Hydraulic fracturing crack model and pulverized coal migration test device

Abstract

The invention discloses a hydraulic fracturing crack model and a pulverized coal migration test device. The hydraulic fracturing fracture model comprises a model body and a model body, the model body is installed on a main body, a main fracture and a plurality of secondary fractures are arranged in the model body, the main fracture is communicated with the secondary fractures, the secondary fractures are arranged on the two sides of the main fracture at intervals, in addition, the model body is provided with a main injection port, a secondary injection port and a production port, and the main injection port is communicated with the secondary injection port. The main injection port is communicated with one end of the main crack, the output port is communicated with the other end of the main crack, and the secondary injection port is communicated with the secondary crack. The device can simulate the actual migration condition of the pulverized coal in the hydrofracture crack, so that the test effect of the device for testing the migration of the pulverized coal in the hydrofracture crack is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of hydraulic fracturing, and specifically relates to a hydraulic fracturing crack model and a coal powder migration test device. Background Art

[0002] Hydraulic fracturing is an effective means to improve the development effect of coalbed methane. However, during the fracturing and production increase operation, a large amount of coal powder will be produced in the coal seam. During the drainage stage, the coal powder migrates in the proppant-filled fractures with the flow of gas and water. During the migration process, the coal powder settles and blocks the fractures, reducing the conductivity of the fractures and increasing the resistance of fluid seepage, resulting in a serious reduction in the production of coalbed methane wells. Therefore, in order to discharge the coal powder in the fracture channel in time, avoid the precipitation and blockage of the fractures during the migration process, and reduce the impact of coal powder migration on coalbed methane production. It is necessary to study the migration law of coal powder in hydraulic fracturing fractures, so as to make a corresponding hydraulic fracturing fracture model, so as to carry out hydraulic fracturing fracture coal powder migration test in the hydraulic fracturing fracture coal powder migration test device.

[0003] At present, the hydraulic fracturing fracture model in the relevant technology only has the main fracture in the hydraulic fracturing fracture, and ignores the secondary fractures connected to the main fracture. The secondary fractures are not set in the hydraulic fracturing fracture model, which is quite different from the fracture morphology and distribution in the real coal seam, resulting in deviation in the test effect of the hydraulic fracturing fracture coal powder migration test device. Summary of the invention

[0004] The present application aims to at least to some extent solve the technical problem that the current hydraulic fracturing fracture model is only provided with a main fracture but no secondary fracture, which leads to the deviation of the test effect of the hydraulic fracturing fracture coal powder migration test device. To this end, the present application provides a hydraulic fracturing fracture model and a hydraulic fracturing fracture coal powder migration test device.

[0005] The technical solution of this application is:

[0006] In a first aspect, the present application proposes a hydraulic fracturing fracture model, the hydraulic fracturing fracture model comprising:

[0007] A model body, wherein a main crack and a plurality of secondary cracks connected to the main crack are arranged inside the model body, and the plurality of secondary cracks are arranged at intervals on both sides of the main crack;

[0008] The model body is provided with a main injection port, a secondary injection port and a production port, the main injection port is connected to one end of the main fracture, the production port is connected to the other end of the main fracture, and the secondary injection port is connected to the secondary fracture;

[0009] The model body is installed on the main body.

[0010] In some embodiments, at least one of the primary crack and the secondary crack penetrates the model body;

[0011] The main body includes one or more cover plates, and the cover plates are connected to the model body to block the main cracks and / or the secondary cracks.

[0012] In some embodiments, the main crack and the secondary crack run through two ends of the model body, and the two cover plates are respectively arranged at the two ends of the model body to block the main crack and the secondary crack.

[0013] In some embodiments, the model body and / or the cover plate are at least partially made of a transparent material, so that the primary crack and the secondary crack can be observed through the transparent material.

[0014] In some embodiments, the body further comprises:

[0015] Two fixing frames are respectively arranged on the two cover plates opposite to each other;

[0016] A connecting piece is used to fixedly connect the two fixing frames.

[0017] In some embodiments, the main body further comprises a gasket, and the gasket is sealingly disposed between the model body and the cover plate;

[0018] The gasket is a hollow structure, and the hollow structure corresponds to the shapes of the main crack and the secondary crack.

[0019] In some embodiments, the cross-sectional area of ​​the main fracture along the direction from the main injection port to the output port tends to increase;

[0020] The cross-sectional area of ​​the secondary crack along the direction from the secondary injection port to the main crack tends to increase.

[0021] In some embodiments, a plurality of the secondary injection ports are provided, and each of the secondary injection ports is connected to a plurality of the secondary fractures.

[0022] In some embodiments, the primary crack is disposed at an angle to the secondary crack.

[0023] In the second aspect, the present application also proposes a hydraulic fracturing fracture coal powder migration test device, the hydraulic fracturing fracture coal powder migration test device comprising:

[0024] The hydraulic fracturing fracture model described above;

[0025] A main injection system, connected to the injection port, for injecting coal powder suspension, formation water and methane into the hydraulic fracturing fracture model through the main injection system;

[0026] A secondary injection system is connected to the secondary injection port to inject the coal powder suspension, the formation water and the methane into the hydraulic fracturing fracture model through the secondary injection system;

[0027] an output system, connected to the output outlet, so as to adjust the pressure of the output outlet through the output system, collect and measure the output liquid, and detect the coal powder concentration in the output liquid;

[0028] an ultrasonic system connected to the model body so as to load ultrasonic waves to the hydraulic fracturing fracture model through the ultrasonic system;

[0029] A monitoring system is provided corresponding to the primary crack and the secondary crack, so as to photograph and record the coal powder migration state in the primary crack and the secondary crack through the monitoring system;

[0030] A control system, wherein the primary injection system, the secondary injection system, the output system, the ultrasonic system and the monitoring system are all electrically connected to the control system respectively.

[0031] The embodiments of the present application have at least the following beneficial effects:

[0032] The present application provides a hydraulic fracturing crack coal powder migration test device, including a hydraulic fracturing crack model, a model body installed in the main body of the hydraulic fracturing crack model, and the model body is fixed by the main body to facilitate the test. When conducting a hydraulic fracturing crack coal powder migration test, the test solution can be injected into the model body from the main injection port and the secondary injection port of the model body at the same time, and the test solution enters the main fracture through the main injection port of the model body, and enters the secondary fracture through the secondary injection port of the model body. The solution entering from the main injection port and the secondary injection port of the model body is mixed in the main fracture of the model body, and then discharged from the output port of the model body, so as to simulate the actual migration of coal powder in the hydraulic fracturing crack, thereby improving the test effect of the hydraulic fracturing crack coal powder migration test device. By observing the migration of coal powder in the main fracture and the secondary fracture, the coal powder migration law is obtained, and the hydraulic fracturing coalbed methane mining method is optimized, thereby increasing the coalbed methane mining volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1A schematic diagram of the structure of a hydraulic fracturing fracture model according to an embodiment of the present application;

[0035] Figure 2 for Figure 1 A cross-sectional view of the model body in FIG.

[0036] Figure 3 for Figure 1 Top view of the hydraulic fracturing fracture model in ;

[0037] Figure 4 for Figure 1 A schematic diagram of the structure of the gasket in FIG.

[0038] Figure 5 This is a schematic structural diagram of a hydraulic fracturing fracture coal powder migration test device according to an embodiment of the present application.

[0039] Reference numerals:

[0040] 10. Main body; 11. Model body; 111. Main fracture; 112. Secondary fracture; 113. Main injection port; 114. Secondary injection port; 115. Output port; 12. Cover plate; 13. Connector; 14. Fixing frame; 15. Gasket; 151. Hollow structure; 20. Main injection system; 21. First coal powder suspension storage tank; 22. First formation water storage tank; 23. First methane storage tank; 24. First injection pump; 30. Secondary injection system; 31. First The second coal powder suspension storage tank; 32. The second formation water storage tank; 33. The second methane storage tank; 34. The second injection pump; 40. The output system; 41. The recovery pump; 42. The first liquid collection and weighing equipment; 43. The drainage gas collecting tank; 44. The second liquid collection and weighing equipment; 50. The ultrasonic system; 51. The ultrasonic generator; 52. The ultrasonic converter; 60. The monitoring system; 61. The camera; 70. The control system; 80. The valve; 90. The pressure gauge. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific examples of processes and materials, but those of ordinary skill in the art may recognize the application of other processes and / or the use of other materials.

[0043] The present application is described below with reference to the accompanying drawings and specific embodiments:

[0044] See also Figure 1 , which is a structural schematic diagram of a hydraulic fracturing crack model of an embodiment of the present application. The hydraulic fracturing crack model of the embodiment of the present application simulates the actual migration of coal powder in the hydraulic fracturing crack by setting a main crack 111 and a secondary crack 112 in the model body 11, thereby improving the test effect of the hydraulic fracturing crack coal powder migration test device.

[0045] Combination Figure 1 as well as Figure 2 The hydraulic fracturing fracture model proposed in the embodiment of the present application includes a model body 11 and a model body 11. The model body 11 is installed on the main body 10. A main fracture 111 and a plurality of secondary fractures 112 are arranged inside the model body 11. The main fracture 111 is connected to the plurality of secondary fractures 112. The plurality of secondary fractures 112 are respectively arranged on both sides of the main fracture 111 at intervals. In addition, the model body 11 is provided with a main injection port 113, a secondary injection port 114 and a production port 115. The main injection port 113 is connected to one end of the main fracture 111, the production port 115 is connected to the other end of the main fracture 111, and the secondary injection port 114 is connected to the secondary fracture 112.

[0046] Specifically, the model body 11 is installed in the main body 10 of the hydraulic fracturing crack model, and the model body 11 is fixed by the main body 10 to facilitate the test. When conducting the hydraulic fracturing crack coal powder migration test, the test solution can be injected into the model body 11 from the main injection port 113 and the secondary injection port 114 of the model body 11 at the same time, and the test solution enters the main fracture 111 through the main injection port 113 of the model body 11, and enters the secondary fracture 112 through the secondary injection port 114 of the model body 11. The solutions entering from the main injection port 113 and the secondary injection port 114 of the model body 11 are mixed in the main fracture 111 of the model body 11, and then discharged from the output port 115 of the model body 11, so as to simulate the actual migration of coal powder in the hydraulic fracturing crack, thereby improving the test effect of the hydraulic fracturing crack coal powder migration test device. By observing the migration of coal powder in the main fracture 111 and the secondary fracture 112, the coal powder migration law is obtained, and the hydraulic fracturing coalbed methane production method is optimized, thereby increasing the coalbed methane production.

[0047] In some embodiments, at least one of the primary crack 111 and the secondary crack 112 of the model body 11 penetrates the model body 11 ; the main body 10 includes one or more cover plates 12 , which are connected to the model body 11 to block the primary crack 111 and / or the secondary crack 112 .

[0048] In order to process the main crack 111 and the secondary crack 112 on the model body 11, it is necessary to open at least one end of the model body 11, and then process the main crack 111 and the secondary crack 112 inside the model body 11 through the opening. The opening can be on the main crack 111, through which the main crack 111 is processed, and then the secondary crack 112 is further extended to be processed; the opening can also be on the secondary crack 112, through which the secondary crack 112 is processed, and then the main crack 111 is further extended to be processed; of course, the opening can also be on the main crack 111 and the secondary crack 112 at the same time, through which the main crack 111 and the secondary crack 112 are processed at the same time. Then the cover plate 12 is used to block the opening, so as to block the main crack 111 and the secondary crack 112 of the model body 11. In addition, the opening can be opened at one end of the model body 11 or at both ends of the model body 11 to meet the processing requirements of the main crack 111 and the secondary crack 112, and then the opening can be blocked by the cover plate 12. Further, the main injection port 113, the secondary injection port 114 and the output port 115 of the model body 11 can be directly processed by drilling.

[0049] In some embodiments, Figure 1 As shown, the main crack 111 and the secondary crack 112 run through both ends of the model body 11 , and two cover plates 12 are respectively disposed on both ends of the model body 11 , and the two cover plates 12 block the main crack 111 and the secondary crack 112 .

[0050] In order to facilitate the processing of the main crack 111 and the secondary crack 112 of the model body 11, the main crack 111 and the secondary crack 112 are directly made to penetrate the two ends of the model body 11, and laser cutting machines, wire cutting machines, water cutting machines, etc. can be used for processing, and the embodiment of the present application does not limit this. Then, only two cover plates 12 need to be used to cover the two ends of the model to block the two ends of the penetration direction of the main crack 111 and the secondary crack 112.

[0051] In some embodiments, the model body 11 and / or the cover plate 12 are at least partially made of transparent material, so that the primary cracks 111 and the secondary cracks 112 can be observed through the transparent material.

[0052] There are many ways to observe the coal dust migration in the main cracks 111 and the secondary cracks 112 of the model body 11, such as using a built-in camera to shoot the inside of the model body 11, using an X-ray camera to shoot the model body 11, etc. Of course, the most intuitive way is to set the part of the model body 11 that needs to be observed as a transparent material, and directly shoot the transparent part of the model body 11 through an external camera. Since the penetration direction of the main cracks 111 and the secondary cracks 112 of the model body 11 is the main observation position, the two ends of the penetration direction of the main cracks 111 and the secondary cracks 112 of the model body 11 are blocked by a cover plate 12, so it is necessary to set the part of the cover plate 12 that needs to be observed as a transparent material, and shoot the transparent part of the model body 11 through an external camera. Further, in order to facilitate processing, transparent materials such as organic glass can be directly used as materials for processing the model body 11 and the cover plate 12. The main cracks 111 and the secondary cracks 112 are set in the model body 11 in a completely transparent state, which is more conducive to experimental observation.

[0053] In some embodiments, Figure 1 as well as Figure 3 As shown, the main body 10 further includes a connecting member 13 and two fixing frames 14 . The two fixing frames 14 are respectively arranged on the two cover plates 12 opposite to each other, and the connecting member 13 is fixedly connected to the two fixing frames 14 .

[0054] Since it is necessary to apply a certain pressure to the main crack 111 and the secondary crack 112 of the model body 11 when conducting the hydraulic fracturing crack coal powder migration test, in order to ensure the sealing of the main crack 111 and the secondary crack 112, a fixing frame 14 is set on the cover plate 12 at both ends of the model body 11, and then the fixing frames 14 at both ends of the model body 11 are connected together by the connecting member 13, thereby improving the connection tightness between the model body 11 and the cover plate 12, and ensuring the sealing of the main crack 111 and the secondary crack 112. The connecting member 13 can be a bolt, a buckle, etc., and the embodiment of the present application is not limited to this.

[0055] In some embodiments, Figure 1 as well as Figure 4 As shown, the main body 10 further includes a gasket 15 , which is sealed between the model body 11 and the cover plate 12 ; the gasket 15 is a hollow structure 151 , and the hollow structure 151 corresponds to the shapes of the main crack 111 and the secondary crack 112 .

[0056] In order to further improve the sealing performance of the main cracks 111 and the secondary cracks 112 of the model body 11, a gasket 15 is provided between the model body 11 and the cover plate 12. The hollow structure 151 of the gasket 15 corresponds to the shape of the main cracks 111 and the secondary cracks 112 of the model body 11, so as to avoid the gasket 15 affecting the movement of the experimental solution in the main cracks 111 and the secondary cracks 112, thereby affecting the effect of the hydraulic fracturing fracture coal powder migration test.

[0057] In some embodiments, Figure 2 As shown, the cross-sectional area of ​​the main fracture 111 along the direction from the main injection port 113 to the production port 115 tends to increase; the cross-sectional area of ​​the secondary fracture 112 along the direction from the secondary injection port 114 to the main fracture 111 tends to increase.

[0058] So that the main cracks 111 and the secondary cracks 112 of the model body 11 can be more in line with the actual situation. In the actual hydraulic fracturing cracks, the cross-sectional area of ​​the main cracks 111 gradually decreases in the direction away from the shaft, and the cross-sectional area of ​​the secondary cracks 112 gradually decreases in the direction away from the main cracks 111. Therefore, the same setting method is adopted in the model body 11 to further improve the test effect of the hydraulic fracturing crack coal powder migration test device.

[0059] In some embodiments, Figure 1 As shown, a plurality of secondary injection ports 114 are provided, and each secondary injection port 114 is communicated with a plurality of secondary fractures 112 .

[0060] As mentioned above, the main injection port 113, secondary injection port 114 and output port 115 of the model body 11 can be directly processed by drilling. Since multiple secondary cracks 112 are provided in the model body 11, if each secondary crack 112 is connected to a secondary injection port 114 alone, it will lead to too many external pipes connected to the secondary injection port 114 of the model body 11, which will increase the test cost and affect the test effect. Therefore, each secondary injection port 114 is connected to multiple secondary cracks 112 to ensure the amount of test solution entering the secondary injection port 114 while avoiding too many secondary injection ports 114. In addition, Figure 2 As shown, in order to ensure the amount of experimental solution entering the main injection port 113 and the amount of output liquid discharged from the output port 115, the main injection port 113 and the output port 115 of the model body 11 are both provided with a plurality of them, and the plurality of main injection ports 113 and the plurality of output ports 115 are arranged at intervals along the penetration direction of the main fracture 111. It should be noted that the main fracture 111 of the model body 11 is in a long strip shape in the cross section in the penetration direction, that is, the plurality of secondary fractures 112 are respectively arranged at intervals on both sides of the length direction of the main fracture 111, and correspondingly, the plurality of secondary injection ports 114 are arranged at intervals along the length direction of the main fracture 111.

[0061] In some embodiments, Figure 2 As shown, the primary crack 111 and the secondary crack 112 are arranged at an angle.

[0062] By setting the main crack 111 and the secondary crack 112 of the model body 11 at an angle, the main crack 111 and the secondary crack 112 of the model body 11 can be more in line with the actual situation, thereby improving the test effect of the hydraulic fracturing crack coal powder migration test device. In addition, in order to ensure the stability of the test, the main crack 111 of the model body 11 is set perpendicular to the secondary crack 112, that is, the secondary crack 112 of the model body 11 is also in a long strip shape in the cross section of the penetration direction, and the length direction of the secondary crack 112 is set along the width direction of the main crack 111. It should be noted that when conducting a hydraulic fracturing crack coal powder migration test, the penetration direction of the main crack 111 and the secondary crack 112 of the model body 11 is a horizontal direction, and accordingly, the length direction of the secondary crack 112 is a vertical direction. In this way, the migration of coal powder in the hydraulic fracturing crack under the action of gravity can be simulated to be more in line with the actual situation and improve the test effect.

[0063] In some embodiments, proppant is disposed in the primary fracture 111 and the secondary fracture 112 .

[0064] In actual production, proppant is filled in hydraulic fracturing cracks to support the cracks from closing due to stress release, thereby maintaining high conductivity, allowing coalbed methane to flow smoothly and increasing coalbed methane production. Therefore, proppant is arranged in the main crack 111 and the secondary crack 112 of the model body 11 to simulate the internal conditions of the actual hydraulic fracturing cracks and improve the test effect.

[0065] When conducting a hydraulic fracturing fracture coal powder migration test method, the hydraulic fracturing fracture model is applied to the coal powder migration test. The hydraulic fracturing fracture coal powder migration test method includes:

[0066] Injecting coal powder suspension into the main fracture 111 and the secondary fracture 112 of the model body 11 through the main injection port 113 and the secondary injection port 114 of the model body 11, adjusting the pressure of the output port 115 of the model body 11 to the design pressure, collecting and measuring the output liquid of the output port 115 of the model body 11, and detecting the coal powder concentration in the output liquid;

[0067] Different proportions of formation water and methane are injected into the main fractures 111 and the secondary fractures 112 of the model body 11 through the main injection port 113 and the secondary injection port 114 of the model body 11 to simulate the migration of coal powder at different drainage stages, and the coal powder concentration in the output fluid under different proportions of formation water and methane is detected;

[0068] Loading ultrasonic waves on the model body 11 to obtain the movement dynamics of coal powder under the condition of loading ultrasonic waves;

[0069] The coal powder migration state in the primary cracks 111 and the secondary cracks 112 of the model body 11 is photographed and recorded.

[0070] In order to realize the above-mentioned hydraulic fracturing fracture coal powder migration test method, based on the same inventive concept, please refer to Figure 5 The embodiment of the present application also provides a hydraulic fracturing crack coal powder migration test device, which includes a main injection system 20, a secondary injection system 30, an output system 40, an ultrasonic system 50, a monitoring system 60, a control system 70 and the above-mentioned hydraulic fracturing crack model.

[0071] like Figure 5 As shown, the main injection system 20 is connected to the main injection port 113 to inject coal powder suspension, formation water and methane into the hydraulic fracturing fracture model through the main injection system 20; the secondary injection system 30 is connected to the secondary injection port 114 to inject coal powder suspension, formation water and methane into the hydraulic fracturing fracture model through the secondary injection system 30; the output system 40 is connected to the output port 115 to adjust the pressure of the output port 115 of the model body 11 through the output system 40, collect and measure the output fluid, and detect the coal powder concentration in the output fluid; the ultrasonic system 50 is connected to the model body 11 is connected so as to load ultrasonic waves into the hydraulic fracturing fracture model through the ultrasonic system 50; the monitoring system 60 is arranged corresponding to the main fracture 111 and the secondary fracture 112 so as to photograph and record the coal powder migration state in the main fracture 111 and the secondary fracture 112 of the model body 11 through the monitoring system 60; the control system 70, the main injection system 20, the secondary injection system 30, the output system 40, the ultrasonic system 50 and the monitoring system 60 are respectively electrically connected to the control system 70 so as to control each system in the hydraulic fracturing fracture coal powder migration test device through the control system 70.

[0072] In some embodiments, Figure 5As shown, the main injection system 20 includes a first coal powder suspension storage tank 21, a first formation water storage tank 22, a first methane storage tank 23 and a first injection pump 24, wherein the outlet of the first coal powder suspension storage tank 21 is connected to the main injection port 113, the outlet of the first formation water storage tank 22 is connected to the main injection port 113, the outlet of the first methane storage tank 23 is connected to the main injection port 113, the first coal powder suspension storage tank 21, the first formation water storage tank 22 and the first methane storage tank 23 are respectively connected to the first injection pump 24, and the first injection pump 24 is connected to the control system 70. The control system 70 controls the first injection pump 24 to drive the coal powder suspension in the first coal powder suspension storage tank 21, the formation water in the first formation water storage tank 22 and the methane in the first methane storage tank 23 into the hydraulic fracturing fracture model. In addition, three first injection pumps 24 are provided, and the first coal powder suspension storage tank 21, the first formation water storage tank 22 and the first methane storage tank 23 are respectively connected to a first injection pump 24, so as to achieve the purpose of driving the storage tank corresponding to the first injection pump 24 by controlling different first injection pumps 24.

[0073] In some embodiments, Figure 5 As shown, the secondary injection system 30 includes a second coal powder suspension storage tank 31, a second formation water storage tank 32, a second methane storage tank 33 and a second injection pump 34, wherein the outlet of the second coal powder suspension storage tank 31 is connected to the secondary injection port 114, the outlet of the second formation water storage tank 32 is connected to the secondary injection port 114, the outlet of the second methane storage tank 33 is connected to the secondary injection port 114, the second coal powder suspension storage tank 31, the second formation water storage tank 32 and the second methane storage tank 33 are respectively connected to the second injection pump 34, and the second injection pump 34 is connected to the control system 70. The control system 70 controls the second injection pump 34 to drive the coal powder suspension in the second coal powder suspension storage tank 31, the formation water in the second formation water storage tank 32 and the methane in the second methane storage tank 33 into the hydraulic fracturing fracture model. In addition, three second injection pumps 34 are provided, and the second coal powder suspension storage tank 31, the second formation water storage tank 32 and the second methane storage tank 33 are respectively connected to a second injection pump 34, so as to achieve the purpose of driving the storage tank corresponding to the second injection pump 34 by controlling different second injection pumps 34.

[0074] In some embodiments, Figure 5As shown, the production system 40 includes a recovery pump 41, a first liquid collecting and weighing device 42, a drainage gas collecting tank 43, and a second liquid collecting and weighing device 44, wherein the recovery pump 41 is connected between the production outlet 115 and the inlet of the first liquid collecting and weighing device 42, the outlet of the first liquid collecting and weighing device 42 is connected to the inlet of the drainage gas collecting tank 43, and the outlet of the drainage gas collecting tank 43 is connected to the inlet of the second liquid collecting and weighing device 44. The pressure of the production outlet 115 of the model body 11 is adjusted by the recovery pump 41, the output liquid is collected and measured by the first liquid collecting and weighing device 42, the drainage gas collecting tank 43, and the second liquid collecting and weighing device 44, and the coal powder concentration in the output liquid is detected.

[0075] In some embodiments, Figure 5 As shown, the ultrasonic system 50 includes an ultrasonic generator 51 and an ultrasonic converter 52. The model body 11 is connected to the ultrasonic converter 52, the ultrasonic converter 52 is connected to the ultrasonic generator 51, and the ultrasonic generator 51 is connected to the control system 70. The ultrasonic generator 51 is controlled by the control system 70 to load ultrasonic waves onto the model body 11.

[0076] In some embodiments, Figure 5 As shown, the monitoring system 60 includes a plurality of cameras 61, and cameras 61 are respectively arranged in the length direction, width direction and penetration direction of the main crack 111, and the plurality of cameras 61 are connected to the control system 70. The plurality of cameras 61 are controlled by the control system 70 to shoot and record the movement dynamics of the coal powder in the main crack 111 and the secondary crack 112.

[0077] In some embodiments, Figure 5 As shown, the hydraulic fracturing coal powder transportation test device includes a valve 80 and a pressure gauge 90, and valves 80 and pressure gauges 90 are respectively provided between the first coal powder suspension storage tank 21 and the main injection port 113, between the first formation water storage tank 22 and the main injection port 113, between the first methane storage tank 23 and the main injection port 113, between the second coal powder suspension storage tank 31 and the secondary injection port 114, between the second formation water storage tank 32 and the secondary injection port 114, between the second methane storage tank 33 and the secondary injection port 114, and between the recovery pump 41 and the output port 115, and all valves 80 and pressure gauges 90 are connected to the control system 70 so that all valves 80 can be controlled by the control system 70 according to the values ​​of all pressure gauges 90.

[0078] The control system 70 may include a logic controller, a microprogram controller, etc., which is not limited in the embodiment of the present application.

[0079] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0080] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0081] It should be noted that all directional indications in the embodiments of the present application are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0082] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0083] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0085] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0086] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A hydraulic fracturing fracture model, characterized in that: include: A model body, wherein a main crack and a plurality of secondary cracks connected to the main crack are arranged inside the model body, and the plurality of secondary cracks are arranged at intervals on both sides of the main crack; The model body is provided with a main injection port, a secondary injection port and a production port, the main injection port is connected to one end of the main fracture, the production port is connected to the other end of the main fracture, and the secondary injection port is connected to the secondary fracture; The model body is installed on the main body.

2. The hydraulic fracturing fracture model according to claim 1, characterized in that: At least one of the primary crack and the secondary crack penetrates the model body; The main body includes one or more cover plates, and the cover plates are connected to the model body to block the main cracks and / or the secondary cracks.

3. The hydraulic fracturing fracture model according to claim 2, characterized in that: The main crack and the secondary crack run through two ends of the model body, and the two cover plates are respectively arranged on the two ends of the model body to block the main crack and the secondary crack.

4. The hydraulic fracturing fracture model according to claim 3, characterized in that: The model body and / or the cover plate are at least partially made of transparent material, so that the main crack and the secondary crack can be observed through the transparent material.

5. The hydraulic fracturing fracture model according to claim 3, characterized in that: The subject also includes: Two fixing frames are respectively arranged on the two cover plates opposite to each other; A connecting piece is used to fixedly connect the two fixing frames.

6. The hydraulic fracturing fracture model according to claim 3, characterized in that: The main body further comprises a gasket, which is sealingly arranged between the model body and the cover plate; The gasket is a hollow structure, and the hollow structure corresponds to the shapes of the main crack and the secondary crack.

7. The hydraulic fracturing fracture model according to any one of claims 1 to 6, characterized in that: The cross-sectional area of ​​the main fracture along the direction from the main injection port to the output port tends to increase; The cross-sectional area of ​​the secondary crack along the direction from the secondary injection port to the main crack tends to increase.

8. The hydraulic fracturing fracture model according to any one of claims 1 to 6, characterized in that: A plurality of secondary injection ports are provided, and each of the secondary injection ports is communicated with a plurality of the secondary fractures.

9. The hydraulic fracturing fracture model according to any one of claims 1 to 6, characterized in that: The main crack and the secondary crack are arranged at an angle.

10. A method for testing coal powder migration in hydraulic fracturing fractures, characterized in that: include: The hydraulic fracturing fracture model according to any one of claims 1 to 9; A main injection system, connected to the injection port, for injecting coal powder suspension, formation water and methane into the hydraulic fracturing fracture model through the main injection system; A secondary injection system is connected to the secondary injection port to inject the coal powder suspension, the formation water and the methane into the hydraulic fracturing fracture model through the secondary injection system; an output system, connected to the output outlet, so as to adjust the pressure of the output outlet through the output system, collect and measure the output liquid, and detect the coal powder concentration in the output liquid; an ultrasonic system connected to the model body so as to load ultrasonic waves to the hydraulic fracturing fracture model through the ultrasonic system; A monitoring system is provided corresponding to the primary crack and the secondary crack, so as to photograph and record the coal powder migration state in the primary crack and the secondary crack through the monitoring system; A control system, wherein the primary injection system, the secondary injection system, the output system, the ultrasonic system and the monitoring system are all electrically connected to the control system respectively.

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