Sand prevention evaluation experiment device and method under different filling conditions

Abstract

The invention discloses a sand prevention evaluation experiment device and method under different filling conditions, and the device comprises a sand prevention model system, a filling density measurement system, a sample preparation and injection system, and a waste liquid recovery system. The filling density measuring system is connected with the side wall of the sand prevention model system; a sand-liquid mixed transportation part and a pure liquid input part are arranged in the sample preparation and injection system, the sand-liquid mixed transportation part is connected with the upper end of the sand prevention model system, and the pure liquid input part is connected with the side wall of the sand prevention model system; the waste liquid recovery system is connected with the lower end and the side wall of the sand prevention model system. According to the device and the method, the underground extrusion filling construction condition of the sand prevention well can be highly simulated, and the influence of different filling compactness on the sand production amount can be obtained, so that the corresponding filling compactness when the sand production amount is minimum can be determined according to the actual underground working condition, and the effect of optimizing the filling construction process is achieved.

Description

Technical Field

[0001] This invention relates to the field of backfilling technology, specifically to an experimental apparatus and method for evaluating sand control under different backfilling conditions. Background Technology

[0002] With the continuous development of oil fields and changes in formation pressure, the original formation pressure decreases or the differences between layers increase, leading to increasingly prominent reservoir sand production problems. Sand production is a significant obstacle to further tapping the potential of oil and gas production. Formation sand production refers to the phenomenon where formation sand particles are produced into the wellbore or surface along with formation fluids during the extraction of loose sandstone reservoirs for oil and natural gas, as well as natural gas hydrate reservoirs. Sand production in oil and gas wells can cause tubing erosion, damage to the Christmas tree and surface equipment, and accelerated wear of various components of downhole electric pumps. In severe cases, it can lead to reservoir sand burial, tubing sand blockage, manifold sand blockage, and well abandonment, resulting in well shutdowns and increased extraction costs. Furthermore, sand production can pose serious safety and environmental hazards. Commonly used sand control technologies in the field include compression packing and annular packing. These methods involve filling the annular space between the screen pipe and the well wall or casing with gravel or ceramsite to form a gravel-filled sand control layer, preventing formation sand from entering the screen pipe and thus suppressing sand production.

[0003] Gravel packing is a commonly used bottom hole sand control method, mainly including in-tube gravel packing and out-of-tube gravel packing. In the field of gravel packing sand control completion technology, there is a lot of research in China on gravel packing simulation experimental devices and experimental methods.

[0004] Announcement No. CN112177570B discloses an experimental device and method for simulating the compression filling morphology of gravel-filled sand control wells. The device simulates the downhole compression filling construction of sand control wells, studies the compression filling morphology of gravel layers in various types of loose sandstone reservoirs under different well conditions and construction parameters, and investigates the influence of the vertical heterogeneity of loose sandstone reservoirs on the compression filling morphology of gravel layers. Based on the experimental results, the device provides a basis for optimizing the construction scheme and process parameters of gravel filling operations under different conditions.

[0005] Publication No.: CN113356802A discloses an apparatus and method for evaluating the effect of gravel filling. It uses the physical property of temperature to accurately evaluate the effect of gravel filling in formations, obtains the gravel filling rate and the formation conditions of the filling area, and obtains the real filling effect under complex filling conditions.

[0006] Announcement No. CN114320243B discloses a gravel filling simulation experimental system for multi-branch horizontal wells in natural gas hydrate reservoirs. The main wellbore and branch wellbores of the experimental system are made of transparent materials, which can intuitively and transparently simulate and observe the gravel filling process of the main wellbore and branch wellbores. The system explores the filling dynamics and process of the main wellbore and each branch wellbore during the gravel filling process of multi-branch horizontal wells, tests the filling effect and filling rate, and analyzes the influence of various parameters on the filling effect.

[0007] The experimental apparatus disclosed above simulates the gravel filling process and effect, but it is still lacking in terms of accurate measurement of gravel filling volume, measurement of filling density, and the influence of different densities on sand control effect. Further improvements to the experimental apparatus are needed.

[0008] In summary, the technical solutions, technical problems to be solved, and beneficial effects of the above-disclosed technologies are all different from those of the present invention. Regarding the more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the Invention

[0009] In view of the above-mentioned defects in the existing technology, the purpose of this invention is to provide an experimental device and method for evaluating sand control under different filling conditions.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] On one hand, the present invention provides an experimental device for evaluating sand control under different filling conditions, including a sand control model system, and further including a filling density measurement system, a sample preparation and injection system, and a waste liquid recovery system; the filling density measurement system is connected to the side wall of the sand control model system; the sample preparation and injection system is provided with a sand-liquid mixing and conveying section and a pure liquid input section, the sand-liquid mixing and conveying section is connected to the upper end of the sand control model system, and the pure liquid input section is connected to the side wall of the sand control model system; the waste liquid recovery system is connected to the lower end and side wall of the sand control model system.

[0012] Furthermore, the sand control model system includes a model body, the upper end of which is provided with a top cover, and the model body is cylindrical;

[0013] Specifically, the model body and the top cover form a sealed chamber. A lower interface is provided at the center of the lower end of the model body. At least two evenly distributed radial interfaces are provided on the side wall of the model body. An upper interface is provided at the center of the top cover. At least two layers and at least four evenly distributed measurement interfaces are provided on the side wall of the model body. The lower interface, radial interface, and upper interface are all connected to the sealed chamber.

[0014] Specifically, the lower interface is provided with a sealing mounting seat in the sealed cavity, a well wall support frame is installed in the sealing mounting seat, a simulated screen tube is installed in the well wall support frame, a simulated perforation is provided in the well wall support frame, a sand body support frame is also provided between the well wall support frame and the side wall of the model body, and holes are drilled on the walls of both the sand body support frame and the well wall support frame, and the outer walls are wrapped with screen mesh;

[0015] Specifically, the sand body support frame divides the sealed chamber formed by the model body and the top cover into two chambers: the oil ring chamber and the sand body chamber.

[0016] Furthermore, the upper cover is connected and sealed to the circumferential edge of the model body by a quick-release clamp;

[0017] Specifically, the model body has a first rotation axis and a second rotation axis on its side wall, which are rotatably connected to an adjustable angle bracket.

[0018] Furthermore, the sand-liquid mixing and conveying section of the sample preparation and injection system includes a liquid preparation tank, an injection pump, and a sealed sand addition device connected in sequence;

[0019] Specifically, the liquid preparation tank and the injection pump are connected through a sample preparation pipeline, and a sample preparation valve is installed on the sample preparation pipeline;

[0020] Specifically, the injection pump and the sealed sand adding device are connected through an injection pipeline, an injection valve is installed on the injection pipeline, and a safety valve and a first pressure gauge are also connected to the injection pipeline.

[0021] Specifically, the sealed sand adding device includes a sand storage tank, with a feed inlet at the upper end and a sand outlet at the lower end. The sand outlet is connected to a screw propeller, which is driven by a servo motor. A sand outlet valve is provided on the sand outlet. The screw propeller is connected to a filling pipeline through a mixing output pipeline, which is equipped with a mixing valve.

[0022] Specifically, the pure liquid input section includes a pure liquid pipeline, which is connected to the filling pipeline. The pure liquid pipeline is connected to the injection pipeline between the safety valve and the injection valve. The pure liquid pipeline is equipped with a pure liquid valve.

[0023] Specifically, the filling pipeline is equipped with a pressure gauge, and the filling pipeline is connected to the upper interface through a filling valve and to the radial interface through a flushing valve.

[0024] Furthermore, the waste liquid recovery system includes a circulating pump, a hydrocyclone separator, and a waste liquid collection section;

[0025] Specifically, the cyclone separator is provided with an oil-water-sand inlet, an oil-water outlet, and a sand outlet;

[0026] Specifically, the circulating pump is connected to the oil and water outlet, and the circulating pump is connected to the liquid preparation tank through a recovery pipeline, and a recovery valve is installed on the recovery pipeline;

[0027] Specifically, the sand outlet is connected to the waste liquid collection section;

[0028] Specifically, the oil-water-sand inlet is connected to the liquid outlet pipeline, the liquid outlet pipeline is connected to the lower interface through the first liquid outlet valve, and the liquid outlet pipeline is connected to the radial interface through the second liquid outlet valve.

[0029] Furthermore, the cyclone separator includes a central tube, a sand storage shell, and an outer tube;

[0030] Specifically, the upper end of the sand storage shell is connected to the top cover via a flange joint, and the outer tube is inserted from the lower end of the sand storage shell and contacts the top cover;

[0031] Specifically, the central tube is installed in the outer tube, the upper end of the central tube extends out of the top cover as an oil and water outlet, the lower end of the central tube is lower than the lower end of the sand storage shell, and the central tube is provided with a rectangular hole array in the inner part of the sand storage shell.

[0032] Specifically, the lower end of the central tube is connected to a fixed shell, a guide cover is provided inside the fixed shell, a guide post is provided at the upper end of the guide cover, a cone is provided at the upper end of the guide post, the cone is below the central tube, and the sand storage shell and the fixed shell are also connected by a balance tube;

[0033] Specifically, the sand storage shell is provided with an oil-water-sand inlet, the axis of which does not pass through the axis of the sand storage shell, and the bottom of the fixed shell is provided with a sand outlet.

[0034] Furthermore, the waste liquid collection section includes a waste liquid collection filter and a waste liquid collection tank;

[0035] Specifically, the sand outlet is connected to a waste liquid collection filter via a waste liquid pipeline, the waste liquid collection filter is installed on a waste liquid collection tank, and a waste liquid valve is installed on the waste liquid pipeline.

[0036] Furthermore, the filling density measurement system includes a pressure sensor with a sand-proof structure, an ultrasonic flow meter, an acoustic sensor, and a programmable controller with a display.

[0037] Specifically, the ultrasonic flow meter, pressure sensor, and acoustic wave sensor are all connected to a programmable controller with a display.

[0038] Specifically, the pressure sensor is connected to the measurement interface via a pressure drain tube, a fixed connector, and the pressure drain tube can slide within the fixed interface;

[0039] Specifically, the ultrasonic flow meter is installed on the filling pipe;

[0040] Specifically, the acoustic sensor is connected to the measurement interface.

[0041] Furthermore, the pressure sensor is a high-pressure pressure sensor, the internal structure of the sandproof structure is a filter screen, and a cylindrical filter element is provided at the front plug of the pressure drainage tube.

[0042] Specifically, the acoustic sensor transmits and receives enhanced PS acoustic signals, with a main frequency of acoustic detection of 20MHz-20KHz and a sampling interval of 0.05μs to 4000μs.

[0043] Secondly, the present invention provides an experimental method for evaluating sand control under different filling conditions, characterized by comprising the following steps:

[0044] A. Determine the experimental process parameters, prepare experimental materials, and adjust the sand-liquid mixing and transportation volume of the sample preparation and injection system;

[0045] B. Connect the sand control model system, filling density measurement system, sample preparation and injection system, and waste liquid recovery system;

[0046] C. Inject sand liquid to form sand bodies of different densities. Monitor the filling density using a filling density measurement system. Stop injection after filling to simulated conditions.

[0047] D. The experimental medium is injected with pure liquid to form the pressure required for the experiment. Under the action of pressure, the liquid enters the waste liquid recovery system for sand-liquid separation and is accurately measured.

[0048] E. Stop the injection, conduct experimental analysis, and the experiment ends.

[0049] Furthermore, in section A, pressure, temperature, and flow conditions are selected based on the sand control pipe to be tested and the simulated formation conditions;

[0050] The closed sand feeding device was calibrated according to the different sand particle sizes used, and the sand feeding flow rate under different sand particle conditions was calibrated. The corresponding particle size was selected through software, and the servo motor speed was automatically adjusted according to the required sand feeding amount set in the experiment to achieve quantitative sand feeding.

[0051] Furthermore, in C, open the filling valve and the second outlet valve, close the flushing valve and the first outlet valve, open the injection valve, the sand outlet valve and the mixing valve, and close the pure liquid valve;

[0052] Turn on the injection pump, and the liquid will be mixed with sand particles through the sealed sand adding device and enter the model body through the upper interface. It will flow evenly into the sand cavity to form sand bodies of different densities. The filling density is monitored by the enhanced PS wave sensor arranged on the side wall of the model body. After filling to the simulated conditions, the injection pump will be turned off.

[0053] Furthermore, in D, the filling valve and the second outlet valve are closed, the flushing valve and the first outlet valve are opened, the injection valve, the sand outlet valve and the mixing valve are closed, and the pure liquid valve is opened;

[0054] The injection pump is turned on to inject the experimental medium into the oil ring cavity and form the pressure required for the experiment. Under the action of pressure, the liquid passes through the sand body support frame - sand body - well wall support frame - simulated screen pipe in the oil ring cavity, and then enters the hydrocyclone separator through the lower interface. The hydrocyclone separator separates the sand-carrying liquid and performs accurate metering.

[0055] Further, in step E, the injection pump and all valves are shut down, experimental analysis is performed, and the experiment ends.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] This invention can highly simulate the downhole compression and filling construction of sand control wells, and can obtain the influence of different filling densities on the sand output. Thus, it can determine the filling density corresponding to the minimum sand output based on the actual downhole working conditions, thereby optimizing the filling construction process. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the structure of an experimental device and method for evaluating sand control under different filling conditions according to the present invention;

[0059] Figure 2 This is a schematic diagram of the sand control model system in this invention;

[0060] Figure 3 This is a schematic diagram of the cyclone separator in this invention;

[0061] Figure 4 This is a schematic diagram of the closed sand-adding device in this invention;

[0062] Figure 5 This is a schematic diagram of the pressure sensor with sand-proof structure in this invention.

[0063] In the diagram: 1. Sand control model system; 11. Quick-release clamp; 12. Top cover; 13. Model body; 14. Adjustable angle bracket; 15. Oil ring cavity; 16. Sand body support frame; 17. Simulated screen pipe; 18. Wellbore support frame; 19. Lower interface; 20. Radial interface; 21. Upper interface; 22. First bearing with seat; 23. Second bearing; 24. Locking ball; 25. Locking wheel; 26. Measurement interface; 27. Sand body cavity; 28. Pressure sensor; 29. ​​Sand control structure; 30. Pressure drainage pipe;

[0064] 2. Filling density measurement system;

[0065] 3. Sealed sand feeding device; 31. Feed inlet; 32. Sand storage tank; 33. Sand outlet; 34. Fully automatic digital control motor; 35. Screw propeller; 36. Fixed bracket;

[0066] 4. Injection pump; 5. Liquid preparation tank; 6. Circulation pump;

[0067] 7. Hydrocyclone separator; 71. Top cover; 72. Central tube; 73. Balance tube; 74. Guide cover; 75. Sand storage shell; 76. Outer tube; 77. Fixed shell;

[0068] 8. Safety valve; 9. Waste liquid collection filter; 10. Waste liquid collection tank. Detailed Implementation

[0069] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] Example 1:

[0071] Please see Figures 1 to 5 The present invention provides an experimental device for evaluating sand control under different filling conditions, including a sand control model system 1, a filling density measurement system 2, a sample preparation and injection system, and a waste liquid recovery system.

[0072] The sand-proof model system 1 includes a model body 13, a top cover 12, and an adjustable angle bracket 14. The model body 13 is cylindrical, with a ring edge on the upper outer wall. The top cover 12 is connected and sealed to the ring edge of the model body 13 by a quick-release clamp 11. The higher the pressure, the better the self-sealing effect. The model body 13 has a first rotating shaft at its left end and a second rotating shaft at its right end. The first and second rotating shafts are coaxial. The adjustable angle bracket 14 includes a U-shaped base. A first bearing 22 with a seat is located on the upper left wall of the U-shaped base, and a rotating lock is located on the upper right wall of the U-shaped base. The first rotating shaft cooperates with the first bearing 22. The rotating lock includes a lock frame, a locking ball 24, and a locking wheel 25. A second bearing 23 is located at the front end of the lock frame, through which the second rotating shaft passes. The locking wheel 25 is located at the right end of the second bearing. The peripheral wall of the locking wheel 25 has evenly distributed ball seat holes. A ball chamber is located at the upper end of the lock frame, and the locking ball 24 is located in the ball chamber and can sit in the ball seat hole to lock the locking wheel 25. By applying force with a tool, the locking ball 24 is forced into the ball chamber, and the locking wheel 25 is rotated to adjust the angle.

[0073] The model body 13 and the upper cover 12 form a sealed chamber. A lower interface 19 is provided at the center of the lower end of the model body 13. At least two evenly distributed radial interfaces 20 are provided on the side wall of the model body 13. An upper interface 21 is provided at the center of the upper cover 12. At least two layers and at least four evenly distributed measurement interfaces 26 are provided on the side wall of the model body 13. The lower interface 19, radial interfaces 20, and upper interface 21 are all connected to the sealed chamber. A sealing mounting seat is provided in the part of the lower interface 19 inside the sealed chamber. A well wall support frame 18 is installed in the sealing mounting seat. A simulated screen tube 17 is installed in the well wall support frame 18. A simulated perforation is provided in the well wall support frame 18. A sand body support frame 16 is also provided between the well wall support frame 18 and the side wall of the model body 13.

[0074] The model body 13 and all the components connected to it are sealed connections.

[0075] The lower interface 19, radial interface 20, and upper interface 21 are used for injecting or discharging experimental liquid. Preferably, eight radial interfaces 20 are provided and are evenly arranged around the model body 1.

[0076] Among them, the well wall support frame 18 is used to simulate the well wall and perforation.

[0077] The sand support frame 16 divides the sealed chamber formed by the model body 13 and the top cover 12 into two chambers—the oil ring chamber 15 and the sand chamber 27. At the same time, the sand support frame 16 is also used to maintain the shape of the sand filling the sand chamber 27.

[0078] Among them, the oil ring cavity 15 is the cavity filled with the experimental medium.

[0079] Among them, sand cavity 27 is a cavity filled with artificial sand particles.

[0080] The sand body support frame 16 and the well wall support frame 18 are both perforated with a density of 3 holes per 100mm, evenly distributed, and their outer walls are wrapped with 40-mesh screens.

[0081] The sample preparation and injection system includes a liquid preparation tank 5, an injection pump 4, and a sealed sand adding device 3 connected in sequence. The sealed sand adding device 3 includes a sand storage tank 32. The sand storage tank 32 is provided with a feed inlet 31 at the upper end and a sand outlet 33 at the lower end. The sand outlet 33 is connected to a screw propeller 35. The screw propeller 35 is driven by a fully automatic digital control motor 34. The sealed sand adding device 3 is mounted on a fixed support 36.

[0082] The liquid preparation tank 5 is connected to the injection pump 4 via a sample preparation pipeline, which is equipped with a sample preparation valve. The injection pump 4 is connected to the sealed sand adding device 3 via an injection pipeline, which is equipped with an injection valve. The injection pipeline is also connected to a safety valve and a first pressure gauge. When the pressure is too high, the safety valve 8 is used to release the pressure. A sand outlet valve is installed on the sand outlet 33. The screw propeller 35 is connected to the filling pipeline via a mixing output pipeline. A pure liquid pipeline is connected between the safety valve and the injection valve in the injection pipeline. The pure liquid pipeline is connected to the filling pipeline. A mixing valve is installed in the mixing output pipeline. A pure liquid valve is installed in the pure liquid pipeline. A pressure gauge is installed in the filling pipeline to control the filling and detect the filling pressure. The filling pipeline is connected to the upper interface 21 via a filling valve and to the radial interface 20 via a flushing valve.

[0083] The injection pump 4 is used to supply liquid to the system and to provide pressure to the closed sand adding device 3.

[0084] Among them, the closed sand adding device 3 can achieve precise quantitative sand adding.

[0085] The waste liquid recovery system includes a circulating pump 6, a hydrocyclone separator 7, a waste liquid collection filter 9, and a waste liquid collection tank 10. The hydrocyclone separator 7 includes a central tube 72, a sand storage shell 75, and an outer tube 76. The upper end of the sand storage shell 75 is connected to a top cover 71 through a flange joint. The outer tube 76 is inserted from the lower end of the sand storage shell 75 and contacts the top cover 71. The central tube 72 is disposed in the outer tube 76. The upper end of the central tube 72 extends out of the top cover 71 as an oil-water outlet. The lower end of the central tube 72 is lower than the lower end of the sand storage shell 75. The central tube 72 has a rectangular hole array inside the sand storage shell 75.

[0086] The lower end of the central tube 72 is connected to the fixed shell 77. The fixed shell 77 is provided with a guide cover 74. The upper end of the guide cover 74 is provided with a guide post. The upper end of the guide post is provided with a cone. The cone is below the central tube 72. The sand storage shell 75 and the fixed shell 77 are also connected by a balance tube 73.

[0087] The sand storage shell 75 is provided with an oil-water-sand inlet, the axis of which does not pass through the axis of the sand storage shell 75. The circulating pump 6 is connected to the oil-water outlet and is connected to the liquid preparation tank 5 through a recovery pipeline. A recovery valve is provided on the recovery pipeline. The bottom of the fixed shell 77 is provided with a sand outlet, which is connected to the waste liquid collection filter 9 through a waste liquid pipeline. The waste liquid collection filter 9 is installed on the waste liquid collection tank 10. A waste liquid valve is provided on the waste liquid pipeline. The oil-water-sand inlet is connected to the liquid outlet pipeline. The liquid outlet pipeline is connected to the lower interface 19 through the first liquid outlet valve and to the radial interface 20 through the second liquid outlet valve.

[0088] Based on the principles of centrifugal sedimentation and density difference, the liquid moves upward from the center of the hydrocyclone separator 72 and then enters the liquid distribution tank 5 for recycling through the circulation pump 6. The sand particles are recycled to the waste liquid collection filter 9 through the guide cover 24. The incompletely separated water-sand mixture is completely separated through the waste liquid collection filter 9, and the waste liquid enters the waste liquid collection tank 10 at the bottom.

[0089] The balance pipe 73 is used to balance the pressure difference between the inlet and outlet to prevent excessive pressure difference from preventing oil, water and sand from entering the separator.

[0090] Among them, the guide cover 74 can prevent waste liquid from backflowing, so that the sand and gravel cannot backflow into the central tube 72.

[0091] The sand storage shell 75 is used to temporarily store sand during high-speed circulation, allowing the liquid to pass through preferentially, while the sand enters the outer tube 76 at low speed.

[0092] The guide column occupies the liquid space, thereby improving the liquid separation rate, while the cone head prevents the accumulation of sand and gravel.

[0093] Among them, the sand particles collected in the waste liquid collection filter 9 can be weighed to obtain data on the sand output.

[0094] The filling density measurement system 2 includes a pressure sensor 28 with a sand-proof structure 29. The pressure sensor 28 is a high-pressure sensor. The internal structure of the sand-proof structure 29 is a filter screen, which blocks fine sand at the bottom, thus preventing the pressure sensor 28 from becoming clogged and causing inaccurate readings. A pressure drainage pipe 30 at the bottom of the pressure sensor is connected to a measurement interface 26 via a fixed interface. The pressure drainage pipe 30 can slide within the fixed interface, and its insertion depth can be adjusted as needed. The pressure drainage pipe 30 can be inserted into the simulated screen pipe 17, the annulus between the simulated screen pipe 17 and the wellbore support frame 18, the sand cavity 27, and the oil annulus cavity 15 to measure the pressure inside the simulated screen pipe 17, the pressure at a certain position in the screen pipe annulus, the pressure in the sand layer of the sand cavity 27, and the pressure in the oil annulus cavity 15. A cylindrical filter element is installed inside the pressure drainage pipe 30 at the plug, which prevents fine sand from flowing into the pressure drainage pipe 30 and clogging the drainage pipe.

[0095] The filling density measurement system 2 also includes an ultrasonic flow meter and a programmable controller with a display. The ultrasonic flow meter is installed on the filling pipe to detect the filling volume. The ultrasonic flow meter and the pressure sensor 28 are both connected to the programmable controller with a display. The programmable controller with a display can be an industrial control computer or a PLC with a display.

[0096] The filling density measurement system 2 also includes an acoustic wave sensor for measuring the filling density. The acoustic wave sensor is connected to the measurement interface 26. The sensor emits and receives enhanced PS acoustic wave signals for saturated extrusion filling and annular filling. It measures the abrupt change points in the acoustic wave signal indicating the filling density. The main acoustic wave detection frequency is 20MHz, and the sampling interval is 0.05μs to 4000μs. The sampling interval can be adjusted according to experimental needs. The acoustic wave detection frequency can be set to 1MHz, 100KHz, and 20KHz, and can also be adjusted according to actual requirements. It should be noted that the acoustic wave sensor capable of emitting and receiving enhanced PS acoustic wave signals is prior art, as is clear to those skilled in the art.

[0097] Example 2:

[0098] Based on Example 1, this example provides an experimental method for evaluating sand control under different filling conditions, specifically including the following steps:

[0099] A. Determine the experimental process parameters and prepare the experimental materials;

[0100] Based on the sand control pipe to be tested and the simulated geological conditions, select appropriate pressure, temperature, flow rate and other conditions;

[0101] The closed sand feeding device is calibrated according to the different sand particle sizes used, and the sand feeding flow rate under different sand particle conditions is calibrated. Then, the corresponding particle size can be selected through software, and the servo motor speed is automatically adjusted according to the required sand feeding amount set in the experiment to achieve quantitative sand feeding.

[0102] B. Connect the various parts of the system according to the experimental design;

[0103] It includes a sand control model system 1, a filling density measurement system 2, a sample preparation and injection system, and a waste liquid recovery system.

[0104] C. Open the filling valve and the second outlet valve, and close the flushing valve and the first outlet valve;

[0105] Open the injection valve, sand outlet valve, and mixing valve; close the pure liquid valve.

[0106] When the injection pump 4 is turned on, the liquid is mixed with sand particles through the sealed sand adding device 3 and enters the model body 13 through the upper interface 21. It then flows evenly into the sand cavity 27, thereby forming sand bodies of different densities. The filling density is monitored by the enhanced PS wave sensors arranged around the model body 3. After filling to the simulated conditions, the injection pump 4 is turned off.

[0107] D. Close the filling valve and the second outlet valve, and open the flushing valve and the first outlet valve;

[0108] Close the injection valve, sand outlet valve, and mixing valve; open the pure liquid valve.

[0109] The injection pump 4 is turned on to inject the experimental medium into the oil ring cavity 15 and form the pressure required for the experiment. Under the action of pressure, the liquid passes through the sand body support frame 16-sand body-well wall support frame 18-simulated screen pipe 17 in the oil ring cavity 15, and then enters the cyclone separator 7 through the lower interface 19. The cyclone separator 7 separates the sand-carrying liquid and performs accurate measurement.

[0110] E. Turn off the injection pump. 4. Close all valves, conduct experimental analysis, and the experiment ends.

[0111] The beneficial effects of this invention are that it can highly simulate the downhole squeezing and filling construction of sand control wells, and can obtain the influence of different filling densities on the sand output. Thus, it can determine the filling density corresponding to the minimum sand output based on the actual downhole working conditions, thereby optimizing the filling construction process.

[0112] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0113] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0114] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0115] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An experimental apparatus for evaluating sand control under different filling conditions, comprising a sand control model system, characterized in that, It also includes a filling density measurement system, a sample preparation and injection system, and a waste liquid recovery system; The filling density measurement system is connected to the side wall of the sand control model system; The sample preparation and injection system is equipped with a sand-liquid mixing and conveying section and a pure liquid input section. The sand-liquid mixing and conveying section is connected to the upper end of the sand control model system, and the pure liquid input section is connected to the side wall of the sand control model system. The waste liquid recovery system is connected to the lower end and side wall of the sand control model system.

2. The sand control evaluation experimental device under different filling conditions according to claim 1, characterized in that, The sand control model system includes a model body, the upper end of which is provided with a top cover, and the model body is cylindrical. The model body and the top cover form a sealed chamber. A lower interface is provided at the center of the lower end of the model body. At least two evenly distributed radial interfaces are provided on the side wall of the model body. An upper interface is provided at the center of the top cover. At least two layers and at least four evenly distributed measurement interfaces are provided on the side wall of the model body. The lower interface, radial interface, and upper interface are all connected to the sealed chamber. The lower interface is provided with a sealing mounting seat in the sealed cavity. A well wall support frame is installed in the sealing mounting seat. A simulated screen tube is installed in the well wall support frame. The well wall support frame is provided with simulated perforations. A sand support frame is also provided between the well wall support frame and the side wall of the model body. Holes are drilled on the walls of both the sand support frame and the well wall support frame, and the outer walls are wrapped with screens. The sand body support frame divides the sealed chamber consisting of the model body and the top cover into two chambers: the oil ring chamber and the sand body chamber.

3. The sand control evaluation experimental device under different filling conditions according to claim 2, characterized in that, The top cover is connected and sealed to the circumferential edge of the model body by a quick-release clamp; The model body has a first rotation axis and a second rotation axis on its side wall, which are rotatably connected to an adjustable angle bracket.

4. The sand control evaluation experimental device under different filling conditions according to claim 2, characterized in that, The sand-liquid mixing and transport section of the sample preparation and injection system includes a liquid preparation tank, an injection pump, and a closed sand addition device connected in sequence. The liquid preparation tank and the injection pump are connected through a sample preparation pipeline, and a sample preparation valve is installed on the sample preparation pipeline; The injection pump and the sealed sand adding device are connected through an injection pipeline. An injection valve is installed on the injection pipeline, and a safety valve and a first pressure gauge are also connected to the injection pipeline. The sealed sand adding device includes a sand storage tank, with a feed inlet at the upper end and a sand outlet at the lower end. The sand outlet is connected to a screw propeller, which is driven by a servo motor. A sand outlet valve is provided on the sand outlet. The screw propeller is connected to a filling pipeline through a mixing output pipeline, which is equipped with a mixing valve. The pure liquid input section includes a pure liquid pipeline, which is connected to the filling pipeline. The pure liquid pipeline is connected to the injection pipeline between the safety valve and the injection valve. The pure liquid pipeline is equipped with a pure liquid valve. The filling pipeline is equipped with a pressure gauge. The filling pipeline is connected to the upper interface through a filling valve and to the radial interface through a flushing valve.

5. The sand control evaluation experimental device under different filling conditions according to claim 4, characterized in that, The waste liquid recovery system includes a circulating pump, a hydrocyclone separator, and a waste liquid collection section; The cyclone separator is equipped with an oil-water-sand inlet, an oil-water outlet, and a sand outlet. The circulating pump is connected to the oil and water outlet, and the circulating pump is connected to the liquid preparation tank through the recovery pipeline, which is equipped with a recovery valve. The sand outlet is connected to the waste liquid collection section; The oil-water-sand inlet is connected to the liquid outlet pipeline, which is connected to the lower interface via a first liquid outlet valve and to the radial interface via a second liquid outlet valve.

6. The sand control evaluation experimental device under different filling conditions according to claim 5, characterized in that, The cyclone separator includes a central tube, a sand storage shell, and an outer tube; The upper end of the sand storage shell is connected to the top cover via a flange joint, and the outer tube is inserted from the lower end of the sand storage shell and contacts the top cover. The central tube is installed in the outer tube. The upper end of the central tube extends out of the top cover as an oil and water outlet. The lower end of the central tube is lower than the lower end of the sand storage shell. The central tube is provided with a rectangular hole array in the inner part of the sand storage shell. The lower end of the central tube is connected to the fixed shell, the fixed shell is provided with a guide cover, the upper end of the guide cover is provided with a guide post, the upper end of the guide post is provided with a cone head, the cone head is below the central tube, and the sand storage shell and the fixed shell are also connected by a balance tube. The sand storage shell is provided with an oil-water-sand inlet, the axis of which does not pass through the axis of the sand storage shell, and the bottom of the fixed shell is provided with a sand outlet.

7. The sand control evaluation experimental device under different filling conditions according to claim 5, characterized in that, The waste liquid collection section includes a waste liquid collection filter and a waste liquid collection tank; The sand outlet is connected to a waste liquid collection filter via a waste liquid pipeline. The waste liquid collection filter is installed on a waste liquid collection tank, and a waste liquid valve is installed on the waste liquid pipeline.

8. The sand control evaluation experimental device under different filling conditions according to claim 2, characterized in that, The filling density measurement system includes a pressure sensor with a sand-proof structure, an ultrasonic flow meter, an acoustic sensor, and a programmable controller with a display. The ultrasonic flow meter, pressure sensor, and acoustic wave sensor are all connected to a programmable controller with a display. The pressure sensor is connected to the measurement interface via a pressure drain tube, a fixed connector, and the pressure drain tube can slide within the fixed interface. The ultrasonic flow meter is installed on the filling pipe; The acoustic sensor is connected to the measurement interface.

9. The sand control evaluation experimental device under different filling conditions according to claim 8, characterized in that, The pressure sensor is a high-pressure pressure sensor, the internal structure of the sandproof structure is a filter screen, and the pressure drainage tube has a cylindrical filter element at the front plug. The acoustic sensor transmits and receives enhanced PS acoustic signals, with a main frequency of 20MHz-20KHz and a sampling interval of 0.05μs to 4000μs.

10. An experimental method for evaluating sand control under different filling conditions, characterized in that, Includes the following steps: A. Determine the experimental process parameters, prepare experimental materials, and adjust the sand-liquid mixing and transportation volume of the sample preparation and injection system; B. Connect the sand control model system, filling density measurement system, sample preparation and injection system, and waste liquid recovery system; C. Inject sand liquid to form sand bodies of different densities. Monitor the filling density using a filling density measurement system. Stop injection after filling to simulated conditions. D. The experimental medium is injected with pure liquid to form the pressure required for the experiment. Under the action of pressure, the liquid enters the waste liquid recovery system for sand-liquid separation and is accurately measured. E. Stop the injection, conduct experimental analysis, and the experiment ends.

11. The experimental method for evaluating sand control under different filling conditions according to claim 10, characterized in that, In section A, pressure, temperature, and flow conditions are selected based on the sand control pipe to be tested and the simulated formation conditions. The closed sand feeding device was calibrated according to the different sand particle sizes used, and the sand feeding flow rate under different sand particle conditions was calibrated. The corresponding particle size was selected through software, and the servo motor speed was automatically adjusted according to the required sand feeding amount set in the experiment to achieve quantitative sand feeding.

12. The experimental method for evaluating sand control under different filling conditions according to claim 10, characterized in that, In C, open the filling valve and the second outlet valve, close the flushing valve and the first outlet valve, open the injection valve, the sand outlet valve and the mixing valve, and close the pure liquid valve; Turn on the injection pump, and the liquid will be mixed with sand particles through the sealed sand adding device and enter the model body through the upper interface. It will flow evenly into the sand cavity to form sand bodies of different densities. The filling density is monitored by the enhanced PS wave sensor arranged on the side wall of the model body. After filling to the simulated conditions, the injection pump will be turned off. In D, close the filling valve and the second outlet valve, open the flushing valve and the first outlet valve, close the injection valve, the sand outlet valve and the mixing valve, and open the pure liquid valve; The injection pump is turned on to inject the experimental medium into the oil ring cavity and form the pressure required for the experiment. Under the action of pressure, the liquid passes through the sand body support frame - sand body - well wall support frame - simulated screen pipe in the oil ring cavity, and then enters the hydrocyclone separator through the lower interface. The hydrocyclone separator separates the sand-carrying liquid and performs accurate metering. In step E, shut down the injection pump and all valves, perform experimental analysis, and the experiment ends.

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