A device and method for simulating the spreading and migration of sand-carrying fluid in horizontal wells

Abstract

The present invention provides a device and method for simulating the spreading and migration of sand-carrying fluid in a horizontal well. The simulation device includes an injection pump, a sand-carrying fluid tank, a horizontal wellbore, an intelligent flow rate control valve, parallel glass plates, a back pressure valve, a reflux pipe, and a clean water tank. The simulation method includes: checking air tightness and removing air; setting the flow rate of the control valve; sucking the sand-carrying fluid into the wellbore and recording the migration of the sand-carrying fluid; the sand-carrying fluid spreads in the glass plate and recording the migration of proppant particles; adjusting the opening and closing of the pump and valve and recording the natural sedimentation of the proppant particles; adjusting the opening and closing of the valve after the sedimentation is completed, restarting the pump to suck clean water into the reflux pipe, driving the sand-carrying fluid to flow toward the wellbore, re-spreading the proppant particles, and recording the reflux of the sand-carrying fluid and proppant particles in the glass plate. The simulation method of the present invention can simulate the migration of proppant particles in flow-limiting fracturing and post-fracturing flowback. The simulation device of the present invention can visually observe the spreading and migration of proppant particles.

Description

Technical Field

[0001] The present invention relates to the technical field of unconventional oil and gas reservoir reconstruction, and in particular to a device and method for simulating the spreading and migration of sand-carrying fluid in a horizontal well. Background Art

[0002] As conventional oil and gas resources gradually deplete, the development of unconventional oil and gas reservoirs has become a key development direction. Unconventional oil and gas reservoirs typically have low porosity and low permeability, making their development extremely difficult and requiring the resolution of many key technical issues.

[0003] Horizontal wells are a common well type used to develop unconventional oil and gas resources. They offer large drainage areas and oil and gas production rates several times higher than vertical wells, making them a key area of ​​development for unconventional oil and gas reservoirs. Staged fracturing in horizontal wells has proven to be a core technology for developing low-permeability reservoirs. During staged fracturing, multiple perforation clusters exist within the same fracturing stage, leading to significant competition between fractures initiating and propagating from the perforation holes. This uneven absorption of fracturing fluid by the perforation clusters results in poorly balanced reservoir stimulation during staged fracturing. To improve reservoir stimulation, fracturing engineers have developed a multi-cluster perforation flow-limiting fracturing method that controls flow distribution within the perforation clusters, thereby achieving uniformly sized hydraulic fractures around the horizontal well. When sand-carrying fluid is injected into the formation, proppant enters the fractures along with the fracturing fluid and spreads within them, supporting the fractures and forming fracture channels with long-term flow conductivity. During pumping and depressurization, some fracturing fluid flows back from the hydraulic fractures into the wellbore, causing proppant to flow back into the wellbore. However, currently, there is a lack of experimental devices and methods that can simultaneously simulate the migration behavior of proppant particles during flow-limiting fracturing and post-fracturing flowback during multi-cluster perforation fracturing in horizontal wells. Therefore, it is of great significance to provide a device and method for simulating the spread and migration of proppant particles in horizontal wells that can effectively simulate the entire process of sand-carrying fluid injection into fractures and flowback to the wellbore during multi-cluster perforation fracturing, and can also visualize the spread and migration of proppant particles.

[0004] A Chinese patent application numbered "CN202111037458.0," titled "Proppant Wellbore Migration Experimental Simulation System and Simulation Method Thereof," discloses a proppant wellbore migration experimental simulation system and simulation method thereof, capable of simulating proppant migration in an underground wellbore and observing the migration process and state of the sand-carrying fluid in the wellbore. The simulation system comprises: a fluid reservoir; a proppant reservoir; a sand mixing device capable of communicating with the fluid reservoir and the proppant reservoir; a drive pump capable of connecting to the outlet of the sand mixing device via a first pipeline; a simulated wellbore having an inlet and an outlet, the inlet connected to the outlet of the drive pump via a second pipeline, the outlet connected to the sand mixing device, a switch mechanism provided on a third pipeline, and an observation portion made of a transparent material. Multiple blastholes connected to the interior of the simulated wellbore are inserted into the sidewall of the simulated wellbore to simulate perforation, each blasthole being connected to a liquid production tank via a fourth pipeline, and a first valve provided on the fourth pipeline. This simulation system can simulate proppant migration in an underground wellbore and observe the migration process and state of the sand-carrying fluid in the wellbore, thereby studying the migration patterns. However, this simulation system differs from the simulation device of the present application in structure and does not have the ability to simulate and observe proppant migration and / or settlement in fractures, nor does it have the ability to simulate and observe proppant migration during the post-fracturing flowback phase. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to address one or more of the aforementioned problems. For example, one of the objectives of the present invention is to provide a device and method for simulating the spread and migration of sand-carrying fluid in a horizontal well, capable of simulating and observing the migration of sand-carrying fluid and proppant particles during both the flow-limiting fracturing and post-fracturing flowback stages.

[0006] In order to achieve the above-mentioned objectives, the present invention provides, on the one hand, a horizontal well sand-carrying fluid spreading and migration simulation device, which includes an injection pump, a sand-carrying fluid pool, a horizontal wellbore, an intelligent flow rate control valve, parallel glass plates, a back pressure valve, a return pipe and a clear water pool, wherein the inlet end of the injection pump is respectively connected to the sand-carrying fluid pool and the clear water pool, and the outlet end is respectively connected to the horizontal wellbore and the return pipe, so as to simulate the process of the fracturing pump truck injecting the sand-carrying fluid into the horizontal wellbore and returning the sand after hydraulic pressure; the horizontal wellbore is respectively connected to multiple intelligent flow rate control valves, which can simulate the multi-cluster perforation flow-limiting fracturing of the horizontal well; the intelligent flow rate control valves are respectively connected to the parallel glass plates, which can simulate the spreading, migration and natural settlement of the sand-carrying fluid in the hydraulic fracture; the parallel glass plates are respectively connected to the back pressure valve, and the back pressure valve is connected to the return pipe.

[0007] According to an exemplary embodiment of one aspect of the present invention, the simulation device may further include a waste liquid pool, which is connected to the inlet pipeline of the horizontal wellbore and the return pipe respectively.

[0008] According to an exemplary embodiment of an aspect of the present invention, the number of the intelligent flow rate control valves may be no less than 3, and the intelligent flow rate control valves can simulate a perforation cluster with a flow-limiting fracturing function.

[0009] According to an exemplary embodiment of one aspect of the present invention, the back pressure valve can automatically release pressure when the fluid pressure rises to a certain level to prevent the parallel glass plates from being broken.

[0010] According to an exemplary embodiment of one aspect of the present invention, the horizontal wellbore may be a transparent cylinder, the diameter of which may be 0.5 to 1.5 m, and the length of which may be not less than 3 m.

[0011] According to an exemplary embodiment of one aspect of the present invention, the parallel glass plates may be transparent glass plates to facilitate visual observation or recording of the migration process of the sand-carrying fluid and proppant particles by a camera.

[0012] Another aspect of the present invention provides a method for simulating the spreading and migration of sand-carrying fluid in a horizontal well. The simulation method can be implemented by the above-mentioned device for simulating the spreading and migration of sand-carrying fluid in a horizontal well. The simulation method comprises the following steps:

[0013] Adjust the switches of each valve and check the air tightness of the simulation device pipeline;

[0014] Set the flow rate of the intelligent flow control valve switch;

[0015] Make clean water circulate in the pipeline of the simulation device to remove the air in the pipeline;

[0016] Turn on the injection pump to pump the sand-carrying fluid into the horizontal wellbore and record the migration of the sand-carrying fluid and proppant particles in the horizontal wellbore;

[0017] The sand-carrying fluid enters the parallel glass plates through the intelligent flow rate control valve and spreads out in them, recording the migration of proppant particles in the parallel glass plates;

[0018] Adjust the pump and valve opening and closing, and record the natural settling of proppant particles in the parallel glass plates;

[0019] After the sedimentation is completed, adjust the valve opening and closing, restart the pump, and pump clean water into the reflux pipe to drive the sand-carrying fluid to flow in the opposite direction of the horizontal wellbore, so that the proppant particles can be spread again. Record the reflux of the sand-carrying fluid and proppant particles in the parallel glass plates.

[0020] Furthermore, the step of adding a dye to the sand-carrying fluid may be included before turning on the injection pump to suck the sand-carrying fluid.

[0021] According to an exemplary embodiment of another aspect of the present invention, the simulation method may further include changing simulation parameters, repeating the test multiple times, observing and video recording the spreading, migration, settling and / or reflux process of the sand-carrying fluid and / or proppant particles.

[0022] Furthermore, the simulation parameters may include at least one of the sand-carrying fluid, the set flow rate of the intelligent flow rate control valve, and the number of intelligent flow rate control valves.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The horizontal well sand-carrying fluid spreading and migration simulation device proposed in the present invention can simulate the horizontal well multi-cluster perforation flow-limiting fracturing process by controlling the flow rate of the intelligent flow rate control valve;

[0025] (2) The horizontal well sand-carrying fluid spreading and migration simulation device proposed in the present invention can simulate the fracturing operation in which a fracturing pump truck injects sand-carrying fluid into a horizontal wellbore;

[0026] (3) The horizontal well sand-carrying fluid spreading and migration simulation method proposed in the present invention can simulate the fracturing fluid backflow during actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects and features of the present invention will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0028] Figure 1 A schematic structural diagram of a horizontal well sand-carrying fluid spreading and migration simulation device according to an exemplary embodiment of the present invention is shown;

[0029] Figure 2 A top view of a device for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to an exemplary embodiment of the present invention is shown.

[0030] Reference numerals:

[0031] 1-Sand carrying liquid tank, 2-Clean water tank, 3-Injection pump, 4-Horizontal wellbore, 5-Intelligent flow rate control valve, 501-Intelligent flow rate control valve K1, 502-Intelligent flow rate control valve K2, 503-Intelligent flow rate control valve K3, 6-Parallel glass plates, 601-First parallel glass plate, 602-Second parallel glass plate, 603-Third parallel glass plate, 7-Back pressure valve, 701-Back pressure valve K4, 702-Back pressure valve K5, 703-Back pressure valve K6, 8-Reflux pipe, 9-Waste liquid tank, 901-First waste liquid tank, 902-Second waste liquid tank, 10-Valve K7, 11-Valve K8, 12-Valve K9, 13-Valve K10, 14-Valve K11, 15-Valve K12. DETAILED DESCRIPTION

[0032] Hereinafter, a device and method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0033] It should be noted that terms such as "first," "second," "third," and "K" are used solely for ease of description and distinction and should not be construed as indicating or implying relative importance. Terms such as "upper," "lower," and "middle" are used solely for ease of description and to establish relative orientation or positional relationships and should not be construed as indicating or implying that the components referred to must have a specific orientation or position.

[0034] Figure 1 A schematic structural diagram of a horizontal well sand-carrying fluid spreading and migration simulation device according to an exemplary embodiment of the present invention is shown; Figure 2 A top view of a device for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to an exemplary embodiment of the present invention is shown.

[0035] In a first exemplary embodiment of the present invention, as Figure 1 As shown in the figure, the horizontal well sand-carrying fluid spreading and migration simulation device mainly includes a sand-carrying fluid pool 1, a clean water pool 2, an injection pump 3, a horizontal wellbore 4, an intelligent flow rate control valve 5, parallel glass plates 6, a back pressure valve 7 and a return pipe 8.

[0036] The inlet of injection pump 3 is connected to the outlets of the sand-carrying fluid tank 1 and the clean water tank 2, respectively. A valve K11 14 is installed on the outlet pipeline of sand-carrying fluid tank 1, and a valve K12 15 is installed on the outlet pipeline of clean water tank 2. The outlet of injection pump 3 is connected to the horizontal wellbore 4 and the return pipe 8, respectively. A valve K9 12 is installed on the pipeline between injection pump 3 and horizontal wellbore 4, and a valve K8 11 is installed on the pipeline between injection pump 3 and return pipe 8. When injection pump 3 pumps sand-carrying fluid from sand-carrying fluid tank 1 and flows through horizontal wellbore 4, it simulates the process of a fracturing pump truck injecting sand-carrying fluid into the horizontal wellbore during a fracturing operation. When injection pump 3 pumps clean water from clean water tank 2, flows through return pipe 8, and enters parallel glass plates 6, it drives the sand-carrying fluid into the horizontal wellbore 4, redistributing the proppant particles in the sand-carrying fluid, simulating the flowback process after sand-carrying fluid is hydraulically pumped.

[0037] The tubular body (not the end) of the horizontal wellbore 4 is connected to multiple intelligent flow control valves 5, spaced a predetermined distance apart. By controlling the flow rate of the intelligent flow control valves, the process of multi-cluster perforation flow restriction and fracturing in the horizontal well can be simulated.

[0038] Multiple intelligent flow control valves 5 are connected to multiple parallel glass plates 6, with the outlet of each intelligent flow control valve connected to the inlet of each parallel glass plate. As the sand-carrying fluid enters and spreads across the parallel glass plates 6, proppant particles also migrate and settle within them. The parallel glass plates simulate hydraulic fractures with long-term flow conductivity. The migration of the sand-carrying fluid and proppant particles within the glass plates can be observed visually or recorded with a camera. This simulation device can simulate and observe the spreading, migration, and natural settlement of the sand-carrying fluid and / or proppant particles within the hydraulic fracture.

[0039] The plurality of parallel glass plates 6 are respectively connected to the plurality of back pressure valves 7, that is, the outlet end of one parallel glass plate is connected to the inlet end of one back pressure valve. The outlet end of each back pressure valve is connected to the pipe body of the return pipe.

[0040] In this exemplary embodiment, Figure 2 As shown in FIG, the horizontal well sand-carrying fluid spreading and migration simulation device may further include a waste liquid tank 9. A first waste liquid tank 901 is connected to the inlet pipeline of the horizontal wellbore 4, and a valve K10 13 is installed on the inlet pipeline of the first waste liquid tank 901. A second waste liquid tank 902 is connected to the return pipe 8, and a valve K7 10 is installed on the inlet pipeline of the second waste liquid tank 902. Valves K7 through K12 can be conventional valves in the art.

[0041] In this exemplary embodiment, the intelligent flow rate control valve can simulate a perforation cluster with flow-limiting fracturing function. Figure 1 As shown in FIG, a horizontal wellbore 4 is connected to multiple (at least three) intelligent flow rate control valves 5. For example, in a fracturing well section with three perforation clusters, intelligent flow rate control valve K1 501 simulates the first perforation cluster, intelligent flow rate control valve K2 502 simulates the second perforation cluster, and intelligent flow rate control valve K3 503 simulates the third perforation cluster.

[0042] In this exemplary embodiment, Figure 1 As shown in FIG, back-pressure valve K4 701 serves as the back-pressure valve for the first parallel glass plate 601, back-pressure valve K5 702 serves as the back-pressure valve for the second parallel glass plate 602, and back-pressure valve K6 703 serves as the back-pressure valve for the third parallel glass plate 603. When the fluid pressure within the hydraulic fracture exceeds a certain value, the corresponding back-pressure valve 7 automatically opens to relieve pressure, preventing the glass plates from cracking due to the fluid pressure.

[0043] In this exemplary embodiment, the horizontal wellbore may be a transparent cylinder with a diameter of 0.5 to 1.5 m and a length of not less than 3 m. For example, the horizontal wellbore may be a transparent cylinder with a diameter of 1.0 m and a length of 4 m.

[0044] In this exemplary embodiment, the parallel glass plates may be transparent glass plates to facilitate visual observation or recording of the spreading, migration, and natural settling processes of the sand-carrying fluid and proppant particles by a camera.

[0045] A second exemplary embodiment of the present invention provides a method for simulating the spreading and migration of sand-carrying fluid in a horizontal well. The simulation method can be implemented by the apparatus for simulating the spreading and migration of sand-carrying fluid in a horizontal well described in the first exemplary embodiment. The simulation method mainly includes the following steps:

[0046] Adjust the switches of each valve and check the air tightness of each pipe section of the simulation device.

[0047] The flow rate of the intelligent flow control valve switch is preset.

[0048] Turn on the injection pump to draw clean water from the clean water tank, allowing the clean water to circulate in the pipelines of the simulation device to remove air from the pipelines.

[0049] The injection pump is turned on to pump the sand-carrying fluid in the sand-carrying fluid pool into the horizontal wellbore. At this time, the migration of the sand-carrying fluid and proppant particles in the horizontal wellbore can be observed and recorded by video.

[0050] The sand-carrying fluid enters the parallel glass plates through the intelligent flow rate control valve and spreads out in them. At this time, the spreading of the sand-carrying fluid in the parallel glass plates and the migration of the proppant particles in the parallel glass plates can be observed and recorded by video.

[0051] Adjust the injection pump and the opening and closing states of each valve to allow the proppant particles to naturally settle in the parallel glass plates. At this time, the natural settling of the proppant particles in the parallel glass plates can be observed and recorded by video.

[0052] After the sedimentation is completed, adjust the opening and closing status of each valve, reopen the injection pump, and pump clean water from the clean water suction tank to the return pipe, driving the sand-carrying fluid to flow in the opposite direction of the horizontal wellbore, so that the proppant particles can be re-spread. At this time, the backflow of the sand-carrying fluid and proppant particles in the parallel glass plates can be observed and recorded by video.

[0053] Furthermore, before the injection pump is turned on to draw the sand-carrying fluid, a step of adding a dye to the sand-carrying fluid may be included. Adding an appropriate amount of dye to the sand-carrying fluid to distinguish it from clear water allows for more convenient and clear observation of the migration of the sand-carrying fluid and / or proppant particles in the simulation device.

[0054] In this exemplary embodiment, the simulation method may further include changing simulation parameters, repeating the test multiple times, and observing and video recording the spreading, migration, natural settling and / or backflow process of the sand-carrying fluid and / or proppant particles.

[0055] In this exemplary embodiment, the simulation parameters may include at least one of the sand-carrying fluid, the set flow rate of the intelligent flow control valve, and the number of intelligent flow control valves. Here, proppant particles are suspended in the sand-carrying fluid in the sand-carrying fluid pool. The mass ratio of the proppant particles and the rheological properties of the fluid are determined based on the on-site fracturing process parameters. Alternatively, the sand-carrying fluid used in on-site fracturing can be directly used. Using different sand-carrying fluids can simulate flow-restricted fracturing under different conditions. Changing the set flow rate of the intelligent flow control valve can simulate flow-restricted fracturing under different conditions. Providing different numbers of intelligent flow control valves can simulate different multi-cluster perforation flow-restricted fracturing conditions.

[0056] In order to better understand the above exemplary embodiments of the present invention, they are further described below with reference to specific examples.

[0057] Example 1

[0058] Combine Figure 1 The horizontal well sand-carrying fluid spreading and migration simulation device shown in the figure can simulate the migration of sand-carrying fluid in the horizontal wellbore as follows.

[0059] S1: Investigate the actual fracturing plan on site and prepare the sand-carrying fluid and clean water.

[0060] S2: Adjust the working status of each switch and check the air tightness of the pipeline.

[0061] S3: Open the K1, K2 and K3 switches and set the flow rate of each switch.

[0062] S4: Open K4, K5, K6, K7, K9, and K12.

[0063] S5: Close K8, K10, and K11.

[0064] S6: Turn on the pump to allow clean water to circulate in the pipes and remove the air in the pipes.

[0065] S7: Turn off the pump, open K11, and close K12.

[0066] S8: Restart the pump to pump the colored sand-carrying fluid into the horizontal wellbore.

[0067] S9: Observe and record the migration of sand-carrying fluid and proppant particles in the horizontal wellbore.

[0068] Example 2

[0069] Combine Figure 1 The horizontal well sand-carrying fluid spreading and migration simulation device shown in FIG, the steps of simulating the sand-carrying fluid spreading of the horizontal well multi-cluster perforation flow-limiting fracturing can be as follows.

[0070] S1: Investigate the actual fracturing plan on site and prepare the sand-carrying fluid and clean water.

[0071] S2: Adjust the working status of each switch and check the air tightness of the pipeline.

[0072] S3: Open the K1, K2 and K3 switches and set the flow rate of each switch.

[0073] S4: Open K4, K5, K6, K7, K9, and K12.

[0074] S5: Close K8, K10, and K11.

[0075] S6: Turn on the pump to allow clean water to circulate in the pipes and remove the air in the pipes.

[0076] S7: Turn off the pump, open K11, and close K12.

[0077] S8: Restart the pump to pump the colored sand-carrying fluid into the horizontal wellbore.

[0078] S9: Observe and record the spreading of the sand-carrying liquid on the transparent parallel glass plates through video.

[0079] S10: Observe and record the migration of proppant particles on the transparent parallel glass plates by video.

[0080] Example 3

[0081] Combine Figure 1 The horizontal well sand-carrying fluid spreading and migration simulation device shown in FIG, and the steps for simulating the natural settling of proppant particles in multi-cluster perforation flow-limiting fracturing in a horizontal well can be as follows.

[0082] S1: Investigate the actual fracturing plan on site and prepare the sand-carrying fluid and clean water.

[0083] S2: Adjust the working status of each switch and check the air tightness of the pipeline.

[0084] S3: Open the K1, K2 and K3 switches and set the flow rate of each switch.

[0085] S4: Open K4, K5, K6, K7, K9, and K12.

[0086] S5: Close K8, K10, and K11.

[0087] S6: Turn on the pump to allow clean water to circulate in the pipes and remove the air in the pipes.

[0088] S7: Turn off the pump, open K11, and close K12.

[0089] S8: Restart the pump to pump the colored sand-carrying fluid into the horizontal wellbore.

[0090] S9: Observe and record the spreading of the sand-carrying liquid on the transparent parallel glass plates through video.

[0091] S10: Observe and record the migration of proppant particles on the transparent parallel glass plates by video.

[0092] S11: When the sand-carrying fluid reaches the vicinity of K4, K5 and K6 valves, stop the pump immediately and close K7.

[0093] S12: Observe and record the natural settling of proppant particles on the transparent parallel glass plates by video.

[0094] Example 4

[0095] Combine Figure 1 The horizontal well sand-carrying fluid spreading and migration simulation device shown in FIG, and the steps of the horizontal well multi-cluster perforation flowback limiting sand-carrying fluid reflux simulation can be as follows.

[0096] S1: Investigate the actual fracturing plan on site and prepare the sand-carrying fluid and clean water.

[0097] S2: Adjust the working status of each switch and check the air tightness of the pipeline.

[0098] S3: Open the K1, K2 and K3 switches and set the flow rate of each switch.

[0099] S4: Open K4, K5, K6, K7, K9, and K12.

[0100] S5: Close K8, K10, and K11.

[0101] S6: Turn on the pump to allow clean water to circulate in the pipes and remove the air in the pipes.

[0102] S7: Turn off the pump, open K11, and close K12.

[0103] S8: Restart the pump to pump the colored sand-carrying fluid into the horizontal wellbore.

[0104] S9: Observe and record the spreading of the sand-carrying liquid on the transparent parallel glass plates through video.

[0105] S10: Observe and record the migration of proppant particles on the transparent parallel glass plates by video.

[0106] S11: When the sand-carrying fluid reaches the vicinity of K4, K5 and K6 valves, stop the pump immediately and close K7.

[0107] S12: Observe and record the natural settling of proppant particles on the transparent parallel glass plates by video.

[0108] S13: When the proppant particles have finished settling in the parallel glass plates, K8, K10, and K12 are opened, and K9 and K11 are closed.

[0109] S14: Restart the pump to pump clean water into the return pipe, driving the sand-carrying fluid to flow toward the horizontal wellbore.

[0110] S15: Observe and record the backflow of the sand-carrying liquid on the transparent parallel glass plates by video.

[0111] S16: Observe and record the backflow of the proppant particles on the transparent parallel glass plates by video.

[0112] In summary, the advantages proposed by the present invention include at least one of the following:

[0113] (1) The horizontal well sand-carrying fluid spreading and migration simulation device proposed in the present invention can effectively simulate the entire process of sand-carrying fluid injection into the horizontal wellbore and fractures during multi-cluster perforation flow-limiting fracturing and its return to the wellbore after fracturing;

[0114] (2) The intelligent flow rate control valve proposed in the present invention can simulate a perforation cluster with flow-limiting fracturing function;

[0115] (3) The glass plate proposed in the present invention can simulate hydraulic cracks with long-term flow conductivity;

[0116] (4) The horizontal well sand-carrying fluid spreading and migration simulation method proposed in the present invention can visualize the spreading and migration of sand-carrying fluid and proppant particles, which helps to improve the understanding of the horizontal well multi-cluster perforation flow-limiting fracturing technology.

[0117] Although the above description of a horizontal well sand-carrying fluid spreading and migration simulation device and simulation method of the present invention has been described in combination with exemplary embodiments, it should be clear to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A method for simulating the spreading and migration of sand-carrying fluid in a horizontal well, characterized in that: The simulation method is implemented by a horizontal well sand-carrying fluid spreading and migration simulation device, which includes an injection pump, a sand-carrying fluid pool, a horizontal wellbore, an intelligent flow rate control valve, parallel glass plates, a back pressure valve, a return pipe and a clear water pool, wherein the inlet end of the injection pump is connected to the sand-carrying fluid pool and the clear water pool respectively, and the outlet end is connected to the horizontal wellbore and the return pipe respectively, so as to simulate the process of the fracturing pump truck injecting the sand-carrying fluid into the horizontal wellbore and returning the sand after hydraulic pressure; the horizontal wellbore is respectively connected to multiple intelligent flow rate control valves, which can simulate the multi-cluster perforation flow-limiting fracturing of the horizontal well; the intelligent flow rate control valves are respectively connected to the parallel glass plates, which can simulate the spreading, migration and natural settlement of the sand-carrying fluid in the hydraulic fracture; the parallel glass plates are respectively connected to the back pressure valve, and the back pressure valve is connected to the return pipe; the simulation method includes the steps of: Adjust the switches of each valve and check the air tightness of the simulation device pipeline; Set the flow rate of the intelligent flow control valve switch; Make clean water circulate in the pipeline of the simulation device to remove the air in the pipeline; Turn on the injection pump to pump the sand-carrying fluid into the horizontal wellbore and record the migration of the sand-carrying fluid and proppant particles in the horizontal wellbore; The sand-carrying fluid enters the parallel glass plates through the intelligent flow rate control valve and spreads out in them, recording the migration of proppant particles in the parallel glass plates; Adjust the pump and valve opening and closing, and record the natural settling of proppant particles in the parallel glass plates; After the sedimentation is completed, adjust the valve opening and closing, restart the pump, and pump clean water into the reflux pipe to drive the sand-carrying fluid to flow in the opposite direction of the horizontal wellbore, so that the proppant particles can be spread again. Record the reflux of the sand-carrying fluid and proppant particles in the parallel glass plates.

2. The horizontal well sand-carrying fluid spreading and migration simulation method according to claim 1, characterized in that: The step of adding a dye into the sand-carrying liquid is included before the injection pump is turned on to suck the sand-carrying liquid.

3. The horizontal well sand-carrying fluid spreading and migration simulation method according to claim 1, characterized in that: The simulation method further includes changing simulation parameters, repeating the test multiple times, and observing and recording the spreading, migration, settling and / or backflow process of the sand-carrying fluid and / or proppant particles by video.

4. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 3, wherein: The simulation parameters include at least one of the sand-carrying fluid, the set flow rate of the intelligent flow rate control valve, and the number of the intelligent flow rate control valves.

5. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 1, wherein: The simulation device further includes a waste liquid pool, which is connected to the inlet pipeline of the horizontal wellbore and the return pipe respectively.

6. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 1, wherein: The number of the intelligent flow rate control valves is no less than 3, and the intelligent flow rate control valves can simulate a perforation cluster with a flow-limiting fracturing function.

7. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 1, wherein: The back pressure valve can automatically release pressure when the fluid pressure rises to a certain level to prevent the parallel glass plates from being broken.

8. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 1, wherein: The horizontal wellbore is a transparent cylinder with a diameter of 0.5 to 1.5 m and a length of not less than 3 m.

9. The method for simulating the spreading and migration of sand-carrying fluid in a horizontal well according to claim 1, wherein: The parallel glass plates are transparent glass plates to facilitate observation with the naked eye or recording of the migration process of the sand-carrying fluid and the proppant particles with a camera.

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