Air cushion sealing device, salt cavern cavity forming pipe group, salt cavern cavity forming structure and cavity forming method

Abstract

The invention discloses an air cushion sealing device, a salt cavern cavity forming pipe set, a salt cavern cavity forming structure and a cavity forming method. The air cushion sealing device comprises a short section pipe, an outer ring sleeve, an annular base, a sliding sleeve, an elastic piece and a rubber sleeve. The short section pipe is coaxially sleeved with the outer ring sleeve, the short section pipe is coaxially sleeved with the annular base, and the outer wall of the annular base is connected with the inner lower end of the outer ring sleeve. The sliding sleeve is arranged outside the short section pipe, the outer wall of the sliding sleeve is in sliding sealing contact with the inner wall of the outer ring sleeve, and the short section pipe, the annular base, the outer ring sleeve and the sliding sleeve jointly define an annular cavity; the annular seat is provided with a pressure balance hole which is through up and down and is communicated with the interior of the annular cavity; the elastic piece is arranged in the annular cavity, the rubber sleeve is arranged outside the outer annular sleeve in a sleeving mode, the two ends of the rubber sleeve are connected in a sealed mode to jointly define an expansion cavity, a vent hole communicated with the interior of the expansion cavity is formed in the middle of the inner wall of the outer annular sleeve, an air inlet valve is embedded in the vent hole, the structure is simple, and the hole plugging effect is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of salt cavern storage, and in particular relates to an air cushion sealing device, a salt cavern cavity forming tube group, a salt cavern cavity forming structure and a cavity forming method. Background Art

[0002] Natural gas is a safe, efficient, high-quality, clean energy source, and its consumption is increasing in the energy mix. Salt cavern gas storage technology is an advanced method for storing natural gas in underground salt deposits. By injecting water to dissolve the salt deposits, a gas storage space is created. This allows for flexible regulation of natural gas supply, balancing seasonal fluctuations or consumption fluctuations while meeting energy storage needs. Salt deposits can also be used in underground energy storage facilities, improving energy efficiency, enhancing energy security, and promoting the development of clean energy.

[0003] During the salt cavern construction process, the height of the cavern formation string must be adjusted multiple times to control the morphology of the resulting cavity. Currently, domestic salt cavern reservoirs primarily use diesel as a roof protection measure to control the cavity shape. While this offers high safety and controllability, it results in significant diesel loss and contamination of the surrounding environment. A diesel leak into a salt chemical plant could potentially halt production. Using nitrogen as a dissolving agent overcomes the shortcomings of diesel as a dissolving agent. It offers enhanced environmental protection, safety, and economic benefits, is convenient to operate, and allows for relatively easy monitoring of the gas-liquid interface. This can accelerate reservoir construction to a certain extent, but adjusting the string height requires the release of an air cushion, wasting time and gas resources. Summary of the Invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide an air cushion sealing device with a simple structure and capable of inflating and deflating.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: an air cushion sealing device, comprising a short tube, an outer ring sleeve, an annular seat, a sliding sleeve, an elastic member and a rubber sleeve;

[0006] The short tube is arranged vertically, and the outer ring sleeve is coaxially sleeved outside the short tube, with an annular gap between the two;

[0007] The annular seat is coaxially sleeved on the short tube and is located at the inner lower end of the annular gap, and the outer wall of the annular seat is connected to the inner lower end of the outer ring sleeve;

[0008] The sliding sleeve is arranged outside the short tube and is located in the annular gap. The outer wall of the sliding sleeve is in sliding and sealing contact with the inner wall of the outer ring sleeve. The short tube, the annular seat, the outer ring sleeve and the sliding sleeve are together enclosed to form an annular cavity.

[0009] The annular seat is provided with a pressure balancing hole which passes through the annular cavity from top to bottom and communicates with the annular cavity;

[0010] The elastic member is arranged in the annular cavity, and both ends of the elastic member are respectively against the ends of the annular seat and the sliding sleeve that are close to each other;

[0011] The rubber sleeve is arranged outside the outer ring sleeve, and the outer walls of the outer ring sleeves at both ends of the rubber sleeve are sealed and connected to form an expansion cavity. The middle part of the inner wall of the outer ring sleeve is provided with a vent hole connected to the expansion cavity, and an air intake valve is embedded in the vent hole;

[0012] The elastic force of the elastic member is used to drive the sliding sleeve to move upward until the vent hole is connected to the annular cavity, or when the sliding sleeve is subjected to a downward extrusion force, the sliding sleeve overcomes the elastic force of the elastic member and moves downward to connect the vent hole with the area above the sliding sleeve.

[0013] The beneficial effect of the above technical solution is that: the air cushion sealing device is formed by arranging a rubber sleeve on the outer ring sleeve to enclose an expansion cavity, and the outer ring sleeve is also provided with an air vent connected to the expansion cavity and an air intake valve is provided in the air vent, and the sliding sleeve can move up and down between the short tube and the outer ring sleeve, and has three position states during the up and down movement. In this way, when the sliding sleeve moves upward under the action of the elastic member until the air vent is connected with the annular cavity, the air intake valve is opened to perform exhaust operation, and when the sliding sleeve moves downward to block the air vent, the pressure in the expansion cavity is maintained, and when the sliding sleeve slides downward to the bottom of the air vent, the air intake valve is opened to inflate the expansion cavity, so that the rubber sleeve expands outward to seal and isolate the inside of the pipe.

[0014] In the above technical solution, an annular groove is recessed on the outer side wall of the outer ring sleeve, and the two ends of the rubber sleeve are respectively sealed and connected to the two sides of the notch of the annular groove to block the notch of the annular groove.

[0015] The beneficial effect of the above technical solution is that when the pressure in the expansion chamber is released, the rubber sleeve can be accommodated in the annular groove, thereby making the overall structure beautiful.

[0016] In the above technical solution, a sealing ring is embedded in the contact portion between the annular seat and the short tube.

[0017] The beneficial effect of the above technical solution is that it can improve the reliability of the installation of the annular seat on the short tube.

[0018] In the above technical solution, the inner side of the upper end of the annular seat has a coaxially upwardly protruding partition sleeve, the upper end of the partition sleeve is coaxially recessed with an annular groove, the elastic member is located in the annular groove, and the lower end of the sliding sleeve is inserted into the annular groove and abuts against the upper end of the elastic member.

[0019] The beneficial effect of the above technical solution is that by providing the partition sleeve, the installation effect of the annular seat on the short tube is better.

[0020] The upper end of the pressure balance hole in the above technical solution is located outside the partition sleeve.

[0021] The beneficial effect of the above technical solution is that the pressure balance hole can always remain in communication with the annular cavity.

[0022] In the above technical solution, the outer lower end of the sliding sleeve is provided with a stepped notch. When the sliding sleeve moves downward under the action of external force until the upper end of the notch abuts against the upper end of the partition sleeve, the vent is connected to the area above the sliding sleeve.

[0023] The beneficial effect of the above technical solution is that the partition sleeve can limit the maximum downward stroke of the sliding sleeve, thereby protecting the elastic member.

[0024] In the above technical solution, the air intake valve is a solenoid valve or a one-way valve, and the elastic member is a spring.

[0025] The beneficial effect of the above technical solution is that when the air intake valve adopts a solenoid valve, the expansion chamber can be both inflated and exhausted, while when the air intake valve adopts a one-way valve, the expansion chamber can only be inflated and cannot be exhausted.

[0026] A second object of the present invention is to provide a salt cavern construction tube assembly for constructing salt caverns in stages.

[0027] In order to achieve the above-mentioned purpose, another technical solution of the present invention is as follows: a salt cavern cavity pipe group includes a production casing, an outer cavity pipe, an inner cavity pipe and the air cushion sealing device as described above, which are arranged in sequence from the outside to the inside. The short section pipe is welded to the outer cavity pipe and constitutes a section of the outer cavity pipe.

[0028] The beneficial effect of the above technical solution is that its structure is simple. By arranging an air cushion sealing device on the outer tube for making the cavity, when the outer tube for making the cavity is placed in the production casing, after the expansion cavity is inflated, the rubber sleeve will fit tightly with the inner wall of the production casing to isolate the annular gap.

[0029] A third object of the present invention is to provide a salt cavern formation structure for forming salt caverns in stages.

[0030] To achieve the above-mentioned object, another technical solution of the present invention is as follows: a salt cavern formation structure, comprising a salt cavern body and the salt cavern formation tube assembly as described above, wherein the lower ends of the inner and outer formation tubes are both lowered below the liquid level in the salt cavern body, and the lower end of the inner formation tube is lower than the lower end of the outer formation tube.

[0031] The beneficial effect of the above technical solution is that: its structure is simple, so the salt cavern body can be cavitated in stages, and after each cavitation stage is completed, the cavitation inner tube and the cavitation outer tube are lifted up to proceed to the next cavitation process.

[0032] A fourth object of the present invention is to provide a method for constructing salt caverns in stages.

[0033] In order to achieve the above object, another technical solution of the present invention is as follows: a method for forming a salt cavern structure as described above, comprising the following steps:

[0034] Step 1: Replace the appropriate spring of the air cushion sealing device according to the pre-designed air cushion pressure, test the air tightness of the air cushion sealing device, and assemble it on the outer tube of the cavity creation. At the same time, pre-inflate the expansion cavity so that the rubber sleeve can initially isolate the annulus between the production casing and the outer tube of the cavity creation.

[0035] Step 2: Lowering the outer tube into the production casing until the air cushion sealing device reaches a preset depth and the outer tube is lowered below the liquid level of the salt cavern body, then opening the air inlet valve and introducing compressed gas into the annulus between the production casing and the outer tube until the sliding sleeve moves down to ventilate the expansion chamber and the rubber sleeve continues to expand, thereby improving the effect of the rubber sleeve in isolating the annulus between the production casing and the outer tube;

[0036] Step 3: Lowering the outer tube into the inner tube until the lower end of the inner tube is below the liquid surface and reaches a preset depth to perform staged cavitation;

[0037] Step 4: After the stage-by-stage cavitation operation is completed, the inner tube of the cavitation is removed, and the outer tube of the cavitation is lifted or cut to ensure that the length of the outer tube meets the design height of the next stage;

[0038] Step 5: Re-insert the endocavity tube to the designed height and proceed to the next stage of cavitation operation;

[0039] Step 6: Repeat steps 2 to 5 until the cavity creation operation is completed.

[0040] The beneficial effect of the above technical solution is that it is easy to operate. At this time, the salt cavern body can be cavitated in stages, and the air cushion sealing device mainly isolates the annular gap between the cavity-making outer tube and the production casing. However, the height of the cavity-making outer tube needs to be adjusted in each cavity-making stage, while at the same time, the isolation effect of the air cushion sealing device on the annular gap needs to be maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1Schematic diagram of the structure of the air cushion sealing device according to Examples 1 and 2 of the present invention;

[0042] Figure 2 This is a schematic structural diagram of the salt cavern construction tube assembly described in Example 3 of the present invention;

[0043] Figure 3 This is a structural schematic diagram of the salt cavern formation structure described in Example 4 of the present invention.

[0044] In the figure: 11 short tube; 12 outer ring sleeve; 121 vent hole; 122 intake valve; 123 annular groove; 13 annular seat; 131 sealing ring; 132 partition sleeve; 1321 annular groove; 133 pressure balance hole; 14 sliding sleeve; 141 notch; 15 elastic member; 16 rubber sleeve;

[0045] 1. Air cushion sealing device; 2. Production casing; 3. Production of extraluminal tube; 4. Production of intraluminal tube;

[0046] 100 salt cavern cavity tube set; 200 salt cavern body. DETAILED DESCRIPTION

[0047] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in exact proportions. They are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0048] Example 1

[0049] This embodiment provides an air cushion sealing device, comprising a short tube 11, an outer ring sleeve 12, an annular seat 13, a sliding sleeve 14, an elastic member 15 and a rubber sleeve 16;

[0050] The short tube section 11 is vertically arranged, and the outer ring sleeve 12 is coaxially sleeved outside the short tube section 11 with an annular gap between the two.

[0051] The annular seat 13 is coaxially sleeved on the short tube 11 and is located at the inner lower end of the annular gap. The outer wall of the annular seat 13 is connected to the inner lower end of the outer ring sleeve 12.

[0052] The sliding sleeve 14 is arranged outside the short tube 11 and is located in the annular gap. The outer wall of the sliding sleeve 14 is in sliding and sealing contact with the inner wall of the outer ring sleeve 12. The short tube 11, the annular seat 13, the outer ring sleeve 12 and the sliding sleeve 14 together enclose an annular cavity.

[0053] The annular seat 13 is provided with a pressure balance hole 133 which passes through the annular cavity from top to bottom.

[0054] The elastic member 15 is disposed in the annular cavity, and both ends of the elastic member 15 respectively abut against the ends of the annular seat 13 and the sliding sleeve 14 that are close to each other;

[0055] The rubber sleeve 16 is sleeved outside the outer ring sleeve 12, and the outer walls of the outer ring sleeve 12 at both ends of the rubber sleeve 16 are sealed and connected to form an expansion cavity. The middle part of the inner wall of the outer ring sleeve 12 is provided with a vent hole 121 communicating with the expansion cavity, and an air intake valve 122 is embedded in the vent hole 121;

[0056] The elastic force of the elastic member 15 is used to drive the sliding sleeve 14 to move upward until the vent hole 121 is connected to the annular cavity, or when the sliding sleeve 14 is subjected to a downward extrusion force, it overcomes the elastic force of the elastic member 15 and moves downward until the vent hole 121 is connected to the area above the sliding sleeve 14.

[0057] The operating principle of the air cushion sealing device provided in this embodiment is as follows: a rubber sleeve is provided on the outer ring sleeve to enclose an expansion cavity, and an air vent connected to the expansion cavity is also provided on the outer ring sleeve and an air intake valve is provided in the air vent, and the sliding sleeve can move up and down between the short tube and the outer ring sleeve, and has three position states during the up and down movement. In this way, when the sliding sleeve moves upward under the action of the elastic member until the air vent is connected with the annular cavity, the air intake valve is opened to perform exhaust operation, and when the sliding sleeve moves downward to block the air vent, the pressure in the expansion cavity is maintained, and when the sliding sleeve slides downward to the bottom of the air vent, the air intake valve is opened to inflate the expansion cavity, so that the rubber sleeve expands outward to seal and isolate the inside of the pipe.

[0058] The air cushion sealing device provided in this embodiment should be installed on a carrier (which can be a pipe or a rod section), and the pipe is extended into the hole (which can be a deep well or a pipe). At this time, the expansion chamber can be pre-inflated first (an inflation door core similar to that on a basketball or a football can be provided on the rubber sleeve, so that when the air inlet valve is in the closed state, the expansion chamber can be preliminarily inflated through the inflation door core) to make it initially expand, and then the carrier with the air cushion sealing device is extended to the corresponding depth in the hole. The degree of expansion of the expansion chamber must meet the requirement that the rubber sleeve can preliminarily separate the hole (but the rubber sleeve cannot fit too tightly with the inner wall of the hole, otherwise the friction resistance will increase when it is inserted into the hole, affecting the service life of the rubber sleeve). As for the hole, it is divided into two parts by the air cushion sealing device after being separated. The two parts can be pressurized at this time on the end of the hole near the orifice, and as the pressure increases, the sliding sleeve will be squeezed to slide close to the annular seat until the vent is exposed. After the vent is exposed, it is only necessary to open the air intake valve to inflate the expansion chamber, so that the rubber sleeve fits more closely to the inner wall of the hole (improving its isolation effect on the hole). At this time, the air intake valve can be closed, and then the end of the hole near the orifice can be normally depressurized, and the sliding sleeve will slide upward under the action of the elastic member to reset. At this time, the vent is connected with the annular cavity (as long as the air intake valve is not opened, the pressure in the expansion chamber is still inconvenient), and the annular cavity is connected with the hole through the pressure balance hole. When it is necessary to relieve the pressure in the expansion chamber, it is only necessary to open the air intake valve to relieve the pressure, thereby releasing the rubber sleeve from isolating the hole.

[0059] The rubber sleeve in this embodiment has high requirements for wear resistance, and a steel mesh can be embedded inside it to form a steel wire-rubber composite material, and carbon black is added to the rubber to improve its wear resistance (for rubber material, it is similar to the rubber material used in tires).

[0060] In the above technical solution, an annular groove 123 is recessed on the outer wall of the outer ring sleeve 12, and the two ends of the rubber sleeve 16 are respectively sealed and connected to the two sides of the notch of the annular groove 123 to block the notch of the annular groove 123. This allows the rubber sleeve to be received in the annular groove when the pressure in the expansion chamber is released, thereby making the overall structure beautiful.

[0061] In this embodiment, the width of the annular groove can be 10-20 cm. In this embodiment, the two ends of the rubber sleeve and the outer ring sleeve can be connected by riveting, and after riveting, the two ends of the rubber sleeve are clamped on the outer ring sleeve. At the same time, sealing treatment can be adopted at the contact points between the two ends of the rubber sleeve and the outer ring sleeve (the specific measure of the sealing treatment can be to inject tire repair liquid into the expansion cavity so that it can seal the possible leakage position).

[0062] In the above technical solution, a sealing ring 131 is embedded in the contact portion between the annular seat 13 and the short tube 11 , which can improve the reliability of the installation of the annular seat on the short tube.

[0063] In the above technical solution, the inner side of the upper end of the annular seat 13 has a coaxially upwardly protruding partition sleeve 132, and the upper end of the partition sleeve 132 is coaxially recessed with an annular groove 1321. The elastic member 15 is located in the annular groove 1321, and the lower end of the sliding sleeve 14 is inserted into the annular groove 1321 and abuts against the upper end of the elastic member 15. By providing the partition sleeve, the installation effect of the annular seat on the short section pipe is better.

[0064] In the above technical solution, the upper end of the pressure balance hole 133 is located outside the partition sleeve 132, so that the pressure balance hole can always remain in communication with the annular cavity.

[0065] In the above technical solution, a stepped notch 141 is provided at the outer lower end of the sliding sleeve 14. When the sliding sleeve 14 moves downward under the action of an external force until the upper end of the notch 141 abuts against the upper end of the partition sleeve 132, the vent 121 is connected to the area above the sliding sleeve 14, so that the partition sleeve can limit the maximum downward stroke of the sliding sleeve, thereby protecting the elastic member.

[0066] In this embodiment, the inner side of the upper end of the outer ring sleeve can be slightly bent inward, so that the upward sliding stroke of the sliding sleeve can be limited.

[0067] In the above technical solution, the air intake valve 122 is a solenoid valve, and the elastic member 15 is a spring. When the air intake valve adopts a solenoid valve, the expansion chamber can be inflated or exhausted.

[0068] Since the air intake valve described in the present application adopts a solenoid valve, the conductive wire of the solenoid valve can pass through the upper end of the outer ring sleeve.

[0069] Example 2

[0070] The difference is the same as that of embodiment 1, in which the air inlet valve 122 is a one-way valve, and the expansion chamber can only be inflated but not exhausted.

[0071] In this embodiment, the air inlet valve adopts a one-way valve, which results in the expansion chamber being unable to exhaust after inflation. Therefore, the entire air cushion sealing device can usually be regarded as a disposable item. Since it cannot release pressure, it will be stuck in the hole (unless it is pulled out by hard pulling, but this also requires higher wear resistance of the rubber sleeve. Of course, even if the rubber sleeve is worn and broken by hard pulling, the entire air cushion sealing device can be better withdrawn from the hole, and the rubber sleeve can then be replaced).

[0072] In this embodiment, since the expansion cavity does not need to exhaust gas, the sliding sleeve can also block the vent hole when it is in the reset state, and the vent hole is only exposed during the downward sliding process.

[0073] Example 3

[0074] like Figure 2 As shown, this embodiment provides a salt cavern cavity forming pipe group, including a production casing 2, an outer cavity forming pipe 3, an inner cavity forming pipe 4 and an air cushion sealing device 1 as described in Example 1 or Example 2, which are arranged in sequence from the outside to the inside. The short section pipe 11 is welded to the outer cavity forming pipe 3 and constitutes a section of the outer cavity forming pipe 3.

[0075] The advantages of this embodiment are: its structure is simple. By arranging an air cushion sealing device on the outer tube for creating the cavity, when the outer tube for creating the cavity is placed in the production casing, after the expansion cavity is inflated, the rubber sleeve will fit tightly with the inner wall of the production casing to isolate the annular gap.

[0076] Example 4

[0077] like Figure 3 As shown, this embodiment provides a salt cavern construction structure, comprising a salt cavern main body 200 and a salt cavern construction tube assembly 100 as described in Example 3, wherein the lower ends of the inner and outer cavern construction tubes 4 and 3 are both lowered below the liquid level in the salt cavern main body 200, and the lower end of the inner and outer cavern construction tubes 4 is lower than the lower end of the outer cavern construction tube 3.

[0078] The advantages of this embodiment are: its structure is simple, so the salt cavern body can be cavitated in stages, and after each cavitation stage is completed, the cavitation inner tube and the cavitation outer tube are lifted up to proceed to the next cavitation process.

[0079] Example 5

[0080] This embodiment provides a method for forming a salt cavern structure as described in Example 4, comprising the following steps:

[0081] Step 1: Replace the appropriate spring of the air cushion sealing device 1 according to the pre-designed air cushion pressure, test the air tightness of the air cushion sealing device 1, and assemble it on the outer tube 3 for cavity creation. At the same time, pre-inflate the expansion cavity so that the rubber sleeve 16 can initially isolate the annulus between the production casing 2 and the outer tube 3 for cavity creation.

[0082] Step 2: Lower the outer cavity tube 3 into the production casing 2 until the air cushion sealing device 1 reaches a preset depth and the outer cavity tube 3 is lowered below the liquid level of the salt cavern body 200. Then, open the air inlet valve 122 and introduce compressed gas into the annulus between the production casing 2 and the outer cavity tube 3 until the sliding sleeve 14 moves downward to ventilate the expansion chamber and the rubber sleeve 16 continues to expand, thereby improving the effect of the rubber sleeve 16 in isolating the annulus between the production casing 2 and the outer cavity tube 3.

[0083] Step 3: Lower the outer cavity tube 3 into the inner cavity tube 4 until the lower end of the inner cavity tube 4 is below the liquid surface and reaches a preset depth, and then perform staged cavity creation;

[0084] Step 4: After the staged cavitation operation is completed, the inner cavitation tube 4 is removed, and the outer cavitation tube 3 is lifted or cut to ensure that the length of the outer cavitation tube 3 meets the design height of the next stage;

[0085] Step 5: Re-insert the endocavity tube 4 to the designed height and proceed to the next stage of endocavity operation;

[0086] Step 6: Repeat steps 2 to 5 until the cavity creation operation is completed.

[0087] The advantages of this embodiment are: it is easy to operate, the cavern body can be caverned in stages, and the air cushion sealing device mainly isolates the annular gap between the cavern outer tube and the production casing. However, the height of the cavern outer tube needs to be adjusted in each caverning stage, while at the same time, the air cushion sealing device needs to maintain its isolation effect on the annular gap.

[0088] It should be noted that the above detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0089] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0090] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present application described herein can, for example, be implemented in an order other than that illustrated or described herein.

[0091] Also, when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementations.

[0092] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product or apparatus.

[0093] For ease of description, spatially relative terms, such as "on," "above," "on the upper surface of," and "upper," may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0094] For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can encompass both an orientation of "above" and "below." The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0095] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in this industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. An air cushion sealing device, characterized in that: It comprises a short tube (11), an outer ring sleeve (12), an annular seat (13), a sliding sleeve (14), an elastic member (15) and a rubber sleeve (16); The short tube section (11) is arranged vertically, and the outer ring sleeve (12) is coaxially sleeved outside the short tube section (11), with an annular gap between the two. The annular seat (13) is coaxially sleeved on the short tube (11) and is located at the inner lower end of the annular gap, and the outer wall of the annular seat (13) is connected to the inner lower end of the outer ring sleeve (12); The sliding sleeve (14) is arranged outside the short tube (11) and is located in the annular gap. The outer wall of the sliding sleeve (14) is in sliding and sealing contact with the inner wall of the outer ring sleeve (12). The short tube (11), the annular seat (13), the outer ring sleeve (12) and the sliding sleeve (14) together enclose an annular cavity. The annular seat (13) is provided with a pressure balance hole (133) penetrating vertically and communicating with the annular cavity; The elastic member (15) is arranged in the annular cavity, and two ends of the elastic member (15) respectively abut against one end of the annular seat (13) and the sliding sleeve (14) that are close to each other; The rubber sleeve (16) is sleeved outside the outer ring sleeve (12), and the outer walls of the outer ring sleeve (12) at both ends of the rubber sleeve (16) are sealed and connected to form an expansion cavity together, and a vent hole (121) communicating with the expansion cavity is provided in the middle of the inner wall of the outer ring sleeve (12), and an air intake valve (122) is embedded in the vent hole (121); The elastic force of the elastic member (15) is used to drive the sliding sleeve (14) to move upward until the vent hole (121) is connected to the annular cavity, or when the sliding sleeve (14) is subjected to a downward extrusion force, it overcomes the elastic force of the elastic member (15) and moves downward until the vent hole (121) is connected to the area above the sliding sleeve (14).

2. The air cushion sealing device according to claim 1, characterized in that: An annular groove (123) is recessed on the outer side wall of the outer ring sleeve (12), and the two ends of the rubber sleeve (16) are respectively sealed and connected to the two sides of the notch of the annular groove (123) to seal the notch of the annular groove (123).

3. The air cushion sealing device according to claim 1, characterized in that: A sealing ring (131) is embedded at the contact point between the annular seat (13) and the short tube (11).

4. The air cushion sealing device according to claim 1, characterized in that: The inner side of the upper end of the annular seat (13) is provided with a partition sleeve (132) protruding coaxially upwards, the upper end of the partition sleeve (132) is coaxially provided with an annular groove (1321), the elastic member (15) is located in the annular groove (1321), and the lower end of the sliding sleeve (14) is inserted into the annular groove (1321) and abuts against the upper end of the elastic member (15).

5. The air cushion sealing device according to claim 4, characterized in that: The upper end of the pressure balance hole (133) is located outside the partition sleeve (132).

6. The air cushion sealing device according to claim 4, characterized in that: The outer lower end of the sliding sleeve (14) is provided with a stepped notch (141); when the sliding sleeve (14) moves downward under the action of an external force until the upper end of the notch (141) abuts against the upper end of the partition sleeve (132), the vent hole (121) is connected to the area above the sliding sleeve (14).

7. The air cushion sealing device according to claim 4, characterized in that: The air intake valve (122) is a solenoid valve or a one-way valve, and the elastic member (15) is a spring.

8. A salt cavern construction tube assembly, characterized in that: It comprises a production casing (2), an outer cavity tube (3), an inner cavity tube (4) and an air cushion sealing device (1) as described in any one of claims 1 to 7, which are arranged in sequence from the outside to the inside; the short section tube (11) is welded to the outer cavity tube (3) and constitutes a section of the outer cavity tube (3).

9. A salt cavern formation structure, characterized in that: The invention comprises a salt cavern body (200) and a salt cavern cavity-making tube group (100) as claimed in claim 8, wherein the lower ends of the inner cavity-making tube (4) and the outer cavity-making tube (3) are both lowered below the liquid surface in the salt cavern body (200), and the level of the lower end of the inner cavity-making tube (4) is lower than the level of the lower end of the outer cavity-making tube (3).

10. A method for making a salt cavern structure according to claim 9, characterized in that: The steps include: Step 1: Replace the appropriate spring of the air cushion sealing device (1) according to the pre-designed air cushion pressure, test the air tightness of the air cushion sealing device (1), and assemble it on the cavity-making outer tube (3), and pre-inflate the expansion cavity so that the rubber sleeve (16) can initially isolate the annulus between the production casing (2) and the cavity-making outer tube (3); Step 2: lowering the outer cavity tube (3) into the production casing (2) until the depth of the air cushion sealing device (1) reaches a preset depth and the outer cavity tube (3) is lowered below the liquid surface of the salt cavern body (200), then opening the air inlet valve (122) and introducing compressed gas into the annulus between the production casing (2) and the outer cavity tube (3) until the sliding sleeve (14) moves down to ventilate the expansion chamber and the rubber sleeve (16) continues to expand, so as to improve the effect of the rubber sleeve (16) in isolating the annulus between the production casing (2) and the outer cavity tube (3); Step 3: lowering the outer cavity-making tube (3) into the inner cavity-making tube (4) until the lower end of the inner cavity-making tube (4) is below the liquid surface and reaches a preset depth, and then performing phased cavity-making; Step 4: After the staged cavity creation operation is completed, the inner cavity creation tube (4) is removed, and the outer cavity creation tube (3) is lifted up or the tube is cut so that the length of the outer cavity creation tube (3) meets the design height of the next stage; Step 5: Re-insert the cavity-forming inner tube (4) to the designed height and proceed to the next stage of cavity-forming operation; Step 6: Repeat steps 2 to 5 until the cavity creation operation is completed.

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