Backpressure control device, method and application

Abstract

The invention provides a back pressure control device and method and application. The back pressure control device comprises a control box, a movable part, a back pressure pipeline, a control pipeline, an inlet pipeline, an outlet pipeline and a pressure generation assembly. A pressure return cavity is formed in the control box, and the movable part is movably arranged in the pressure return cavity; the inlet pipeline and the outlet pipeline are respectively communicated with the back pressure cavity; the back pressure pipeline is arranged on the movable part; the pressure generation assembly is communicated with the pressure return cavity through the control pipeline and used for providing set air pressure for the side, away from the inlet pipeline, of the movable part; the movable part can move towards or away from the inlet pipeline under the set air pressure so that the inlet pipeline can be disconnected from or communicated with the outlet pipeline. The back pressure control device has the advantages that the influence of fluid on the back pressure control device is reduced, and the service life of the back pressure control device is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of gas reservoir development, and in particular to a back pressure control device, method and application. Background Art

[0002] Before constructing a gas reservoir-type gas storage, it is necessary to fully understand the original physical properties of the gas reservoir, study the injection and production operation mechanism of the gas reservoir converted into a gas storage and its main influencing factors, especially the impact of pressure on the gas storage capacity parameter indicators during gas production operation, so as to guide the optimization of the gas storage injection and production operation plan.

[0003] my country's underground gas storage facilities are primarily porous. High-speed, high-flow injection and production, as well as water intrusion, significantly impact the utilization of gas-bearing pore volume during operation. Furthermore, the reservoir physical properties are moderate and highly heterogeneous. Despite eight to nine complete injection and production cycles, the expansion of gas storage capacity has been slow. Currently, research on injection and production experiments for reservoir-type gas storage primarily focuses on simulations of the injection and production processes. However, there are deficiencies in the control of fluid production back pressure in these simulations. The injection and production operations of reservoir-type gas storage are influenced by multiple factors, including formation temperature, injection and production rates, operating pressure range, and water intrusion. Conventional gas reservoir development experimental methods are unable to simulate the reciprocating high-speed injection and production patterns of gas storage under these formation temperature and pressure conditions, nor do they affect the efficiency of the reservoir construction.

[0004] Therefore, there is an urgent need to develop a high-temperature and high-pressure fluid back pressure control device to control the back pressure of gas production fluid during physical simulation experiments under the temperature and pressure conditions of the gas storage reservoir. Summary of the Invention

[0005] In order to reduce the impact of the fluid itself on the back pressure control device and increase the service life of the back pressure control device, this application proposes a back pressure control device, method and application, and adopts the following technical solutions:

[0006] In a first aspect, the present application discloses a back pressure control device comprising a control box, a movable part, a back pressure pipeline, a control pipeline, an inlet pipeline, an outlet pipeline and a pressure generating assembly;

[0007] A back-pressure chamber is provided in the control box, and the movable member is movably arranged in the back-pressure chamber;

[0008] The inlet pipeline and the outlet pipeline are respectively connected to the back pressure chamber;

[0009] The back pressure pipeline is arranged on the movable part;

[0010] The pressure generating assembly is in communication with the back-pressure chamber via the control line, and is used to provide a set pressure to a side of the movable part away from the inlet line;

[0011] The movable member can move toward or away from the inlet pipeline under a set pressure to disconnect or connect the inlet pipeline with the outlet pipeline.

[0012] Optionally, the back pressure pipeline includes a first pipeline and a second pipeline that are interconnected;

[0013] The first pipeline is in communication with the back pressure chamber and the inlet pipeline;

[0014] The second pipeline can move along with the movable member under a set gas pressure to be connected with or disconnected from the outlet pipeline.

[0015] Optionally, the first pipeline and the second pipeline are both opened in the movable part.

[0016] Optionally, the inlet pipeline includes a first inlet pipeline and a second inlet pipeline;

[0017] The first inlet pipeline is arranged on a side of the control box opposite to the outlet pipeline, and the second inlet pipeline is connected to the back pressure chamber area on the side of the movable part away from the control pipeline;

[0018] Both ends of the back-pressure pipeline are connected to or disconnected from the first inlet pipeline and the outlet pipeline respectively as the movable part moves.

[0019] Optionally, the pressure generating assembly includes a gas cylinder and an air pressure pump, and the gas cylinder, air pressure pump and control pipeline are connected in sequence.

[0020] Optionally, the back pressure control device further comprises a fluid supply chamber;

[0021] The fluid supply chamber is disposed at the other end of the inlet pipeline and is used to provide high-temperature and high-pressure fluid.

[0022] Optionally, the back pressure control device further includes a first pressure sensor and a second pressure sensor;

[0023] The first pressure sensor is provided on the inlet pipeline and is used to obtain pressure data of the outlet of the fluid supply chamber;

[0024] The second pressure sensor is provided on the control pipeline and is used to obtain set pressure data.

[0025] Optionally, the back pressure control device further includes a constant temperature box;

[0026] The control box and the fluid supply chamber are both located in the constant temperature box.

[0027] Optionally, the back pressure control device further includes a controller;

[0028] The controller is connected to the pressure generating assembly, the first pressure sensor, and the second pressure sensor, and is used to control the pressure generating assembly to provide a set pressure according to the pressures of the inlet pipeline and the control pipeline.

[0029] In a third aspect, the present application discloses a back pressure control method using the back pressure control device as described in the second aspect.

[0030] In a fourth aspect, the present application discloses an application of the back pressure control device as described in the second aspect in a core depletion gas production simulation experiment.

[0031] Based on the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0032] The back pressure control device in the embodiment of the present application can simulate the gas production process in the development of gas reservoir depletion, and set different pressure points for depletion gas production through the pressure generating assembly. The other end of the inlet pipeline is connected to the high-temperature and high-pressure gas fluid, and the pressure generating assembly is used to provide a set air pressure to the back pressure chamber. When the set air pressure is less than the pressure on one side of the inlet pipeline, the high-temperature and high-pressure gas fluid is produced under its own pressure; when the set air pressure exceeds the pressure on one side of the inlet pipeline, the high-temperature and high-pressure gas fluid stops being produced. Thus, the effect of producing fluid at different pressure values ​​is achieved. Since the fluid is only in contact with the pipeline, the adverse effects of the fluid itself on the back pressure control assembly are reduced, so that the back pressure control device as a whole has a long service life, and the overall structure is simple and the cost is low, which is conducive to universal use. In addition, the data monitoring and operation automation of the back pressure control device are applicable to different temperature ranges, different gas production pressure intervals, etc., and can solve the problem of simulating gas production processes at different pressure levels in indoor experiments of gas reservoirs. Through this back pressure control device, further research on the gas production and seepage mechanism of underground reservoirs of various types of gas reservoirs can be carried out, the influence of gas production rate on gas reservoir production efficiency can be analyzed, and the gas production operation plan for gas reservoir development can be optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the back pressure control device in Example 1 of the present application when the back pressure pipeline is disconnected;

[0034] Figure 2 This is a schematic diagram of the back-pressure control device in Example 1 of the present application when the back-pressure pipeline is connected;

[0035] Figure 3 This is a schematic diagram of the back pressure control device in Example 2 of the present application when the back pressure pipeline is disconnected;

[0036] Figure 4 This is a schematic diagram of the back-pressure control device in Example 2 of the present application when the back-pressure pipeline is connected;

[0037] Explanation of the accompanying drawings: 1. Control box; 2. Moving parts; 3. Control pipeline; 4. Back pressure pipeline; 41. First pipeline; 42. Second pipeline; 5. Inlet pipeline; 51. First inlet pipeline; 52. Second inlet pipeline; 6. Outlet pipeline; 7. Pressure generating assembly; 71. Gas cylinder; 72. Air pressure pump; 8. Fluid supply chamber; 9. First pressure sensor; 10. Second pressure sensor; 11. Controller; 12. Back pressure chamber; 13. Constant temperature box. DETAILED DESCRIPTION

[0038] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0040] In the description of this disclosure, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this disclosure and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on the specific circumstances.

[0042] Currently, research on injection-production simulation systems for depleted gas storage reservoirs primarily focuses on simulations of the injection and production processes within the reservoir, studying the mechanisms of reservoir construction and injection-production. However, there are still deficiencies in the control of back-pressure during fluid production experiments. Due to the large fluctuations in flow rate and temperature of produced fluids, and their wide range of enthalpy variations, unstable back-pressure control can lead to flash evaporation if the pressure drops suddenly. Furthermore, excessive pressure prevents the produced fluid from effectively passing through the back-pressure control device, resulting in excessively low temperatures, a significant increase in crude oil viscosity, and pipeline blockage. Both of these extreme scenarios, triggered by back-pressure fluctuations, can force the experiment to terminate.

[0043] The inventors have discovered that currently conventional back-pressure controllers are mainly implemented through back-pressure valves. When fluid enters from one side of the valve body, the valve core is pushed toward the other side by the pressure, thereby opening the valve and allowing the fluid to pass. When the fluid enters from the other side, the valve core is pushed back to its original position by the pressure, closing the valve and preventing the fluid from passing. However, since the extracted fluid itself has the characteristics of high temperature, high pressure and strong corrosiveness, it is easy to cause wear and tear on the valve body and reed during the process of contact with the valve body, thereby affecting the service life of the back-pressure valve. Therefore, in order to reduce the impact of the fluid itself on the back-pressure control device and increase the service life of the back-pressure control device, the present application provides a back-pressure control device, method and application.

[0044] Example 1

[0045] In a first aspect, an embodiment of the present application provides a back pressure control device.

[0046] Reference Figure 1 The back pressure control device includes a control box 1, a movable part 2, a back pressure pipeline 4, a control pipeline 3, an inlet pipeline 5, an outlet pipeline 6 and a pressure generating assembly 7; a back pressure chamber 12 is opened in the control box 1, and the movable part 2 is movably arranged in the back pressure chamber 12; the inlet pipeline 5 and the outlet pipeline 6 are respectively connected to the back pressure chamber 12; the back pressure pipeline 4 is arranged on the movable part 2, and one end of the back pressure pipeline 4 is connected to the inlet pipeline 5; the pressure generating assembly 7 is connected to the back pressure chamber 12 through the control pipeline 3, and is used to provide a set pressure to the side of the movable part 2 away from the inlet pipeline 5; the movable part 2 can move toward or away from the inlet pipeline 5 under the set pressure, so as to disconnect or connect the inlet pipeline 5 and the outlet pipeline 6.

[0047] The backpressure control device in the embodiment of the present application can be used in core model depletion development gas production simulation experiments. Depletion gas production is performed by setting different pressure points using the pressure generating assembly 7. Specifically, the other end of the inlet pipeline 5 is connected to a high-temperature, high-pressure gas stream. The pressure generating assembly 7 provides a set pressure within the backpressure chamber 12. When the set pressure is less than the pressure on the inlet pipeline 5 side, the movable member 2 moves away from the inlet pipeline 5 to the bottom of the control box 1, connecting the inlet pipeline 5, the backpressure pipeline 4, and the outlet pipeline 6. The high-temperature, high-pressure gas stream is produced under its own pressure. When the set pressure exceeds the pressure on the inlet pipeline 5 side, the movable member 2 moves toward the inlet pipeline 5 to the top of the control box 1 due to the pressure difference between the inlet pipeline 5 and the control pipeline 3 on both sides, disconnecting the inlet pipeline 5 from the outlet pipeline 6, and stopping the production of the high-temperature, high-pressure gas stream. This achieves the effect of producing fluid at different pressure values. Since the fluid only contacts the pipeline, the adverse effects of the fluid itself on the backpressure control assembly are reduced, resulting in a long service life for the backpressure control device as a whole. The overall structure is simple and low-cost, making it suitable for widespread use.

[0048] In an optional embodiment, the pressure generating assembly 7 employs a gas generating assembly to provide a set air pressure. Specifically, the pressure generating assembly 7 includes a gas cylinder 71 and an air pump 72, which are sequentially connected to the gas cylinder 71, the air pump 72, and the control line 3. The air pump 72 provides air pressure to the control box 1 via the control line 3. By adjusting the pressure of the air pump 72, fluid extraction simulation experiments can be performed at different pressures.

[0049] In an alternative embodiment, movable member 2 may be a piston, which divides back-pressure chamber 12 within control box 1 into two sections, one of which is connected to inlet pipeline 5 and the other to control pipeline 3. Therefore, the piston can move toward or away from inlet pipeline 5 due to the pressure difference between these two sections. Outlet pipeline 6 is located on one side of control box 1 perpendicular to the direction of piston movement.

[0050] In an optional embodiment, the back-pressure line 4 includes a first line 41 and a second line 42 that are interconnected. Specifically, the first line 41 and the second line 42 are disposed within the movable member 2 and extend to the exterior of the movable member 2. The first line 41 is connected to the back-pressure chamber 12 and the inlet line 5, while the second line 42 extends toward the outlet line 6 and can move with the movable member 2 to connect or disconnect with the outlet line 6 under a set air pressure. When the movable member 2 moves under a pressure differential, the opening of the second line 42 can move to connect with the outlet line 6 or to abut against the inner wall of the control box 1 to disconnect from the outlet line 6.

[0051] It should be noted that in other embodiments, the first pipeline 41 and the second pipeline 42 may also be fixedly arranged on the outer surface of the movable part 2, as long as the movable part 2 can drive the first pipeline 41 and the second pipeline 42 to move.

[0052] In an alternative embodiment, the first pipeline 41 and the second pipeline 42 can be arranged perpendicular to each other, i.e., the first pipeline 41 is parallel to the inlet pipeline 5, and the second pipeline 42 is parallel to the outlet pipeline 6. Alternatively, both the first pipeline 41 and the second pipeline 42 can be arranged at an angle. Alternatively, the back-pressure pipeline 4 can be a curved pipe that connects the outlet pipeline 6 and the inlet pipeline 5.

[0053] Therefore, under a set pressure differential, back pressure control is performed by moving the movable member 2, thereby connecting and disconnecting the inlet pipeline 5 and the outlet pipeline 6, thereby achieving normal fluid extraction and stopping fluid extraction. By providing a simple and efficient back pressure control device, costs are saved, and the outlet pipeline 6 and the inlet pipeline 5 can be quickly disconnected when the pressure changes, making the control process more precise.

[0054] In an optional embodiment, a spacer is provided on the side of the movable member 2 near the inlet pipeline 5 to isolate the fluid from the movable member 2. This reduces the impact of the fluid's own corrosiveness on the top of the movable member 2 when the movable member 2 moves to the bottom of the control box 1. The spacer can be an anti-corrosion coating applied to the top of the movable member 2 or a polytetrafluoroethylene plastic.

[0055] It should be noted that, during the actual simulation experiment, the control box 1 can be placed vertically or horizontally, so the movable part 2 can move vertically or horizontally.

[0056] In an optional embodiment, the back pressure control device further includes a fluid supply chamber 8, which is disposed at the other end of the inlet pipeline 5 and is configured to provide high-temperature, high-pressure fluid. Specifically, in this embodiment, the fluid supply chamber 8 may be a core holder, which, under the action of a corresponding clamping force, can squeeze out the high-temperature, high-pressure fluid.

[0057] In an optional embodiment, the back pressure control device further includes a constant temperature box, and the control box 1 and the fluid supply chamber 8 are both arranged in the constant temperature box 13, and the constant temperature box 13 is used to heat the control box 1 and the fluid supply chamber 8 to a predetermined experimental temperature.

[0058] Furthermore, the back pressure control device also includes a first pressure sensor 9 and a second pressure sensor 10; the first pressure sensor 9 is arranged on the inlet pipeline 5, for obtaining pressure data at the outlet of the fluid supply chamber 8; the second pressure sensor 10 is arranged on the control pipeline 3, for obtaining set pressure data.

[0059] In an optional embodiment, valves are provided on the inlet pipeline 5, the outlet pipeline 6 and the control pipeline 3 to respectively control the connection and disconnection of the corresponding pipelines.

[0060] Furthermore, the back-pressure control device also includes a controller 11, to which the air pressure pump 72, the first pressure sensor 9, the second pressure sensor 10, and the thermostat 13 are connected. The controller 11 is used to monitor and record the pressure data at the outlet of the fluid supply chamber 8 and the air pressure pump 72, as well as the experimental ambient temperature, during the core model depletion development and gas production simulation experiment. It also controls the pressure generating assembly 7 to provide a set pressure based on the pressures in the inlet pipeline 5 and the control pipeline 3. This ensures that the high-temperature and high-pressure resistance of each component meets the experimental requirements, ensuring stable experimental test signals.

[0061] In summary, the data monitoring and operation automation of the back pressure control device in the embodiment of the present application are suitable for different temperature ranges, different gas production pressure intervals, etc., and can solve the problem of simulating gas production processes at different pressure levels in indoor experiments of gas reservoirs. Through this back pressure control device, further research on the gas production seepage mechanism of underground reservoirs of various types of gas reservoirs can be carried out, the influence of gas production rate on gas reservoir production efficiency can be analyzed, and the gas production operation plan for gas reservoir development can be optimized.

[0062] In a second aspect, an embodiment of the present application further discloses a back pressure control method, using the back pressure control device of the first aspect.

[0063] In a third aspect, an embodiment of the present application discloses an application of a back pressure control device as in the first aspect in a core depletion gas production simulation experiment.

[0064] The specific process of the core depletion gas production simulation experiment is described in detail below:

[0065] According to the gas reservoir depletion gas production operation conditions, the applicable temperature range of the device is 0℃-180℃, and the applicable pressure range is 0MPa-70MPa.

[0066] First, the controller 11 is used to set the upper and lower pressure limits of the exhaustion gas production simulation experiment;

[0067] Then, the experimental system is heated to a predetermined experimental temperature of 90° C. through the constant temperature box 13 , and the initial pressure of the air pump 72 is set to 50 MPa through the controller 11 . At this time, the fluid in the fluid supply chamber 8 is at an initial pressure of 50 MPa.

[0068] Furthermore, the pressure of the air pump 72 is set according to the first pressure point. Since the set pressure value is lower than the initial pressure of the fluid in the fluid supply chamber 8 by 50 MPa, the movable part 2 in the back-pressure chamber 12 moves downward to the bottom of the back-pressure chamber 12. At this time, the back-pressure pipeline 4 is connected with the outlet pipeline 6, and the outlet of the fluid supply chamber 8, the inlet pipeline 5, the back-pressure pipeline 4, and the outlet pipeline 6 form a passage. The fluid in the fluid supply chamber 8 can flow out from this passage, and the exhaustion gas extraction at the first pressure point begins.

[0069] As the gas fluid in the fluid supply chamber 8 gradually flows out, the gas fluid pressure in the fluid supply chamber 8 decreases. When it is lower than the first pressure point of the air pressure pump 72, the movable part 2 in the back pressure chamber 12 moves upward to the top of the control box 1, and the back pressure pipeline 4 is disconnected from the outlet pipeline 6. At this time, the outlet of the fluid supply chamber 8, the inlet pipeline 5, the back pressure pipeline 4, and the outlet pipeline 6 form a short circuit, and the gas fluid in the fluid supply chamber 8 stops flowing out. The exhaustion gas production at the first pressure point stops. According to the above process, the core exhaustion gas production simulation experiment at 48MPa, 46MPa, 44MPa, 42MPa, 40MPa, 38MPa, and 36MPa pressure points under the control of the controller 11 is realized in turn, as shown in Table 1:

[0070] Table 1 Basic data of pressure change in gas storage depletion gas production simulation experiment

[0071]

[0072] It should be noted that since factors such as the physical properties and scale of the core model will affect depletion gas production, the seepage capacity of different core models varies. The setting of the gas production pressure point should be appropriately adjusted according to the seepage capacity of the core model.

[0073] Example 2

[0074] The back pressure control device in this embodiment differs from that in Example 1 in that the inlet pipeline 5 in this embodiment includes a first inlet pipeline 51 and a second inlet pipeline 52, both of which are in communication with the fluid supply chamber 8. Taking the control box 1 in a vertical position as an example, the first inlet pipeline 51 is disposed on the side of the control box 1 opposite the outlet pipeline 6, and the end of the second inlet pipeline 52 away from the fluid supply chamber 8 is in communication with the back pressure chamber 12 region on the side of the movable member 2 away from the control pipeline 3.

[0075] Furthermore, in this embodiment, the back-pressure pipeline 4 is a separate pipeline, with its two ends respectively passing through the two sides of the movable part 2. The two ends of the back-pressure pipeline 4 are connected or disconnected with the first inlet pipeline 51 and the outlet pipeline 6 respectively as the movable part 2 moves. Specifically, the back-pressure pipeline 4 can be a pipeline opened in the horizontal direction, with its two ends located at the same height. In this case, the first inlet pipeline 51 and the outlet pipeline 6 are located at the same height as the control box 1. Of course, the back-pressure pipeline 4 can also be a stepped pipeline formed by connecting multiple sections of pipelines end to end, or a curved pipe with a height difference at both ends. As long as the movable part 2 can drive the two ends of the back-pressure pipeline 4 to connect or disconnect with the first inlet pipeline 51 and the outlet pipeline 6 respectively during movement, it will be sufficient.

[0076] It should be noted that in this embodiment, the high-temperature and high-pressure fluid is divided into two parts through the first inlet pipeline 51 and the second inlet pipeline 52. A part of the fluid enters the upper area of ​​the movable part 2 through the second inlet pipeline 52 to form an air pressure difference between the upper area of ​​the movable part 2 and the lower area of ​​the movable part 2; the other part of the fluid is extracted through the back-pressure pipeline 4.

[0077] Specifically, during the actual simulation experiment, when the set pressure value is lower than the initial pressure of the fluid in the fluid supply chamber 8, the movable member 2 in the back-pressure chamber 12 moves downward to the bottom of the back-pressure chamber 12. At this time, the two ends of the back-pressure pipeline 4 are connected to the first inlet pipeline 51 and the outlet pipeline 6, respectively. The fluid supply chamber 8, the first inlet pipeline 51, the back-pressure pipeline 4, and the outlet pipeline 6 form a passage, through which the fluid in the fluid supply chamber 8 can flow out. When the gas fluid pressure in the fluid supply chamber 8 is lower than the pressure of the air pressure pump 72, the movable member 2 in the back-pressure chamber 12 moves upward to the top of the back-pressure chamber 12. At this time, the two ends of the back-pressure pipeline 4 are disconnected from the first inlet pipeline 51 and the outlet pipeline 6, respectively. At the same time, due to the compression of the movable member 2, the back-pressure chamber 12 and the second inlet pipeline 52 are also disconnected, stopping the fluid extraction process. By diverting the inlet pipeline 5, when fluid extraction stops, the first pipeline and the second pipeline can be isolated from the back-pressure pipeline 4, thereby preventing some fluid from remaining in the back-pressure pipeline 4.

[0078] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it will be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, to the extent that the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including", as explained by the use of "including" as a transitional word in the claims. In addition, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

Claims

1. A back pressure control device, characterized in that: It comprises a control box (1), a movable part (2), a back pressure pipeline (4), a control pipeline (3), an inlet pipeline (5), an outlet pipeline (6) and a pressure generating assembly (7); A back-pressure chamber (12) is provided in the control box (1), and the movable member (2) is movably arranged in the back-pressure chamber (12); The inlet pipeline (5) and the outlet pipeline (6) are respectively connected to the back pressure chamber (12); The inlet pipeline (5) is used for introducing fluid; The back pressure pipeline (4) is arranged on the movable part (2); The pressure generating assembly (7) is in communication with the back pressure chamber (12) via the control line (3) and is used to provide a set pressure to a side of the movable part (2) away from the inlet line (5); The movable member (2) can move toward or away from the inlet pipeline (5) under a set pressure to disconnect or connect the inlet pipeline (5) with the outlet pipeline (6).

2. The back pressure control device according to claim 1, characterized in that: The back-pressure pipeline (4) comprises a first pipeline (41) and a second pipeline (42) that are interconnected; The first pipeline (41) is in communication with the back pressure chamber (12) and the inlet pipeline (5); The second pipeline (42) can move along with the movable member (2) under a set air pressure to connect with or disconnect from the outlet pipeline (6).

3. The back pressure control device according to claim 2, characterized in that: The first pipeline (41) and the second pipeline (42) are both opened in the movable part (2).

4. The back pressure control device according to claim 1, characterized in that: The inlet pipeline (5) includes a first inlet pipeline (51) and a second inlet pipeline (52); The first inlet pipeline (51) is provided on a side of the control box (1) opposite to the outlet pipeline (6), and the second inlet pipeline (52) is connected to a back pressure chamber (12) area on a side of the movable part (2) away from the control pipeline (3); Both ends of the back-pressure pipeline (4) are connected to or disconnected from the first inlet pipeline (51) and the outlet pipeline (6) respectively as the movable part (2) moves.

5. The back pressure control device according to claim 1, characterized in that: The pressure generating assembly (7) comprises a gas cylinder (71) and an air pressure pump (72), and the gas cylinder (71), the air pressure pump (72) and the control pipeline (3) are connected in sequence.

6. The back pressure control device according to claim 1, characterized in that: Also included is a fluid supply chamber (8); The fluid supply chamber (8) is provided at the other end of the inlet pipeline (5) and is used to provide high-temperature and high-pressure fluid.

7. The back pressure control device according to claim 6, characterized in that: Also includes a first pressure sensor (9) and a second pressure sensor (10); The first pressure sensor (9) is provided on the inlet pipeline (5) and is used to obtain pressure data at the outlet of the fluid supply chamber (8); The second pressure sensor (10) is provided on the control pipeline (3) and is used to obtain set pressure data.

8. The back pressure control device according to claim 6, characterized in that: Also includes a constant temperature box (13); The control box (1) and the fluid supply chamber (8) are both located in the constant temperature box (13).

9. The back pressure control device according to claim 7, characterized in that: Also includes a controller (11); The controller (11) is connected to the pressure generating assembly (7), the first pressure sensor (9), and the second pressure sensor (10), and is used to control the pressure generating assembly (7) to provide a set pressure according to the pressure of the inlet pipeline (5) and the control pipeline (3).

10. A back pressure control method, using the back pressure control device according to any one of claims 1 to 9.

11. Use of the back pressure control device according to any one of claims 1 to 9 in a core depletion gas production simulation experiment.

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