Ball valve for well completion operation under pressure

Abstract

The utility model relates to a ball valve for well completion operation under pressure, and belongs to the technical field of oil-gas field development. An upper connector is arranged at the upper end of the cylinder sleeve, a lower connector is arranged at the lower end of the cylinder sleeve, and a piston body in sliding sealing connection with the cylinder sleeve is arranged in a channel of the cylinder sleeve. Channels of the upper connector, the cylinder sleeve, the lower connector and the piston body are correspondingly communicated, a front valve seat in sealing connection with the cylinder sleeve is arranged in the cylinder sleeve and located on the upper portion of the piston body, a rear valve seat is arranged on the end face of the top of the piston body, and a valve element in sealing fit with the front valve seat and the rear valve seat is arranged in the channel of the cylinder sleeve. A shearing piece for pre-fixing the piston body in the cylinder sleeve is arranged between the piston body and the cylinder sleeve; when the piston body is fixed through the shearing piece, the rear valve seat supports the valve element to the position in sealing fit with the front valve seat and the rear valve seat at the same time, and when the pressure in the direction of the upper connector reaches a set value and the shearing piece is sheared off, the piston body slides downwards along a channel of the cylinder sleeve to a stop position. The ball valve provided by the utility model can meet the requirement of well completion operation under pressure under the underground drilling-pipe-free'pocket 'well condition.

Description

Technical Field

[0001] This utility model relates to a ball valve for pressurized well completion operations, belonging to the field of oil and gas field development technology. Background Technology

[0002] During pressurized well completion operations in oil and gas fields, in order to prevent high-pressure fluid from spraying out of the tubing during the well run-in process, a tubing plugging tool needs to be pre-connected to the tubing.

[0003] Currently, most plugging tools used in live well completion operations are valve-core type plugging tools. After the tubing string is lowered to the designed position, the valve core of the plugging tool is knocked off by positive pressure applied to the tubing string and falls into the downhole tailpipe "pocket," achieving fluid communication between the upper and lower parts of the tubing string. This plugging method cannot meet the requirements of live well completion operations in wells without a downhole tailpipe "pocket." Utility Model Content

[0004] The purpose of this invention is to provide a ball valve for pressurized well completion operations, which solves the problem of how to perform pressurized well completion operations in wells without a tailpipe "pocket".

[0005] To achieve the above objectives, the solution of this utility model includes:

[0006] This utility model discloses a ball valve for pressurized well completion operations, comprising a cylinder liner, an upper connector at the upper end of the cylinder liner, a lower connector at the lower end of the cylinder liner, and a piston body slidably and sealingly connected to the cylinder liner within a channel of the cylinder liner. The channels of the upper connector, cylinder liner, lower connector, and piston body are interconnected. A front valve seat, sealingly connected to the cylinder liner, is located on the upper part of the piston body within the cylinder liner. A rear valve seat is opened at the top end face of the piston body. A valve core, sealingly engaged with the front and rear valve seats respectively, is located within a channel of the cylinder liner. A shearing member is provided between the piston body and the cylinder liner to pre-fix the piston body within the cylinder liner. When the piston body is fixed by the shearing member, the rear valve seat supports the valve core to a position simultaneously sealingly engaged with the front and rear valve seats. When the pressure in the direction of the upper connector reaches a set value and shears the shearing member, the piston body slides downward along the channel of the cylinder liner to a stop position.

[0007] When the piston body of this utility model is fixed by the shearing component, the rear valve seat supports the valve core to a position where it simultaneously seals with both the front and rear valve seats. When the pressure in the direction of the upper connector reaches a set value and shears the shearing component, the piston body slides downward along the cylinder liner's channel to the stop position. This utility model's ball valve for pressurized well completion operations can be connected to the wellbore string via the upper and lower connectors in well conditions without a tailpipe "pocket." During the string insertion process, the valve core contacts and seals with the front valve seat under the upward pressure inside the well, preventing high-pressure fluid from spraying out of the string, thus providing blowout protection. When the string reaches the designed position, from... A pressurized fluid with a certain pressure differential is pumped into the tubing string. Under the action of the fluid pressure, the valve core contacts the valve seat downwards and squeezes the piston body. When the pressure in the direction of the upper connector reaches the set value, the shearing component that fixes the piston body and cylinder liner is cut off. The piston body loses its fixation and slides downwards along the cylinder liner channel to the stop position under pressure. In the backwashing well of this utility model, both the valve core and the piston body can move within the channel of the cylinder liner. The reverse circulation channel formed by the lower connector, cylinder liner, piston body, and the channel of the lower connector is unobstructed. That is, the ball valve for pressurized well completion operations of this utility model can meet the requirements of pressurized well completion operations in well conditions without tailpipe "pockets". The valve core of the ball valve is a ball.

[0008] Furthermore, a limiting mechanism that moves and engages with the valve core is provided on the inner wall of the cylinder liner near the front valve seat; when the valve core is simultaneously sealed and engaged with both the front and rear valve seats, the limiting mechanism blocks the valve core; when the shearing component is sheared, the valve core disengages from the front valve seat, and the limiting mechanism is used to intercept the valve core to prevent the valve core from making sealing contact with the front valve seat.

[0009] This invention features a limiting mechanism on the inner wall of the cylinder liner near the front valve seat, which moves in conjunction with the valve core. When the valve core is simultaneously sealed with both the front and rear valve seats, the limiting mechanism blocks the valve core. When the shearing component breaks, the valve core disengages from the front valve seat, and the limiting mechanism intercepts the valve core to prevent it from sealing against the front valve seat. This ensures the smooth flow of the reverse circulation channel (the reverse circulation channel formed by the lower connector, cylinder liner, piston body, and lower connector) during backwashing. Specifically, during backwashing, the backwash hydraulic pressure exerts an upward force on the valve core, causing it to disengage from the rear valve seat. The limiting mechanism, in conjunction with the valve core, intercepts the valve core to prevent sealing against the front valve seat, ensuring successful backwashing. Therefore, this invention's ball valve for pressurized well completion operations meets the requirements for pressurized well completion even in wells without a tailpipe "pocket".

[0010] Furthermore, the limiting mechanism includes a mounting hole on the inner wall of the cylinder liner near the front valve seat, and a telescopic member with an outward tendency is provided at the mounting hole; when the valve core is simultaneously sealed with the front valve seat and the rear valve seat, the telescopic member is squeezed by the valve core and blocks the valve core; when the shearing member shears off, the valve core disengages from the front valve seat, and the telescopic member extends to intercept the valve core to prevent the valve core from sealing with the front valve seat.

[0011] This invention utilizes a telescopic component installed at the mounting hole. When the valve core is simultaneously sealed with both the front and rear valve seats, the telescopic component is pressed against and blocks the valve core. When the shearing component cuts off, the valve core disengages from the front valve seat, and the telescopic component extends to intercept the valve core, preventing it from sealing against the front valve seat. This ensures unobstructed reverse circulation during backwashing, as the backwash hydraulic pressure exerts an upward force on the valve core, causing it to disengage from the rear valve seat. The telescopic component, in conjunction with the valve core, prevents contact between the valve core and the front valve seat, ensuring smooth backwashing. Therefore, this ball valve for pressurized well completion operations meets the requirements even in wells without a tailpipe "pocket." The telescopic component is detachably screwed onto the mounting hole, facilitating future reconfiguration and improving the overall utilization rate of the ball valve.

[0012] Furthermore, the telescopic component is a compression spring.

[0013] The telescopic component with an outward tendency to move in this invention is a compression spring. Specifically, the outward tendency of the compression spring is provided by its own elastic force when it is subjected to pressure. The compression spring is screwed into the mounting hole; the portion of the compression spring screwed into the mounting hole is equivalent to the pressure cap in the embodiment, facilitating later resetting and improving the utilization rate of the ball valve of this invention.

[0014] Furthermore, the telescopic component includes an elastic element, and a limiting claw is provided at one end of the elastic element facing the cylinder liner channel. The limiting claw is set at the mounting hole through the elastic element, and the outward movement tendency of the limiting claw is provided by the elastic element provided between the limiting claw and the mounting hole; the elastic element is a leaf spring or a compression spring.

[0015] The telescopic component of this utility model includes an elastic element and a limiting claw. One end of the elastic element is located at the mounting hole, and the other end of the elastic element, facing the cylinder liner channel, is connected to the limiting claw. The outward movement tendency of the limiting claw is provided by the elastic element. The elastic element is a leaf spring or a compression spring. When the valve core is simultaneously sealing with both the front and rear valve seats, the valve core squeezes the limiting claw, and the limiting claw squeezes the elastic element, causing the elastic element to block the valve core. When the shearing component cuts, the valve core disengages from the front valve seat, and the limiting claw extends freely under the action of the elastic element, intercepting the valve core and preventing it from sealing with the front valve seat. The elastic element is screwed to the mounting hole; the screwed portion of the elastic element is equivalent to the pressure cap in the embodiment, facilitating later reset and improving the utilization rate of the ball valve of this utility model.

[0016] Furthermore, the shearing component is a shearing pin. The side wall of the cylinder liner has a threaded hole for installing the shearing pin, and the outer side wall of the piston body has a pin groove opposite to the threaded hole to accommodate part of the shearing pin, thereby achieving the pre-fixation of the piston body and the cylinder liner by the shearing pin.

[0017] The shearing component of this invention is a shearing pin. The shearing pin is installed in a threaded hole on the side wall of the cylinder liner. A pin groove, opposite to the threaded hole and capable of accommodating part of the shearing pin, is formed on the outer side wall of the piston body. One end of the shearing pin is threaded into the threaded hole, and the other end is located in the pin groove, thus pre-fixing the piston body to the cylinder liner. This invention facilitates replacement of the shearing component through the detachable screw connection between the shearing pin and the threaded hole.

[0018] Furthermore, several retaining ring grooves are provided on the outer side wall of the piston body near the lower connector, and elastic retaining rings are provided at the retaining ring grooves. Several retaining grooves for cooperating with the elastic retaining rings are also provided on the inner side wall of the cylinder liner near the lower connector. When the piston body slides along the inner side wall of the cylinder liner until the opening of the retaining ring groove is aligned with the opening of the retaining groove, the elastic retaining ring is partially embedded in the retaining groove due to its own elastic force, thereby fixing the piston body and the cylinder liner again; the retaining groove forms a stop position.

[0019] This invention features a plurality of retaining ring grooves on the outer side wall of the piston body near the lower connector for mounting elastic retaining rings, and a plurality of retaining grooves on the inner side wall of the cylinder liner near the lower connector for engaging with the elastic retaining rings. When the piston body slides along the inner side wall of the cylinder liner until the opening of the retaining ring groove aligns with the opening of the retaining groove, the elastic retaining ring is partially embedded in the retaining groove due to its own elastic force, thereby re-fixing the piston body and the cylinder liner. The retaining groove forms a stop position, preventing the piston body from sliding up and down along the cylinder liner's channel.

[0020] Furthermore, as the piston body slides along the inner wall of the cylinder liner until the opening of the retaining ring groove aligns with the opening of the retaining groove, the bottom end face of the piston body contacts the upper end face of the lower connector inside the cylinder liner, and the retaining groove and the upper end face of the lower connector together form the stop position.

[0021] In this invention, the piston body slides along the inner wall of the cylinder liner until the opening of the retaining ring groove aligns with the opening of the retaining groove. Simultaneously, the bottom end face of the piston body contacts the upper end face of the lower connector inside the cylinder liner. The retaining groove and the upper end face of the lower connector together form a stop position, preventing the piston body from sliding up and down along the cylinder liner's channel. The upper end face of the lower connector also stops the piston body, reducing the upward force of the backwash hydraulic pressure on the piston body during backwashing, thereby improving the service life of the elastic retaining ring. Before backwashing (when the tubing reaches the designed position, a pressure fluid with a certain pressure differential is pumped into the tubing. Under the action of the liquid pressure, the valve core contacts the valve seat downward and squeezes the piston body, causing the pressure in the direction of the upper connector to reach the set value and shear the shearing piece that fixes the piston body and the cylinder liner. At this point, the piston body loses its fixation and slides down along the cylinder liner's channel to the stop position under pressure), the upper end face of the lower connector stops the piston body, reducing the force on the elastic retaining ring under pressure and improving its service life.

[0022] Furthermore, the lower end face of the upper connector extends into the channel of the cylinder liner to form the front valve seat.

[0023] The lower end face of the upper connector of this utility model extends into the channel of the cylinder liner to form a front valve seat, that is, the upper connector and the front valve seat are integrally set, which facilitates the installation and disassembly of the ball valve for pressurized well completion operations of this utility model.

[0024] Furthermore, a first sealing ring is provided between the portion of the upper connector that extends into the cylinder liner passage and the cylinder liner passage, so as to form a seal between the front valve seat and the cylinder liner passage.

[0025] This invention achieves a sealed connection between the front valve seat and the cylinder liner by setting a first sealing ring between the front valve seat and the cylinder liner passage. The front valve seat is the lower end face of the upper connector that extends into the cylinder liner passage; the first sealing ring can be optionally located on the portion of the upper connector that extends into the cylinder liner passage and / or on the side wall of the cylinder liner passage (inner side wall of the cylinder liner), and the location for installing the first sealing ring is the first sealing groove.

[0026] Furthermore, a second sealing ring is provided between the inner wall of the cylinder liner and the outer wall of the piston body to ensure a sealed connection between the inner wall of the cylinder liner and the outer wall of the piston body.

[0027] This invention achieves a sealed connection between the cylinder liner and the piston body by setting a second sealing ring between the inner wall of the cylinder liner and the outer wall of the piston body. The second sealing ring can be optionally located on the inner wall of the cylinder liner and / or the outer wall of the piston body, and the location for installing the second sealing ring is a second sealing groove. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the reverse sealing structure of the ball valve for pressurized well completion operations according to this utility model;

[0029] Figure 2 This is a schematic diagram of the forward sealing structure of the ball valve for pressurized well completion operations according to this utility model.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Upper connector; 101. First sealing groove; 102. Reverse sealing spherical surface (front valve seat); 2. First sealing ring; 3. Cylinder liner; 301. Threaded stepped hole; 302. Threaded hole; 303. Retaining ring groove; 4. Sealing ball limiting mechanism (limiting mechanism); 401. Pressure cap; 402. Leaf spring (elastic element); 403. Limiting claw; 5. Sealing ball (valve core); 6. Second sealing ring; 7. Piston body; 701. Forward sealing spherical surface (rear valve seat); 702. Second sealing groove; 703. Pin groove; 704. Retaining ring groove; 8. Shearing pin; 9. Elastic retaining ring; 10. Lower connector. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] An embodiment of a ball valve for pressurized well completion operations:

[0034] This invention addresses the current state of live well completion technology by designing a ball valve that can meet the requirements of live well completion operations in wells without tailpipe "pockets".

[0035] A ball valve for pressurized well completion operations, such as Figure 1 As shown, this utility model mainly consists of an upper connector 1, a cylinder liner 3, a sealing ball limiting mechanism 4, a sealing ball 5, a piston body 7, a shearing pin 8, an elastic retaining ring 9, a lower connector 10, a first sealing ring 2, and a second sealing ring 6.

[0036] Specifically, the lower thread of the upper connector 1 is connected to the upper thread of the cylinder liner 3, and the two are sealed by the first sealing ring 2. The lower thread of the cylinder liner 3 is connected to the upper thread of the lower connector 10. The piston body 7 is located inside the cylinder liner 3, and the two are sealed by the second sealing ring 6 and pre-fixed by the shear pin 8. An elastic retaining ring 9 is installed at the retaining ring groove 704 on the lower outer circumference of the piston body 7.

[0037] The sealing ball 5 is located between the reverse sealing ball surface 102 at the lower end of the upper connector 1 and the forward sealing ball surface 701 at the upper end of the piston body 7. Before the ball valve of this utility model enters the well, the sealing ball 5 is in contact with the reverse sealing ball surface 102 and the forward sealing ball surface 701. A sealing ball limiting mechanism 4 is installed at the threaded stepped holes 301 distributed around the upper circumference of the cylinder liner 3. The limiting claw of the sealing limiting mechanism 4 is in contact with the upper hemisphere of the sealing ball 5. If the limiting claw 403 is fully extended, it can isolate the sealing ball 5 from the contact with the reverse sealing ball surface 102.

[0038] The upper connector 1 is located at the top of this utility model. Both the upper and lower parts are provided with connecting threads. The upper thread is connected to the wellhead pipe thread, and the lower thread is connected to the cylinder liner 3 thread. The first sealing groove 101 opened at the end of the lower thread cooperates with the first sealing ring 2. The lower end face has a reverse sealing spherical surface 102, which cooperates with the sealing ball 5 to achieve reverse sealing.

[0039] The cylinder liner 3 is located in the middle of this utility model. Both its upper and lower ends are provided with connecting threads. The cylinder liner 3 is threadedly connected to the upper connector 1 and the lower connector 10 through the connecting threads at the upper and lower ends, respectively. At least two transverse threaded stepped holes 301 are distributed on the upper circumference of the cylinder liner 3. The diameter of the external threaded hole is larger than the diameter of the inner through hole, and the two form a stepped hole structure. The sealing ball limiting mechanism 4 is installed inside. The pressure cap of the sealing ball limiting mechanism 4 is engaged with the external thread, and the step of the inner through hole limits the movement of the limiting claw of the sealing ball limiting mechanism 4. Threaded holes 302 are distributed on the middle circumference and are engaged with the shearing pin 8. The lower inner hole has a retaining ring groove 303, which is engaged with the elastic retaining ring 9 to realize the positioning of the piston body 7.

[0040] The sealing ball limiting mechanism 4 is installed in the transverse threaded stepped hole 301 of the cylinder liner 3. From the outside to the inside, it consists of a pressure cap 401, a leaf spring 402, and a limiting claw 403. In the free state, the limiting claw 403 can extend freely under the action of the leaf spring 402. Under the action of external force, the limiting claw 403 can compress the leaf spring 402 and retract.

[0041] The piston body 7 has a hollow structure. The positive sealing spherical surface 701 on its upper end face cooperates with the sealing ball 5 to achieve positive sealing. The upper circumference of the piston body 7 is provided with a second sealing groove 702 that cooperates with the second sealing ring 6 to achieve sealing of the cylinder liner 3. The lower circumference of the piston body 7 is provided with a retaining ring groove 704 for installing the elastic retaining ring 9. The circumferential surface between the second sealing groove 702 and the retaining ring groove 704 is provided with a pin groove 703 that cooperates with the shearing pin 8 to achieve pre-fixation of the piston body 7 and the cylinder liner 3.

[0042] The lower connector 10 is a hollow structure, and its inner diameter is smaller than that of the cylinder body 3. The two form a stepped hole structure, and the step on its end face limits the downward movement of the piston body 7. The upper and lower parts of the lower connector 10 are provided with connecting threads. The upper thread of the lower connector 10 is connected to the thread of the cylinder liner 3 (cylinder body), and the lower thread of the lower connector 10 is connected to the thread of the well insertion pipe string.

[0043] See Figure 1 When using this utility model, it is used for pressurized well completion operations in stratified water injection wells. According to the design position, it is connected to the well string through the upper thread of the upper connector 1 and the lower thread of the lower connector 10. During the process of lowering the well string, the sealing ball 5 contacts and seals the reverse ball sealing surface 102 at the lower end of the upper connector 1 under the action of the top pressure in the well, preventing the high pressure fluid in the well from being ejected from the well string, thus playing a blowout prevention role.

[0044] See Figure 2When the tubing reaches the designed position, a pressure fluid with a certain pressure difference is pumped into the tubing. Under the action of the liquid pressure, the sealing ball 5 contacts and squeezes the positive sealing ball surface 701 at the upper end face of the piston body 7. Under the rated pressure, the shearing pin 8 that fixes the piston body 7 and the cylinder liner 3 is sheared. The piston body 7 loses its fixation and moves downward under the action of pressure until the end of the piston body 7 contacts and is limited by the end face step of the lower connector 10. At this time, the elastic retaining ring 9 in the retaining ring groove 704 of the piston body 7 is aligned with the retaining ring groove 303 at the lower part of the cylinder liner 3. The elastic retaining ring 9 opens and the body part of the elastic retaining ring 9 is embedded in the retaining ring groove 303, so that the piston body 7 and the cylinder liner 3 are fixed again. Meanwhile, as the sealing ball 5 descends and contacts the piston body 7, the sealing ball 5 disengages from the support of the limiting claw 403 of the sealing ball limiting mechanism 4. Under the action of the leaf spring 402, all the limiting claws 403 extend freely. The distance between the ends of the symmetrically distributed limiting claws 403 is less than the diameter of the sealing ball 5, forming a valve cover. This prevents the sealing ball 5 from contacting the reverse sealing ball surface 102 at the lower part of the upper connector 1 under the action of the backwash fluid, ensuring the smooth flow of the reverse circulation channel. At this time, this utility model functions as a common one-way ball valve, meeting the needs of the water well layered packer for setting and backwashing wells.

[0045] When this invention is used for pressurized completion of an oil well, the original fixed valve of the oil pump is first removed. The upper connecting thread of the upper connector 1 of this invention is connected to the lower thread of the oil pump barrel, and the lower connecting thread of the lower connector 10 of this invention is connected to the lower tailpipe. The working procedure is the same as for stratified water injection well completion. When the tubing reaches the designed position and a certain pressure is pumped in, this invention achieves... Figure 2 In the state shown, this invention realizes the suction function of the fixed valve of the oil pump.

[0046] Application in live-line operations in the Henan Oilfield has shown that this utility model can meet the needs of live-line completion operations for oil, gas, and water wells in "pocket" well conditions without tailpipes, ensuring the smooth progress of live-line completion operations under various working conditions, and has good value for promotion and application.

Claims

1. A ball valve for pressurized well completion operations, characterized in that, The system includes a cylinder liner, an upper connector at the upper end of the cylinder liner, and a lower connector at the lower end of the cylinder liner. A piston body is slidably and sealingly connected to the cylinder liner within a channel of the cylinder liner. The channels of the upper connector, cylinder liner, lower connector, and piston body are interconnected. A front valve seat, sealingly connected to the cylinder liner, is located on the upper part of the piston body within the cylinder liner. A rear valve seat is located on the top end face of the piston body. A valve core, sealingly engaged with the front and rear valve seats respectively, is located within a channel of the cylinder liner. A shearing member is provided between the piston body and the cylinder liner to pre-fix the piston body within the cylinder liner. When the piston body is fixed by the shearing member, the rear valve seat supports the valve core to a position where it simultaneously seals with both the front and rear valve seats. When the pressure in the direction of the upper connector reaches a set value and shears the shearing member, the piston body slides downward along the channel of the cylinder liner to a stop position.

2. The ball valve for pressurized well completion operations according to claim 1, characterized in that, A limiting mechanism that moves in conjunction with the valve core is also provided on the inner side wall of the cylinder liner near the front valve seat; when the valve core is simultaneously sealed in conjunction with the front valve seat and the rear valve seat, the limiting mechanism blocks the valve core; when the shearing member is sheared, the valve core disengages from the front valve seat, and the limiting mechanism is used to intercept the valve core to prevent the valve core from making sealing contact with the front valve seat.

3. The ball valve for pressurized well completion operations according to claim 2, characterized in that, The limiting mechanism includes a mounting hole on the inner wall of the cylinder liner near the front valve seat, and a telescopic member with an outward tendency is provided at the mounting hole; when the valve core is simultaneously sealed with the front valve seat and the rear valve seat, the telescopic member is squeezed by the valve core and blocks the valve core; when the shearing member shears, the valve core disengages from the front valve seat, and the telescopic member extends to intercept the valve core to prevent the valve core from sealing contact with the front valve seat.

4. The ball valve for pressurized well completion operations according to claim 3, characterized in that, The telescopic component includes an elastic element, and a limiting claw is provided at one end of the elastic element facing the cylinder liner channel. The limiting claw is set at the mounting hole through the elastic element, and the outward movement tendency of the limiting claw is provided by the elastic element provided between the limiting claw and the mounting hole; the elastic element is a leaf spring or a compression spring.

5. The ball valve for pressurized well completion operations according to claim 1, characterized in that, The shearing component is a shearing pin. The side wall of the cylinder liner has a threaded hole for installing the shearing pin, and the outer side wall of the piston body has a pin groove opposite to the threaded hole to accommodate part of the shearing pin, thereby achieving the pre-fixation of the piston body and the cylinder liner by the shearing pin.

6. The ball valve for pressurized well completion operations according to any one of claims 1 to 5, characterized in that, Several retaining ring grooves are formed on the outer side wall of the piston body near the lower connector, and elastic retaining rings are provided in the retaining ring grooves. Several retaining grooves for cooperating with the elastic retaining rings are also formed on the inner side wall of the cylinder liner near the lower connector. When the piston body slides along the inner side wall of the cylinder liner until the opening of the retaining ring groove is aligned with the opening of the retaining groove, the elastic retaining ring is partially embedded in the retaining groove due to its own elastic force, thereby fixing the piston body and the cylinder liner again; the retaining groove constitutes the stop position.

7. The ball valve for pressurized well completion operations according to claim 6, characterized in that, As the piston body slides along the inner wall of the cylinder liner until the opening of the retaining ring groove aligns with the opening of the retaining groove, the bottom end face of the piston body contacts the upper end face of the lower connector inside the cylinder liner. The retaining groove and the upper end face of the lower connector together constitute the stop position.

8. The ball valve for pressurized well completion operations according to claim 1, characterized in that, The upper end face of the upper connector extends into the cylinder liner through a channel to form the front valve seat.

9. The ball valve for pressurized well completion operations according to claim 8, characterized in that, A first sealing ring is provided between the portion of the upper connector that extends into the cylinder liner channel and the cylinder liner channel to form a seal between the front valve seat and the cylinder liner channel.

10. The ball valve for pressurized well completion operations according to claim 1 or 9, characterized in that, A second sealing ring is provided between the inner wall of the cylinder liner and the outer wall of the piston body to ensure a sealed connection between the inner wall of the cylinder liner and the outer wall of the piston body.

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