Method for determining fracture conductivity

Abstract

The invention relates to a method for determining fracture conductivity. The method comprises the following steps: determining the sanding concentration in a crack in a propping agent migration process and after a flowback process; acquiring fracture closing pressure, proppant injection flow and proppant flowback flow; a proppant flow conductivity experiment is carried out according to the sanding concentration in the crack, the crack closing pressure and the injection flow of the proppant in the migration process of the proppant, and the crack flow conductivity in the migration process of the proppant is determined based on the proppant flow conductivity experiment; and a proppant flow-back capability experiment is carried out according to the sanding concentration in the crack, the crack closing pressure and the proppant flow-back flow after the proppant flow-back process, and the crack flow conductivity after the proppant flow-back process is determined based on the proppant flow-back capability experiment. According to the method, the size of the flow conductivity in the fracture is effectively calculated, the defect that a visual propping agent migration and flow-back simulation experiment device cannot calculate the flow conductivity is overcome, and the effect and value of a visual propping agent migration and flow-back simulation experiment are broadened.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic fracturing, and particularly to a method for determining fracture conductivity. Background Art

[0002] With the continuous expansion of shale oil production scale, hydraulic fracturing, as one of the necessary means for increasing shale oil production, plays a very important role. During the hydraulic fracturing operation of the formation, a large amount of proppant is pumped into the formation, so that the fracture can still remain open under the action of the reservoir closure stress and provide a high conductivity. Since hydraulic fracturing is often located at a depth of several thousand meters underground, it is impossible to directly detect the distribution pattern of proppant and the fracture conductivity after formation hydraulic fracturing. Therefore, a large number of scholars have carried out visual proppant transport simulation experiments. By using two parallel transparent plexiglass plates to simulate the fracture wall surface, which is filled with a fracturing fluid of a certain viscosity, a sand-carrying fluid is injected at a certain displacement from one end of the fracture simulation experimental device, and the settlement law of proppant particles in the simulated fracture is observed.

[0003] However, for the proppant transport and flowback experiments, it only stays at the level of observing the morphological law of the sand dike, and it is impossible to calculate the conductivity in the fracture after proppant transport and flowback. And the size of the conductivity is the key to evaluating the quality of the fracturing effect. Usually, the greater the fracture conductivity, the better the hydraulic fracturing effect, the longer the effective period, and the greater the benefit obtained from the fracturing. In this regard, a conductivity test device and a visual support fracture conductivity test method have been proposed in the related technology. The conductivity test device directly tests the proppant conductivity through the conductivity device, but this method cannot test the conductivity inside the hydraulic fracture. The visual support fracture conductivity test method overcomes the problem that the transparent plate of the visual proppant transport device cannot withstand high pressure by equivalent the closure pressure to the fracture width and then adjusting the fracture width instead of applying the closure pressure. However, such methods are complex and cumbersome in the operation process. In addition, in the proppant transport and flowback experiments, due to the limitations of the experimental device, it is very difficult to obtain the pressure difference at both ends of the transparent plate, so there are errors in the calculated conductivity. Therefore, in order to evaluate the support effect of proppant in the fracture and optimize the hydraulic fracturing plan, it is urgent to calculate the conductivity in the fracture after proppant transport and flowback, broaden the role and value of the visual proppant transport and flowback simulation experiment, and provide a new method for calculating the conductivity in the fracture. Summary of the Invention

[0004] In view of this, one of the purposes of the present invention is to solve the problem that the conductivity in the fracture cannot be calculated after the visual proppant transport and flowback simulation experiment. To solve the above problem, the present invention provides a method for determining fracture conductivity.

[0005] Specifically, the present invention is realized through the following technical solutions:

[0006] According to a first aspect of the present invention, there is provided a method for determining fracture conductivity, which is used for visualizing the proppant transport and flowback simulation experiment. The method includes: determining the sand concentration in the fracture during the proppant transport process and after the flowback process; obtaining the fracture closure pressure, the proppant injection flow rate, and the proppant flowback flow rate; conducting a proppant conductivity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant injection flow rate during the proppant transport process, and determining the fracture conductivity during the proppant transport process based on the proppant conductivity experiment; conducting a proppant flowback capacity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant flowback flow rate after the proppant flowback process, and determining the fracture conductivity after the proppant flowback process based on the proppant flowback capacity experiment.

[0007] In some embodiments, the step of determining the sand concentration in the fracture during the proppant transport process specifically includes: determining the mass of the proppant required during the proppant transport process; determining the fracture area according to the proppant transport simulation experimental device; and determining the sand concentration in the fracture during the proppant transport process based on the proppant mass and the fracture area.

[0008] In some embodiments, the step of determining the fracture area according to the proppant transport simulation experimental device specifically includes: determining the length and width of the proppant transport simulation experimental device; and the product of the length and width is the fracture area.

[0009] In some embodiments, the step of determining the sand concentration in the fracture during the proppant transport process based on the proppant mass and the fracture area specifically includes: calculating the ratio of the proppant mass to the fracture area, and the ratio is the sand concentration in the fracture during the proppant transport process.

[0010] In some embodiments, the step of determining the sand concentration in the fracture after the proppant flowback process specifically includes: determining the mass of the proppant required during the proppant transport process; determining the mass of the proppant discharged after the proppant flowback process; calculating the difference between the mass of the proppant required during the proppant transport process and the mass of the proppant discharged after the proppant flowback process; determining the fracture area; and determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area.

[0011] In some embodiments, the step of determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area specifically includes: calculating the ratio of the difference to the fracture area, and the ratio is the sand concentration in the fracture after the proppant flowback process.

[0012] In some embodiments, the steps of determining the fracture conductivity during proppant migration based on the proppant conductivity experiment specifically include: obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; determining the fracture conductivity during proppant migration according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port.

[0013] In some embodiments, to determine the fracture conductivity during proppant migration according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port, the following formula is specifically used for calculation:

[0014]

[0015] where: d 1 is the fracture conductivity during proppant migration, μ is the viscosity of the fracturing fluid under the test temperature conditions, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the flow diversion chamber, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

[0016] In some embodiments, the steps of determining the fracture conductivity after proppant backflow based on the proppant backflow capacity experiment specifically include: obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; determining the fracture conductivity after proppant backflow according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port.

[0017] In some embodiments, to determine the fracture conductivity after proppant backflow according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow diversion chamber, and the pressure difference between the first pressure port and the second pressure port, the following formula is specifically used for calculation:

[0018]

[0019] where: d 2To support the conductivity of the fracture after the proppant backflow process, μ is the viscosity of the fracturing fluid under the test temperature condition, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the diversion chamber, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

[0020] The technical solution provided by the present invention at least brings the following beneficial effects: By weighing the mass of the proppant after migration and backflow and the fracture area, the proppant sand concentration after the migration and backflow experiment is obtained. Combining with the conductivity experiment, the magnitude of the conductivity in the fracture of the visual proppant migration and backflow simulation experiment is obtained, as well as the influence of backflow on the supporting effect of the proppant in the fracture. This method simply and effectively calculates the magnitude of the conductivity in the fracture, overcomes the deficiency that the visual proppant migration and backflow simulation experiment device cannot calculate the conductivity, broadens the role and value of the visual proppant migration and backflow simulation experiment, and provides a new method for calculating the conductivity in the fracture. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or related technologies. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic flowchart of a method for determining the fracture conductivity provided by an embodiment of the present invention;

[0024] Figure 2 It is a visual proppant migration and backflow simulation experiment device provided by an embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of the proppant migration stage provided by an embodiment of the present invention;

[0026] Figure 4 It is a schematic diagram of the proppant backflow stage provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Refer to Figure 1 , an embodiment of the present invention provides a method for determining the fracture conductivity, which is used for the visualization of proppant transport and flowback simulation experiments. The method may include the following steps:

[0029] S101. Determine the sand concentration in the fracture during the proppant transport process and after the flowback process;

[0030] S102. Obtain the fracture closure pressure, proppant injection flow rate, and proppant flowback flow rate;

[0031] S103. Conduct a proppant conductivity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant injection flow rate during the proppant transport process, and determine the fracture conductivity during the proppant transport process based on the proppant conductivity experiment;

[0032] S104. Conduct a proppant flowback capacity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant flowback flow rate after the proppant flowback process, and determine the fracture conductivity after the proppant flowback process based on the proppant flowback capacity experiment.

[0033] In some embodiments, the step of determining the sand concentration in the fracture during the proppant transport process specifically includes: determining the mass of the proppant required during the proppant transport process; determining the fracture area according to the proppant transport simulation experimental device; and determining the sand concentration in the fracture during the proppant transport process according to the proppant mass and the fracture area.

[0034] In some embodiments, the step of determining the fracture area according to the proppant transport simulation experimental device specifically includes: determining the length and width of the proppant transport simulation experimental device; and the product of the length and width is the fracture area.

[0035] In some embodiments, the step of determining the sand concentration in the fracture during the proppant transport process according to the proppant mass and the fracture area specifically includes: calculating the ratio of the proppant mass to the fracture area, and the ratio is the sand concentration in the fracture during the proppant transport process.

[0036] In some embodiments, the steps of determining the sand concentration in the fracture after the proppant flowback process specifically include: determining the mass of proppant required during the proppant migration process; determining the mass of the proppant discharged after the proppant flowback process; calculating the difference between the mass of the proppant required during the proppant migration process and the mass of the proppant discharged after the proppant flowback process; determining the fracture area; and determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area.

[0037] In some embodiments, the steps of determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area specifically include: calculating the ratio of the difference to the fracture area, and the ratio is the sand concentration in the fracture after the proppant flowback process.

[0038] In some embodiments, the steps of determining the fracture conductivity during the proppant migration process based on the proppant conductivity experiment specifically include: obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; and determining the fracture conductivity during the proppant migration process according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port.

[0039] In some embodiments, to determine the fracture conductivity during the proppant migration process according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port, the following formula is specifically used for calculation:

[0040]

[0041] Where: d 1 is the fracture conductivity during the proppant migration process, μ is the viscosity of the fracturing fluid under the test temperature conditions, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the flow-through cell, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

[0042] In some embodiments, the steps of determining the fracture conductivity after the proppant backflow process based on the proppant backflow capacity experiment specifically include: obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the diversion chamber, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; determining the fracture conductivity after the proppant backflow process according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the diversion chamber, and the pressure difference between the first pressure port and the second pressure port.

[0043] In some embodiments, the fracture conductivity after the proppant backflow process is determined according to the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the diversion chamber, and the pressure difference between the first pressure port and the second pressure port. Specifically, the following formula is used for calculation:

[0044]

[0045] Where: d 2 is the fracture conductivity after the proppant backflow process, μ is the viscosity of the fracturing fluid under the test temperature conditions, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the diversion chamber, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

[0046] In some embodiments, the influence degree f of the backflow on the proppant support in the fracture can be determined according to the fracture conductivity during the proppant migration process and the fracture conductivity after the proppant backflow process. Specifically, the influence degree f = (d 2 - d 1 ) / d 1 .

[0047] The following further illustrates the application in combination with Figure 2 , Figure 3 , Figure 4 and specific embodiments:

[0048] The first step: Weigh the weight m 1 of the proppant required for the experiment. As shown in Figure 2 , measure the length l and width w of the visual proppant migration simulation experimental device to obtain the fracture area s, where the fracture area s = l × w.

[0049] The second step: Obtain the sand concentration c 1 during the proppant migration process by the ratio of the proppant weight m 1 to the fracture area s. The process during the proppant migration stage is as shown inFigure 3 as shown

[0050] Step 3: According to the sand-laying concentration c 1 , the reservoir closure pressure p 1 and the injection flow rate Q 1 , conduct a proppant conductivity experiment to obtain the fracture conductivity d during the proppant migration process 1 .

[0051]

[0052] where: μ—the viscosity of the fracturing fluid under the test temperature conditions, with the unit of millipascal-second (mPa·s);

[0053] Q—the flow velocity, with the unit of cubic centimeter per second (cm 3 / s);

[0054] L—the length between the pressure ports, with the unit of centimeter (cm);

[0055] w—the width of the diversion chamber, with the unit of centimeter (cm);

[0056] Δp—the pressure difference (upstream pressure minus downstream pressure), with the unit of kilopascal (kPa).

[0057] Step 4: Turn on the visualization proppant migration and flowback simulation experimental device, inject the sand-carrying fluid at the experimental design flow rate, and conduct the proppant migration experiment

[0058] Step 5: After the proppant injection is completed, open the fracture end filtration loss port and the fracture opening flowback port of the visualization proppant migration simulation experimental device, start the screw pump, and inject the flowback fluid from the fracture end filtration loss port. The process during the proppant flowback stage is as Figure 4 shown

[0059] Step 6: After the flowback is completed, weigh the mass m of the proppant discharged at the outlet end 2 , and obtain the mass m of the proppant in the fracture by subtracting the mass m of the proppant after flowback from the mass m of the proppant during migration 1 2 3 .

[0060] Step 7: According to the ratio of the mass m of the proppant in the fracture after flowback to the fracture area s, obtain the sand-laying concentration c of the proppant in the fracture 3 , c 2 = m 2 / s 3 .

[0061] Step 8: Repeat Step 3 to obtain the fracture internal conductivity d after the proppant flowback 2 .

[0062] ​​Step 9: By calculating the diversion capacities of the migration experiment and the flowback experiment, the diversion capacity in the fracture for different fracturing schemes and the influence degree f of flowback on the proppant support in the fracture can be obtained, where the influence degree f = (d 2 - d 1 ) / d 1 .

[0063] The method for determining the fracture diversion capacity provided by this application solves the problem that the diversion capacity in the fracture cannot be calculated after proppant migration and flowback. This method overcomes the problem that the transparent plate of the visual proppant migration device cannot withstand high pressure, realizes the direct calculation of the diversion capacity of the visual supported fracture, effectively makes up for the defect that the visual proppant migration device cannot test the diversion capacity, and greatly improves the role of the visual proppant migration device in the optimization design of hydraulic fracturing.

[0064] Although this specification contains many specific implementation details, these should not be construed as limiting the scope of any invention or the scope of what is claimed, but are mainly used to describe the features of specific embodiments of a particular invention. Certain features described in multiple embodiments in this specification can also be combined and implemented in a single embodiment. On the other hand, various features described in a single embodiment can also be separately implemented in multiple embodiments or implemented in any suitable sub-combination. In addition, although features may function in certain combinations as described above and are even initially claimed as such, one or more features from the claimed combination can in some cases be removed from the combination, and the claimed combination can be directed to a sub-combination or a variant of the sub-combination.

[0065] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve the desired result. In addition, the processes depicted in the figures are not necessarily the specific order or sequential order shown to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0066] It should be noted that in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0067] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for determining fracture conductivity, characterized in that, for visualizing the proppant transport and flowback simulation experiment, the method for determining fracture conductivity includes: Determining the sand concentration in the fracture during the proppant transport process and after the flowback process; Obtaining the fracture closure pressure, proppant injection flow rate, and proppant flowback flow rate; Conducting a proppant conductivity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant injection flow rate during the proppant transport process, and determining the fracture conductivity during the proppant transport process based on the proppant conductivity experiment; Conducting a proppant flowback capacity experiment based on the sand concentration in the fracture, the fracture closure pressure, and the proppant flowback flow rate after the proppant flowback process, and determining the fracture conductivity after the proppant flowback process based on the proppant flowback capacity experiment.

2. The method for determining fracture conductivity according to claim 1, characterized in that, The step of determining the sand concentration in the fracture during the proppant transport process specifically includes: Determining the mass of proppant required during the proppant transport process; Determining the fracture area according to the proppant transport simulation experimental device; Determining the sand concentration in the fracture during the proppant transport process according to the proppant mass and the fracture area.

3. The method for determining fracture conductivity according to claim 2, characterized in that, The step of determining the fracture area according to the proppant transport simulation experimental device specifically includes: Determining the length and width of the proppant transport simulation experimental device; The product of the length and the width is the fracture area.

4. The method for determining fracture conductivity according to claim 2, characterized in that, The step of determining the sand concentration in the fracture during the proppant transport process according to the proppant mass and the fracture area specifically includes: Calculating the ratio of the proppant mass to the fracture area, and the ratio is the sand concentration in the fracture during the proppant transport process.

5. The method for determining fracture conductivity according to claim 1, characterized in that, The step of determining the sand concentration in the fracture after the proppant flowback process specifically includes: Determining the mass of proppant required during the proppant transport process; Determining the mass of the proppant discharged after the proppant flowback process; Calculating the difference between the mass of proppant required during the proppant transport process and the mass of the proppant discharged after the proppant flowback process; Determining the fracture area; Determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area.

6. The method for determining fracture conductivity according to claim 5, characterized in that, The step of determining the sand concentration in the fracture after the proppant flowback process based on the difference and the fracture area specifically includes: Calculating the ratio of the difference to the fracture area, and the ratio is the sand concentration in the fracture after the proppant flowback process.

7. The method for determining fracture conductivity according to claim 1, characterized in that, The steps of determining the fracture conductivity during the proppant migration process based on the proppant conductivity experiment specifically include: Obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; Determining the fracture conductivity during the proppant migration process based on the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port.

8. The method for determining fracture conductivity according to claim 7, wherein, The step of determining the fracture conductivity during the proppant migration process based on the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port specifically uses the following formula for calculation: Where: d 1 is the fracture conductivity during the proppant migration process, μ is the viscosity of the fracturing fluid under the test temperature conditions, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the flow conductivity chamber, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

9. The method for determining fracture conductivity according to claim 1, wherein, The steps of determining the fracture conductivity after the proppant backflow process based on the proppant backflow capacity experiment specifically include: Obtaining the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port at the experimental temperature; Determining the fracture conductivity after the proppant backflow process based on the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port.

10. The method for determining fracture conductivity according to claim 9, wherein, The step of determining the fracture conductivity after the proppant backflow process based on the viscosity of the fracturing fluid, the flow rate of the proppant, the length between the first pressure port and the second pressure port, the width of the flow-through cell, and the pressure difference between the first pressure port and the second pressure port specifically uses the following formula for calculation: Where: d 2 is the fracture conductivity after the proppant backflow process, μ is the viscosity of the fracturing fluid under the test temperature condition, with the unit of mPa·s, Q is the flow rate of the proppant, with the unit of cm 3 / s, L is the length between the first pressure port and the second pressure port, with the unit of cm, w is the width of the flow-through cell, with the unit of cm, and Δp is the pressure difference between the first pressure port and the second pressure port, with the unit of kPa.

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