Shaft leakage simulation system and method

Abstract

The invention discloses a shaft leakage simulation system and method. The system comprises a shaft simulation unit and a gas injection recovery unit, the shaft simulation unit comprises a horizontal section, a bent section and a vertical section which are connected in sequence, the end, away from the vertical section, of the horizontal section forms an inlet end, the upper end of the vertical section forms an outlet end, and wellhead equipment is arranged at the outlet end; the shaft simulation unit comprises an outer-layer pipe and an inner-layer pipe arranged in the outer-layer pipe, and an annulus is formed between the inner-layer pipe and the outer-layer pipe; a plurality of threaded holes are formed in the inner-layer pipe, and blasting bolts which can be broken under preset pressure to enable the inner-layer pipe to be communicated with the annulus are arranged in the threaded holes; the two ends of the gas injection and recovery unit are communicated with the inner layer pipe and wellhead equipment respectively, and the gas injection and recovery unit is used for injecting gas into the inner layer pipe and recovering gas exhausted through the inner layer pipe and the annulus; and a detection element communicated with the annulus is arranged at a port of the wellhead equipment and is used for monitoring a sound wave signal at an outlet of the annulus. And sound wave signals during initial leakage of the shaft tubular column can be simulated and detected more truly.

Description

Technical Field

[0001] The present invention relates to the technical field of leakage monitoring of oil and gas hazardous chemicals, and in particular to a wellbore leakage simulation system and method. Background Art

[0002] Wellbore integrity is a crucial barrier to prevent underground fluid crossflow or leakage, and is crucial to the safe production of oil and gas and the safety of carbon dioxide geological storage. To develop methods for monitoring and diagnosing downhole casing and tubing leaks on the surface, a series of downhole casing and tubing leak detection simulation experiments are required. Existing casing and tubing leak simulation systems primarily simulate wellbore leakage by directly drilling leak holes in the inner tubing. These systems are capable of acoustically locating casing and tubing leaks under high pressure and high flow rates. Summary of the Invention

[0003] The inventors of the present application have discovered that existing oil casing leakage simulation systems have the following problems during application: they are unable to simulate the moment of rupture of the oil casing and fail to pick up the initial acoustic wave signal generated by the leakage; and the existing simulation method of directly opening a leakage hole in the inner layer pipe makes it difficult to control the size and position of the leakage hole and difficult to replace it. At the same time, since the existing oil casing leakage simulation system has a leakage hole in the inner layer oil pipe, it is difficult to maintain the stability of the gas flow when injecting gas into the inner layer oil pipe, which greatly interferes with the leakage acoustic wave, thereby affecting the accuracy of the monitoring results.

[0004] In view of the above problems, the present invention is proposed to provide a wellbore leakage simulation system and method that overcome the above problems or at least partially solve the above problems.

[0005] In a first aspect, an embodiment of the present invention provides a wellbore leakage simulation system, comprising: a wellbore simulation unit, a gas injection recovery unit;

[0006] The wellbore simulation unit includes a horizontal section, a curved section, and a vertical section connected in sequence, wherein an end of the horizontal section away from the vertical section forms an inlet end, an upper end of the vertical section forms an outlet end, and the outlet end is provided with a wellhead device;

[0007] The wellbore simulation unit includes: an outer tube and an inner tube disposed within the outer tube, an annulus being formed between the inner tube and the outer tube; a plurality of threaded holes are provided on the inner tube, blasting bolts are provided in the threaded holes, and the blasting bolts can be ruptured under a preset pressure difference to connect the inner tube with the annulus;

[0008] The two ends of the gas injection and recovery unit are respectively connected to the inner pipe and the wellhead equipment, and are used to inject gas into the inner pipe and recover the gas discharged through the inner pipe and the annulus;

[0009] The port of the wellhead equipment is provided with a detection element, which is in communication with the annulus and is used to monitor the acoustic wave signal at the annulus outlet.

[0010] In an optional embodiment, the wellbore leakage simulation system provided by the embodiment of the present invention further includes: a water supply and drainage unit;

[0011] The water supply and drainage unit is in communication with the annulus and is used for injecting liquid into the annulus and / or for extracting liquid from the annulus.

[0012] In an optional embodiment, a hydrophone is installed on the surface of the inner pipe to monitor the acoustic wave signal at the sound source of the inner pipe leakage in the annular liquid surface.

[0013] In an optional embodiment, the gas injection recovery unit includes:

[0014] A nitrogen generator, a gas buffer tank, a booster pump, a high-pressure gas storage tank, a filter, a dryer and a gas flow controller connected in sequence;

[0015] The gas flow controller is in communication with the inner tube, and the gas buffer tank is in communication with the inlet equipment;

[0016] A first one-way valve is sequentially arranged between the boost pump and the high-pressure gas storage tank.

[0017] In an optional embodiment, the wellhead equipment is a tubing spool;

[0018] The first port of the oil pipe spool is connected to the outlet end, the second port and the third port are connected to the annulus outlet, the detection element is arranged on the third port, and the fourth port is connected to the inner layer pipe outlet;

[0019] The second port and the fourth port are respectively communicated with the gas buffer tank, and a second one-way valve is provided between the second port and the gas buffer tank, and a third one-way valve is provided between the fourth port and the gas buffer tank.

[0020] In an optional embodiment, the water supply and drainage unit includes:

[0021] a water tank and a water pump connected by a first connecting pipe, a second connecting pipe connecting the water pump and the inlet of the inner layer pipe, a third connecting pipe communicating with the first connecting pipe and the second connecting pipe, and a fourth connecting pipe connecting the second connecting pipe and the water tank;

[0022] The first connecting pipeline, the second connecting pipeline and the fourth connecting pipeline are respectively provided with a first switch valve, a second switch valve and a third switch valve, so that when the first switch valve and the second switch valve are opened and the third switch valve is closed, the liquid in the water tank is injected into the annulus through a water pump, and when the first switch valve and the second switch valve are closed and the third switch valve is opened, the liquid in the annulus is extracted into the water tank through a water pump.

[0023] In an optional embodiment, a safety valve is provided on the outer tube body.

[0024] In an optional embodiment, a pressure and temperature transmitter is provided on the connecting pipeline between the gas flow controller and the inner tube inlet, on the outer tube, and on the third port of the oil pipe cross-connection;

[0025] A flow meter is provided on the connecting pipeline between the second port and the gas buffer tank, and on the connecting pipeline between the third port and the gas buffer tank.

[0026] In an optional embodiment, the wellbore leakage simulation system provided in this embodiment further includes: a monitoring unit;

[0027] The monitoring unit is electrically connected to the hydrophone, the detection element, the pressure and temperature transmitter and the flow meter.

[0028] In an optional embodiment, an operating window corresponding to the position of the threaded hole is opened on the outer tube for installing and removing the blasting bolt;

[0029] Furthermore, the operation window can be covered with a sealing blind plate to achieve sealing.

[0030] In an optional embodiment, a centralizer is provided between the outer tube and the inner tube.

[0031] Based on the same inventive concept, an embodiment of the present invention also provides a wellbore leakage simulation method implemented based on the above-mentioned wellbore leakage simulation system, including: injecting gas into the inner layer pipe through a gas injection and recovery unit, and after the pressure in the inner layer pipe reaches a preset pressure, the blasting bolt in the target threaded hole ruptures to connect the inner layer pipe with the annulus, and the gas leaks into the annulus through the inner layer pipe, and uses a detection element to monitor the acoustic wave signal at the annulus outlet at the moment of blasting bolt rupture; and the gas in the inner layer pipe and the annulus flows back to the gas injection and recovery unit through the wellhead equipment.

[0032] In an optional embodiment, the wellbore leakage simulation method provided in this embodiment further includes: using a water supply and drainage unit to inject a preset amount of liquid into the annulus, and using a hydrophone to monitor the sound wave signal at the inner pipe leakage sound source below the annulus liquid surface at the moment the blasting bolt ruptures.

[0033] The beneficial effects of the above technical solutions provided by the embodiments of the present invention include at least:

[0034] The wellbore leakage simulation system provided by the embodiment of the present invention is provided with a threaded hole on the inner layer pipe, and a blasting bolt that can be broken under a preset pressure difference is provided in the threaded hole, so as to simulate the leakage moment of the inner layer pipe by the rupture of the blasting bolt, and monitor the acoustic signal at the annulus outlet at the moment of leakage of the inner layer pipe by the detection element. Compared with the existing wellbore leakage simulation system with a leakage hole on the inner layer pipe, the wellbore leakage simulation system of this embodiment reflects the leakage of the oil pipe by monitoring the acoustic signal at the moment of leakage of the oil pipe. In the prior art, when the leakage hole is directly provided on the inner layer pipe, it is difficult to maintain the stability of the gas flow when gas is started to be injected into the inner layer pipe, that is, after the gas enters the inner layer pipe, it is difficult to determine whether it flows along the inner layer pipe or flows into the annulus from the leakage hole, and how much the gas flows. It is uncontrollable, and the stable airflow in the inner pipe needs to be maintained by the gas injection recovery unit, which is also uncontrollable; and the acoustic wave signal at the annulus outlet at the moment of leakage of the inner pipe is not affected by the stability of the gas flow. Therefore, compared with the acoustic wave signal at the annulus outlet after the leakage of the inner pipe, it can better reflect the rupture of the inner pipe, that is, the wellbore leakage simulation system provided by the embodiment of the present invention can more realistically simulate and detect the acoustic wave signal at the initial leakage of the inner pipe, and the obtained wellbore leakage monitoring result is more timely and more accurate; at the same time, after the inner pipe and the outer pipe are installed, the system can also simulate different leakage conditions by changing the installation position of the blasting bolts and installing blasting bolts of different specifications. There is no need to disassemble and reinstall the oil pipe, which improves the convenience of the test.

[0035] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0036] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 Schematic diagram of the framework structure of the wellbore leakage simulation system in an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the detailed structure of the wellbore leakage simulation system in an embodiment of the present invention;

[0040] Figure 3 This is a partially enlarged view of the water supply and drainage unit in the wellbore leakage simulation system in an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 100, wellbore simulation unit; 200, gas injection recovery unit; 300, water supply and drainage unit;

[0043] 1. High-pressure gas storage tank; 2. Ball valves (28, 29, and 37); 3. Filter; 4. Dryer; 5. Gas flow controller; 6. Pressure and temperature transmitters (14, 18, 23, and 26); 7. First on-off valve; 8. Water tank; 9. Third on-off valve; 10. Tee; 11. Second on-off valve; 12. Water pump; 13. Outer pipe; 15. Inner pipe; 16. Sealing coupling; 17 and 20 are hydrophones; 19. Connecting flange; 21. Blasting bolt; 22. Liquid; 24. Safety valve; 25. Detection element; 27. Wellhead equipment; 30 and 31 are flow meters; 32. Second one-way valve; 33. Third one-way valve; 38. First one-way valve; 34. Nitrogen generator; 35. Gas buffer tank; 36. Booster pump; 40. Monitoring unit.

[0044] 81. First connecting pipeline; 82. Second connecting pipeline; 83. Third connecting pipeline; 84. Fourth connecting pipeline; 271. First port; 272. Second port; 273. Third port; 274. Fourth port. DETAILED DESCRIPTION

[0045] 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.

[0046] In the description of the present invention, 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 and simplify the description of the present invention. They are not intended to 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0048] The inventors of the present application have discovered that the existing wellbore leakage simulation system, which directly opens leakage holes on the inner oil pipe, has the following problems during application: ① It is unable to simulate the moment of rupture of the oil casing and fails to pick up the initial acoustic wave signal generated by the leakage; ② The existing structure fails to achieve in-situ monitoring of leakage acoustic waves below the liquid surface; ③ When simulating leakage holes of different sizes, positions and shapes, the existing wellbore leakage simulation system needs to remove and reinstall the inner casing with the leakage hole, that is, the position and size of the leakage hole are not easy to change during the experiment; ④ Full-size oil casing requires a higher gas source reserve, and the stability of the gas flow in the oil pipe is difficult to maintain, which greatly interferes with the leakage acoustic wave.

[0049] In order to solve the problems existing in the prior art, Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a wellbore leakage simulation system, comprising: a wellbore simulation unit 100, a gas injection recovery unit 200;

[0050] The wellbore simulation unit 100 includes a horizontal section, a curved section, and a vertical section connected in sequence. The end of the horizontal section away from the vertical section forms an inlet end, and the upper end of the vertical section forms an outlet end. The outlet end is provided with a wellhead device 27.

[0051] The wellbore simulation unit 100 includes an outer tube 13 and an inner tube 15 disposed within the outer tube 13, forming an annulus between the inner tube 15 and the outer tube 13; the inner tube 15 is provided with a plurality of threaded holes, each of which is provided with a blasting bolt 21. The blasting bolt 21 can rupture at a preset pressure to connect the inner tube 15 with the annulus;

[0052] The two ends of the gas injection and recovery unit 200 are respectively connected to the inner pipe 15 and the wellhead equipment 27, and are used to inject gas into the inner pipe 15 and recover the gas discharged through the inner pipe 15 and the annulus, so as to simulate and control the gas flow in the wellbore simulation unit 100;

[0053] A detection element 25 is provided at the port of the wellhead equipment 27. The detection element 25 is in communication with the annulus and is used to monitor the acoustic wave signal at the annulus outlet.

[0054] Specifically, refer to Figure 2As shown, the outer layer pipe 13 includes: a horizontal section casing, a curved section oil pipe connected to one end of the horizontal section casing, and a vertical section casing connected to the upper end of the curved section casing; the inner layer pipe 15 includes: a horizontal section oil pipe, a curved section oil pipe connected to one end of the horizontal section oil pipe, and a vertical section oil pipe connected to the upper end of the curved section oil pipe.

[0055] Among them, the horizontal section oil pipe is installed in the horizontal section casing, the curved section oil pipe is installed in the curved section casing, and the vertical section oil pipe is installed in the vertical section casing. The oil pipe sections are connected by sealing couplings 16, and the casing sections are connected by connecting flanges 19.

[0056] In the wellbore leakage simulation system provided by the embodiment of the present invention, the pipe body of the wellbore simulation unit 100 adopts a double-layer structure of an inner layer pipe 15 and an outer layer pipe 13 to form an annular space, and a series of threaded holes are provided on the inner layer pipe 15, and a blasting bolt 21 that can rupture under a preset pressure difference is provided in the threaded hole. The blasting bolt 21 ruptures under a certain pressure difference to form a leakage channel, so as to simulate the leakage moment of the inner layer pipe 15 through the rupture of the blasting bolt 21, and monitor the acoustic wave signal at the annular space outlet at the moment of leakage of the inner layer pipe 15 through the detection element. Compared with the existing wellbore leakage simulation system in which a leakage hole is opened on the inner layer pipe 15, the wellbore leakage simulation system of this embodiment reflects the leakage of the oil pipe by monitoring the acoustic wave signal at the moment of leakage of the oil pipe. In the prior art, when the leakage hole is directly set on the inner layer pipe 15, it is difficult to maintain the stability of the gas flow when the gas is started to be injected into the inner layer pipe 15, that is, after the gas enters the inner layer pipe 15, it is difficult to determine whether it flows along the inner layer pipe 15 or from the leakage hole. The flow into the annulus and the amount of its flow are uncontrollable, and the stable airflow in the inner tube 15 needs to be maintained by the gas injection recovery unit 200, which is also uncontrollable and cannot truly simulate the stable gas flow conditions underground. The acoustic wave signal at the annulus outlet at the moment of leakage of the inner tube 15 is less affected by the stability of the gas flow. Therefore, compared with the acoustic wave signal at the annulus outlet after the leakage of the inner tube 15, it can better reflect the rupture of the inner tube 15. That is, the wellbore leakage simulation system provided by the embodiment of the present invention can more realistically simulate and detect the acoustic wave signal at the initial leakage of the inner tube 15, and the obtained wellbore leakage monitoring results are more timely and more accurate; at the same time, after the inner tube 15 and the outer tube 13 are installed, the system can also simulate different leakage conditions by changing the installation position of the blasting bolt 21 and installing blasting bolts 21 of different specifications. There is no need to disassemble and reinstall the oil pipe, which improves the convenience of the experiment and reduces the experimental cost.

[0057] The embodiment of the present invention does not specifically limit the specific material and structure of the blasting bolt 21 . It only needs to be compatible with the corresponding leakage hole and be able to rupture under a preset pressure difference.

[0058] The wellbore simulation unit 100 of the embodiment of the present invention includes: a horizontal section, a curved section and a vertical section. Compared with the wellbore simulation unit 100 in the existing structure that only includes a horizontal section or a vertical section, the structure of this embodiment can simulate the leakage of a vertical wellbore, a horizontal wellbore and a combined wellbore structure.

[0059] Furthermore, in order to ensure that the inner tube 15 is located in the middle of the outer tube 13 after installation, a centralizer may be provided between the inner tube 15 and the outer tube 13 .

[0060] In order to facilitate the removal and installation of the blasting bolt 21, an operating window corresponding to the position of the threaded hole can be opened on the outer tube 13, and the operating window can be covered with a sealing blind plate to achieve sealing when conducting a wellbore leakage simulation experiment; the setting of the operating window allows the position of the blasting bolt 21 to be changed directly through the operating window during the simulation experiment, or blasting bolts 21 of different specifications can be installed through the operating window to achieve the purpose of simulating different leakage conditions, without having to remove the oil pipe and reinstall the oil pipe with the target measurement leakage hole, thereby improving the convenience of the simulation experiment. For example: before installation, a series of threaded holes can be machined on the oil pipe where the experiment is required, and blasting bolts 21 that rupture under the corresponding preset pressure difference can be installed. After the end of an experiment, when the position of the leakage point needs to be changed, the sealing part can be installed on the ruptured position through the operating window and the next test can be continued; wherein, the sealing part can be a blasting bolt 21, and the preset blasting pressure difference of the blasting bolt 21 is greater than the maximum pressure difference to be tested.

[0061] Optional, see Figure 2 As shown, the wellbore leakage simulation system also includes: a water supply and drainage unit 300, which is connected to the annulus between the inner oil pipe and the outer casing, and is used to inject liquid 22 into the annulus and / or to extract liquid 22 in the annulus to simulate the working condition of the leakage hole below the liquid level; that is, in order to facilitate the control of the liquid level height in the annulus, the water supply and drainage unit 300 is provided with two circulation pipelines, one pipeline is used to inject liquid into the annulus, and the other pipeline is used to extract liquid in the annulus. By switching different pipelines, the liquid level height in the annulus can be adjusted to simulate and control the height of the annulus protection liquid.

[0062] Among them, reference Figure 2 and Figure 3 As shown, the water supply and drainage unit 300 may include: a water tank 8 and a water pump 12 connected by a first connecting pipe 81, a second connecting pipe 82 connecting the water pump 12 and the inlet of the inner layer pipe 15, a third connecting pipe 83 communicating with the first connecting pipe 81 and the second connecting pipe 82, and a fourth connecting pipe 84 connecting the second connecting pipe 82 and the water tank 8. For details, refer to Figure 2As shown, the second connecting pipeline 82 , the second connecting pipeline 82 and the third connecting pipeline 83 are connected through a tee 10 .

[0063] The first connecting pipeline 81, the second connecting pipeline 82 and the fourth connecting pipeline 84 are respectively provided with a first switch valve 7, a second switch valve 11 and a third switch valve 9, so that when the first switch valve 7 and the second switch valve 11 are opened and the third switch valve 9 is closed, the liquid in the water tank 8 is injected into the annulus through the water pump 12, and when the first switch valve 7 and the second switch valve 11 are closed and the third switch valve 9 is opened, the liquid in the annulus is extracted into the water tank 8 through the water pump 12.

[0064] When the first switch valve 7 and the second switch valve 11 are open and the third switch valve 9 is closed, the water pump 12 extracts the liquid in the water tank 8, and the liquid flows through the first connecting pipe 81 and the second connecting pipe 82 and is injected into the annulus; when the first switch valve 7 and the second switch valve 11 are closed and the third switch valve 9 is open, the water pump 12 extracts the liquid in the annulus, and the liquid flows through the fourth connecting pipe and the third connecting pipe and is returned to the water tank 8; that is, the water supply and drainage unit 300 of this embodiment connects the water pump 12, the water tank 8 and the annulus through the connecting pipe, and injects liquid into or extracts liquid from the annulus by switching the open or closed state of the first switch valve 7, the second switch valve 11 and the third switch valve 9.

[0065] Optional, see Figure 2 As shown, hydrophones 17 and 20 can be installed on the surface of the inner pipe 15 to monitor the acoustic wave signal at the leakage sound source of the inner pipe 15 in the annular liquid surface. That is, when the wellbore leakage system provided by the embodiment of the present invention is used to simulate the working condition where the leakage point is below the liquid surface, in addition to using the acoustic wave sensor to monitor the acoustic wave signal at the annular space outlet, the hydrophone can also be used to monitor the acoustic wave signal at the leakage sound source in the liquid surface (that is, the leakage point). This provides a data basis for subsequent research on the propagation and attenuation laws of acoustic wave signals in the working condition where the leakage point is below the liquid surface, and provides effective support for the subsequent research and development of wellbore leakage detection technology.

[0066] In an alternative embodiment, referring to Figure 2 As shown, the gas injection recovery unit 200 includes: a nitrogen generator 34, a gas buffer tank 35, a booster pump 36, a high-pressure gas storage tank 1, a filter 3, a dryer 4 and a gas flow controller 5 connected in sequence;

[0067] The gas flow controller 5 is connected to the inner tube 15, and the gas buffer tank 35 is connected to the inlet device 27;

[0068] A first one-way valve 38 is sequentially provided between the boost pump 36 and the high-pressure gas storage tank 1 .

[0069] In order to effectively control the flow direction and flow rate of the gas in the inner tube 15, the gas injection recovery unit 200 is equipped with a one-way valve and a gas flow controller 5; and a gas filter 3 and a dryer 4 are arranged between the high-pressure gas storage tank 1 and the gas flow controller 5, so as to filter out impurities in the connecting pipeline (for example, debris caused by rust in the pipeline, etc.) through the filter 3 to prevent impurities from entering the gas flow controller 5 and affecting the normal operation of the gas flow controller 5, and use the dryer 4 to dry the filtered gas so that the gas meets the operating state of the gas flow controller 5.

[0070] Specifically, nitrogen is produced by the nitrogen generator 34, which then flows into the gas buffer tank for storage before flowing into the booster pump 36. After being pressurized by the booster pump 36, the nitrogen flows through the high-pressure gas storage tank 1. The nitrogen is then processed by the filter 3 and the dryer 4 to meet the operating requirements of the gas flow controller 5 before flowing into the inner tube 15 through the gas flow controller 5. A first one-way valve 38 between the booster pump 36 and the high-pressure gas storage tank 1 prevents gas from flowing back from the high-pressure gas storage tank 1 into the booster pump 36 when the pressure of the gas in the high-pressure gas storage tank 1 is higher than that in the booster pump 36, thereby affecting the overall experimental process.

[0071] In one embodiment, referring to Figure 2 As shown, the wellhead equipment 27 is a tubing spool;

[0072] The first port 271 of the oil pipe spool is connected to the outlet, the second port 272 and the third port 273 are connected to the annulus outlet, and the detection element is set on the third port 273, and the fourth port 274 is connected to the outlet of the inner layer pipe 15;

[0073] The second port 272 and the fourth port 274 are respectively connected to the gas buffer tank, and a second one-way valve 32 is provided between the second port 272 and the gas buffer tank, and a third one-way valve 33 is provided between the fourth port 274 and the gas buffer tank.

[0074] Specifically, the oil pipe four-way is connected to the oil pipe and casing to form a closed annulus; and the two ends of the second port 272 of the oil pipe four-way are connected to the annulus outlet and the gas buffer tank respectively, and the two ends of the fourth port 274 are connected to the inner pipe 15 outlet and the gas buffer tank respectively, so that the gas in the annulus flows back to the gas buffer tank through the second port 272, and the gas in the inner casing flows back to the gas buffer tank 35 through the fourth port 274, so as to be used to recover the high-pressure gas in the wellbore simulation unit 100. Compared with the existing structure of directly venting the gas, the interference of the noise generated during direct venting on the experiment is reduced.

[0075] The detection element in this embodiment may be an acoustic wave sensor, which is installed on the third port 273 of the oil pipe spool and is connected to the annulus for monitoring the acoustic wave signal at the annulus outlet.

[0076] Among them, reference Figure 2 As shown, ball valves 37, 2, 29 and 28 are arranged between the boost pump 36 and the first one-way valve 38, between the high-pressure gas storage tank 1 and the filter 3, between the fourth port 274 and the gas buffer tank, and between the second port 272 and the gas buffer tank to control the flow of gas by opening and closing the ball valves.

[0077] Further, refer to Figure 2 As shown, a safety valve is provided on the outer tube 13. When the high-pressure gas in the annulus accumulates to a set threshold, the safety valve can automatically open to release the pressure in the annulus, preventing the accidental release of high-pressure gas in the annulus from threatening the personal safety of the experimenters, thereby ensuring the operability of the high-pressure gas leakage experiment and the safety of the experimental process.

[0078] In one embodiment, referring to Figure 2 As shown, pressure and temperature transmitters 6, 14, 18, 23 and 26 are provided on the connecting pipeline between the gas flow controller 5 and the inlet of the inner tube 15, on the outer tube 13, and on the third port 273 of the oil pipe cross;

[0079] Flowmeters 30 and 31 are installed on the connecting pipes between the second port 272 and the gas buffer tank, and between the third port 273 and the gas buffer tank. The system can also be equipped with monitoring instruments to detect vibration signals on the wellbore string during leakage. Pressure and temperature transmitters and flowmeters can be used to monitor the stability of the entire system during the experiment.

[0080] In one embodiment, the wellbore leakage simulation system of the embodiment of the present invention may further include: a monitoring unit 40;

[0081] Among them, the monitoring unit 40 is electrically connected to the hydrophones 17, 20, the detection element 25, the pressure and temperature transmitters 6, 14, 18, 23, 26 and the flow meter, so as to receive the acoustic wave signals transmitted by the detection elements and the hydrophones, the temperature and pressure signals transmitted by the pressure and temperature transmitters, and the flow signal transmitted by the flow meter, and can store the received relevant information for subsequent research.

[0082] Based on the same inventive concept, an embodiment of the present invention also provides a wellbore leakage simulation method implemented based on the above-mentioned wellbore leakage simulation system, including: injecting gas into the inner layer pipe through the gas injection and recovery unit, and after the pressure in the inner layer pipe reaches a preset pressure, the blasting bolt in the target threaded hole ruptures to connect the inner layer pipe with the annulus, and the gas leaks into the annulus through the inner layer pipe, and uses a detection element to monitor the acoustic wave signal at the annulus outlet at the moment of blasting bolt rupture; and the gas in the inner layer pipe and the annulus flows back to the gas injection and recovery unit through the wellhead equipment.

[0083] In an optional embodiment, the wellbore leakage simulation method provided by the embodiment of the present invention also includes: using a water supply and drainage unit to inject a preset amount of liquid into the annulus, and using a hydrophone to monitor the sound wave signal at the inner pipe leakage sound source below the annulus liquid surface at the moment the blasting bolt ruptures.

[0084] The wellbore leakage simulation method of this embodiment is implemented based on the above-mentioned wellbore leakage simulation system. The role and use of each component in the wellbore leakage simulation system in the wellbore simulation method have been explained in detail in the above-mentioned description of the wellbore leakage simulation system and will not be explained in detail here.

[0085] The above-mentioned wellbore leakage simulation system and method of the embodiment of the present invention can simulate wellbore leakage conditions under different leakage pressures, temperatures, flow rates, apertures, etc., can simulate vertical wellbores, horizontal wellbores and their combined wellbore structures, and can simultaneously simulate complex conditions where the tubing leakage point is located above and below the liquid level; by setting blasting bolts and simulating the rupture moment of the inner oil pipe through the rupture moment of the blasting bolts, the acoustic wave signal when the wellbore tubing leaks can be more realistically simulated and detected, and the position of the leakage hole can be easily replaced; at the same time, through the method and system of the embodiment of the present invention, in-situ monitoring of leakage acoustic wave signals can be achieved, and the obtained wellbore leakage simulation information can provide effective support for subsequent wellbore leakage detection technology, and provide experimental conditions and technical support for realizing all-round detection of downhole oil casing leakage status on the ground.

[0086] It should be understood that the specific order or hierarchy of steps in the disclosed processes is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0087] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention comprises less than all the features of any individual disclosed embodiment. The appended claims are therefore hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0088] The foregoing 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 purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to encompass all such changes, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent 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 in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

Claims

1. A wellbore leakage simulation system, characterized in that: include: Wellbore simulation unit, gas injection recovery unit; The wellbore simulation unit includes a horizontal section, a curved section, and a vertical section connected in sequence, wherein an end of the horizontal section away from the vertical section forms an inlet end, an upper end of the vertical section forms an outlet end, and the outlet end is provided with a wellhead device; The wellbore simulation unit includes: an outer tube and an inner tube disposed within the outer tube, an annulus being formed between the inner tube and the outer tube; a plurality of threaded holes are provided on the inner tube, blasting bolts are provided in the threaded holes, and the blasting bolts can be ruptured under a preset pressure difference to connect the inner tube with the annulus; The two ends of the gas injection and recovery unit are respectively connected to the inner pipe and the wellhead equipment, and are used to inject gas into the inner pipe and recover the gas discharged through the inner pipe and the annulus; The port of the wellhead equipment is provided with a detection element, which is in communication with the annulus and is used to monitor the acoustic wave signal at the annulus outlet.

2. The wellbore leakage simulation system according to claim 1, characterized in that: Also includes: Water supply and drainage unit; The water supply and drainage unit is in communication with the annulus and is used for injecting liquid into the annulus and / or for extracting liquid from the annulus.

3. The wellbore leakage simulation system according to claim 2, characterized in that: A hydrophone is installed on the surface of the inner pipe to monitor the sound wave signal at the sound source of the inner pipe leakage in the annular liquid surface.

4. The wellbore leakage simulation system according to claim 1, characterized in that: The gas injection recovery unit comprises: A nitrogen generator, a gas buffer tank, a booster pump, a high-pressure gas storage tank, a filter, a dryer and a gas flow controller connected in sequence; The gas flow controller is in communication with the inner tube, and the gas buffer tank is in communication with the inlet equipment; A first one-way valve is sequentially arranged between the booster pump and the high-pressure gas storage tank.

5. The wellbore leakage simulation system according to claim 4, characterized in that: The wellhead equipment is a tubing spool; The first port of the oil pipe spool is connected to the outlet end, the second port and the third port are connected to the annulus outlet, the detection element is arranged on the third port, and the fourth port is connected to the inner layer pipe outlet; The second port and the fourth port are respectively communicated with the gas buffer tank, and a second one-way valve is provided between the second port and the gas buffer tank, and a third one-way valve is provided between the fourth port and the gas buffer tank.

6. The wellbore leakage simulation system according to claim 2, characterized in that: The water supply and drainage unit comprises: a water tank and a water pump connected by a first connecting pipe, a second connecting pipe connecting the water pump and the inlet of the inner layer pipe, a third connecting pipe communicating with the first connecting pipe and the second connecting pipe, and a fourth connecting pipe connecting the second connecting pipe and the water tank; The first connecting pipeline, the second connecting pipeline and the fourth connecting pipeline are respectively provided with a first switch valve, a second switch valve and a third switch valve, so that when the first switch valve and the second switch valve are opened and the third switch valve is closed, the liquid in the water tank is injected into the annulus through a water pump, and when the first switch valve and the second switch valve are closed and the third switch valve is opened, the liquid in the annulus is extracted into the water tank through a water pump.

7. The wellbore leakage simulation system according to claim 1, characterized in that: The outer tube body is provided with a safety valve.

8. The wellbore leakage simulation system according to claim 5, characterized in that: A pressure and temperature transmitter is provided on the connecting pipeline between the gas flow controller and the inner tube inlet, on the outer tube, and on the third port of the oil pipe cross-connection; A flow meter is provided on the connecting pipeline between the second port and the gas buffer tank, and on the connecting pipeline between the third port and the gas buffer tank.

9. The wellbore leakage simulation system according to claim 8, characterized in that: Also includes: Monitoring unit; The monitoring unit is electrically connected to the hydrophone, the detection element, the pressure and temperature transmitter and the flow meter.

10. The wellbore leakage simulation system according to claim 1, wherein: The outer tube is provided with an operating window corresponding to the position of the threaded hole for installing and removing the blasting bolt; Furthermore, the operation window can be covered with a sealing blind plate to achieve sealing.

11. The wellbore leakage simulation system according to any one of claims 1 to 10, characterized in that: A centralizer is provided between the outer layer tube and the inner layer tube.

12. A method for simulating wellbore leakage, characterized in that: The wellbore leakage simulation system is implemented based on any one of claims 1-10, comprising: injecting gas into the inner pipe through a gas injection recovery unit; after the pressure in the inner pipe reaches a preset pressure, the blasting bolt in the target threaded hole ruptures to connect the inner pipe with the annulus, and the gas leaks into the annulus through the inner pipe, and a detection element is used to monitor the acoustic wave signal at the annulus outlet at the moment the blasting bolt ruptures; and the gas in the inner pipe and the annulus flows back to the gas injection recovery unit through the wellhead equipment.

13. The wellbore leakage simulation method according to claim 12, wherein: The method also includes: injecting a preset amount of liquid into the annulus using a water supply and drainage unit, and monitoring the acoustic wave signal at the inner pipe leakage sound source below the annulus liquid surface at the moment of rupture of the blasting bolt using a hydrophone.

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