Proppant laying simulation experiment device with adjustable secondary crack trend and inclination angle

Abstract

The invention discloses a proppant laying simulation experiment device with adjustable secondary fracture trend and inclination angle. The proppant laying simulation experiment device can realize preparation and conveying of sand-carrying fluids with different formulas and sand ratios, laying of a proppant in a fracture network, real-time image acquisition and waste liquid recovery. In the simulation process of a propping agent laying experiment in a crack network, a motor is used for driving a flexible belt to drive a second-stage crack dip angle rotating disc, and therefore the second-stage crack dip angle is adjusted. And by adjusting the length of the second-stage crack supporting rod, the second-stage crack rotates with the second-stage crack trend rotating column as the center, and adjustment of the trend of the second-stage crack is achieved. By means of the two methods, the trend and the inclination angle of the secondary crack of the crack network can be flexibly set, and quantitative analysis of the laying condition of the proppant in the crack network of different forms is achieved. According to the invention, the defect that the trend and the tendency of the secondary crack are fixed in the previous crack network experimental equipment is overcome, and the method has important significance on optimization design of sand-carrying fluid construction parameters in hydraulic fracturing of unconventional reservoirs.

Description

Technical Field

[0001] The invention belongs to the research field of improving crude oil recovery by transforming unconventional oil and gas reservoirs in petroleum and natural gas engineering, and is a proppant laying simulation experimental device with adjustable secondary fracture direction and inclination. Background Art

[0002] my country has abundant unconventional oil and gas reserves, and giving full play to its resource advantages plays a vital role in ensuring my country's energy security. However, the porosity and permeability of unconventional oil and gas reservoirs are extremely poor, and traditional development technologies are difficult to achieve economical and effective utilization of them. Volumetric fracturing technology has become one of the most core means of developing such oil and gas resources, making unconventional oil and gas gradually become the main force in oil and gas production.

[0003] The purpose of volume fracturing is to create a high-speed seepage channel network for oil and natural gas in unconventional oil and gas reservoirs, thereby increasing the productivity of unconventional oil and gas wells. During the fracturing process, the fracturing fluid forms a complex fracture network in the reservoir, and then the sand-carrying fluid is used to fill the fracture network with proppant to prevent the fracture network from closing under the action of the closure pressure. The fracture network is composed of multiple levels of fractures, and the orientation and inclination of each level of fracture are different. Their complex positional relationship directly affects the overall distribution of the proppant in the fracture network. Therefore, experimental equipment that can simulate the transport of sand-carrying fluid in fracture networks of different forms is of great significance for the accurate quantitative simulation of proppant laying in complex fracture networks.

[0004] However, the direction and inclination of secondary fractures in the experimental equipment currently used to study the placement of proppants in the fracture network after volume fracturing of unconventional oil and gas reservoirs are fixed. There is a lack of experimental equipment and experimental methods that can flexibly adjust the direction and inclination of secondary fractures. It is impossible to use one device to simulate the placement characteristics of proppants in different fracture networks, which restricts the design of unconventional oil and gas fracturing and the formulation of post-fracturing development systems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a proppant laying simulation experimental device with adjustable secondary fracture direction and inclination, which has the advantages of simple structure, convenient installation and layout, and reliable working performance, in view of the deficiencies in the above-mentioned prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A proppant paving simulation experimental device with adjustable secondary fracture direction and inclination, comprising:

[0008] A sand-carrying liquid supply device, wherein the sand-carrying liquid supply device has a sand-carrying liquid output end for supplying the sand-carrying liquid in a quantitative and constant pressure manner;

[0009] A fracture network system, the fracture network system is used to simulate the distribution of proppant in the sand-carrying fluid in the fracture network of secondary fractures with different orientations and inclinations, and the input end of the fracture network system is connected to the sand-carrying fluid output end of the sand-carrying fluid supply device;

[0010] A waste liquid recovery tank, wherein the waste liquid recovery tank is connected to an output end of the fracture network system;

[0011] The image acquisition system has an observation direction toward the fracture network system and is used to acquire the laying image of the proppant in the sand-carrying fluid in the fractures of the fracture network system.

[0012] Preferably, the fracture network system comprises a closed primary fracture system and a secondary fracture system, wherein the primary fracture system and the secondary fracture system respectively have a primary fracture space and a secondary fracture space therein, the output end of the sand-carrying fluid is connected to the input end of the primary fracture system, the output end of the primary fracture system is connected to a waste liquid recovery tank, the input end of the secondary fracture system is connected to the middle of the primary fracture system, and the primary fracture space and the secondary fracture space are interconnected, and the output end of the secondary fracture system is connected to a waste liquid recovery tank.

[0013] Preferably, the primary crack system and the secondary crack system are both plate-like structures, and an angle is formed between the main extension direction of the primary crack system and the main extension direction of the secondary crack system.

[0014] Preferably, a secondary crack inclination rotating disk is provided on one main extension surface of the primary crack system, the secondary crack inclination rotating disk is sealedly connected to the primary crack system, and the secondary crack system is connected to the primary crack system via the secondary crack inclination rotating disk;

[0015] The proppant paving simulation experimental device with adjustable secondary fractures also includes a rotation driving device, which is connected to the secondary fracture inclination turntable and is used to adjust the relative position of the plane where the primary fracture system and the secondary fracture system are located.

[0016] Preferably, a secondary crack direction rotating column is provided on one main extension surface of the primary crack system, the secondary crack direction rotating column is sealedly connected to the secondary crack inclination rotating disk, and the secondary crack system is connected to the primary crack system through the secondary crack direction rotating column and the secondary crack inclination rotating disk;

[0017] The proppant paving simulation experimental device with adjustable secondary fractures also includes an inclination adjustment device, which is connected to the secondary fracture system and is used to adjust the inclination of the secondary fracture system.

[0018] Preferably, the primary crack system comprises a primary crack wall, a primary crack inlet and outlet end plate, a primary crack protective layer, a sand-carrying liquid inlet and outlet wall and a locking assembly, wherein there are two primary crack walls and they are arranged in parallel and opposite to each other, the sides of the two primary crack walls are sealed and primary crack inlet and outlet end plates are respectively arranged at the front and rear ends, the connection between the primary crack inlet and outlet end plate and the primary crack wall is sealed, the end surface of the primary crack wall is provided with a primary crack protective layer, and the primary crack protective layer, the primary crack wall and the primary crack inlet and outlet end plate are locked by the locking assembly to form a seal and form a primary crack assembly;

[0019] A plurality of first-level crack entry and exit holes are provided on the first-level crack entry and exit end plate;

[0020] The sand-carrying liquid inlet and outlet walls are sleeved on the front and rear ends of the primary crack assembly, so that the internal cavity of the sand-carrying liquid inlet and outlet walls is connected with the primary crack space through the primary crack inlet and outlet holes.

[0021] Preferably, the secondary crack system comprises a secondary crack wall, a cushion layer between the secondary crack walls and a locking assembly, wherein there are two secondary crack walls and they are arranged in parallel and opposite to each other, the sides of the two secondary crack walls are sealed, the fronts of the two secondary crack walls are open, and a cushion layer between the secondary crack walls is arranged at the tails of the two secondary crack walls, and the cushion layer between the secondary crack walls is locked with the two secondary crack walls by the locking assembly;

[0022] A plurality of secondary crack inlet and outlet holes are provided on the secondary crack wall cushion layer.

[0023] Preferably, the sand-carrying liquid supply equipment includes a sand mixing tank for storing sand-carrying liquid, the output end of the sand mixing tank is connected to the input end of the fracture network system through a pipeline, and a screw pump, a sand-carrying liquid flow meter and a sand-carrying liquid pressure gauge are arranged on the pipeline between the sand mixing tank and the fracture network system.

[0024] Preferably, the sand mixing tank has a stirring device inside;

[0025] The sand-carrying liquid supply equipment also includes a sand storage tank, a medicine tank and a water storage tank, which are respectively connected to the sand mixing tank through pipelines, and pumps and valves are arranged on the output pipelines of the sand storage tank, the medicine tank and the water storage tank.

[0026] Preferably, the image acquisition system comprises a first high-speed camera and a second high-speed camera, and image acquisition ends of the first high-speed camera and the second high-speed camera are respectively directed toward the primary crack system and the secondary crack system.

[0027] The beneficial effects of using the present invention are:

[0028] The invention discloses a proppant laying simulation experimental device with adjustable secondary fracture direction and inclination, which belongs to the field of unconventional oil and gas reservoir transformation and improving crude oil recovery in petroleum and natural gas engineering. The simulation device mainly includes sand-carrying liquid supply equipment, a fracture network system and an image acquisition system. The invention can realize the configuration and transportation of sand-carrying liquid with different formulas and sand ratios, the laying of proppant in the fracture network, and real-time image acquisition and waste liquid recovery. In the simulation process of proppant laying experiment in the fracture network, a motor is used to drive a flexible belt to drive a secondary fracture inclination turntable, so as to adjust the secondary fracture inclination. By adjusting the length of the secondary fracture support rod, the secondary fracture rotates around the secondary fracture direction rotating column as the center, so as to achieve the adjustment of the secondary fracture direction. By the above two methods, the direction and inclination of the secondary fracture of the fracture network can be flexibly set, and the quantitative analysis of the proppant laying situation in the fracture network with different shapes can be realized. The invention makes up for the shortcomings of the fixed direction and inclination of the secondary fracture in the previous fracture network experimental equipment, and has important significance for the optimization design of sand-carrying liquid construction parameters in hydraulic fracturing of unconventional reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an overall schematic diagram of the proppant laying simulation experimental device with adjustable secondary fracture direction and inclination of the present invention.

[0030] Figure 2 for Figure 1 Schematic diagram of the medium fracture network system.

[0031] Figure 3 for Figure 2 AA` section of the middle fracture network system.

[0032] Figure 4 for Figure 2 Sections BB` and DD` of the middle fracture network system.

[0033] Figure 5 for Figure 2 Section view of CC` of the middle crack network system.

[0034] Figure 6 for Figure 5 EE` section of the middle crack network system.

[0035] Figure 7 for Figure 3 FF` section of the middle crack network system.

[0036] Reference numerals include:

[0037] 1—sand storage tank; 2—medicine tank; 3—water storage tank;

[0038] 4—water tank valve; 5—water pump; 6—water meter;

[0039] 7—Pharmaceutical tank valve; 8—Pharmaceutical pump; 9—Sand storage tank valve;

[0040] 10—sand conveying pump; 11—sand mixing tank; 12—screw pump;

[0041] 13—sand-carrying liquid flow rate 14—sand-carrying liquid pressure gauge; 15—computer;

[0042] 16—first high-speed camera 17—second high-speed camera; Machine; 18—motor;

[0043] 19—crack network system 21—primary crack wall system; 20—waste liquid recovery tank; surface;

[0044] 22—First-level crack screw 23—First-level crack screw 24—Sand-carrying liquid inlet and outlet plug; Mother; Wall;

[0045] 25—inlet and outlet of sand-carrying fluid 26—inclination angle of secondary fracture 27—space for the direction of secondary fracture; Rotating plate; Rotating column;

[0046] 28—secondary crack wall 29—secondary crack screw 30—secondary crack screw surface; nut; bolt;

[0047] 31—Secondary crack space 32—Secondary crack support 33—First-level crack space; Rod; Space;

[0048] 34—First-level crack entry and exit 35—First-level crack protection 36—First-level crack entry and exit end plate; layer; hole;

[0049] 37—upper and lower first cracks 38—end plates between walls of second cracks; cushion layer; 39—flexible belt;

[0050] 40—Secondary crack entrance and exit hole. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the technical solution more clear, the technical solution is further described in detail below in conjunction with specific implementation methods. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the technical solution.

[0053] like Figure 1As shown, this embodiment proposes a proppant paving simulation experimental device with adjustable secondary fracture direction and inclination, a sand-carrying liquid supply device, the sand-carrying liquid supply device has a sand-carrying liquid output end, and the sand-carrying liquid supply device is used to supply the sand-carrying liquid in a quantitative and constant pressure manner; a fracture network system 19, the fracture network system 19 is used to simulate the distribution of proppant in the sand-carrying liquid in the fracture network of secondary fractures with different directions and inclinations, and the input end of the fracture network system 19 is connected to the sand-carrying liquid output end of the sand-carrying liquid supply device; a waste liquid recovery tank 20, the waste liquid recovery tank 20 is connected to the output end of the fracture network system 19; an image acquisition system, whose observation direction is toward the fracture network system 19, and is used to acquire images of sand-carrying liquid paving in the fractures in the fracture network system 19.

[0054] Specifically, the sand-carrying liquid supply equipment in this embodiment includes a sand storage tank 1, a reagent tank 2 and a water storage tank 3, wherein the sand storage tank 1, the reagent tank 2 and the water storage tank 3 are respectively filled with sand, reagent and water, and the sand storage tank 1, the reagent tank 2 and the water storage tank 3 are respectively connected with the sand mixing tank 11 through pipelines, and a sand storage tank valve 9 and a sand delivery pump 10 are arranged on the pipeline between the sand storage tank 1 and the sand mixing tank 11, a reagent tank valve 7 and a reagent pump 8 are arranged on the pipeline between the reagent tank 2 and the sand mixing tank 11, and a water storage tank valve 4, a water delivery pump 5 and a water meter 6 are arranged on the pipeline between the water storage tank 3 and the sand mixing tank 11. The sand storage tank 1, the reagent tank 2 and the water storage tank 3 can deliver corresponding raw materials to the sand mixing tank 11 through the corresponding pump bodies on their output pipelines, and after delivering the raw materials to the sand mixing tank 11, the corresponding valves on each pipeline are closed. The sand mixing tank 11 has a sand mixing device inside, and the input sand material, reagent and water can be fully mixed into a sand carrying liquid through the sand mixing tank 11.

[0055] The sand mixing tank 11 is connected to the fracture network system 19 through a pipeline, and is used to directly output the sand-carrying liquid to the fracture network system 19. A screw pump 12, a sand-carrying liquid flow meter 13, and a sand-carrying liquid pressure gauge 14 are arranged on the pipeline between the sand mixing tank 11 and the fracture network system 19. The screw pump 12 can stably deliver the sand-carrying liquid to the fracture network system 19 by screw delivery. In this process, the delivery amount and delivery pressure of the sand-carrying liquid are measured by the sand-carrying liquid flow meter 13 and the sand-carrying liquid pressure gauge 14.

[0056] A waste liquid recovery tank 20 is provided at the output end of the fracture network system 19 , and the output end of the fracture network system 19 is connected to the waste liquid recovery tank 20 through a pipeline.

[0057] The image acquisition system includes a computer 15, a first high-speed camera 16 and a second high-speed camera 17. The computer 15 is connected to the first high-speed camera 16 and the second high-speed camera 17 respectively. The computer 15 controls the two high-speed cameras and receives image information captured by the high-speed cameras for processing.

[0058] like Figure 2-Figure 7As shown, in this embodiment, the fracture network system 19 includes a closed primary fracture system and a secondary fracture system, and the primary fracture system and the secondary fracture system have a primary fracture space 33 and a secondary fracture space 31 respectively, the output end of the sand-carrying liquid is connected to the input end of the primary fracture system, the output end of the primary fracture system is connected to the waste liquid recovery tank 20, the input end of the secondary fracture system is connected to the middle of the primary fracture system, and the primary fracture space 33 and the secondary fracture space 31 are interconnected, and the output end of the secondary fracture system is connected to the waste liquid recovery tank 20.

[0059] like Figure 3 As shown, both the primary fracture system and the secondary fracture system are plate-like structures, and an angle is formed between the main extension direction of the primary fracture system and the main extension direction of the secondary fracture system, i.e., the direction of the secondary fracture. A secondary fracture inclination turntable 26 is provided on one main extension surface of the primary fracture system, and the secondary fracture inclination turntable 26 is sealedly connected to the primary fracture system, and the secondary fracture system is connected to the primary fracture system through the secondary fracture inclination turntable 26; the proppant laying simulation experimental device with adjustable secondary fracture direction and inclination also includes a rotation drive device, which is connected to the secondary fracture inclination turntable 26 and is used to adjust the relative position of the plane where the primary fracture system and the secondary fracture system are located.

[0060] In this embodiment, the rotation driving device is a motor 18 and a flexible belt 39, wherein the output end of the motor 18 is connected to the secondary crack inclination rotating disk 26 through the flexible belt 39, and the secondary crack inclination rotating disk 26 is driven by the servo orientation of the motor 18 to rotate to a predetermined angle. Preferably, the surface of the secondary crack inclination rotating disk 26 is engraved with an angle to facilitate the determination of the secondary crack inclination.

[0061] A secondary fracture direction rotating column 27 is arranged on one main extension surface of the primary fracture system, and the secondary fracture direction rotating column 27 is sealedly connected to the secondary fracture inclination rotating disk 26. The secondary fracture system is connected to the primary fracture system through the secondary fracture direction rotating column 27 and the secondary fracture inclination rotating disk 26; the proppant laying simulation experimental device with adjustable secondary fracture direction and inclination also includes an inclination adjusting device, which is connected to the secondary fracture system and is used to adjust the inclination of the secondary fracture system.

[0062] Preferably, the secondary crack direction rotation column 27 is a flexible component that can be stretched and compressed to facilitate the rotation of the secondary crack.

[0063] In this embodiment, the direction adjustment device is a secondary crack support rod 32, which is a hydraulic telescopic rod to assist in adjusting the length of the support rod. An angle is engraved on the surface of the secondary crack support rod 32 to facilitate determining the direction of the secondary crack.

[0064] The number and arrangement of the primary crack inlets and outlets and the number and arrangement of the secondary crack outlets may be different.

[0065] The primary crack system includes a primary crack wall 21, a primary crack inlet and outlet end plate 34, a primary crack protective layer 35, a sand-carrying liquid inlet and outlet wall 24 and a locking assembly. There are two primary crack walls 21 and they are arranged in parallel and opposite to each other. The sides of the two primary crack walls 21 are sealed and the primary crack inlet and outlet end plates 34 are respectively arranged at the front and rear ends. The connection between the primary crack inlet and outlet end plates 34 and the primary crack wall 21 is sealed. The end surface of the primary crack wall 21 is provided with a primary crack protective layer 35. The primary crack protective layer 35, the primary crack wall 21 and the primary crack inlet and outlet end plate 34 are locked and sealed by the locking assembly to form a primary crack assembly. A plurality of primary crack inlet and outlet holes 36 are provided on the primary crack inlet and outlet end plate 34. The sand-carrying liquid inlet and outlet wall 24 is installed at the front and rear ends of the primary crack assembly so that the internal cavity of the sand-carrying liquid inlet and outlet wall 24 is connected to the primary crack space 33 through the primary crack inlet and outlet holes 36. The left and right sides of the primary crack wall 21 are sealed by the primary crack upper and lower end plates 37.

[0066] The locking components in the primary crack system in this embodiment include multiple groups of primary crack bolts 22 and primary crack nuts 23. Each group of primary crack bolts 22 and primary crack nuts 23 are connected around two primary crack walls 21 by screwing, thereby achieving clamping and sealing around the primary crack wall 21.

[0067] The secondary crack system includes a secondary crack wall 28, a secondary crack wall cushion 38 and a locking assembly, wherein there are two secondary crack walls 28 and they are arranged in parallel and opposite to each other, the sides of the two secondary crack walls 28 are sealed, the fronts of the two secondary crack walls 28 are open, and the secondary crack wall cushion 38 is arranged at the tails of the two secondary crack walls 28, and the secondary crack wall cushion 38 is locked with the two secondary crack walls 28 by the locking assembly; a plurality of secondary crack access holes 40 are opened on the secondary crack wall cushion 38. Both the primary crack wall 21 and the secondary crack wall 28 are made of a light-transmissive high-toughness material.

[0068] Similarly, the locking assembly in the secondary crack system in this embodiment includes multiple groups of secondary crack bolts 30 and secondary crack nuts 29. Each group of secondary crack bolts 30 and secondary crack nuts 29 are connected around the two secondary crack walls by screwing, thereby achieving clamping and sealing around the secondary crack walls.

[0069] The operation method of the above-mentioned secondary fracture adjustable proppant paving simulation experimental device comprises the following steps:

[0070] Step 1: Place an appropriate amount of purified water in the water storage tank 3;

[0071] Step 2: Weigh the required sand-carrying liquid agent and place it in the agent tank 2;

[0072] Step 3, select the required proppant, weigh it and place it in the sand storage tank 1;

[0073] Step 4: Open the water tank valve 4 and the water delivery pump 5, inject the required purified water into the sand mixing tank 11, and close the water delivery pump 5 and the water tank valve 4;

[0074] Step 5: Open the medicine tank valve 7 and the medicine pump 8, inject the required medicine into the sand mixing tank 11, and close the medicine pump 8 and the medicine tank valve 7;

[0075] Step 6: Turn on the agitator of the sand mixing tank 11 to stir the purified water and the reagent;

[0076] Step 7: Open the sand storage tank valve 9 and the sand delivery pump 10, inject the required proppant into the sand mixing tank 11, stir to form a sand-carrying liquid, and close the sand delivery pump 10 and the sand storage tank valve 9;

[0077] Step 8, start the motor 18, adjust the length of the secondary crack support rod 32, and set the inclination and direction of the secondary cracks in the crack network system 19;

[0078] Step nine, turning on the computer 15, the first high-speed camera and the second high-speed camera;

[0079] Step ten, open the screw pump 12, transport the sand-carrying liquid through the pipeline to the fracture network system 19, and discharge it to the waste liquid recovery tank 20; in this process, the sand-carrying liquid enters the sand-carrying liquid inlet and outlet space 25, passes through the primary fracture inlet and outlet hole 36, enters the primary fracture space 33, the secondary fracture space 31, and finally returns to the waste liquid recovery tank 20.

[0080] Step 11, recording the placement of proppant in the primary fracture and the secondary fracture during the proppant transportation process;

[0081] Step 12: turn off the screw pump 12, the first high-speed camera, the second high-speed camera and the computer 15 in sequence, dispose of the proppant and experimental waste liquid, and the experiment is finished.

[0082] In general, the device has a simple structure, reasonable design, easy installation and operation, low investment cost, few ground equipment, small footprint, and can flexibly adjust the fracturing fluid formula and proppant ratio as well as the secondary fracture direction and inclination, and can conduct in-depth research on the proppant placement in different fracture network forms. When measuring the proppant placement in the fracture, the device fully reflects the influence of the secondary fracture direction and inclination on the proppant distribution, which is more in line with the actual situation of post-fracture development of unconventional oil reservoirs;

[0083] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present technical content. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of this patent.

Claims

1. A proppant paving simulation experimental device with adjustable secondary fracture direction and inclination, characterized in that: include A sand-carrying liquid supply device, wherein the sand-carrying liquid supply device has a sand-carrying liquid output end for supplying the sand-carrying liquid in a quantitative and constant pressure manner; A fracture network system, the fracture network system is used to simulate the distribution of proppant in the sand-carrying fluid in the fracture network of secondary fractures with different orientations and inclinations, and the input end of the fracture network system is connected to the sand-carrying fluid output end of the sand-carrying fluid supply device; A waste liquid recovery tank, wherein the waste liquid recovery tank is connected to an output end of the fracture network system; The image acquisition system has an observation direction toward the fracture network system and is used to acquire the laying image of the proppant in the sand-carrying fluid in the fractures of the fracture network system.

2. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 1 is characterized in that: The fracture network system comprises a closed primary fracture system and a secondary fracture system, wherein the primary fracture system and the secondary fracture system respectively have a primary fracture space and a secondary fracture space inside, the sand-carrying liquid output end is connected to the input end of the primary fracture system, the output end of the primary fracture system is connected to a waste liquid recovery tank, the input end of the secondary fracture system is connected to the middle of the primary fracture system, and the primary fracture space and the secondary fracture space are interconnected, and the output end of the secondary fracture system is connected to the waste liquid recovery tank.

3. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 2 is characterized in that: The primary crack system and the secondary crack system are both plate-like structures, and an angle is formed between the main extension direction of the primary crack system and the main extension direction of the secondary crack system, which is the direction of the secondary crack.

4. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 3 is characterized in that: A secondary crack inclination rotating disk is provided on one main extension surface of the primary crack system, the secondary crack inclination rotating disk is sealedly connected to the primary crack system, and the secondary crack system is connected to the primary crack system through the secondary crack inclination rotating disk; The proppant paving simulation experimental device with adjustable secondary fractures also includes a rotation driving device, which is connected to the secondary fracture inclination turntable and is used to adjust the relative position of the plane where the primary fracture system and the secondary fracture system are located.

5. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 4 is characterized in that: A secondary crack direction rotating column is provided on one main extension surface of the primary crack system, the secondary crack direction rotating column is sealedly connected to the secondary crack inclination rotating disk, and the secondary crack system is connected to the primary crack system through the secondary crack direction rotating column and the secondary crack inclination rotating disk; The proppant paving simulation experimental device with adjustable secondary fractures also includes an inclination adjustment device, which is connected to the secondary fracture system and is used to adjust the inclination of the secondary fracture system.

6. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to any one of claims 2 to 5, characterized in that: The primary crack system comprises a primary crack wall, a primary crack inlet and outlet end plate, a primary crack protective layer, a sand-carrying liquid inlet and outlet wall and a locking assembly. There are two primary crack walls and they are arranged in parallel and opposite to each other. The sides of the two primary crack walls are sealed and primary crack inlet and outlet end plates are respectively arranged at the front and rear ends. The connection between the primary crack inlet and outlet end plate and the primary crack wall is sealed. The end surface of the primary crack wall is provided with a primary crack protective layer. The primary crack protective layer, the primary crack wall and the primary crack inlet and outlet end plate are locked and sealed by the locking assembly to form a primary crack assembly. A plurality of first-level crack entry and exit holes are provided on the first-level crack entry and exit end plate; The sand-carrying liquid inlet and outlet walls are sleeved on the front and rear ends of the primary crack assembly, so that the internal cavity of the sand-carrying liquid inlet and outlet walls is connected with the primary crack space through the primary crack inlet and outlet holes.

7. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to any one of claims 2 to 5, characterized in that: The secondary crack system comprises a secondary crack wall, a cushion layer between the secondary crack walls and a locking assembly, wherein there are two secondary crack walls which are arranged in parallel and opposite to each other, the sides of the two secondary crack walls are sealed, the fronts of the two secondary crack walls are open, and a cushion layer between the secondary crack walls is arranged at the tails of the two secondary crack walls, and the cushion layer between the secondary crack walls is locked with the two secondary crack walls by the locking assembly; A plurality of secondary crack inlet and outlet holes are provided on the secondary crack wall cushion layer.

8. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 1 is characterized in that: The sand-carrying liquid supply equipment includes a sand mixing tank for storing sand-carrying liquid, the output end of the sand mixing tank is connected to the input end of the fracture network system through a pipeline, and a screw pump, a sand-carrying liquid flow meter and a sand-carrying liquid pressure gauge are arranged on the pipeline between the sand mixing tank and the fracture network system.

9. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 1, characterized in that: The sand mixing tank is provided with a stirring device inside; The sand-carrying liquid supply equipment also includes a sand storage tank, a medicine tank and a water storage tank, which are respectively connected to the sand mixing tank through pipelines, and pumps and valves are arranged on the output pipelines of the sand storage tank, the medicine tank and the water storage tank.

10. The proppant paving simulation experimental device with adjustable secondary fracture direction and inclination according to claim 2, characterized in that: The image acquisition system comprises a first high-speed camera and a second high-speed camera, wherein image acquisition ends of the first high-speed camera and the second high-speed camera are respectively directed toward the primary crack system and the secondary crack system.

Images