave ; S4. After the fracturing, perform a step-down test and obtain the total hole friction resistance P through the fracturing analysis software perf总 S5. Determine the number of perforation clusters to be opened and determine the dosage of temporary plugging agent. The method for adding temporary plugging agent for dynamic temporary plugging of tight gas horizontal wells provided by this invention combines laboratory experiments with numerical simulations to achieve precise placement of temporary plugging agent, improve the success rate of dynamic temporary plugging, increase the fracturing stimulation volume, and enhance post-fracturing production capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of reservoir transformation, and particularly relates to a method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well. Background Art

[0002] In recent years, through continuous research, the Changqing tight gas horizontal wells have developed a segmented multi-cluster transformation technology with inter-segment bridge plug separation, intra-segment flow-limiting fracturing + dynamic temporary plugging.

[0003] Currently, the following problems still exist in staged multi-cluster fracturing of horizontal wells:

[0004] ① The perforation clusters within a section do not fracture, fracture unevenly, and have large variations in gas production contribution, significantly reducing the fracturing volume and severely impacting post-fracturing productivity. ② Currently, dynamic temporary plugging is used to achieve balanced expansion of the perforation clusters, but there is a lack of an optimized method for temporary plugging agent dosage. ③ During the fracturing process, the perforation shapes change irregularly due to abrasion, which affects the determination of the temporary plugging agent dosage.

[0005] Research indicates that currently available methods for optimizing temporary plugging agent dosage are difficult to apply to dynamic temporary plugging of tight gas horizontal wells in the Changqing Basin. For example, Zhao Xurong et al., in their paper "Study on Optimization of Temporary Plugging Agent Dosage Combinations Based on the Pressurization Effect of Shallow-Medium Wells," optimized temporary plugging agent dosage for a specific block based on multiple field tests. However, this method lacks theoretical support.

[0006] Patent publication number CN111502593A discloses a method for determining the dosage of a phase-change temporary plugging agent for temporary plugging within fractures, Patent publication number CN113705011A discloses a method for determining the timing of temporary plugging and optimizing the dosage of temporary plugging materials based on fracture expansion morphology, and Patent publication number CN111980652A discloses a method for determining the type, size combination, and dosage of temporary plugging agents within fractures. These patents all disclose methods for optimizing the dosage of temporary plugging agents for temporary plugging within fractures or for sealing purposes. However, these methods are not applicable to the dynamic temporary plugging of Changqing tight gas horizontal wells, which use blasthole temporary plugging. Crump's article SPE-15474-PA describes a method for determining borehole friction and blasthole morphology through laboratory experiments. However, the large amounts of sand and fluid required for fracturing Changqing tight gas horizontal wells make laboratory experiments difficult. Summary of the Invention

[0007] The present invention provides a method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well, aiming to apply the provided design method to improve the balanced expansion of perforation clusters, thereby improving the effectiveness of the perforation clusters and increasing the post-fracturing productivity.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well comprises the following steps:

[0010] S1. Establish a single-cluster hole abrasion model using Ansys finite element analysis software;

[0011] S2. Calibrate the single-cluster hole abrasion model established in S1 through indoor hole abrasion experiments;

[0012] S3. Use the single cluster hole abrasion model established in S1 to simulate the fracturing process and obtain the hole friction resistance P perf , hole diameter after pressing D ave ;

[0013] S4. After fracturing, perform a step-down flow test and obtain the total perforation friction resistance Pperf using fracturing analysis software;

[0014] S5. Determine the number of perforation clusters to be opened and determine the amount of temporary plugging agent to be added.

[0015] Furthermore, the single-cluster hole abrasion model established by the Ansys finite element analysis software in step S1 is a solid-liquid bidirectional coupling mathematical model.

[0016] Furthermore, the model in step S1 takes into account the abrasive effect of the fracturing proppant on the perforation, and the abrasion model uses Long's calculation model:

[0017]

[0018]

[0019] Where: D0 is the initial hole diameter, mm;

[0020] C e is the proppant concentration, kg / m 3 ;

[0021] v is the flow velocity of the liquid through the hole in m / s;

[0022] C d is the flow coefficient;

[0023] α and β are the hole abrasion coefficients.

[0024] Furthermore, the indoor hole abrasion experiment S2 calibrates the single-cluster hole abrasion model established in S1, wherein the calibration parameters include hole abrasion coefficients α and β. The calibration operation method specifically includes the following steps:

[0025] The S2 indoor hole abrasion experiment calibrates the single cluster hole abrasion model established in S1, wherein the calibration parameters include hole abrasion coefficients α and β. The calibration operation method specifically includes the following steps:

[0026] S201, conduct a borehole abrasion test under certain casing size, displacement, sand concentration and pumping program to obtain the borehole friction resistance at the end of the test;

[0027] S202, using the single-cluster hole abrasion model established in S1 to simulate under the same parameters, repeatedly changing the hole abrasion coefficients α and β until the error between the hole friction results simulated by the single-cluster hole abrasion model and the experimental results is less than 0.1 MPa;

[0028] S203, changing the casing size, displacement, sand concentration and pumping program, and repeating steps S201 and S202 multiple times until the borehole abrasion coefficients α and β under different experimental conditions can meet the error between the simulated borehole friction resistance result and the experimental result <0.1MPa.

[0029] Preferably, the casing in the above steps uses the same steel grade and size as on-site casing.

[0030] Preferably, the types and proportions of the fracturing fluid and proppant in step S2 are the same as those on site.

[0031] Preferably, in step S2, the model is calibrated by performing an indoor abrasion test at a small displacement and a small sand ratio.

[0032] Preferably, the experimental device used in the indoor hole abrasion experiment is an indoor hole abrasion experimental device, which includes a tank body, a liquid storage tank, a liquid inlet pipeline and a return pipeline. A transverse casing is provided in the tank body, and a plurality of perforation holes are arranged at intervals on the transverse casing, and a pressure sensor is installed on each perforation hole; one end of the liquid inlet pipeline is connected to the liquid outlet of the liquid storage tank, and the other end of the liquid inlet pipeline extends into the tank body and is connected to the liquid inlet of the transverse casing, and the liquid outlet of the transverse casing is connected to the liquid inlet of the liquid storage tank through the return pipeline, and a horizontal flow pump and a pressure gauge are installed on the liquid inlet pipeline, and the pressure gauge is located between the horizontal flow pump and the liquid inlet of the tank body.

[0033] Furthermore, in step S3, the single cluster hole abrasion model established in S1 is used to simulate the fracturing process and obtain the hole friction resistance P perf , hole diameter after pressing D ave The specific operation method is:

[0034] The single cluster hole abrasion model established by Ansys finite element analysis software is used to simulate the fracturing process and obtain the hole friction resistance P at the end time. perf , hole diameter after pressing D ave .

[0035] Preferably, the liquid volume and sand volume in the above simulation experiment are the same as those in the on-site pumping procedure.

[0036] During the simulated fracturing experiment, the pressure values ​​at both ends of the perforation holes are read. perf is the sum of the pressure differences of each perforation hole;

[0037] During the simulated fracturing experiment, the fluid is a mixture of fracturing fluid and sand, which will cause abrasion on the perforations when passing through them. At the end of the experiment, the perforations are abraded from their original regular circles to irregular circles. The diameter corresponding to the area of ​​the irregular circle is the post-fracturing hole diameter Dave.

[0038] Furthermore, the specific operation of the step-by-step displacement reduction test after the medium pressure in step S4 is as follows: for the fracturing section that needs temporary plugging, after all the liquid is pumped into the first-stage fracturing, the displacement is gradually reduced in a step-by-step manner, wherein the step-by-step displacement reduction has at least 3 steps, and the highest displacement does not exceed the minimum displacement in the pumping program of the fracturing section. After the pressure stabilizes at each displacement, it is reduced to the next step, and the time for each displacement is not less than 3 minutes.

[0039] Furthermore, the number n of perforation clusters opened in step S5 is obtained by the following formula:

[0040]

[0041] Where, P perf is the hole friction, P perf总 is the total hole friction.

[0042] Furthermore, the principle of adding temporary plugging agent is For: When D ave ≤1.2D0, temporary plugging agent input amount n a =1.0n ρ ;

[0043] When D ave >1.2D0, temporary plugging agent input

[0044] where n p =n×ρ 孔

[0045] Where n p is the number of holes opened;

[0046] ρ 孔 is the number of perforations in a single cluster.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention achieves precise delivery of temporary plugging agents through a method combining indoor experiments with numerical simulations, improves the success rate of dynamic temporary plugging, increases the volume of fracturing transformation, and improves post-fracturing production capacity.

[0049] 2. The present invention can carry out differentiated design of temporary plugging agents required for each fracturing stage, and realize precise control of the amount of temporary plugging agents added.

[0050] 3. The amount of temporary plugging agent to be added is determined on-site based on experience. The present invention fills the gap in the current method of adding temporary plugging agent.

[0051] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other design solutions and drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 This is a flow chart of the method for adding temporary plugging agent in dynamic temporary plugging of tight gas horizontal wells;

[0054] Figure 2 Schematic diagram of the indoor hole abrasion experimental device.

[0055] Description of reference numerals:

[0056] 1. Tank body;

[0057] 101, transverse casing; 102, perforation holes;

[0058] 2. Liquid storage tank;

[0059] 3. Horizontal flow pump;

[0060] 4. Liquid inlet pipeline;

[0061] 5. Return line;

[0062] 6. Pressure gauge. DETAILED DESCRIPTION

[0063] The present invention can be further understood by reference to the following detailed description of the preferred embodiments of the present invention and the included Examples. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in the present invention, the definition of the term provided in the present invention shall prevail.

[0064] Reference Figure 1The present invention provides a method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well, comprising the following steps:

[0065] S1. Establish a single-cluster hole abrasion model using Ansys finite element analysis software;

[0066] S2. Calibrate the single-cluster hole abrasion model established in S1 through indoor hole abrasion experiments;

[0067] S3. Use the single cluster hole abrasion model in S1 to simulate the fracturing process and obtain the hole friction resistance P perf , hole diameter after pressing D ave ;

[0068] S4. After fracturing, conduct a step-down flow rate test and obtain the total perforation friction resistance P through fracturing analysis software. perf总 ;

[0069] S5. Determine the number of perforation clusters to be opened and determine the amount of temporary plugging agent to be added.

[0070] Furthermore, the single-cluster hole abrasion model established by Ansys finite element analysis software is a solid-liquid bidirectional coupling mathematical model.

[0071] The method of establishing a single cluster hole abrasion model using Ansys finite element analysis software specifically includes:

[0072] S101: Build a geometric model based on the actual wellbore structure data of the target well. Since the wellbore structure of the actual well is relatively complex, the modeling process should ensure that the geometric model is consistent with the measured depth of the benchmark well and that the model fits the actual wellbore structure of the target well as closely as possible.

[0073] S102, meshing, meshing the constructed geometric model

[0074] You can choose to divide the grid automatically or customize it. When dividing the grid, be careful not to divide the grid too finely, which will cause the model to take too long to run, nor too coarsely, which will cause inaccurate results.

[0075] S103, setting material parameters, including elastic modulus, Poisson's ratio, friction coefficient, etc., according to the actual wellbore material of the target well;

[0076] S104: Generate a single-cluster hole abrasion model.

[0077] Considering the abrasive effect of fracturing proppant on the perforations, the single cluster perforation abrasion model in step S1 uses Long's calculation model:

[0078]

[0079]

[0080] Where: D0 is the initial hole diameter, mm;

[0081] C e is the proppant concentration, kg / m 3 ;

[0082] v is the flow velocity of the liquid through the hole in m / s;

[0083] C d is the flow coefficient;

[0084] t is time, s;

[0085] α and β are the hole abrasion coefficients.

[0086] The single-cluster hole abrasion model established by S1 was calibrated using an indoor hole abrasion experimental device. The calibration parameters include hole abrasion coefficients α and β. The calibration operation method includes:

[0087] S201, conduct a borehole abrasion test under certain casing size, displacement, sand concentration and pumping program to obtain the borehole friction resistance at the end of the test;

[0088] S202, using the single-cluster hole abrasion model established in S1 to simulate under the same parameters, repeatedly changing the hole abrasion coefficients α and β until the error between the hole friction results simulated by the single-cluster hole abrasion model and the experimental results is less than 0.1 MPa;

[0089] S203, changing the casing size, displacement, sand concentration and pumping program, and repeating steps S201 and S202 multiple times until the borehole abrasion coefficients α and β under different experimental conditions can meet the error between the simulated borehole friction resistance result and the experimental result <0.1MPa.

[0090] Specifically, refer to Figure 2 The indoor hole abrasion experimental device includes a tank body 1, a liquid storage tank 2, a liquid inlet pipeline 4 and a return pipeline 5. A transverse casing 101 is provided in the tank body 1, and a plurality of perforation holes 102 are arranged at intervals on the transverse casing 101. A pressure sensor 103 is installed on each perforation hole 102; one end of the liquid inlet pipeline 4 is connected to the liquid outlet of the liquid storage tank 2, and the other end of the liquid inlet pipeline 4 extends into the tank body 1 and is connected to the liquid inlet of the transverse casing 101. The liquid outlet of the transverse casing 101 is connected to the liquid inlet of the liquid storage tank 2 through the return pipeline 5. A horizontal flow pump 3 and a pressure gauge 6 are installed on the liquid inlet pipeline 4, and the pressure gauge 6 is located between the horizontal flow pump 3 and the liquid inlet of the tank body 1.

[0091] It should be noted that the casing used in the above steps is of the same steel grade and size as that used on site.

[0092] Furthermore, the single cluster hole abrasion model established by S1 is used to simulate the fracturing process and obtain the hole friction resistance P perf , hole diameter after pressing D ave The specific operation method is:

[0093] The single cluster hole abrasion model established by Ansys finite element analysis software is used to simulate the fracturing process and obtain the hole friction resistance P at the end time. perf , hole diameter after pressing D ave .

[0094] During the simulated fracturing experiment, the fluid will generate a pressure difference at both ends of the perforation hole. The sum of the pressure differences of each perforation hole is the perforation friction P. perf , which is obtained from the pressure counter values ​​at both ends of the perforation hole.

[0095] During the simulated fracturing experiment, the fluid is a mixture of fracturing fluid and sand, which will cause abrasion on the perforations when passing through them. At the end of the experiment, the perforations are abraded from their original regular circles to irregular circles. The diameter corresponding to the area of ​​the irregular circle is the post-fracturing hole diameter Dave.

[0096] It should be further explained that the amount of liquid and sand used in the simulated fracturing process in step S3 are the same as those in the on-site pumping procedure.

[0097] Furthermore, the specific operation of the step-by-step flow reduction test after the intermediate pressure in step S4 is as follows: for the fracturing section requiring temporary plugging, after all the fluid has been pumped into the first stage of the fracturing, the flow rate is gradually reduced in a step-by-step manner. Preferably, the step-by-step flow reduction consists of at least three steps, with the highest flow rate not exceeding the minimum flow rate in the pumping program for that fracturing section. After the pressure stabilizes at each flow rate, it is reduced to the next step, and each flow rate is maintained for at least three minutes.

[0098] Specifically, the fracturing analysis software in step S4 includes FracproPT, Meyer or Stimplan.

[0099] The number of perforation clusters n opened in step S5 is obtained by the following formula:

[0100]

[0101] Where, P perf is the hole friction, P perf总 is the total hole friction.

[0102] The principle of adding temporary plugging agent in step S5 is: when the hole diameter D ave ≤1.2D0, temporary plugging agent input amount n a =1.0n ρ ; After pressing, the hole diameter D ave >1.2D0, temporary plugging agent input

[0103] Among them, n p =n×ρ 孔

[0104] Where n p is the number of holes opened;

[0105] ρ 孔 is the number of perforations in a single cluster.

[0106] In a specific embodiment, a method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well includes the following steps:

[0107] S1. Establish a single cluster hole abrasion model using Ansys finite element analysis software;

[0108] S2. Calibrate the model through indoor hole abrasion experiments;

[0109] S3. Simulate the fracturing process through the model in S1 and obtain the hole friction resistance P perf , hole diameter after pressing D ave ;

[0110] S4. After fracturing, conduct a step-down flow rate test and obtain the total perforation friction resistance P through fracturing analysis software. perf总 ;

[0111] S5. Determine the number of perforation clusters to be opened and determine the amount of temporary plugging agent to be added.

[0112] Furthermore, in step S1, a solid-liquid bidirectional coupling mathematical model is established using Ansys finite element analysis software.

[0113] Furthermore, the model in step S1 takes into account the abrasive effect of the fracturing proppant on the perforation, and the abrasion model uses Long's calculation model:

[0114]

[0115]

[0116] Furthermore, in step S2, the casing is of the same steel grade and size as on-site, namely, steel grade P110, casing outer diameter 114.3 mm, wall thickness 7.37 mm, and initial hole diameter 9.7 mm.

[0117] Furthermore, the types and proportions of the fracturing fluid and proppant in step S2 are the same as those used on site: guar gum is used as the fracturing fluid, and 40 / 70 mesh quartz sand is used as the proppant.

[0118] Furthermore, the model correction parameters in step S2 include the hole abrasion coefficients α and β. After correction, when α=1.2*10-13 β=2.0*10 -8 When the model simulation results are compared with the experimental results, the error is less than 0.1MPa.

[0119] Furthermore, in step S3, the model established in S1 is used to simulate perforation erosion during the fracturing process, and the pressure differential inside and outside the perforation and the post-fracturing perforation diameter are obtained. The simulation results show a pressure differential of 5.6 MPa and a post-fracturing perforation diameter of 11.3 mm.

[0120] Furthermore, in the step S4, for the fracturing section that needs temporary plugging, after all the liquid is pumped into the first stage fracturing, the displacement is gradually reduced in a step-down manner.

[0121] Preferably, the stepwise reduction of displacement in step S4 has at least three steps, and the pressure is reduced to the next step after stabilization at each displacement, and the time for each displacement is not less than 3 minutes.

[0122] Furthermore, the number n of perforation clusters opened in step S5 is obtained by the following formula:

[0123]

[0124] Furthermore, the number of holes opened in step S5 is n. p Obtained by the following formula:

[0125] n p =n×ρ 孔 =3×16=48;

[0126] where is the number of perforations in a single cluster.

[0127] Furthermore, the principle of adding temporary plugging agent in step S5 is: when D ave ≤1.2D0, temporary plugging agent input amount n a =1.0n p When D ave >1.2D0, temporary plugging agent input

[0128] In this embodiment, D ave ≤1.2D0, the amount of temporary plugging agent input is n a =1.0n p =48.

[0129] In summary, the method for adding temporary plugging agent in the dynamic temporary plugging of tight gas horizontal wells provided by the present invention combines indoor experiments with numerical simulations to achieve precise delivery of temporary plugging agent, improve the success rate of dynamic temporary plugging, increase the fracturing transformation volume, and improve the post-fracturing production capacity.

[0130] The above describes the preferred embodiments of the present invention, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well, characterized in that: The steps include: S1. Establish a single-cluster hole abrasion model using Ansys finite element analysis software; S2. Calibrate the single-cluster hole abrasion model established in S1 through an indoor hole abrasion experiment, wherein the calibration parameters include hole abrasion coefficients α and β. The calibration operation method specifically includes the following steps: S201, conduct a borehole abrasion test under certain casing size, displacement, sand concentration and pumping program to obtain the borehole friction resistance at the end of the test; S202, using the single-cluster hole abrasion model established in S1 to simulate under the same parameters, repeatedly changing the hole abrasion coefficients α and β until the error between the hole friction results simulated by the single-cluster hole abrasion model and the experimental results is less than 0.1 MPa; S203, changing the casing size, displacement, sand concentration and pumping program, repeating steps S201 and S202 multiple times until the borehole abrasion coefficients α and β under different experimental conditions can meet the error between the simulated borehole friction results and the experimental results <0.1MPa; S3. Use the single cluster hole abrasion model established in S1 to simulate the fracturing process and obtain the hole friction resistance P perf , hole diameter after pressing D ave ; S4. After fracturing, conduct a step-down flow rate test and obtain the total perforation friction resistance P through fracturing analysis software. perf总 ; S5. Determine the number of perforation clusters to be opened and determine the amount of temporary plugging agent to be added. The number of perforation clusters to be opened, n, is obtained by the following formula: Where, P perf is the hole friction, P perf总 is the total hole friction; The principle of adding temporary plugging agent is: After pressing, the hole diameter D ave ≤1.2D0, temporary plugging agent input amount n a =1.0n ρ ; After pressing, the hole diameter D ave >1.2D0, temporary plugging agent input ; in, Where D0 is the initial hole diameter, mm; n p is the number of holes opened; ρ 孔 is the number of perforations in a single cluster.

2. The method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well according to claim 1, characterized in that: The single-cluster hole abrasion model established by the Ansys finite element analysis software in step S1 is a solid-liquid bidirectional coupling mathematical model.

3. The method for adding temporary plugging agent in dynamic temporary plugging of tight gas horizontal wells according to claim 1, characterized in that: The single-cluster hole abrasion model in step S1 uses Long's calculation model, specifically: Where: D0 is the initial hole diameter, mm; C e is the proppant concentration, kg / m 3 ; v is the flow velocity of the liquid through the hole in m / s; C d is the flow coefficient; t is time, s; α and β are the hole abrasion coefficients.

4. The method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well according to claim 1, characterized in that: The experimental device used in the indoor borehole abrasion experiment is an indoor borehole abrasion experimental device, which comprises a tank body (1), a liquid storage tank (2), a liquid inlet pipeline (4) and a return pipeline (5). A transverse casing (101) is provided in the tank body (1), and a plurality of perforated holes (102) are arranged at intervals on the transverse casing (101). A pressure sensor is installed on each perforated hole (102); one end of the liquid inlet pipeline (4) is connected to the liquid outlet of the liquid storage tank (2), and the other end of the liquid inlet pipeline (4) extends into the tank body (1) and is connected to the liquid inlet of the transverse casing (101). The liquid outlet of the transverse casing (101) is connected to the liquid inlet of the liquid storage tank (2) through the return pipeline (5). A horizontal flow pump (3) and a pressure gauge (6) are installed on the liquid inlet pipeline (4), and the pressure gauge (6) is located between the horizontal flow pump (3) and the liquid inlet of the tank body (1).

5. The method for adding temporary plugging agent in dynamic temporary plugging of tight gas horizontal wells according to claim 1, characterized in that: In step S3, the single-cluster hole abrasion model established in step S1 is used to simulate the fracturing process and obtain the hole friction P perf , hole diameter after pressing D ave The specific operation method is: The single cluster hole abrasion model established by Ansys finite element analysis software is used to simulate the fracturing process and obtain the hole friction resistance P at the end time. perf , hole diameter after pressing D ave .

6. The method for adding a temporary plugging agent in dynamic temporary plugging of a tight gas horizontal well according to claim 5, characterized in that: During the simulated fracturing experiment, the pressure values ​​at both ends of the perforation holes are read. perf is the sum of the pressure differences of each perforation hole; During the simulated fracturing experiment, the fluid is a mixture of fracturing fluid and sand. When passing through the perforation holes, it will cause abrasion to the holes. At the end of the experiment, the perforation holes are abraded from the original regular circle to an irregular circle. The diameter corresponding to the area of ​​the irregular circle is the hole diameter after fracturing D. ave .

7. The method for adding temporary plugging agent in dynamic temporary plugging of tight gas horizontal wells according to claim 1, characterized in that: The specific operation of the step-by-step displacement reduction test after the medium pressure in step S4 is as follows: for the fracturing section that needs temporary plugging, after all the liquid is pumped into the first-stage fracturing, the displacement is gradually reduced in a step-by-step manner, wherein the step-by-step displacement reduction has at least 3 steps, and the highest displacement does not exceed the minimum displacement in the pumping program of the fracturing section. After the pressure stabilizes at each displacement, it is reduced to the next step, and the time for each displacement is not less than 3 minutes.

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