Ball throwing sliding sleeve

Abstract

An upper outer cylinder provided with a liquid inlet hole is connected with a lower outer cylinder, an inner cylinder provided with a liquid inlet hole and a ball seat and connected with a lower connector at the lower end is connected with the lower outer cylinder through a shear pin, and a locking ring is located in an annular space formed by the upper outer cylinder, the lower outer cylinder and the inner cylinder and connected with the inner cylinder. In the process of descending the gas injection tubular column into a well, the liquid inlet holes between the upper outer cylinder and the inner cylinder are communicated with each other; and when the packer in the gas injection tubular column is set, the liquid inlet hole between the upper outer barrel and the inner barrel is closed. The requirement for automatic grouting of the process pipe column can be met, and the construction difficulty of pipe column tripping-in and the labor intensity of on-site operators are greatly reduced; meanwhile, a construction site can be kept clean, the environmental protection requirement of construction is met, and technical support is provided for setting of a follow-up packer of the gas injection tubular column. The utility model has obvious use effect, can obtain good economic benefit and social benefit, and has huge popularization and application value and popularization space.

Description

TECHNICAL FIELD

[0001] The utility model relates to the downhole gas injection tool of CO2 injection well, concretely is a kind of ball sleeve. BACKGROUND

[0002] To improve oil recovery, supplement formation energy, CO2 miscible flooding is a new technology in recent years, and many oil reservoirs have been developed by CO2 flooding. Some gas injection wells are deployed in the development block to improve the recovery of crude oil by using gas injection string for gas injection production. To facilitate the testing requirements in the later stage, a gas injection process string equipped with a hollow injection distributor is needed for gas injection production, and the connected hollow injection distributor is a kind of gas injection valve.

[0003] Currently, in order to ensure the safety of the construction of the gas injection string in the later stage, the hollow injection distributor in the gas injection process string is designed to have a structure with anti-backflow function, which makes it difficult to form a circulating channel in the wellbore for the gas injection process string and to facilitate the setting of the packer in the gas injection process string in the later stage.

[0004] Due to the structure of the hollow injection distributor connected in the gas injection process string with anti-backflow function, the gas injection process string cannot be automatically grouted during the running-in process.

[0005] If the gas injection process string equipped with a hollow injection distributor is run into the well by using the artificial grouting construction method at the wellhead, the construction efficiency is low, the labor intensity of the construction personnel is high, the construction time is long, and environmental pollution is likely to occur.

[0006] In order to solve the above problems and facilitate automatic grouting of the above gas injection string during the running-in process, a toe sleeve capable of being opened first and closed later needs to be installed at the lower end of the string to ensure that the above string can realize automatic liquid feeding during the running-in process ， Avoid the various disadvantages brought by the artificial grouting construction method. Furthermore, the construction efficiency can be greatly improved, the construction cycle can be shortened, the labor intensity of the workers can be reduced, environmental pollution can be reduced, and production costs can be reduced.

[0007] The tools similar to the tool required in the gas injection process string with a hollow injection distributor are as follows, but they cannot realize the functions of being opened first and closed later and automatic grouting required above, such as the following prior art:

[0008] A toe sleeve disclosed in the authorized announcement No. CN216894333U includes: upper joint, connecting head, lower joint connected in sequence, and forms hollow pipeline structure, connecting head is provided with pressure guide channel, and connecting port is provided on inner wall, valve channel is provided in lower joint, and port is provided on inner wall, valve channel is communicated with pressure guide channel, port is blocked by soluble plug, and control valve with normally closed is provided in valve channel.

[0009] The toe sliding sleeve is a tubular member that is run into the well along with the cementing string. When the cementing operation is completed, the toe sliding sleeve is opened by a special triggering method, and then subsequent operations are carried out.

[0010] The toe sliding sleeve device disclosed in authorization publication No. CN113803024B belongs to the technical field of well completion and reservoir reconstruction in the oil and gas industry. The device comprises an outer cylinder, a fracturing hole is arranged on the outer cylinder, and an annular groove is arranged on the inner side of the outer cylinder. An inner cylinder is arranged at the lower part of the annular groove. In the annular groove, a cavity is formed between the outer cylinder and the inner cylinder, and the upper part of the annular groove forms an annular opening. A liquid cylinder is connected to the upper part of the cavity, and the liquid cylinder blocks the fracturing hole and the annular opening. When the liquid cylinder is disconnected from the outer cylinder and falls to the lower part of the cavity, the fracturing hole and the annular opening are communicated.

[0011] The above-mentioned invention adopts a built-in design, which avoids the blockage caused by the cement slurry entering the sliding space during cementing. In addition, the upper part of the inner cylinder is provided with a soluble material pre-positioning ring, which can ensure the smooth opening of the sliding sleeve even if the soluble material pre-positioning ring is not completely dissolved.

[0012] The toe sliding sleeve and oil well string disclosed in application publication No. CN114059983A comprise a body joint, a sliding sleeve protection sleeve, a sliding sleeve, a break disc, and a rotary through valve assembly. The body joint is provided with an axial through hole, a pressure transmission hole, a break disc mounting hole, and a rotary through valve assembly mounting hole. The pressure transmission hole is parallel and spaced apart from the axial through hole. The break disc mounting hole is arranged along the radial direction of the body joint and is in communication with the pressure transmission hole and the axial through hole. The rotary through valve assembly mounting hole is parallel and spaced apart from the break disc mounting hole on one side of the break disc mounting hole. The sliding sleeve protection sleeve is fixedly arranged outside the body joint and forms an annulus between the sliding sleeve protection sleeve and the body joint. The pressure transmission hole is in communication with the annulus. The sliding sleeve is arranged in the annulus through a shear pin. The break disc is arranged in the break disc mounting hole and can block the pressure transmission hole. The rotary through valve assembly is arranged in the rotary through valve assembly mounting hole and can control the opening and closing of the pressure transmission hole.

[0013] The working principle is that the tool is connected to the cementing casing string according to the design requirements, and is lowered to the predetermined position to provide temporary plugging for the casing string, and normal cementing operation is carried out (the sum of the wellhead pump pressure and the static column pressure of the position of the delayed opening toe sleeve during the cementing operation should be less than the rupture pressure value of the rupture disc); after the cementing operation, the cement is completely cured and reaches the design strength before the fracturing operation is carried out. During the fracturing operation, the normal fracturing wellhead and fracturing truck are connected, and the ground pipeline is pressure tested to the design value; after the wellhead is depressurized, the fracturing truck is connected with the wellbore through the ground pipeline by opening the wellhead valve, and the fracturing truck is pressure tested to the full wellbore design pressure value (the sum of the pressure test value and the static column pressure of the position of the delayed opening toe sleeve is greater than the rupture pressure value of the rupture disc). At this time, the rupture disc in the delayed opening toe sleeve breaks, the fluid in the wellbore flows through the rupture disc to the piston activator and the rotary access valve, which is blocked by the rotary access valve, and the fluid pressure pushes the piston activator to move outward along the radial direction of the tool and contacts the battery timer to activate the battery timer to start timing. When the battery timer reaches the set value, it will automatically provide current for the drive motor, the drive motor is opened and drives the rotary access valve to rotate 90 degrees to make the pressure transmission hole conductive, and the fluid flows along the pressure transmission hole to the sleeve and pushes the sleeve to move along the axial direction of the tool. The fracturing holes on the body joint and the fracturing holes on the sleeve protective sleeve are conductive, the in-hole and out-hole fracturing channels are established, and the normal first-stage fracturing operation is carried out.

[0014] From the above description, it can be seen that the tool is mainly used for the first-stage fracturing operation after the cementing of the oil and gas well, especially the horizontal well, provides the fracturing channel between the casing and the formation for the full wellbore pressure test and the first-stage fracturing operation of the oil and gas well, and finally improves the efficiency of the completion operation and reduces the risk of the completion operation.

[0015] The main purpose of the above-mentioned application is to automatically open the sleeve to establish the fracturing channel under the premise of not exceeding the pressure test value.

[0016] The toe sleeve mentioned in the article "Application Analysis and Structure Improvement of Toe Sleeve Based on Well Conditions" published in "Natural Gas Industry" in 2022 is mainly composed of an upper joint, an inner sleeve, an outer cylinder, a lower joint, a shear pin and a locking mechanism. With the casing string being lowered into the well and cementing being carried out. After the waiting period ends, the ground pump truck pressurizes the casing, the differential pressure surface of the inner sleeve generates a pushing force to shear the shear pin, the inner sleeve moves downward, compresses the liquid in the differential pressure chamber, and discharges it to the annulus through the pressure transmission hole, thereby opening the sleeve. The locking mechanism and the outer cylinder are locked to prevent the inner sleeve from moving backward to close the sleeve. After the sleeve is opened, the next step of fracturing operation can be carried out.

[0017] In 2023, the application of casing and sliding sleeve integrated string for fracturing and production was published in Drilling and Production Technology, Vol. 46, No. 4, 2023. A casing and sliding sleeve integrated string is disclosed, which is to lower the toe end sliding sleeve and the casing sliding sleeve together with the completion casing to the designed position, then cement the well, pressurize the wellhead to directly open the toe end sliding sleeve, perform the first layer fracturing, and then put different specifications of soluble balls into the wellhead in sequence to open the corresponding casing sliding sleeve to complete the continuous fracturing of the subsequent layers. The key tool inside can test the pressure of the toe end sliding sleeve, and its sealing and pressure bearing performance is reliable. After the starting disc is opened, it can not only meet the wellbore pressure testing requirements, but also quickly establish a fracturing channel by relying on the dissolution of the soluble disc.

[0018] Through analysis, it is found that the above sliding sleeves are closed when they are lowered into the well, and are opened by hydraulic pressure or mechanical force after being lowered to the fixed position to form a circulating channel in the wellbore.

[0019] However, in the current gas injection process string with anti-backflow function design, the sliding sleeve required at the lower end is in an open state when the string is lowered into the well, and is closed only when the packer needs to be pressurized and set after the string is lowered to the fixed position. However, there is currently no such open-first and close-later tool to meet the needs of this gas injection process string. Therefore, a new type of ball-throwing sliding sleeve is needed to solve the above problems. Content of the utility model

[0020] The utility model aims at providing a ball-throwing sliding sleeve to solve the problems that the current gas injection process string with a hollow injection distributor cannot automatically grout ， when it is lowered into the well, the labor intensity of construction personnel is high, and the construction site cannot meet the environmental protection requirements. The utility model facilitates the lowering and construction of the gas injection process string with a hollow injection distributor, reduces the labor intensity of construction personnel, improves the construction efficiency, shortens the construction period, and thus reduces the production cost.

[0021] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0022] A ball-throwing sliding sleeve, wherein:

[0023] The upper outer cylinder provided with a liquid inlet hole is connected with the lower outer cylinder;

[0024] The inner cylinder provided with a liquid inlet hole and a ball seat and connected with the lower joint at the lower end is connected with the lower outer cylinder through a shear pin;

[0025] The locking ring is located in the annulus formed by the upper outer cylinder, the lower outer cylinder and the inner cylinder and is connected with the inner cylinder;

[0026] During the lowering of the gas injection string into the well, the liquid inlet holes between the upper outer cylinder and the inner cylinder are in communication with each other;

[0027] When the packer in the gas injection string is set, the liquid inlet holes between the upper outer cylinder and the inner cylinder are closed.

[0028] Preferably, the inner thread of the locking ring is a dog tooth.

[0029] Preferably, the inner cylinder is a non-equal diameter cylindrical body and the ball seat is arranged at the upper end of the cylindrical body of the inner cylinder and is funnel-shaped as a whole, a tapered inner circle is arranged between the large inner diameter of the upper part of the ball seat and the small hole diameter of the lower part, the maximum inner diameter of the tapered inner circle is larger than the outer diameter of the sealing ball, and the minimum inner diameter of the tapered inner circle is smaller than the outer diameter of the sealing ball.

[0030] Preferably, the outer circle of the inner cylinder at the position of the ball seat and the outer circles on both sides of the liquid inlet hole are each provided with a sealing ring groove and a sealing ring is arranged in the sealing ring groove; and the outer circle of the lower part of the inner cylinder is provided with a threaded connection section and can be threadedly connected with the lower joint.

[0031] Preferably, a dog tooth threaded section and a shear pin groove for connecting with the locking ring are arranged in the outer circle below the sealing ring groove in the inner cylinder, the outer diameter of the inner cylinder below the dog tooth threaded section is smaller than the outer diameter of the upper inner cylinder, forming a reduced diameter section; and the shear pin groove is arranged above the threaded connection section.

[0032] Preferably, a flow assisting groove and a shear pin hole are arranged in the lower outer cylinder, the lower outer cylinder is a non-equal diameter cylindrical body and the small outer diameter section of the upper part of the outer circle is provided with external threads for threadedly connecting with the upper outer cylinder, the flow assisting groove is arranged in the inner circle of the lower outer cylinder, and the shear pin hole is arranged in the body of the lower outer cylinder at a position where the flow assisting groove is not arranged.

[0033] Preferably, the flow assisting groove in the lower outer cylinder corresponds to the reduced diameter section of the outer circle of the inner cylinder and forms an annular cavity.

[0034] Preferably, the flow assisting groove and the shear pin hole in the lower outer cylinder are arranged in one and more than one, respectively; and the shear pin arranged in the shear pin hole can be inserted into the shear pin groove of the inner cylinder.

[0035] Preferably, the inner circle of the upper outer cylinder is a non-equal diameter inner circle and is provided with an upper connection cavity, an inner cylinder sliding cavity, a locking ring mounting cavity and a lower outer cylinder connection cavity from top to bottom, the upper connection cavity and the lower outer cylinder connection cavity are each provided with an inner thread; the inner thread in the upper connection cavity is a tubing thread capable of threadedly connecting with a gas injection pipe column, and the inner thread in the lower outer cylinder connection cavity is capable of threadedly connecting with the lower outer cylinder.

[0036] Preferably, the ball dropping sliding sleeve is connected at the bottom of the gas injection pipe column; and the lower part of the body of the lower joint is a semicircular structure.

[0037] Compared with the prior art, the utility model has the following advantages:

[0038] (1) The working principle of the utility model is reliable, the structure is simple, the processing is easy, and the utility model is not prone to failure in the well.

[0039] (2) the utility model is connected in the lower end of the gas injection process pipe column with hollow matching injector, can meet the demand of automatic grouting of process pipe column, can greatly reduce the construction difficulty of pipe column lowering and the labor intensity of on-site operator, and can keep the construction site clean and meet the environmental protection requirements of construction.

[0040] (3) the utility model has the automatic closing function when the packer in the pipe column is set after the pipe column is lowered to the design position, which realizes automatic grouting in the pipe column lowering process and eliminates the defects of manual grouting, and guarantees the overall performance of the pipe column in the later period.

[0041] (4) the flow assisting groove in the lower outer cylinder corresponds to the ring cavity formed by the reduced section of the outer circle of the inner cylinder, which can avoid the problem of liquid inlet hole closing caused by the dead cavity at the position, and guarantees the overall sealing performance of the pipe column.

[0042] The utility model meets the demand of automatic grouting in the gas injection pipe column lowering process of carbon dioxide injection well, and provides technical support for the setting of the packer of the gas injection pipe column.

[0043] In summary, the utility model has remarkable use effect and can obtain good economic benefit and social benefit, and has great popularization value and popularization space. BRIEF DESCRIPTION OF DRAWINGS

[0044] The drawings are used to provide further understanding of the utility model, and constitute a part of the specification, and are used to explain the utility model together with the embodiments of the utility model, and do not constitute the limitation to the utility model. In the drawings:

[0045] Figure 1 It is the structure schematic view of the utility model.

[0046] Figure 2 It is the structure schematic view of the utility model. Figure 1 It is the structure schematic view of the utility model.

[0047] Figure 3 It is the structure schematic view of the utility model. Figure 1 It is the structure schematic view of the utility model.

[0048] Figure 4 It is the structure schematic view of the utility model. Figure 1 It is the structure schematic view of the utility model.

[0049] In the drawings:

[0050] Upper outer cylinder 1, upper connecting cavity 1-1, inner cylinder sliding cavity 1-2, lock ring mounting cavity 1-3;

[0051] Inner cylinder 2, ball seat 2-1, shear pin groove 2-2, zigzag buckle thread section 2-3;

[0052] Lower outer cylinder 3, flow guide groove 3-1, shear pin hole 3-2;

[0053] Lower joint 4, locking ring 5. DETAILED DESCRIPTION

[0054] The accompanying drawings are only used for reference and illustration, and are not used to limit the protection scope of the utility model. The technical solutions in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0055] In order to make the purpose, technical scheme and advantages of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not used to limit the utility model.

[0056] In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model. In addition, in the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0057] Referring to Figure 1 - Figure 4 A ball-throwing sliding sleeve, wherein:

[0058] The upper outer cylinder 1 provided with the liquid inlet hole is connected with the lower outer cylinder 3;

[0059] The inner cylinder 2 provided with the liquid inlet hole and the ball seat 2-1 and connected with the lower joint 4 at the lower end is connected with the lower outer cylinder 3 through the shear pin, and the locking ring 5 is connected with the inner cylinder 2 in the annular space formed by the upper outer cylinder 1, the lower outer cylinder 3 and the inner cylinder 2;

[0060] During the process of lowering the gas injection pipe string into the well, the liquid inlet holes between the upper outer cylinder 1 and the inner cylinder 2 are connected with each other;

[0061] When the packer in the gas injection pipe string is set, the liquid inlet holes between the upper outer cylinder 1 and the inner cylinder 2 are closed.

[0062] The liquid inlet hole arranged between the upper outer cylinder 1 and the inner cylinder 2 is in communication with each other and is in an open state during the process of lowering the gas injection pipe column into the well.

[0063] Meanwhile, when the gas injection pipe column is lowered to a predetermined position and the packer in the pipe column needs to be set, the sealing ball is put and seated on the ball seat 2-1 in the inner cylinder 2, the shear pin between the inner cylinder 2 and the lower outer cylinder 3 is sheared by the relative movement of the two, the inner cylinder 2 moves downward along the locking ring 5, and the liquid inlet hole between the upper outer cylinder 1 and the inner cylinder 2 is closed, at this time, the sliding sleeve is in a closed state.

[0064] The utility model solves the problem that the gas injection process pipe column with a hollow injection distributor cannot automatically grout when being lowered into a well, and also meets the sealing requirement and safety guarantee of one-way injection and anti-backflow required in the later stage of the above-mentioned gas injection process pipe column.

[0065] The utility model has the advantages of simple structure, convenient connection, operation and use, facilitates the lowering construction of the gas injection process pipe column with a hollow injection distributor, greatly reduces the labor intensity of the on-site construction personnel, effectively improves the construction efficiency, shortens the construction period and significantly reduces the production cost while ensuring the environmental protection requirement on site.

[0066] Based on the above-mentioned embodiment one, the utility model also has the following embodiments:

[0067] In an preferred embodiment, the locking ring 5 and the inner cylinder 2 are connected through a zigzag thread, and the locking effect is good.

[0068] In an preferred embodiment, the inner cylinder 2 is a non-equal-diameter cylindrical body, the ball seat 2-1 is arranged at the upper end of the cylindrical body of the inner cylinder 2 and is in a funnel shape as a whole, the large inner diameter of the upper part of the ball seat 2-1 and the small hole diameter of the lower part are a conical inner circle, the maximum inner diameter of the conical inner circle is greater than the outer diameter of the sealing ball, the minimum inner diameter of the conical inner circle is less than the outer diameter of the sealing ball, and the sealing ball is seated in the conical inner circle of the ball seat 2-1.

[0069] In an preferred embodiment, the outer circle of the inner cylinder 2 at the position of the ball seat 2-1 and the outer circles on both sides of the liquid inlet hole are provided with sealing ring grooves and sealing rings are installed to ensure the sealing performance of the utility model.

[0070] In an preferred embodiment, the lower outer circle of the inner cylinder 2 is provided with an external thread connection section and can be threadedly connected with the lower joint 4.

[0071] A preferred embodiment: the outer circle below the sealing ring groove in the inner cylinder 2 is provided with a ratchet thread segment 2-3 connected with the locking ring 5 and a shear pin groove 2-2, the outer diameter of the inner cylinder 2 below the ratchet thread segment 2-3 is smaller than that of the upper part of the inner cylinder 2, forming a reduced diameter segment; the shear pin groove 2-2 is provided above the outer thread connection segment.

[0072] A preferred embodiment: the lower outer cylinder 3 is provided with a flow-aiding groove 3-1 and a shear pin hole 3-2, the lower outer cylinder 3 is a non-constant diameter cylinder and the small outer diameter segment of the upper part of the outer circle is provided with outer threads for thread connection with the upper outer cylinder 1, the flow-aiding groove 3-1 is provided in the inner circle of the lower outer cylinder 3, and the shear pin hole 3-2 is provided in the body of the lower outer cylinder 3 at a position where the flow-aiding groove 3-1 is not provided. To ensure the strength of the lower outer cylinder 3, the shear pin hole 3-2 needs to be provided in the body of the lower outer cylinder 3 where the flow-aiding groove 3-1 is not provided.

[0073] A preferred embodiment: the flow-aiding groove 3-1 in the lower outer cylinder 3 corresponds to the reduced diameter segment of the outer circle of the inner cylinder 2 and forms an annular cavity. When the packer in the gas injection string is pressed and set, the shear pin between the inner cylinder 2 and the lower outer cylinder 3 is sheared, and the well fluid in the annular cavity can be smoothly discharged from the flow-aiding groove 3-1, avoiding the risk of poor liquid inlet due to the formation of a dead space at this position.

[0074] A preferred embodiment: the flow-aiding groove 3-1 and the shear pin hole 3-2 in the lower outer cylinder 3 are provided in one and more than one, respectively; the shear pin installed in the shear pin hole 3-2 can be inserted into the shear pin groove 2-2 of the inner cylinder 2. When the shear pin hole 3-2 in the lower outer cylinder 3 is broken by the setting pressure of the packer, the inner cylinder 2 moves downward along the locking ring 5 to the position of the lower outer cylinder 3, and the lower outer cylinder 3 provided with the flow-aiding groove 3-1 and the shear pin hole 3-2 also has a centralizing effect on the inner cylinder 2.

[0075] A preferred embodiment: the inner circle of the upper outer cylinder 1 is a non-constant diameter inner circle and is provided with an upper connection cavity 1-1, an inner cylinder sliding cavity 1-2, a locking ring installation cavity 1-3, and a lower outer cylinder connection cavity from top to bottom, and the upper connection cavity 1-1 and the lower outer cylinder connection cavity are both provided with internal threads; the internal threads in the upper connection cavity 1-1 are capable of thread connection with the gas injection string, and the internal threads in the lower outer cylinder connection cavity are capable of thread connection with the lower outer cylinder 3.

[0076] A preferred embodiment: the ball-throwing sliding sleeve is connected at the bottom of the gas injection string; the lower part of the body of the lower joint 4 is a semicircular structure, which can serve as a guide head of the gas injection string.

[0077] The above-described embodiments are merely typical embodiments, but the utility model is not limited to these embodiments, and a person skilled in the art can make modifications without deviating from the spirit and inspiration of the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, a person skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacement to part of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and concept of the utility model should be included in the protection scope of the utility model. Therefore, the protection scope is not limited to the foregoing description.

Claims

1. A ball launching sleeve characterized by, The upper outer cylinder with liquid inlet hole is connected with the lower outer cylinder; The inner cylinder with liquid inlet hole and ball seat is connected with the lower outer cylinder through the shear pin; The locking ring is connected with the inner cylinder in the annular space formed by the upper outer cylinder and the lower outer cylinder and the inner cylinder; The liquid inlet holes between the upper outer cylinder and the inner cylinder are connected with each other during the process of lowering the gas injection string into the well; The liquid inlet holes between the upper outer cylinder and the inner cylinder are closed when the packer in the gas injection string is set.

2. A ball launching slipper as claimed in claim 1, wherein, The internal thread of the locking ring is a dog tooth.

3. A ball launching slipper as defined in claim 2 wherein, The inner cylinder is a non-equal-diameter cylindrical body, and the ball seat is arranged at the upper end of the cylinder body of the inner cylinder and has a funnel shape as a whole, the upper part of the ball seat has a large inner diameter and the lower part has a small hole diameter, and the tapered inner circle between the large inner diameter and the small hole diameter is conical, the maximum inner diameter of the tapered inner circle is larger than the outer diameter of the sealing ball, and the minimum inner diameter of the tapered inner circle is smaller than the outer diameter of the sealing ball.

4. A ball launching slipper as defined in claim 3 wherein, The outer circle of the inner cylinder at the position of the ball seat and the outer circles on both sides of the liquid inlet hole are provided with seal ring grooves and installed with seal rings; the lower part of the outer circle of the inner cylinder is provided with an external thread connection section and can be threadedly connected with the lower joint.

5. A ball launching slipper according to any one of claims 1 to 4, wherein the ball launching slipper is configured to be used in a ball launching game. The outer diameter of the inner cylinder below the seal ring groove is smaller than the outer diameter of the upper part of the inner cylinder, forming a reduced diameter section; the shear pin groove is arranged above the external thread connection section.

6. A ball launching slipper as defined in claim 5 wherein the The lower outer cylinder is provided with a flow guide groove and a shear pin hole, the lower outer cylinder is a non-equal-diameter cylindrical body, and the small outer diameter section of the upper part of the outer circle is provided with an external thread for threadedly connecting with the upper outer cylinder, the flow guide groove is arranged in the inner circle of the lower outer cylinder, and the shear pin hole is arranged in the body of the lower outer cylinder at a position where the flow guide groove is not arranged.

7. A ball launching slipper as defined in claim 6 wherein, The flow guide groove in the lower outer cylinder corresponds to the reduced diameter section of the outer circle of the inner cylinder and forms an annular cavity.

8. A ball launching slipper as defined in claim 7 wherein, The flow guide groove and the shear pin hole in the lower outer cylinder are arranged in one and more than one, respectively; the shear pin installed in the shear pin hole can be inserted into the shear pin groove of the inner cylinder.

9. A ball launching slipper as defined in claim 8 wherein, The inner circle of the upper outer cylinder is a non-equal-diameter inner circle and is provided with an upper connection cavity, an inner cylinder sliding cavity, a locking ring installation cavity and a lower outer cylinder connection cavity from top to bottom, and the upper connection cavity and the lower outer cylinder connection cavity are both provided with internal threads; the internal thread in the upper connection cavity is a tubing thread capable of threadedly connecting with the gas injection string, and the internal thread in the lower outer cylinder connection cavity is capable of threadedly connecting with the lower outer cylinder.

10. The ball launching slipper of claim 9, wherein the ball launching slipper further comprises a ball launching mechanism. The ball dropping sliding sleeve is connected at the bottom of the gas injection string; and the lower part of the body of the lower joint is a semicircular structure.

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