Casing annular air channeling simulation test method and device

Abstract

The invention relates to the technical field of natural gas extraction, in particular to a casing annular gas channeling simulation test method and device.The method comprises the following steps that S1, a crack is formed in a cement plunger in the radial direction, a rock core plunger with a certain permeability is selected, and the cement plunger and the rock core plunger are filled into a gas channeling channel; s2, well completion fluid is injected into the annular cavity, high-pressure gas is introduced into the bottom of the rock core plunger, and the high-pressure gas sequentially passes through internal holes of the rock core plunger and the cement plunger to enter the annular cavity; and S3, simulating and analyzing the annular air channeling condition of the casing by combining the liquid level height and the pressure change rule along with time in the annular cavity. The characteristics and rules of casing annulus channeling are analyzed according to the change rules of the liquid level height and the pressure in the annular cavity along with time, and therefore selection of the casing annulus snubbing well treatment opportunity and formulation of a treatment scheme are guided. The device provided by the invention is used in combination with the method, so that the casing annular air channeling simulation experiment test can be effectively and reliably carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas exploitation, and more specifically, to a casing ring air channeling simulation test method and device. Background Art

[0002] During the development of natural gas, as the exploitation time increases, the problem of annular pressure in gas wells increases year by year. There are two main reasons for the annular pressure: First, the temperature of the oil-casing annulus and the casing annulus increases, and the fluid expands due to heat in a limited space, resulting in annular pressure increase. Second, the annular pressure increases due to natural gas leakage, mainly including the failure of the oil pipe string, casing string seal and cement ring seal. Among them, the annular pressure caused by the thermal expansion of the fluid in the annulus can be solved by reducing production, using insulation materials or proper pressure relief. For the annular pressure caused by natural gas leakage due to oil-casing seal failure, the leakage situation can be analyzed through leakage testing, engineering logging and other means, and corresponding control measures can be formulated.

[0003] However, for the problem of casing annulus pressure caused by cement ring sealing failure, existing experimental or engineering testing methods are difficult to accurately analyze the gas channeling rules of the cement ring and the gas channeling conditions at different stages, and it is difficult to form targeted control measures. No relevant simulation test methods and devices have been disclosed in the prior art. Summary of the invention

[0004] In order to overcome the problem in the prior art that it is difficult to simulate and analyze the casing annulus pressure condition caused by cement ring seal failure, the present invention provides a casing annulus air channeling simulation test method.

[0005] Another object of the present invention is to provide a device for implementing the above method.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a casing ring air channeling simulation test method, using a casing ring air channeling simulation test device for testing, the device has an annular cavity at the upper end and an air channeling channel at the lower end, the annular cavity is connected to the air channeling channel, the method comprises the following steps:

[0007] S1: Create radial cracks on the cement plug, select a core plug with a certain permeability, and fill the cement plug and the core plug into the gas channel;

[0008] S2: injecting completion fluid into the annular cavity, and introducing high-pressure gas into the bottom of the core plug, so that the high-pressure gas passes through the internal pores of the core plug and the cement plug in turn and enters the annular cavity;

[0009] S3: Combined with the time-varying patterns of the liquid level and pressure in the annular cavity, simulate and analyze the air leakage in the casing ring.

[0010] In the technical scheme of the present invention, the underground gas channeling layer structure in the actual mining process is simulated by means of cement plungers and core plungers after seaming, the annular space state in the well is simulated by means of an annular cavity filled with completion fluid, and the casing annulus air channeling state is simulated by means of high-pressure gas entering through the core plunger and cement plunger. The characteristics and laws of casing annulus air channeling are analyzed by means of the variation patterns of liquid level and pressure in the annular cavity over time, thereby guiding the selection of timing for casing annulus zone pressure well control and the formulation of a control plan.

[0011] Preferably, in step S1, the cement plunger is irregularly cut into cracks along the radial direction, and the cracks are filled with quartz sand of a certain mesh size and then fixed.

[0012] Preferably, in step S1, the permeability of the core plug is similar to that of the gas channeling reservoir, and the core plug absorbs saturated simulated formation water.

[0013] Preferably, the simulated formation water is configured according to the components of gas channeling formation water.

[0014] Preferably, a filling cavity is formed outside the side wall of the gas channeling channel. In step S2, fluid is injected into the filling cavity for pressurization so that the side wall of the gas channeling channel is closely attached to the outer peripheral surface of the cement plug and the core plug.

[0015] Preferably, the fluid pressure in the filling cavity is greater than the pressure of the high-pressure gas entering the bottom of the core plunger.

[0016] Preferably, the completion fluid is configured according to the components of cementing slurry spacer fluid.

[0017] Preferably, the method further comprises the following steps: when the pressure in the annular cavity rises to a certain value, the annular cavity is depressurized, and the on-site depressurization situation is simulated according to the variation of the liquid level and pressure in the cavity over time after the depressurization.

[0018] Preferably, the annular cavity is repeatedly depressurized, and the repeated depressurization on site is simulated according to the time variation pattern of the liquid level and pressure in the cavity during the repeated depressurization process.

[0019] Preferably, the repeated pressure relief comprises the following steps: connecting the top of the annular cavity with the outside atmosphere for pressure relief, then closing the annular cavity, and repeating the pressure relief after the pressure reaches a predetermined value.

[0020] The present invention also provides a casing ring air channeling simulation test device for implementing the above method, the device comprises a casing assembly and an air channeling simulation assembly, the air channeling simulation assembly is connected to the bottom of the casing assembly, a closed annular cavity is formed vertically inside the casing assembly, the casing assembly is connected to an injection pump through a pipeline, the injection pump is communicated with the annular cavity, the air channeling simulation assembly comprises a cylinder and a high-pressure gas source device, an air channeling channel is formed vertically inside the cylinder, the top of the cylinder is connected to the bottom of the casing assembly and the air channeling channel is communicated with the annular cavity, the bottom of the air channeling channel is connected to the high pressure gas source device, The cylinder body comprises a confining pressure cylinder and a rubber cylinder, the interior of the rubber cylinder forms the air channeling channel, the confining pressure cylinder is sleeved on the outside of the rubber cylinder, and a closed filling chamber is formed between the confining pressure cylinder and the rubber cylinder, the filling chamber is connected to a fluid pump through a pipeline, the sleeve assembly is connected to a first pressure gauge for measuring the pressure of the annular cavity, the air channeling simulation assembly is connected to a second pressure gauge for measuring the pressure of the high-pressure air source device, the air channeling simulation assembly is connected to a third pressure gauge for measuring the internal pressure of the filling chamber, and the upper end of the annular cavity is provided with a pipeline connected to the outside, and a pressure relief valve is provided on the pipeline.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The casing annulus air channeling simulation test method of the present invention analyzes the characteristics and laws of casing annulus air channeling through the time-varying laws of the liquid level and pressure in the annular cavity, thereby guiding the selection of the timing for casing annulus well killing treatment and the formulation of a treatment plan.

[0023] 2. The casing annulus air blowby simulation test method of the present invention can simulate the influence of pressure rise caused by temperature rise after shutting down the well and resuming production on the annulus air blowby, and simulate the influence of on-site pressure relief on the annulus air blowby; it can also simulate and analyze the influence of repeated well opening and closing or pressure relief on the annulus air blowby, thereby guiding the selection of the timing for casing annulus pressure well control and the formulation of the control plan.

[0024] 3. The casing ring air channeling simulation test device of the present invention is used to implement the above-mentioned test method, thereby effectively and reliably performing casing ring air channeling simulation experimental tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the casing ring air channeling simulation test device of the present invention;

[0026] Figure 2 1 is a graph showing the annular space pressure and liquid level height changing with time in Example 1.

[0027] In the accompanying drawings: 1. casing assembly; 11. annular cavity; 12. inner tube; 13. outer tube; 14. upper cover; 15. lower cover; 2. gas channeling simulation assembly; 21. cylinder; 211. confining pressure cylinder; 212. rubber cylinder; 213. filling cavity; 22. high-pressure gas source device; 23. gas channeling channel; 24. plug; 25. end cover; 26. pressing piece; 251. gas injection channel; 27. intermediate container; 3. liquid injection pump; 4. fluid pump; 5. first pressure gauge; 6. second pressure gauge; 7. third pressure gauge; 8. pressure relief valve; 100. cement plunger; 200. core plunger. DETAILED DESCRIPTION

[0028] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0029] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "long", "short" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0031] Example 1

[0032] This embodiment discloses a casing ring air channeling simulation test method, which uses a casing ring air channeling simulation test device for testing. Figure 1 The device has an annular cavity 11 at the upper end and an air channel 23 at the lower end, and the annular cavity 11 is connected to the air channel 23.

[0033] The method of this embodiment includes the following steps:

[0034] S1: irregularly cut cracks in the radial direction of the cement plug 100, fill the cracks with quartz sand of a certain mesh size and fix them to prepare the cement plug 100 with cracks; select a permeability similar to that of the gas-channeling reservoir, so that the core plug 200 absorbs saturated simulated formation water, and the simulated formation water is configured according to the components of the gas-channeling formation water; fill the cement plug 100 and the core plug 200 into the gas-channeling channel 23 of the cylinder 21, wherein the cement plug 100 is located above the core plug 200.

[0035] S2: Inject completion fluid into the annular cavity 11 through the injection pump 3, and the completion fluid is configured according to the components of the cementing cement slurry spacer fluid; inject fluid into the filling cavity 213 through the fluid pump 4 to pressurize it, so that the side walls of the gas channel 23 are close to the outer peripheral surfaces of the cement plunger 100 and the core plunger 200; pass high-pressure gas into the bottom of the core plunger 200 through the high-pressure gas source device 22, so that the high-pressure gas passes through the internal pores of the core plunger 200 and the cement plunger 100 in turn and enters the annular cavity 11, wherein the fluid pressure in the filling cavity 213 is higher than the gas pressure provided by the high-pressure gas source device 22.

[0036] S3: Record the time-varying patterns of the liquid level and pressure in the annular cavity 11.

[0037] Through the above method, the effect of pressure rise caused by temperature rise on annular air breakthrough after shut-in and resumption of production is simulated, and the casing annulus zone well killing management is guided based on the experimental data obtained.

[0038] Furthermore, the method may further include step S4: when the pressure in the annular cavity 11 rises to a certain value, the pressure relief valve is opened to relieve the pressure in the annular cavity 11, and the change pattern of the liquid level and pressure in the annular cavity 11 over time is recorded, thereby simulating the effect of on-site pressure relief on annular air leakage.

[0039] Furthermore, the method may further include step S5: closing the pressure relief valve after the pressure relief is completed, repeating step S4, repeatedly releasing the pressure in the annular cavity 11, and recording the time variation pattern of the liquid level and pressure in the annular cavity 11, thereby simulating and analyzing the effect of repeatedly opening and closing the well or releasing the pressure on the annular air leakage.

[0040] Example 2

[0041] This embodiment conducts experiments based on the method of embodiment 1 in combination with actual mining conditions, obtains data and results, and proposes corresponding treatment plans.

[0042] The annular pressure of the casing of Well M is 2.2MPa. According to the analysis of the annular gas sample, the annular pressure is caused by the gas pipe leaking out of the production layer. The leaking gas contains 26% CO2 and no H2S, which poses a certain risk of casing corrosion. At present, the pressure of the gas production layer is 7.5MPa, and the average permeability is 48.6md. In the on-site pressure relief test, the annular pressure can be released to zero, and the pressure returns to 2.2MPa and stabilizes 26 hours after the pressure relief is stopped. In order to analyze the impact of the pressure relief operation on the annular gas leakage, a simulation test and analysis of the casing annular gas leakage was carried out.

[0043] 1. Drill a cement plug with a diameter of 2.5 cm and a length of 10 cm, cut it open longitudinally, fill the cracks with a layer of 230-200 mesh quartz sand, and fix the cement plug.

[0044] 2. According to the permeability of the gas channeling layer and the core inventory, a core with a diameter of 2.5 cm, a length of 8.3 cm, and a permeability of 47.5 md was selected for simulation experiments. Simulated formation water was configured according to the ion composition of the formation water in the gas channeling layer, and the core plunger was saturated with simulated formation water.

[0045] 3. Install the processed cement plunger and core plunger into the rubber cylinder of the test device in sequence, assemble the test device, and use the injection pump to add a confining pressure of 2MPa to the filling cavity.

[0046] 4. The liquid in the gas breakthrough annulus is cementing slurry isolation fluid. The simulated test fluid is prepared according to the isolation fluid formula, and the simulated test fluid is pumped into the space between the inner cylinder and the outer cylinder by an injection pump until the annulus is filled.

[0047] 5. The injection pump increases the surrounding pressure in the filling chamber to 4.2MPa, and injects gas into the intermediate container through the high-pressure gas source device to the experimental pressure of 2.2MPa.

[0048] 6. Slowly open the valve between the plug and the intermediate container and start timing, observe and record the changes in the pressure and liquid level of the annular cavity over time; release the annular cavity pressure three times at 30min, 60min and 90min, each time for 0.5min, and record the changes in pressure and liquid level before and after the pressure release.

[0049] 7. After 120 minutes, turn off the high-pressure gas source, release the pressure and clean the experimental equipment.

[0050] The experimental data are sorted as shown in the following table, and the pressure and liquid level of the annular cavity are plotted as a function of time. Figure 2 shown.

[0051]

[0052] It can be seen from the experimental results that with the increase in the number of annular pressure releases, the leakage rate gradually increases. Therefore, the recommendations for the management of annular pressure in Well M are: maintain production, strengthen annular pressure monitoring, avoid annular pressure release as much as possible during production, and regularly add alkaline anti-corrosion fluid to control annular CO2 corrosion.

[0053] Example 3

[0054] refer to Figure 1 The present embodiment discloses a casing ring air channeling simulation test device, comprising a casing assembly 1 and an air channeling simulation assembly 2, the air channeling simulation assembly 2 is connected to the bottom of the casing assembly 1, a closed annular cavity 11 is formed vertically inside the casing assembly 1, the casing assembly 1 is connected to an injection pump 3 through a pipeline, the injection pump 3 is communicated with the annular cavity 11, the air channeling simulation assembly 2 comprises a cylinder 21 and a high-pressure gas source device 22, an air channeling channel 23 is formed vertically inside the cylinder 21, the top of the cylinder 21 is connected to the bottom of the casing assembly 1 and the air channeling channel 23 is communicated with the annular cavity 11, the bottom of the air channeling channel 23 is connected to the high-pressure gas source device 22, the cylinder 21 It includes a confining pressure cylinder 211 and a rubber cylinder 212, an air channel 23 is formed inside the rubber cylinder 212, the confining pressure cylinder 211 is sleeved on the outside of the rubber cylinder 212, and a closed filling chamber 213 is formed between the confining pressure cylinder 211 and the rubber cylinder 212, the filling chamber 213 is connected to a fluid pump 4 through a pipeline, the sleeve assembly 1 is connected to a first pressure gauge 5 for measuring the pressure of the annular cavity 11, the air channeling simulation assembly 2 is connected to a second pressure gauge 6 for measuring the pressure of the high-pressure gas source device 22, the air channeling simulation assembly 2 is connected to a third pressure gauge 7 for measuring the internal pressure of the filling chamber 213, and a pipeline connected to the outside is provided at the upper end of the annular cavity 11, and a pressure relief valve 8 is provided on the pipeline.

[0055] The casing annulus air channeling simulation test device of this embodiment injects completion fluid into the annular cavity 11 inside the casing assembly 1 through the injection pump 3 to simulate the annular state in the well. The gas channeling channel 23 formed by the cylinder 21 is used to fill the cement plunger 100 and the core plunger 200, wherein the cement plunger 100 is located at the upper end of the gas channeling channel 23, and the core plunger 200 is located below the cement plunger 100. The high-pressure gas source device 22 is used to inject high-pressure gas below the core plunger 200, so that the high-pressure gas penetrates into the annular cavity 11 through the cracks of the core plunger 200 and the cement plunger 100, simulating the annular air channeling situation.

[0056] refer to Figure 1The cylinder 21 includes a confining pressure cylinder 211 and a rubber cylinder 212. The confining pressure cylinder 211 is sleeved on the outside of the rubber cylinder 212, and a closed filling chamber 213 is formed between the confining pressure cylinder 211 and the rubber cylinder 212. High-pressure fluid is injected into the filling chamber 213 by the fluid pump 4, so that the rubber cylinder 212 can be attached to the outer peripheral surface of the core plunger 200 and the cement plunger 100. In this way, when high-pressure gas is injected into the bottom of the core plunger 200 by the high-pressure gas source device 22, it can prevent the gas from escaping from the gas channeling channel 23 and the circumferential gap between the core plunger 200 and the cement plunger 100, thereby improving the accuracy of the simulation test.

[0057] Among them, the first pressure gauge 5, the second pressure gauge 6 and the third pressure gauge 7 are used to monitor the pressure of the annular cavity 11, the pressure of the high-pressure gas and the pressure of the filling cavity 213 respectively. During the test, the pressure of the filling cavity 213 should be greater than the pressure of the high-pressure gas, that is, the value of the third pressure gauge 7 is greater than the value of the second pressure gauge 6, so as to ensure that the rubber cylinder 212 is tightly attached to the outer peripheral surface of the cement plunger 100 and the core plunger 200. The pressure relief valve 8 is arranged at the upper end of the casing assembly 1, connected to the upper end of the annular cavity 11, and the pressure of the annular cavity 11 can be relieved by opening and closing the pressure relief valve 8.

[0058] refer to Figure 1 The gas channeling simulation component 2 also includes a plug 24, an end cover 25 and a clamping member 26. The upper end of the end cover 25 is fixedly connected to the bottom of the cylinder 21. The plug 24 is arranged in the end cover 25. One end of the clamping member 26 is adjustably connected to the end cover 25, and the other end of the clamping member 26 abuts against the bottom of the plug 24. An injection channel 251 is provided in the plug 24. One end of the injection channel 251 is connected to the core plunger 200, and the other end of the injection channel 251 is connected to the high-pressure gas source device 22. The clamping member 26 can be a threaded push rod. The bottom of the end cover 25 is provided with a threaded hole, and the threaded push rod is threadedly connected to the threaded hole. The plug 24 can be pressed against the bottom of the core plunger 200 by the threaded push rod being threadedly connected to the bottom of the end cover 25. High-pressure gas is injected from one end of the gas injection channel 251 of the core plunger 200 through the high-pressure gas source device 22 . The high-pressure gas enters the core plunger 200 through the gas injection channel 251 , and then escapes from the cracks of the cement plunger 100 and enters the annular cavity 11 .

[0059] refer to Figure 1In this embodiment, the axial cross-section of the plug 24 can be roughly inverted T-shaped, the upper end of the plug 24 can be roughly cylindrical and match the lower end entrance of the gas channel 23, and the lower end of the plug 24 is disc-shaped with a slightly larger diameter. The upper end of the plug 24 can be fixedly connected to the lower end of the gas channel 23, or it can be abutted against the lower end of the gas channel 23 through other components, thereby blocking the lower end entrance of the gas channel 23. A roughly L-shaped gas injection channel 251 is provided in the plug 24, and the gas injection channel 251 connects the upper end face and the lower end side face of the plug 24. The upper end face of the plug 24 is butted against the bottom of the core plunger 200, and the gas flow channel on the lower end side face of the plug 24 is connected to the external high-pressure gas source device 22. The high-pressure gas source device 22 can pass the high-pressure gas through the gas injection channel 251 inside the plug 24 into the core plunger 200. Since the plug 24 can block the lower entrance of the gas channel 23, high-pressure gas will enter the core plunger 200, reducing gas leakage.

[0060] refer to Figure 1 The end cover 25 may be composed of an inlet cover and a compression dome. The inlet cover is roughly annular, and the upper end of the inlet cover is sleeved on the outside of the bottom of the cylinder 21, for example, by a threaded connection, so as to fix the inlet cover to the cylinder 21. The compression dome is a cover with an opening at the top, and the upper end of the compression dome is fixedly connected to the lower end of the inlet cover. For example, an annular groove is provided in the circumference of the bottom of the inlet cover, and a protrusion is provided along the radial inner side of the upper end opening of the compression dome, and the inlet cover is connected to the compression dome by clamping the protrusion in the annular groove. The inlet cover is axially connected, and the upper end of the plug 24 passes through the axial assembly of the inlet cover, and the lower end of the plug 24 is located in the dome cover. The upper end of the plug 24 may be an interference fit with the inlet cover to improve the tightness of the connection.

[0061] refer to Figure 1 The gas channeling simulation assembly 2 further includes an intermediate container 27, one end of which is connected to the gas injection channel 251 through a pipeline, and the other end of the intermediate container 27 is connected to the high-pressure gas source device 22 through a pipeline. The completion fluid flowing out of the annular cavity 11 can be stored through the intermediate container 27. The third pressure gauge 7 can be connected to the inner cavity of the intermediate container 27, and the pressure value of the high-pressure gas is obtained by measuring the pressure value in the intermediate container 27. Corresponding valves are arranged on each pipeline.

[0062] refer to Figure 1The casing assembly 1 includes an inner tube 12, an outer tube 13, an upper cover 14 and a lower cover 15. The outer tube 13 is sleeved on the outer side of the inner tube 12, the upper cover 14 is fixedly connected to the upper ends of the inner tube 12 and the outer tube 13, and the lower cover 15 is fixedly connected to the lower ends of the inner tube 12 and the outer tube 13. An annular cavity 11 is formed among the inner tube 12, the outer tube 13, the upper cover 14 and the lower cover 15. The lower cover 15 is provided with a channel connected to the annular cavity 11, and the channel is connected to the top of the gas channel 23.

[0063] refer to Figure 1 , an annular rubber seal may be provided between the inlet cover and the cylinder 21 to improve the air tightness of the connection. The rubber seal may include a first sealing section along the axial direction at the upper end and a second sealing section along the radial direction at the lower end. The first sealing section may be matched and fitted on the inner wall of the bottom opening of the gas channel 23, and the upper end of the plug 24 may be tightly fitted with the first sealing section in the circumferential direction, thereby improving the air tightness. The second sealing section is radially arranged between the lower end surface of the cylinder 21 and the shoulder formed at the upper end of the inlet cover to improve the air tightness of the connection between the inlet cover and the cylinder 21. Sealing rings are provided at the contacting parts of the inner tube 12, the outer tube 13, the upper cover 14 and the lower cover 15, which can effectively improve the air tightness of the sleeve assembly 1.

[0064] refer to Figure 1 In this embodiment, a valve is provided on the pipeline connecting the injection pump 3 and the annular cavity 11, a valve is provided on the pipeline connecting the fluid pump 4 and the filling chamber 213, a valve is provided on the pipeline connecting the intermediate container 27 and the plug 24, a valve is provided on the pipeline connecting the intermediate container 27 and the outside, and a valve is provided on the pipeline connecting the high-pressure gas source device 22 and the intermediate container 27.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A casing ring air channeling simulation test method, using a casing ring air channeling simulation test device for testing, characterized in that: The device comprises an annular cavity (11) at the upper end and an air channel (23) at the lower end, wherein the annular cavity (11) is connected to the air channel (23). The method comprises the following steps: S1: creating radial cracks on the cement plug (100), selecting a core plug (200) with a certain permeability, and filling the cement plug (100) and the core plug (200) into the gas channel (23); S2: injecting completion fluid into the annular cavity (11), and introducing high-pressure gas into the bottom of the core plunger (200), so that the high-pressure gas passes through the internal pores of the core plunger (200) and the cement plunger (100) in sequence and enters the annular cavity (11); S3: Combined with the time-varying patterns of the liquid level and pressure in the annular cavity (11), simulate and analyze the air leakage in the casing ring.

2. The casing ring air channeling simulation test method according to claim 1, characterized in that: In step S1, the cement plunger (100) is irregularly cut into cracks along the radial direction, and the cracks are filled with quartz sand of a certain mesh size and then fixed.

3. The casing ring air channeling simulation test method according to claim 1, characterized in that: In step S1, the core plug (200) has a permeability similar to that of the gas channeling reservoir, and the core plug (200) absorbs saturated simulated formation water.

4. The casing ring air channeling simulation test method according to claim 3 is characterized in that: The simulated formation water is configured according to the components of the gas channeling formation water.

5. The casing ring air channeling simulation test method according to claim 1, characterized in that: The side wall of the gas channel (23) is surrounded by a filling cavity (213). In step S2, fluid is injected into the filling cavity (213) for pressurization, so that the side wall of the gas channel (23) is closely attached to the outer peripheral surface of the cement plug (100) and the core plug (200).

6. The casing ring air channeling simulation test method according to claim 5, characterized in that: The fluid pressure in the filling cavity (213) is greater than the pressure of the high-pressure gas entering the bottom of the core plunger (200).

7. The casing ring air channeling simulation test method according to claim 1, characterized in that: The completion fluid is configured according to the components of the cementing slurry spacer fluid.

8. The casing ring air channeling simulation test method according to claim 1, characterized in that: The method further comprises the following steps: when the pressure in the annular cavity (11) rises to a certain value, the annular cavity (11) is depressurized, and according to the time variation pattern of the liquid level and pressure in the cavity after depressurization, the on-site depressurization situation is simulated.

9. The casing ring air channeling simulation test method according to claim 8, characterized in that: The annular cavity (11) is repeatedly depressurized, and according to the time variation pattern of the liquid level and pressure in the cavity during the repeated depressurization process, the repeated depressurization situation on site is simulated.

10. A casing ring air channeling simulation test device, used to implement the method according to any one of claims 1 to 9, characterized in that: The invention comprises a casing assembly (1) and a gas channeling simulation assembly (2), wherein the gas channeling simulation assembly (2) is connected to the bottom of the casing assembly (1), a closed annular cavity (11) is formed vertically inside the casing assembly (1), the casing assembly (1) is connected to an injection pump (3) through a pipeline, the injection pump (3) is communicated with the annular cavity (11), the gas channeling simulation assembly (2) comprises a cylinder (21) and a high-pressure gas source device (22), a gas channeling channel (23) is formed vertically inside the cylinder (21), the top of the cylinder (21) is connected to the bottom of the casing assembly (1) and the gas channeling channel (23) is communicated with the annular cavity (11), the bottom of the gas channeling channel (23) is connected to the high-pressure gas source device (22), the cylinder (21) comprises a confining pressure cylinder (211) and a A rubber cylinder (212), the interior of the rubber cylinder (212) forms the gas channel (23), the confining pressure cylinder (211) is sleeved on the outside of the rubber cylinder (212), and a closed filling chamber (213) is formed between the confining pressure cylinder (211) and the rubber cylinder (212), the filling chamber (213) is connected to a fluid pump (4) through a pipeline, the sleeve assembly (1) is connected to a first pressure gauge (5) for measuring the pressure of the annular cavity (11), the gas channeling simulation assembly (2) is connected to a second pressure gauge (6) for measuring the pressure of the high-pressure gas source device (22), the gas channeling simulation assembly (2) is connected to a third pressure gauge (7) for measuring the internal pressure of the filling chamber (213), and a pipeline connected to the outside is provided at the upper end of the annular cavity (11), and a pressure relief valve (8) is provided on the pipeline.

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