Fracture simulation system and method for calculating productivity of fractured gas wells considering reservoir damage

Abstract

The application provides a fracturing simulation system and a method for calculating the productivity of a fractured gas well considering reservoir damage, and the method comprises the following steps: calculating the steady-state productivity of the target fractured gas well; determining the average core damage degree of the target fractured gas well by using the fracturing simulation system; calculating the productivity correction coefficient of the target fractured gas well according to the average core damage degree; and then calculating the gas well productivity of the target fractured gas well considering the reservoir damage caused by fracturing fluid invasion. Therefore, when calculating the gas well productivity of the fractured gas well, the steady-state productivity is corrected by using the productivity correction coefficient calculated according to the average core damage degree, so that the finally obtained gas well productivity considers the reservoir damage caused by fracturing fluid invasion, and the accuracy of the productivity budget result of the fractured gas well is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil development, in particular to a fracturing simulation system and a fracturing gas well productivity calculation method considering reservoir damage caused by fracturing fluid invasion, wherein the fracturing gas well productivity calculation method uses the fracturing simulation system. BACKGROUND

[0002] Low-permeability gas reservoirs are widely distributed in China and have abundant reserves, and are the next key exploration and development objects in China. Low-permeability gas reservoirs have the characteristics of low porosity and low permeability, and industrial productivity cannot be obtained by using conventional means. Fracturing reconstruction is an important means for developing low-permeability gas reservoirs. In the fracturing process, a large amount of fracturing fluid needs to be injected into the reservoir through the wellbore quickly to make the bottom hole pressure exceed the rock fracture pressure, and then form a fracture to communicate the flow channel and improve the productivity of the gas well. However, in the fracturing process, part of the fracturing fluid will invade into the matrix pores, and due to the action of capillary pressure, this part of the fracturing fluid is difficult to drain. The fracturing fluid invading into the matrix will block the matrix pores, increase the flow resistance of the gas, cause reservoir damage, and then reduce the productivity of the fracturing gas well. However, the existing fracturing gas well does not consider the reservoir damage caused by the invasion of the fracturing fluid when calculating the productivity, so that the productivity budget result of the fracturing gas well is not accurate enough, and the predicted production of the fracturing gas well is often higher than the actual production of the gas well. SUMMARY

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a fracturing simulation system which can simulate the fracturing process and is beneficial to considering the reservoir damage caused by the invasion of the fracturing fluid when calculating the productivity of the fracturing gas well.

[0004] To achieve the above object, the present application provides a fracturing simulation system, which comprises a driving pump, an intermediate container, a core holder, a gas storage tank, a first pipeline, a second pipeline, a third pipeline and a fourth pipeline, the intermediate container is internally provided with a slidable driving piston, an injection driving cavity distributed on one side of the driving piston and a fracturing fluid cavity distributed on the other side of the driving piston, the core holder comprises a holder shell, a fixed sleeve fixedly arranged in the holder shell, an enclosed pressure cavity formed between the holder shell and the fixed sleeve, a core fixing cavity formed in the fixed sleeve, an enclosed pressure pressurizing assembly connected with the enclosed pressure cavity and a vacuum pumping assembly connected with the core fixing cavity, the enclosed pressure cavity and the core fixing cavity are not communicated with each other, the first pipeline is connected between the driving pump and the injection driving cavity, the second pipeline is connected between the fracturing fluid cavity and the core fixing cavity, the second pipeline is provided with a first valve and a second valve distributed in sequence along the direction from the fracturing fluid cavity to the core fixing cavity, the third pipeline is connected between the core fixing cavity and the gas storage tank, the third pipeline is provided with a third valve, the fourth pipeline is connected with the second pipeline and the connection points of the two pipelines are distributed between the first valve and the second valve, and the fourth pipeline is provided with a fourth valve.

[0005] Optionally, the core fixing cavity is a cylindrical cavity, and the second pipeline and the third pipeline are respectively connected to the two axial ends of the core fixing cavity.

[0006] Optionally, the fracturing simulation system further comprises a pressure gauge, the pressure gauge is installed on the third pipeline, and the pressure gauge and the third valve are distributed in sequence along the direction from the gas storage tank to the core fixing cavity.

[0007] The present application also provides a fracturing gas well productivity calculation method considering reservoir damage, which comprises the following steps:

[0008] S1, calculating the steady-state productivity Q of a target fracturing gas well;

[0009] S2, determining the average core damage degree of the target fracturing gas well by using the fracturing simulation system which comprises the following sub-steps in sequence:

[0010] S201, taking a plurality of reservoir core samples of the same specification of the target fracturing gas well, and measuring the original gas permeability K of the reservoir core samples C ;

[0011] S202, fixing one of the reservoir core samples in the core fixing cavity of the core holder;

[0012] S203, closing the second valve and the third valve, opening the enclosed pressure pressurizing assembly, until the enclosed pressure in the enclosed pressure cavity is added to the overburden pressure of the reservoir depth, then closing the enclosed pressure pressurizing assembly and opening the vacuum pumping assembly to vacuumize the reservoir core sample in the core fixing cavity;

[0013] S204, close the second valve, open the third valve, use the gas tank to saturate the reservoir core sample in the core fixing cavity with gas until the internal gas pressure of the gas tank is equal to the original formation pressure of the reservoir;

[0014] S205, close the first valve, the second valve, the third valve and the fourth valve, use the drive pump to pressurize the injection drive cavity until the pressure in the injection drive cavity is higher than the original formation pressure of the reservoir; then, open the first valve and the second valve, make the fracturing fluid in the fracturing fluid cavity inject into the reservoir core sample in the core fixing cavity, simulate the fracturing fluid injection process, the injection time is the same as the field fracturing pump-in time;

[0015] S206, close the first valve and the second valve, simulate the soak process, the soak time is the same as the field soak time;

[0016] S207, open the second valve and the fourth valve, simulate the flowback process;

[0017] S208, take out the reservoir core sample in the core fixing cavity, measure the gas-measured permeability K D after flowback of the reservoir core sample;

[0018] S209, calculate the core damage degree D according to the gas-measured permeability K D after flowback and the original gas-measured permeability K C ;

[0019]

[0020] S210, repeat the above steps S22 to S29, calculate the core damage degree Di of all reservoir core samples, and then calculate the average core damage degree

[0021] S3, calculate the productivity correction factor m of the target fracturing gas well according to the average core damage degree ;

[0022]

[0023] A=-0.001lnK+0.0018;

[0024] t=0.0055lnK+0.0325;

[0025] y0=0.0238lnK-0.1332;

[0026] K is the average permeability of the reservoir;

[0027] S4, calculate the gas well productivity Q of the target fracturing gas well considering the reservoir damage caused by fracturing fluid invasionm :

[0028] Q m = (1 - m) x Q.

[0029] Optionally, in the step S201, the number of the reservoir core samples is more than 3.

[0030] Optionally, in the step S201, the reservoir core sample is in a cylindrical shape, and the axial length of the reservoir core sample is 8.00 cm.

[0031] Optionally, in the step S205, the pressure injected into the driving cavity is 1-2 MPa higher than the original formation pressure of the reservoir.

[0032] As described above, the fracturing simulation system and the method for calculating the productivity of a fractured gas well considering reservoir damage have the following beneficial effects:

[0033] In the calculation of the productivity of a fractured gas well, the productivity correction coefficient calculated according to the average damage degree of the core is used to correct the steady-state productivity, so that the finally obtained gas well productivity considers the reservoir damage caused by the invasion of the fracturing fluid, and the accuracy of the budget result of the productivity of the fractured gas well is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 FIG. 1 is a structural schematic diagram of the fracturing simulation system in the present application.

[0035] Figure 2 FIG. 2 is a flow chart of the method for calculating the productivity of a fractured gas well considering reservoir damage in the present application.

[0036] ELEMENT NUMBER EXPLANATION

[0037] 10 driving pump

[0038] 20 intermediate container

[0039] 21 driving piston

[0040] 22 injection driving cavity

[0041] 23 fracturing fluid cavity

[0042] 30 core holder

[0043] 31 holder shell

[0044] 32 fixing sleeve

[0045] 33 confining pressure cavity

[0046] 34 core fixing cavity

[0047] 40 gas storage tank

[0048] 50 first conduit

[0049] 60 second conduit

[0050] 70 third conduit

[0051] 80 fourth conduit

[0052] 90 first valve

[0053] 110 second valve

[0054] 120 third valve

[0055] 130 fourth valve

[0056] 140 pressure gauge DETAILED DESCRIPTION

[0057] The present application is herein described, by way of example only, with reference to certain embodiments thereof. It is to be understood that variations and modifications of the embodiments can be made while still remaining within the scope of the application.

[0058] It should be noted that the structures, proportions, sizes, and the like shown in the drawings for the embodiments herein are intended to convey concepts in conjunction with the description provided herein and are presented by way of example only and, therefore, are not intended to limit the scope of the application, and as such, any modification of the structure, change of the proportion, or adjustment of the size which do not change the functions and the effects to be achieved by the present application should be construed as still falling within the scope of the present application. Also, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in the present specification are intended to facilitate the description and are not intended to limit the scope of the present application, and any change of the relative relationship or adjustment without changing the technical contents should be construed as still falling within the scope of the present application.

[0059] It is further noted that when an element such as a layer, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can also be present. In contrast, when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through one or more intervening elements.

[0060] In addition, the descriptions involving "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0061] The present application provides a fracturing simulation system and a method for calculating the productivity of a fractured gas well considering the reservoir damage caused by fracturing fluid invasion. In the following embodiments, the fractured gas well to be budgeted is defined as the target fractured gas well, and the average core damage degree of the target fractured gas well is determined by the fracturing simulation system, so as to realize the budgeted productivity of the target fractured gas well considering the reservoir damage caused by fracturing fluid invasion.

[0062] As shown in Figure 2 The method for calculating the productivity of a fractured gas well considering the reservoir damage caused by fracturing fluid invasion provided by the present application comprises the following steps.

[0063] The present application also provides a method for calculating the productivity of a fractured gas well considering the reservoir damage, which comprises the following steps.

[0064] S1, calculating the steady-state productivity Q of the target fractured gas well, which can be calculated according to the formula of the productivity of a fractured gas well.

[0065] S2, determining the average core damage degree of the target fractured gas well by using the fracturing simulation system As shown in Figure 1As shown, the fracturing simulation system comprises a driving pump 10, an intermediate container 20, a core holder 30, a gas storage tank 40, a first pipeline 50, a second pipeline 60, a third pipeline 70, a fourth pipeline 80 and a pressure gauge 140. The intermediate container 20 is internally provided with a slidable driving piston 21, injection driving cavities 22 distributed on the lower side of the driving piston 21, and fracturing fluid cavities 23 distributed on the upper side of the driving piston 21, the injection driving cavities 22 and the fracturing fluid cavities 23 are separated by the driving piston 21 and different from each other, the liquid in the injection driving cavities 22 is water, and the liquid in the fracturing fluid cavities 23 is fracturing fluid. The core holder 30 comprises a holder shell 31, a fixed sleeve 32 fixedly arranged in the holder shell 31, an enclosure pressure cavity 33 formed between the holder shell 31 and the fixed sleeve 32, a core fixing cavity 34 formed in the fixed sleeve 32, an enclosure pressure pressurizing assembly connected with the enclosure pressure cavity 33, and a vacuum pumping assembly connected with the core fixing cavity 34, the enclosure pressure cavity 33 and the core fixing cavity 34 are not communicated with each other and are separated by the fixed sleeve 32, and the core fixing cavity 34 is a left-right extending cylindrical cavity. The first pipeline 50 is connected between the driving pump 10 and the injection driving cavities 22, connecting the driving pump 10 and the intermediate container 20. The second pipeline 60 is connected between the fracturing fluid cavities 23 and the left end of the core fixing cavity 34, connecting the intermediate container 20 and the core holder 30; the second pipeline 60 is provided with a first valve 90 and a second valve 110, and the first valve 90 and the second valve 110 are distributed in sequence along the flow direction of the fracturing fluid cavities 23 to the core fixing cavity 34. The third pipeline 70 is connected between the right end of the core fixing cavity 34 and the gas storage tank 40, connecting the core holder 30 and the gas storage tank 40; the third pipeline 70 is provided with a third valve 120, and the pressure gauge 140 is installed on the third pipeline 70, the pressure gauge 140 and the third valve 120 are distributed in sequence along the flow direction of the gas storage tank 40 to the core fixing cavity 34, and the internal gas pressure of the gas storage tank 40 can be measured through the pressure gauge 140. The fourth pipeline 80 is connected with the second pipeline 60, and the connection points of the fourth pipeline 80 and the second pipeline 60 are distributed between the first valve 90 and the second valve 110, i.e. the first valve 90, the connection points of the fourth pipeline 80 and the second pipeline 60, and the second valve 110 are distributed in sequence along the flow direction of the fracturing fluid cavities 23 to the core fixing cavity 34; the fourth pipeline 80 is provided with a fourth valve 130.

[0066] Based on the indoor core experiment, the damage degree of the matrix core is evaluated, and the average damage degree of the core of the target fracturing gas well is measured by using the fracturing simulation system The steps are as follows.

[0067] S201, a representative target fracturing gas well reservoir core sample is taken, the number of reservoir core samples is more than 3, the specifications of each reservoir core sample are the same, the reservoir core sample is in a cylindrical shape, the axial length of the reservoir core sample is 8.00 cm, and the original gas permeability KC .

[0068] S202, take a reservoir core sample and fix it in the core fixing cavity 34 of the core holder 30.

[0069] S203, close the second valve 110 and the third valve 120, open the confining pressure adding assembly, add confining pressure to the confining pressure cavity 33, simulate the underground state, until the confining pressure in the confining pressure cavity 33 reaches the overburden pressure of the reservoir depth; then, close the confining pressure adding assembly, open the vacuumizing assembly, and vacuumize the reservoir core sample in the core fixing cavity 34.

[0070] S204, close the second valve 110 and open the third valve 120, the second pipeline 60 connects the gas tank 40 and the core fixing cavity 34, so that the reservoir core sample in the core fixing cavity 34 is saturated with the gas in the gas tank 40, until the internal gas pressure of the gas tank 40 equals the original formation pressure of the reservoir.

[0071] S205, close the first valve 90, the second valve 110, the third valve 120 and the fourth valve 130, use the driving pump 10 to pressurize the injection driving cavity 22, until the pressure in the injection driving cavity 22 is 1-2 MPa higher than the original formation pressure of the reservoir; then, open the first valve 90 and the second valve 110, increase the injection pressure to the bottom hole pressure during the fracturing of the reservoir, the second pipeline 60 connects the fracturing fluid cavity 23 and the core fixing cavity 34, so that the fracturing fluid in the fracturing fluid cavity 23 is injected into the reservoir core sample in the core fixing cavity 34, simulating the injection process of the fracturing fluid, and the injection time is the same as the pump-in time in the field fracturing.

[0072] S206, when the injection time reaches the pump-in time in the field fracturing, close the first valve 90 and the second valve 110, stop the injection of the fracturing fluid, simulate the soaking process, and the soaking time is the same as the soaking time in the field fracturing.

[0073] S207, when the soaking time reaches the soaking time in the field fracturing, open the second valve 110 and the fourth valve 130, the core fixing cavity 34, the second pipeline 60 and the fourth pipeline 80 are connected in sequence, the fracturing fluid returned from the reservoir core sample is returned out through the second pipeline 60 and the fourth pipeline 80, simulating the return process.

[0074] S208, when the value of the pressure gauge 140 is stable, take out the reservoir core sample in the core fixing cavity 34, and measure the gas-measured permeability K D .

[0075] S209, calculate the core damage degree D according to the gas-measured permeability K D after the return and the original gas-measured permeability K C .

[0076]

[0077] S210. Replace the reservoir core sample in the core holder 30, and repeat steps S22 to S29 above to calculate the core damage degree Di for all reservoir core samples, i = 1, 2, 3, 4, n; after the core damage degree D of all reservoir core samples has been measured, calculate the average core damage degree.

[0078]

[0079] S3. Based on the average damage level of the core sample Calculate the production correction factor m for the target fracturing gas well:

[0080]

[0081] In the formula: A = -0.001lnK + 0.0018;

[0082] t = 0.0055lnK + 0.0325;

[0083] y0 = 0.0238lnK - 0.1332;

[0084] K represents the average permeability of the reservoir.

[0085] S4. Calculate the well productivity Q of the target fracturing gas well after considering reservoir damage caused by fracturing fluid invasion. m :

[0086] Q m = (1-m)×Q.

[0087] In summary, this application uses a production correction coefficient calculated based on the average damage level of the core sample to correct the steady-state production capacity when calculating the production capacity of fracturing gas wells. This ensures that the final gas well production capacity takes into account the reservoir damage caused by fracturing fluid intrusion, effectively improving the accuracy of the fracturing gas well production capacity budget results.

[0088] The following description, using a fractured gas well from a gas field as an example, further illustrates the method for calculating the production capacity of the fractured gas well involved in this application.

[0089] The main parameters of the fractured gas well are shown in Table 1 below.

[0090] Table 1. Main parameters of fractured gas wells

[0091]

[0092] I. Calculate the steady-state production capacity Q of a fracturing gas well based on the fracturing gas well production capacity formula:

[0093]

[0094] In the above formula:

[0095]

[0096] L f is the half-length of the fracturing fracture; W f is the fracture opening; K f is the permeability of the fracturing fracture; K0 is the effective permeability of the reservoir; h e is the effective thickness of the reservoir; R e is the gas bleeding radius; p i is the original gas reservoir pressure, obtained from logging data; p a is the standard condition pressure, obtained from logging data; p wf is the bottom hole flowing pressure; μ g is the underground gas viscosity; Z is the gas deviation factor; T a is the temperature at standard conditions; T r is the temperature under gas reservoir conditions; e is the natural logarithm.

[0097] According to the formula of the above steady-state productivity Q, the main parameters of the fractured gas well and the gas reservoir parameters, the steady-state productivity Q of the fractured gas well is calculated as: Q = 3.024 x 10 4 m 3 .

[0098] II. Based on the indoor core experiment, the damage degree of the matrix core is evaluated, and the average damage degree of the core is determined

[0099] 2.1. Take three representative cores of the fractured gas well, cut and polish to obtain three reservoir core samples with a length of 8.00 cm; according to the test method specified in the national standard SY / T 6385-2016, measure the core permeability of each reservoir core sample by gas measurement, and obtain the original gas measurement permeability K C .

[0100] 2.2. Put one reservoir core sample into the core fixing cavity 34 of the core holder 30, and sequentially add confining pressure to the reservoir depth overburden pressure and perform vacuumization on the reservoir core sample.

[0101] 2.3. Close the second valve 110, open the third valve 120, and use the gas storage tank 40 to saturate the reservoir core sample in the core fixing cavity 34 with gas until the internal gas pressure of the gas storage tank 40 is equal to 48.25 MPa.

[0102] 2.4, close the first valve 90, the second valve 110, the third valve 120 and the fourth valve 130, use the drive pump 10 to pressurize the injection drive cavity 22 to 50 MPa; then, open the first valve 90 and the second valve 110, simulate the fracturing fluid injection process, and the injection time is 2 hours.

[0103] 2.5, when the injection time reaches 2 hours, stop injection, close the first valve 90 and the second valve 110, simulate the soak process, and the soak time is 48 hours.

[0104] 2.6, after the soak is completed, open the second valve 110 and the fourth valve 130, simulate the flowback process; when the value of the pressure gauge 140 is stable, take out the reservoir core sample, and according to the test method specified in the national standard SY / T 6385-2016, re-gas the core permeability of the reservoir core sample to obtain the flowback gas permeability K of the reservoir core sample. D .

[0105] 2.7, calculate the core damage degree D.

[0106] 2.8, replace the reservoir core sample in the core holder 30 until the core damage degree Di of all reservoir core samples is calculated, and the average core damage degree D of the core is obtained. The specific test results are shown in Table 2.

[0107] Table 2 Core damage degree test results

[0108] Numbering of reservoir core samples Original gas permeability K C ]] Post-flush gas-logged permeability K D ]]> Degree of core damage D 1# 0.315 0.203 0.355 2# 0.174 0.123 0.293 3# 0.216 0.154 0.287

[0109] According to the core damage degree test results in Table 2 above, the average core damage degree D of the core is:

[0110]

[0111] According to the average core damage degree D of the core , the productivity correction coefficient m of the fractured gas well is calculated:

[0112] A = -0.001lnK + 0.0018 = 0.003147;

[0113] t = 0.0055lnK + 0.0325 = -0.1653;

[0114] y0 = 0.0238lnK - 0.1332 = 0.02509;

[0115]

[0116] ​IV. According to the steady-state productivity Q and productivity correction factor m of the fractured gas well, the gas well productivity Q of the fractured gas well considering the reservoir damage caused by fracturing fluid invasion is calculated m :

[0117] Q m =(1-m) x Q=(1-0.0444) x 3.024 x 10 4 =2.886 x 10 4 .

[0118] Therefore, the productivity of the fractured gas well after fracturing is 2.886 x 10 4 m 3 , and the prediction accuracy is higher.

[0119] In summary, the present application effectively overcomes the shortcomings in the prior art and has a high industrial utilization value.

[0120] The above examples only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for calculating the productivity of fracturing gas wells considering reservoir damage, characterized in that: Includes the following steps: S1. Calculate the steady-state production capacity Q of the target fracturing gas well; S2. Use a fracturing simulation system to determine the average core damage level of the target fracturing gas well. The fracturing simulation system includes a drive pump (10), an intermediate container (20), a core holder (30), a gas storage tank (40), a first pipeline (50), a second pipeline (60), a third pipeline (70), and a fourth pipeline (80). The intermediate container (20) is provided with a slidable drive piston (21), an injection drive chamber (22) distributed on one side of the drive piston (21), and a fracturing fluid chamber (23) distributed on the other side of the drive piston (21). The core holder (30) includes a holder shell (31), a fixing sleeve (32) fixedly arranged in the holder shell (31), a confining pressure chamber (33) formed between the holder shell (31) and the fixing sleeve (32), a core fixing chamber (34) formed in the fixing sleeve (32), a confining pressure pressurization component connected to the confining pressure chamber (33), and a component connected to the core fixing chamber (34). The vacuum assembly has a confining pressure chamber (33) that is not connected to the core fixing chamber (34). The first pipe (50) is connected between the drive pump (10) and the injection drive chamber (22). The second pipe (60) is connected between the fracturing fluid chamber (23) and the core fixing chamber (34). The second pipe (60) is provided with a first valve (90) and a second valve (110) distributed sequentially along the direction from the fracturing fluid chamber (23) to the core fixing chamber (34). The third pipe (70) is connected between the core fixing chamber (34) and the gas storage tank (40). The third pipe (70) is provided with a third valve (120). The fourth pipe (80) is connected to the second pipe (60), and the connection point between the two is distributed between the first valve (90) and the second valve (110). The fourth pipe (80) is provided with a fourth valve (130). This step S2 includes the following sub-steps in sequence: S201. Take multiple reservoir core samples of the same size from the target fractured gas well and determine the original gas permeability K of the reservoir core samples. C ; S202. Fix one of the reservoir core samples in the core fixing cavity (34) of the core holder (30); S203. Close the second valve (110) and the third valve (120), and open the confining pressure pressurization assembly until the confining pressure in the confining pressure chamber (33) reaches the pressure of the overlying strata at the reservoir depth; then, close the confining pressure pressurization assembly, open the vacuum pumping assembly, and vacuum the reservoir core sample in the core fixing chamber (34). S204. Close the second valve (110), open the third valve (120), and use the gas storage tank (40) to saturate the reservoir core sample in the core fixing chamber (34) with gas until the internal gas pressure of the gas storage tank (40) is equal to the original formation pressure of the reservoir. S205. Close the first valve (90), the second valve (110), the third valve (120), and the fourth valve (130). Use the drive pump (10) to pressurize the injection drive chamber (22) until the pressure in the injection drive chamber (22) is higher than the original formation pressure of the reservoir. Then, open the first valve (90) and the second valve (110) to inject the fracturing fluid in the fracturing fluid chamber (23) into the reservoir core sample in the core fixing chamber (34) to simulate the fracturing fluid injection process. The injection time is the same as the fracturing pump injection time in the mine. S206. Close the first valve (90) and the second valve (110) to simulate the well-sealing process. The well-sealing time is the same as the well-sealing time in the mine. S207. Open the second valve (110) and the fourth valve (130) to simulate the backflow process; S208. Remove the reservoir core sample from the core fixing chamber (34) and determine the gas permeability K of the reservoir core sample after backflow. D ; S209, Based on the permeability K measured after the backflow... D and the original gas permeability K C Calculate the degree of core damage D: S210. Repeat steps S202 to S209 above to calculate the core damage degree Di for all reservoir core samples, and then calculate the average core damage degree. S3. Based on the average damage level of the core sample Calculate the production correction factor m for the target fracturing gas well: In the formula: A = -0.001lnK + 0.0018; t = 0.0055lnK + 0.0325; y0 = 0.0238lnK - 0.1332; K is the average permeability of the reservoir; S4. Calculate the well productivity Q of the target fracturing gas well after considering reservoir damage caused by fracturing fluid invasion. m : Q m =(1-m)×Q。 2. The method for calculating the production capacity of a fracturing gas well according to claim 1, characterized in that: In step S201, the number of reservoir core samples is more than 3.

3. The method for calculating the production capacity of a fracturing gas well according to claim 1, characterized in that: In step S201, the reservoir core sample is cylindrical and has an axial length of 8.00 cm.

4. The method for calculating the production capacity of a fracturing gas well according to claim 1, characterized in that: In step S205, the pressure inside the injection drive cavity (22) is 1-2 MPa higher than the original formation pressure of the reservoir.

5. The method for calculating the production capacity of a fracturing gas well according to claim 1, characterized in that: The core fixing cavity (34) is a cylindrical cavity, and the second pipe (60) and the third pipe (70) are respectively connected to the two ends of the core fixing cavity (34) in the axial direction.

6. The method for calculating the production capacity of a fracturing gas well according to claim 1, characterized in that: The fracturing simulation system also includes a pressure gauge (140), which is installed on the third pipeline (70). The pressure gauge (140) and the third valve (120) are distributed sequentially along the direction from the gas storage tank (40) to the core fixing chamber (34).

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