Device and method for testing migration of proppant in shale reservoir

Abstract

The invention relates to the technical field of petroleum engineering, in particular to a device and method for testing migration of a proppant in a shale reservoir, and the device comprises a model system, an injection system, a vacuumizing system, a pressure field measurement system, a differential pressure measurement system, a back pressure system and a data acquisition and processing system. The model system comprises a model box, a test bin is arranged in the model box, and the test bin penetrates through the side wall of one side in the width extension direction of the model box; the pressing plate can completely cover the test bin and is detachably connected with the model box; the two fluid conveying assemblies are arranged at the two ends of the model box in the length extension direction respectively, the structures are in mirror symmetry, each fluid conveying assembly comprises a first connecting pipe, and the first connecting pipes are communicated with the testing bin. According to the device and the method, different-width fracture and netlike fracture forms of the shale reservoir can be simulated, and the migration rule of shale reservoir fracturing fluid carrying sand in the fractures can be analyzed.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum engineering, and specifically to a proppant migration test device and method in a shale reservoir. Background Art

[0002] A shale reservoir refers to a natural gas reservoir enriched and generated in a formation of shale lithology, with extremely high gas content and rich resource potential. Shale gas reservoirs usually have low permeability. To effectively exploit shale gas, fracturing technology needs to be adopted to form fractures and increase the permeability of the reservoir. During the fracturing process, high-pressure fluid is injected into the reservoir to form fractures, and then proppants are injected to keep the fractures open, thereby improving the gas flow capacity.

[0003] A simulation device for studying the migration and conductivity of proppants during the injection of fracturing fluid in a shale reservoir indoors can simulate the migration process of proppants inside the reservoir and the relationship between flow rate and pressure during the injection of fracturing fluid, optimize proppants, etc. By observing the proppant migration process before production, studying the variation laws of proppant migration on fracture propagation, sand placement, and conductivity can provide value for subsequent effective production. Currently, there is an urgent need for a proppant migration test device in a shale reservoir to simulate different-width fractures and reticulated fracture patterns in the shale reservoir. Summary of the Invention

[0004] The purpose of the present invention is to provide a proppant migration test device and method in a shale reservoir, which can simulate different-width fractures and reticulated fracture patterns in the shale reservoir.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: In the first technical solution, a proppant migration test device in a shale reservoir includes a model system, and the model system includes: a model box, inside which a test chamber is provided, and the test chamber penetrates through one side wall in the width extension direction of the model box; a pressing plate that can completely cover the test chamber and is detachably connected to the model box; two fluid delivery components, respectively arranged at both ends in the length extension direction of the model box, and their structures are mirror-symmetrical. The fluid delivery component includes a first connecting pipe, and the first connecting pipe is communicated with the test chamber.

[0006] In the first technical solution, preferably, the model system further includes two angle control components, which are respectively arranged at both ends in the length extension direction of the model box and are structurally mirror-symmetrical. The angle control component includes: a first connecting frame, fixedly arranged on the end face of the model box, and the first connecting pipe is fixedly connected to the first connecting frame; an adjusting ring, arranged outside the first connecting frame, and the adjusting ring is detachably connected to the first connecting frame; a second connecting frame, arranged outside the adjusting ring, and the adjusting ring is rotatably connected to the second connecting frame; two locking components, both fixedly arranged on the second connecting frame and located on the upper and lower sides of the adjusting ring respectively.

[0007] In the first technical solution, preferably, the first connecting frame includes: a first driving ring, an assembly hole is arranged on the end face of the model box, the first driving ring is arranged in the assembly hole, a plurality of protruding rings are fixedly arranged on the outer side wall of the first driving ring, and the plurality of protruding rings are equally spaced. An assembly groove is also arranged on the end face of the model box, and the plurality of protruding rings are respectively arranged in the plurality of assembly grooves, and the shape of the assembly groove matches the shape of the protruding ring; a second driving ring, the second driving ring includes a plurality of arc-shaped driving plates, and the plurality of arc-shaped driving plates respectively correspond to the positions of the plurality of protruding rings and are fixedly connected to the plurality of protruding rings respectively. A flat driving plate is arranged between adjacent two arc-shaped driving plates, and the flat driving plate is fixedly connected to the arc-shaped driving plate. There is a gap between the flat driving plate and the end face of the model box. The adjusting ring corresponds to the position of the second driving ring, and the adjusting ring is detachably connected to the second driving ring.

[0008] In the first technical solution, preferably, the second connecting frame includes: a bearing ring, an annular sliding groove is arranged on the inner side wall of the bearing ring, an annular convex rib is fixedly arranged on the outer side wall of the adjusting ring, and the annular convex rib is arranged in the annular sliding groove and can slide along the inner wall of the annular sliding groove. The first connecting pipe is fixedly arranged at the inner center of the first driving ring, and the length of the first connecting pipe is greater than the length of the first driving ring; a first support frame, fixedly arranged on the top of the outer side wall of the bearing ring, and one of the locking components is fixedly arranged on the first support frame; a second support frame, fixedly arranged on the bottom of the outer side wall of the bearing ring, and the other locking component is fixedly arranged on the second support frame; the locking component includes: an electric telescopic rod; a force-applying plate, fixedly arranged at the output end of the electric telescopic rod. An avoidance hole is arranged at one end of the bearing ring close to the force-applying plate, and the avoidance hole is communicated with the inside of the annular sliding groove, and the force-applying plate can slide along the inner wall of the avoidance hole; a rubber pad, fixedly arranged on the end face of the force-applying plate facing the adjusting ring.

[0009] In the first technical solution, preferably, a base is provided under the angle control component, the second support frame is fixedly connected to the base, universal wheels are provided at the four corners of the bottom surface of the base, the fluid delivery component also includes a second connecting pipe, the second connecting pipe and the first connecting pipe are located at the same height, a support arm is fixedly provided on the side wall of the second support frame, the second connecting pipe is fixedly connected to the support arm, there is a gap between the second connecting pipe and the first connecting pipe, the second connecting pipe is connected to the first connecting pipe through a hose, and the length of the hose is greater than the distance of the gap between the second connecting pipe and the first connecting pipe.

[0010] In the first technical solution, preferably, it also includes: an injection system, wherein the discharge end of the injection system is connected to the interior of one of the second connecting tubes, for providing circulating fluid to the model system; a vacuum system, for vacuuming the model system; a pressure field measurement system, for measuring the pressure distribution in the test chamber; a differential pressure measurement system, wherein the differential pressure measurement system is electrically connected to the pressure field measurement system; a back pressure system, wherein the discharge end of the back pressure system is connected to the interior of another of the second connecting tubes, for maintaining the outlet pressure of the model system; and a data acquisition and processing system, for real-time acquisition of the upstream pressure of the model system and the pressure values of the pressure measuring points.

[0011] In the second technical scheme, a method for using a proppant migration test device in a shale reservoir is provided. The proppant migration test device in a shale reservoir as described in the first technical scheme is used, and the following steps are included: Step 1, check the entire device to ensure that each component is tightly connected and the measurement accuracy meets the experimental requirements; Step 2, remove the pressure plate, install the core, and then reinstall the pressure plate; Step 3, prepare the corresponding fluid; Step 4, vacuum the model system through a vacuum system, and slowly inject the fluid into the model system through the injection system; Step 5, record the pressure data that changes over time in the test chamber through a pressure field measurement system, a differential pressure measurement system, and a data acquisition and processing system; Step 6, summarize and organize all the original data recorded during the experiment, carefully check the accuracy and completeness of the data, and eliminate abnormal data points.

[0012] In the second technical solution, preferably, in step six, after the test is completed, the pressure plate is removed, and detection is performed using an optical sensor, and a chart is drawn based on the sorted data.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention can simulate different-width fractures and reticulated fracture patterns in shale reservoirs, and can also analyze the migration law of proppant-carrying fracturing fluid in fractures in shale reservoirs. The present invention can simulate the migration process of proppant inside the reservoir during the injection of fracturing fluid and the relationship between flow rate and pressure, optimize proppant, etc. By observing the proppant migration process before production, the variation law of proppant migration on fracture propagation, sand placement, and conductivity can be studied, providing value for subsequent effective production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Is an axonometric view of the model system in the present invention;

[0016] Figure 2 Is an axonometric view of the model box and the pressing plate in the present invention;

[0017] Figure 3 Is Figure 2 An enlarged view of part A in

[0018] Figure 4 Is a side view of the model box in the present invention;

[0019] Figure 5 Is an axonometric view of the fluid delivery assembly in the present invention;

[0020] Figure 6 Is an axonometric view of the angle control assembly in the present invention;

[0021] Figure 7 Is an axonometric view of one angle of the first connecting frame in the present invention;

[0022] Figure 8 Is an axonometric view of another angle of the first connecting frame in the present invention;

[0023] Figure 9 Is an axonometric view of the adjusting ring in the present invention;

[0024] Figure 10 Is an axonometric view of the second connecting frame in the present invention;

[0025] Figure 11 Is Figure 10 An enlarged view of part B in

[0026] Figure 12 Is an axonometric view of the locking assembly in the present invention;

[0027] Figure 13 Is a front view structural schematic diagram of the model box in use in the present invention;

[0028] Figure 14 Is a structural connection schematic diagram of the present invention.

[0029] The reference numerals include:

[0030] 1 - Model system, 11 - Model box, 111 - Test chamber, 112 - Assembly hole, 113 - Assembly groove, 12 - Pressing plate, 13 - Fluid delivery assembly, 131 - First connecting pipe, 132 - Second connecting pipe, 133 - Hose, 14 - Angle control assembly, 141 - First connecting frame, 1411 - First driving ring, 14111 - Protruding ring, 1412 - Second driving ring, 14121 - Arc driving plate, 14122 - Straight driving plate, 142 - Adjusting ring, 1421 - Annular convex rib, 143 - Second connecting frame, 1431 - Bearing ring, 14311 - Annular sliding groove, 14312 - Avoidance hole, 1432 - First support frame, 1433 - Second support frame, 14331 - Support arm, 144 - Locking assembly, 1441 - Electric telescopic rod, 1442 - Force - applying plate, 1443 - Rubber pad, 15 - Base, 16 - Universal wheel, 2 - Injection system, 3 - Vacuum - pumping system, 4 - Pressure - field measurement system, 5 - Differential - pressure measurement system, 6 - Back - pressure system, 7 - Data acquisition and processing system. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figure 1-14 As shown in the figure, the present invention provides a technical solution: a proppant migration test device in a shale reservoir, including a model system 1, an injection system 2, a vacuum - pumping system 3, a pressure - field measurement system 4, a differential - pressure measurement system 5, a back - pressure system 6, and a data acquisition and processing system 7. The model system 1 includes a model box 11, a pressing plate 12, and two fluid delivery assemblies 13. A test chamber 111 is provided inside the model box 11. The fluid delivery assembly 13 includes a first connecting pipe 131. When the present invention is in use, the pressing plate 12 is removed, the core is installed, and then the pressing plate 12 is reinstalled. The prepared fluid can enter the test chamber 111 from the first connecting pipe 131 on one side and discharge from the first connecting pipe 131 on the other side. The present invention can simulate different - width fractures and reticulated fracture morphologies in shale reservoirs. By observing the proppant migration process before production, the variation laws of proppant migration on fracture propagation, sand placement, and flow - conductivity can be studied, providing value for subsequent effective production.

[0033] Please refer to Figure 1-6, the model system 1 further includes two angle control components 14. The angle control component 14 includes a first connecting frame 141, an adjusting ring 142, a second connecting frame 143, and two locking components 144. When the model box 11 rotates, the adjusting ring 142 can be driven by the first connecting frame 141 to rotate on the second connecting frame 143. After the model box 11 rotates to any angle, the two locking components 144 can, through the cooperation of the adjusting ring 142 and the first connecting frame 141, keep the model box 11 at the current angle unchanged and achieve stable locking, thus greatly expanding the scope of research and providing richer simulation scenarios and conditions for related research.

[0034] Please refer to Figure 1-11 , the first connecting frame 141 includes a first driving ring 1411 and a second driving ring 1412. A number of protruding rings 14111 are provided on the outer side wall of the first driving ring 1411. The first driving ring 1411 is arranged in the assembly hole 112 on the end face of the model box 11, and the protruding rings 14111 are arranged in the assembly groove 113 on the end face of the model box 11. When the model box 11 rotates, the model box 11 can drive the first driving ring 1411 to rotate through a number of protruding rings 14111. When the locking component 144 keeps the angle of the model box 11 unchanged, a number of protruding rings 14111 can prevent the model box 11 from resetting under the action of gravity. In either process, a number of protruding rings 14111 can be evenly stressed and ensure that there is no slipping between the first driving ring 1411 and the inner side wall of the assembly hole 112. The second driving ring 1412 includes a number of arc-shaped driving plates 14121 and a number of straight driving plates 14122. The second driving ring 1412 has a closed triangular structure, and the adjusting ring 142 is connected to the second driving ring 1412. When the model box 11 drives the first driving ring 1411 to rotate, the first driving ring 1411 can drive the adjusting ring 142 to rotate through the second driving ring 1412. Since there is a gap between the straight driving plate 14122 and the end face of the model box 11, when the second driving ring 1412 rotates, the second driving ring 1412 will not rub against the end face of the model box 11. The adjusting ring 142 is detachably connected to the second driving ring 1412. No matter which one of the first driving ring 1411, the second driving ring 1412 or the adjusting ring 142 is worn, it can be disassembled and replaced.

[0035] Please refer to Figure 1-11, the second connecting frame 143 includes a bearing ring 1431, a first support frame 1432 and a second support frame 1433. An annular chute 14311 is provided on the inner side wall of the bearing ring 1431. An annular convex rib 1421 is fixedly provided on the outer side wall of the adjusting ring 142. The annular convex rib 1421 is arranged in the annular chute 14311. The first connecting pipe 131 is fixedly provided at the inner center of the first driving ring 1411. Two locking components 144 are respectively arranged on the first support frame 1432 and the second support frame 1433.

[0036] Please refer to Figure 1-12 , the locking component 144 includes an electric telescopic rod 1441, a force-applying plate 1442 and a rubber pad 1443. An avoidance hole 14312 is provided on the bearing ring 1431. When the model box 11 needs to rotate freely, the electric telescopic rod 1441 shortens, driving the force-applying plate 1442 and the rubber pad 1443 to leave the avoidance hole 14312. The rubber pad 1443 does not contact the annular convex rib 1421. At this time, the model box 11 can drive the adjusting ring 142 to rotate through the first connecting frame 141, and the annular convex rib 1421 slides along the inner wall of the annular chute 14311. When it is necessary to keep the angle of the model box 11 unchanged, the electric telescopic rod 1441 extends, driving the force-applying plate 1442 and the rubber pad 1443 to enter the avoidance hole 14312. The rubber pad 1443 abuts against the annular convex rib 1421 and applies pressure to the annular convex rib 1421. Under the action of friction, the annular convex rib 1421 cannot slide along the inner wall of the annular chute 14311, and neither the adjusting ring 142 nor the first connecting frame 141 can rotate.

[0037] Please refer to Figure 1-12 , a base 15 is provided below the angle control component 14. Universal wheels 16 are provided at the four corners of the bottom surface of the base 15. Therefore, the model system 1 can be moved to any position. The fluid delivery component 13 further includes a second connecting pipe 132 and a hose 133. The prepared fluid first enters the second connecting pipe 132 on one side, and then enters the first connecting pipe 131 through the hose 133. The fluid in the test chamber 111 is first discharged into the first connecting pipe 131 on the other side, and then discharged through the hose 133 and the second connecting pipe 132 on the other side. Since the second connecting pipe 132 is fixedly connected to the support arm 14331 on the side wall of the second support frame 1433, the second connecting pipe 132 does not rotate when the model box 11 rotates.

[0038] Please refer to Figure 1-14, the present invention can simulate the migration process of proppants in the reservoir during the injection of fracturing fluid, as well as the relationship between flow rate and pressure and the conductivity. The main parameters of the model system 1 are as follows: Model specifications: 1000×1000×100mm. Temperature: normal temperature to 90 degrees Celsius. Two-dimensional model: maximum working pressure 10MPa. Model material: stainless steel. The model box 11 is rectangular, the model is of steel structure, and a number of hydraulic inlets are provided at the top and bottom of the model box 11. Both the model box 11 and the pressing plate 12 are of steel structure. A rubber sealing ring (not shown in the figure) is provided between the steel structures, and a pair of rectangular steel flanges (not shown in the figure) are on the outside, and bolts are used to apply force to achieve the purpose of sealing. To ensure that the core and the pressing plate 12 can be filled densely, we carefully design the pressing plate 12 into a compaction mechanism, use a metal sealing gasket or a high-performance rubber sealing material (such as perfluoroether rubber, etc.) for sealing, and compact the rock plate by means of tightening screws. The corners of the inner cavity of the cavity are designed with an R-shaped transition. Correspondingly, the compaction head also adopts a piston structure with an R-shaped transition to further ensure the stable operation of the system. A total of 8 measuring points are arranged on the model box 11, on the back of the device, to measure the pressure distribution in the formation before and after the injection of fracturing fluid. There is a row of resistance wires (not shown in the figure) in the test chamber 111, which can heat the entire device to simulate the high temperature of the actual formation. The particle size corresponding to 20 mesh is approximately 0.85mm. Considering from the perspective of the sedimentation space, the thickness of the rock plate should be more than 5-10 times the particle size of the proppant, so as to provide enough space for the proppant to settle in the fluid and better observe the differences in the settling velocity, accumulation morphology, etc. of proppants with different mesh numbers due to particle size differences. The inner diameter of the pipeline through which the fracturing fluid flows must be more than 3 times the diameter of the proppant. Taking 20 mesh as an example, the required pipeline inner diameter is greater than 2.55mm. If the device does not need to be connected in series, a screen can be added at the outlet end to prevent the proppant from flowing out.

[0039] Please refer to Figure 14 , the injection system 2 consists of a constant speed and constant pressure pump, a proppant and fracturing fluid mixing device, a piston container, etc. The proppant and fracturing fluid mixing device is mainly used to fully mix the proppant (such as quartz sand, etc.) and the fracturing fluid evenly and then load them into the intermediate container. The piston container provides circulating fluid for the test and is mainly used to contain water and fracturing fluid (containing proppants) respectively; volume: 3000mL, pressure resistance 16MPa, quantity 3 sets, used to contain oil, water and fracturing fluid.

[0040] Please refer to Figure 14 , the vacuum pumping system 3 is mainly used to pump vacuum for the system. The vacuum pumping system 3 includes a vacuum pump and a vacuum buffer container, quantity 1 set. The model of the vacuum pump is 2X-8 type. The volume of the vacuum buffer container is 2L.

[0041] Please refer to Figure 14, the pressure field measurement system 4 mainly includes a pressure sensor and a digital display secondary instrument.

[0042] Please refer to Figure 14 , the differential pressure measurement system 5 mainly includes a differential pressure sensor, a differential pressure digital display secondary instrument, etc., with a quantity of 3 sets, a differential pressure range of 10 KPa, an absolute pressure of 4 MPa, and an accuracy of 0.1% FS.

[0043] Please refer to Figure 14 , the backpressure system 6 is mainly used to maintain the outlet pressure of the model system 1. The backpressure system 6 mainly includes a backpressure valve, a backpressure pump, a backpressure container, a backpressure gauge, etc., with a quantity of 1 set. The backpressure valve adopts a high-precision backpressure control valve to accurately control the outlet pressure of the system, with a working pressure of 16 MPa, a control fluctuation range within ±0.1 MPa, and a working temperature at room temperature. The model of the high-pressure intermediate container is ZR-2, with a design pressure of 16 MPa, a volume of 200 ml, and stable control pressure. The range of the backpressure gauge is 16 MPa, with an accuracy of 1.5 levels, and a quantity of 1 set.

[0044] Please refer to Figure 14 , the data acquisition and processing system 7 can collect the values of the upstream pressure and the pressure at the pressure measurement points in real time, and visually display the collected data in the form of curves and tables, showing the working state of the control components.

[0045] The preparations before the experiment of the present invention are as follows:

[0046] Device assembly and debugging. Assemble the present invention correctly to ensure that all components are tightly and firmly connected. For example, the connections of parts such as the model system 1, the injection system 2, and the vacuum pumping system 3 are correct. Connect the power supply and calibrate and debug the pressure sensors, flow monitoring instruments, etc. equipped with the device to ensure that their measurement accuracy meets the experimental requirements.

[0047] Operation of filling the rock plate. First, prepare the required rock cores and use wire cutting to cut the shale cores into the required sizes and shapes. The core filler is a shale rock plate, mainly simulating the morphology (main cracks and branch cracks) and crack widths of the cracks. Use sandpaper or a grinding wheel to polish the surface of the cores to remove surface unevenness and scratches. Then, place the cores according to the sizes and shapes, leaving a preset crack width between the cores, glue the cores on the pressing plate 12 to ensure that the cores can be firmly fixed in the test chamber 111, prevent the fracturing fluid from flowing between the cores and the pressing plate 12, then compress the cores, and finally connect the pressing plate 12 to the model box 11, with a layer of metal rubber pad in the middle to prevent the leakage of pressure and fluid, and tighten the screws to prepare for the test.

[0048] Fluid preparation and connection. According to the specific scenario of the experimental simulation, prepare the corresponding fluid (such as water, shale oil and fracturing fluid (including proppant) that may be used in simulating reservoir development. The proppant is fully mixed with a tracer that has fluorescent properties or a tracer that can be made fluorescent by adding fluorescent markers, and then mixed with the fracturing fluid), and the basic physical properties such as density and viscosity of the fluid are accurately measured and recorded. Load the prepared fluid into the liquid storage tank of the injection system, connect the injection pipeline, ensure that there is no leakage in the pipeline, adjust the parameters of the injection pump, and set the initial injection flow rate, pressure and other conditions.

[0049] The present invention operates as follows during the experimental process:

[0050] Experimental process. First, use the vacuum system 3 to evacuate the entire model system 1, and then start the injection pump. According to the set stable flow rate or pressure conditions, slowly inject the fluid into the test chamber 111, and pay attention to the pressure change values at different positions fed back by the pressure sensor, and record the pressure data that changes over time. If the device does not need to be connected in series, add a screen at the outlet to prevent the proppant from flowing out. If multiple devices need to be connected in series, install a pipe with an inner diameter of more than 3 times the diameter of the proppant at the outlet, and keep it as short as possible to reduce the impact of the pipeline on the migration of the proppant.

[0051] Temperature field and pressure field. In order to effectively simulate the high temperature and high pressure environment inside the shale reservoir, there is a row of resistance wires inside the test chamber 111, which can heat the entire device; the pressure in the formation fracture is simulated by the back pressure system 6, so that the proppant can migrate under a pressure background more similar to the actual formation, making the test results closer to the actual working conditions, and then more accurately analyzing the key parameters such as the migration law of the proppant in the formation and the final laying form.

[0052] Tracer monitoring: After the experiment is over, the pressure plate 12 is removed and the optical sensor is used for detection. The migration of the tracer is tracked by receiving the fluorescent signal emitted by the tracer, which accurately reflects the sand concentration of the proppant at a certain position.

[0053] The data processing and analysis after the experiment are as follows:

[0054] Data collation and verification. Turn off the injection pump and other related experimental equipment, summarize and organize all the original data recorded during the experiment (including pressure data, fluid flow data, tracer concentration data, temperature data, etc.), carefully check the accuracy and completeness of the data, and eliminate abnormal data points.

[0055] Result analysis and plotting. Based on the sorted data, various relevant charts are plotted using professional data analysis software or plotting tools, such as pressure change curves, tracer concentration distribution curves, temperature field contour maps, etc., to visually display the experimental results, thereby providing a reliable reference basis for actual engineering applications (such as reservoir development, groundwater seepage control, etc.).

[0056] The advantages of the present invention are as follows:

[0057] The present invention combines the simulation experiment of the model system 1 with computer technology, advanced sensor technology, and automatic control technology to study the transport and diversion ability of proppants. The device model is designed with simulated fillers, which can fill the corresponding core materials according to the actual reservoir physical properties to more accurately study the variation law of the reservoir. The model is designed with a fracturing fluid and injection system 2, which can inject the fracturing fluid from the left side, fill the fracture, and finally discharge it from the right side. The model box 11 can be flipped 180° back and forth, so that various situations from vertical to horizontal can be simulated, fully considering the influence of gravity on the fracturing fluid sand-carrying and proppant transport tests. The whole system is designed modularly, which is convenient for the expansion of functional modules and easy to operate. If a large flow size is required, multiple two-dimensional simulation devices can be connected in series. The fracture morphology and width can be changed flexibly.

[0058] In summary, the present invention can simulate different-width fractures and reticulated fracture morphologies in shale reservoirs, and can also analyze the transport law of fracturing fluid sand-carrying in fractures in shale reservoirs. The present invention can simulate the transport process of proppants inside the reservoir during the injection of fracturing fluid, as well as the relationship between flow rate and pressure, optimize proppants, etc. By observing the proppant transport process before production, the variation law of the proppant transport on the fracture propagation, sand placement, and diversion ability can be studied, which can provide value for the subsequent effective production.

[0059] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0060] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A proppant migration test device in a shale reservoir, characterized in that, including a model system, the model system comprising: a model box, inside which there is a test chamber that penetrates through a side wall on one side in the width extension direction of the model box; a pressing plate that can completely cover the test chamber and is detachably connected to the model box; two fluid delivery components, respectively arranged at both ends in the length extension direction of the model box and structurally mirror-symmetrical, the fluid delivery component including a first connecting pipe that communicates with the test chamber.

2. The proppant transport test device in the shale reservoir according to claim 1, characterized in that, The model system further includes two angle control components, respectively arranged at both ends in the length extension direction of the model box and structurally mirror-symmetrical, the angle control component including: a first connecting frame fixedly arranged on the end face of the model box, and the first connecting pipe is fixedly connected to the first connecting frame; an adjusting ring arranged outside the first connecting frame, and the adjusting ring is detachably connected to the first connecting frame; a second connecting frame arranged outside the adjusting ring, and the adjusting ring is rotatably connected to the second connecting frame; two locking components, both fixedly arranged on the second connecting frame and respectively located on the upper and lower sides of the adjusting ring.

3. The proppant transport testing device in the shale reservoir according to claim 2, wherein The first connecting frame includes: a first driving ring, there is an assembly hole on the end face of the model box, the first driving ring is arranged in the assembly hole, a plurality of protruding rings are fixedly arranged on the outer side wall of the first driving ring, the plurality of protruding rings are equally spaced, there is also an assembly groove on the end face of the model box, the plurality of protruding rings are respectively arranged in the plurality of assembly grooves, and the shape of the assembly groove matches the shape of the protruding ring; a second driving ring, the second driving ring includes a plurality of arc-shaped driving plates, the plurality of arc-shaped driving plates respectively correspond to the positions of the plurality of protruding rings one by one and are fixedly connected to the plurality of protruding rings respectively, there is a straight driving plate between adjacent two arc-shaped driving plates, the straight driving plate is fixedly connected to the arc-shaped driving plate, there is a gap between the straight driving plate and the end face of the model box, the adjusting ring corresponds to the position of the second driving ring, and the adjusting ring is detachably connected to the second driving ring.

4. The proppant transport test device in the shale reservoir according to claim 3, characterized in that The second connecting frame includes: a bearing ring, there is an annular sliding groove on the inner side wall of the bearing ring, an annular convex rib is fixedly arranged on the outer side wall of the adjusting ring, the annular convex rib is arranged in the annular sliding groove and can slide along the inner wall of the annular sliding groove, the first connecting pipe is fixedly arranged at the inner center of the first driving ring, and the length of the first connecting pipe is greater than the length of the first driving ring; a first support frame fixedly arranged on the top of the outer side wall of the bearing ring, and one of the locking components is fixedly arranged on the first support frame; a second support frame fixedly arranged on the bottom of the outer side wall of the bearing ring, and the other locking component is fixedly arranged on the second support frame; The locking component includes: an electric telescopic rod; The force - applying plate is fixedly arranged at the output end of the electric telescopic rod. One end of the bearing ring close to the force - applying plate is provided with an avoidance hole, and the avoidance hole is communicated with the inside of the annular sliding groove. The force - applying plate can slide along the inner wall of the avoidance hole; The rubber pad is fixedly arranged on the end face of the force - applying plate facing the adjusting ring.

5. The proppant transport test device in the shale reservoir according to claim 4, characterized in that, A base is arranged below the angle - control assembly. The second support frame is fixedly connected to the base. Universal wheels are arranged at the four corners of the bottom surface of the base. The fluid delivery assembly further includes a second connecting pipe. The second connecting pipe is at the same height as the first connecting pipe. A support arm is fixedly arranged on the side wall of the second support frame. The second connecting pipe is fixedly connected to the support arm. There is a gap between the second connecting pipe and the first connecting pipe. The second connecting pipe and the first connecting pipe are communicated through a hose. The length of the hose is greater than the distance of the gap between the second connecting pipe and the first connecting pipe.

6. The proppant transport test device in the shale reservoir according to claim 5, characterized in that It further includes: An injection system, the discharge end of which is communicated with the inside of one of the second connecting pipes, for providing circulating fluid to the model system; A vacuum - pumping system, for pumping the model system into a vacuum; A pressure - field measurement system, for measuring the pressure distribution in the test chamber; A differential - pressure measurement system, which is electrically connected to the pressure - field measurement system; A back - pressure system, the discharge end of which is communicated with the inside of the other second connecting pipe, for maintaining the outlet pressure of the model system; A data acquisition and processing system, for real - time acquiring the values of the upstream pressure of the model system and the pressure at the pressure measurement points.

7. A method for using a proppant migration test device in a shale reservoir, using the proppant migration test device in a shale reservoir as described in claim 6, characterized in that, It includes the following steps: Step 1: Check the entire device to ensure that all components are tightly connected and the measurement accuracy meets the experimental requirements; Step 2: Remove the pressure plate, install the core, and then reinstall the pressure plate; Step 3: Prepare the corresponding fluid; Step 4: Perform a vacuum - pumping operation on the model system through the vacuum - pumping system, and slowly inject the fluid into the model system through the injection system; Step 5: Record the pressure data changing with time in the test chamber through the pressure - field measurement system, the differential - pressure measurement system, and the data acquisition and processing system; Step 6: Summarize and organize all the original data recorded during the experiment, carefully check the accuracy and integrity of the data, and eliminate abnormal data points.

8. The method for using the proppant migration test device in a shale reservoir according to claim 7, wherein, In Step 6, when the test is over, remove the pressure plate, detect with an optical sensor, and draw a chart based on the organized data.

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