CN112211590A

CN112211590A - Gas lift circulating valve

Info

Publication number: CN112211590A
Application number: CN201910623208.1A
Authority: CN
Inventors: 闫占辉; 张晓文; 于雷
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2021-01-12
Anticipated expiration: 2039-07-11
Also published as: CN112211590B

Abstract

The invention discloses a gas lift circulating valve which is arranged on an oil pipe close to a well head in an electric pump production pipe column and extends into an oil sleeve annulus along with the oil pipe, the gas lift circulating valve comprises a valve body and a piston, the valve body is of a cylindrical structure arranged along the vertical direction, an accommodating cavity is formed in the cylinder wall of the valve body, a pressurizing hole communicated with the accommodating cavity and a one-way valve communicated to the interior of the valve body in a one-way mode from the accommodating cavity are arranged on the inner wall of the valve body, an air inlet communicated with the accommodating cavity is arranged on the outer wall of the valve body, and the piston is arranged in the accommodating cavity; when the gas lift circulating valve is opened, the piston plugs the pressurizing hole, and the oil sleeve annulus is communicated with the interior of the valve body sequentially through the air inlet hole, the accommodating chamber and the check valve; when the gas lift circulating valve is closed, the piston moves in the accommodating cavity and seals the air inlet. The invention solves the technical problem of natural gas leakage easily caused by overhigh pressure in the oil sleeve annulus at the wellhead.

Description

Gas lift circulating valve

Technical Field

The invention relates to the technical field of oil exploitation, in particular to a gas lift circulating valve.

Background

At present, the electric submersible pump technology is widely applied to the production of oil and gas fields. As shown in fig. 1, an electric pump production string commonly used in an oil field is composed of, from top to bottom, an oil pipe hanger 901, a double male joint 902, a first oil pipe 903, an oil drain 904, a second oil pipe 905, a check valve 906, a third oil pipe 907, an electric pump set 908, a perforated screen pipe 909, a double-cup packer 910, a sand control screen pipe 911, a sand setting pipe 912 and a plug 913 which are connected in sequence, wherein the electric pump set comprises a pump set, a separator, a protector, a motor and the like. For example, drainage gas production commonly used in gas production wells and drainage oil production commonly used in oil production wells both utilize electric pump production technology for drainage production.

Because reservoirs contain a large amount of natural gas in addition to a large amount of oil and water, the natural gas is usually dissolved in crude oil due to the effect of formation pressure, but during the drainage process of the electric pump, the pressure applied to the crude oil is reduced along with the rising of the crude oil in the formation, and the natural gas is released from the crude oil. In order to prevent the electric pump from generating air lock, an oil-gas separator is usually added at the suction inlet of the electric pump to separate the gas part into the oil sleeve annulus, and the liquid part enters the pump body and is lifted to the ground. However, this method has a problem in actual production work: the more natural gas in the oil sleeve annulus can be accumulated, and the oil sleeve annulus pressure is higher and higher at the wellhead position. The pressure resistance of a cable traversing device at the wellhead of the existing electric pump well is only about 12MPa generally, the phenomenon that the pressure in an oil sleeve annulus rises rapidly often occurs when the electric pump is used for liquid drainage production, once the pressure exceeds the pressure resistance grade of the cable traversing device, natural gas leakage can occur at the wellhead, and the danger is very high.

The general method for solving the problem at the present stage is as follows: through the pressure in the staff inspection wellhead oil jacket annular space, when pressure was too high, then need put the gas in the annular space and come the reduce pressure, this kind of method not only the cost of labor is too high, waste time and energy, can't accomplish accurate, timely control wellhead oil jacket annular space in addition pressure, can't follow the problem of the natural gas leakage that easily causes because the pressure is too high in the wellhead department oil jacket annular space of fundamental solution.

Therefore, the inventor provides the gas lift circulating valve by virtue of experience and practice of related industries for many years so as to overcome the defects of the prior art.

Disclosure of Invention

The invention aims to provide a gas lift circulating valve which can introduce natural gas in an oil sleeve annulus into an oil pipe on an electric pump production pipe column, reduce the pressure in the oil sleeve annulus, effectively prevent potential safety hazards of cable penetrators due to breakdown and natural gas leakage and improve the safety of wellhead operation.

The purpose of the invention can be realized by adopting the following technical scheme:

the invention provides a gas lift circulating valve which is arranged on an oil pipe close to a wellhead in an electric pump production pipe column and extends into an oil sleeve annulus along with the oil pipe, the gas lift circulating valve comprises a valve body and a piston, the valve body is of a cylindrical structure arranged along the vertical direction, an accommodating cavity is formed in the cylinder wall of the valve body, a pressurizing hole communicated with the accommodating cavity and a one-way valve communicated to the interior of the valve body in a one-way mode from the accommodating cavity are arranged on the inner wall of the valve body, an air inlet communicated with the accommodating cavity is arranged on the outer wall of the valve body, and the piston is arranged in the accommodating cavity;

when the gas lift circulating valve is opened, the piston plugs the pressurizing hole, and the oil sleeve annulus is communicated with the interior of the valve body sequentially through the air inlet hole, the accommodating chamber and the check valve;

when the gas lift circulating valve is closed, the piston moves in the accommodating cavity and seals the air inlet hole.

In a preferred embodiment of the present invention, the accommodating chamber is a cylindrical chamber disposed along a circumferential direction of the valve body, the pressing hole is located at an upper portion of the accommodating chamber, and the air inlet and the check valve are both located at a lower portion of the accommodating chamber.

In a preferred embodiment of the present invention, the air inlet and the check valve are located at the same height, and the air inlet and the check valve are disposed opposite to the accommodating chamber.

In a preferred embodiment of the present invention, the piston is a cylindrical structure arranged along a vertical direction, and a height of the piston is smaller than a height difference between the pressing hole and the air inlet hole in the vertical direction, so that when the pressing hole is blocked by the piston, the air inlet hole and the accommodating chamber are in a communicating state.

In a preferred embodiment of the present invention, the piston is fixed on the upper portion of the accommodating chamber by a shear pin, so that the piston blocks the pressing hole; and shearing the shearing pin, and moving the piston to the lower part of the accommodating chamber so as to enable the piston to seal the air inlet hole.

In a preferred embodiment of the present invention, the outer wall of the piston is provided with a plurality of second anti-back-off rings at intervals from top to bottom, the inner wall of the accommodating chamber opposite to the outer wall of the piston is fixedly provided with a first anti-back-off ring, and the first anti-back-off ring and each of the second anti-back-off rings are matched with each other to make the first anti-back-off ring anti-back-off in one direction downward.

In a preferred embodiment of the present invention, the first anti-back-off ring is an annular structure, the inner edge of the first anti-back-off ring forms a limiting head, and the plurality of second anti-back-off rings form a zigzag structure continuously arranged from top to bottom at intervals.

In a preferred embodiment of the present invention, a plurality of first sealing rings are fixedly embedded on both the upper outer wall and the upper inner wall of the piston, and each of the first sealing rings is tightly attached to the inner wall of the accommodating chamber.

In a preferred embodiment of the present invention, a plurality of second sealing rings are disposed on two side inner walls of the accommodating chamber corresponding to the outer wall and the inner wall of the piston, and when the gas lift circulation valve is closed, each of the second sealing rings is closely attached to the lower outer wall and the lower inner wall of the piston.

In a preferred embodiment of the present invention, an outer wall of an upper portion of the valve body is provided with an external thread, an inner wall of a lower portion of the valve body is provided with an internal thread, and the upper portion and the lower portion of the valve body are respectively connected to the oil pipe through threads.

From the above, the gas lift circulation valve of the invention has the characteristics and advantages that: an accommodating cavity is formed in the wall of the valve body, a pressurizing hole communicated with the accommodating cavity and a one-way valve communicated with the accommodating cavity in a one-way mode from the accommodating cavity to the interior of the valve body are arranged on the inner wall of the valve body, an air inlet communicated with the accommodating cavity is arranged on the outer wall of the valve body, a piston for plugging the pressurizing hole is arranged in the accommodating cavity, gas in the oil sleeve annulus can enter the valve body through the air inlet, the accommodating cavity and the one-way valve in sequence and is discharged to the ground through an oil pipe connected with the valve body, so that the pressure in the oil sleeve annulus is reduced, the potential safety hazards of the cable penetrator caused by breakdown and natural gas leakage are effectively prevented, the safety of wellhead operation is improved, in addition, the piston can move downwards in the accommodating cavity and plug the air inlet, cleaning liquid is prevented from entering the oil pipe through the valve body, and the operation requirement of a back, the normal operation of oil pumping, pressure reduction and backwashing is ensured.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1: the structure schematic diagram of the electric pump production pipe column in the oil casing annulus in the prior art is shown.

FIG. 2: the structure of the gas lift circulating valve is schematically shown in the oil sleeve annulus along with the electric pump production pipe column.

FIG. 3: the invention is a structural schematic diagram of the gas lift circulating valve in an opening state.

FIG. 4: the structure of the gas lift circulating valve is in a closed state.

FIG. 5: a partial enlarged view of the position a in fig. 4.

Reference numerals in the background art: 901. hanging the oil pipe; 902. a double male connector; 903. a first oil pipe; 904. an oil drain device; 905. a second oil pipe; 906. a check valve; 907. a third oil pipe; 908. an electric pump unit; 909. punching a sieve tube; 910. a double cup packer; 911. a sand control screen pipe; 912. a sand setting pipe; 913. and (5) plugging with a thread.

Reference numerals in the present invention: 1. a valve body; 101. an air inlet; 102. punching a hole; 103. an accommodating chamber; 104. mounting a plate; 2. a piston; 201. a second anti-back ring; 3. shearing the pin; 4. a first anti-back ring; 5. a one-way valve; 6. a first seal ring; 7. a second seal ring.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.

As shown in fig. 2 to 4, the present invention provides a gas lift circulation valve, which is disposed on an oil pipe near a wellhead in an electric pump production string and extends into an oil casing annulus along with the oil pipe. This gas lift circulating valve includes valve body 1 and piston 2, valve body 1 and piston 2 are the cylindric structure that sets up along vertical direction, the inside of valve body 1 is linked together with the inside of oil pipe, form holding chamber 103 in the section of thick bamboo wall of valve body 1, be provided with on the upper portion inner wall of valve body 1 and suppress hole 102 with holding chamber 103 intercommunication, be provided with check valve 5 on the lower part inner wall of valve body 1, check valve 5 is by holding chamber 103 to the inside one-way conduction of valve body 1, be provided with the inlet port 101 with holding chamber 103 intercommunication on the lower part outer wall of valve body 1, piston 2 sets up in holding chamber 103. When the gas lift circulating valve is opened, the piston 2 is fixed on the upper part of the accommodating chamber 103 and seals the pressurizing hole 102, and the oil sleeve annulus is communicated with the interior of the valve body 1 through the air inlet hole 101, the accommodating chamber 103 and the check valve 5 in sequence; when the gas lift circulation valve is closed, the piston 2 moves downwards to the lower part of the accommodating chamber 103 and seals the air inlet hole 101. In the invention, when the piston 2 plugs the pressurizing hole 102, gas in the oil sleeve annulus can enter the valve body 1 through the gas inlet hole 101, the accommodating chamber 103 and the one-way valve 5 in sequence and is discharged to the ground through the oil pipe, thereby achieving the purpose of reducing the natural gas pressure in the oil sleeve annulus, effectively preventing the potential safety hazard of cable penetrator breakdown and natural gas leakage, improving the safety of wellhead operation, in addition, the piston 2 can move downwards in the accommodating chamber 103 and plug the gas inlet hole 101, and preventing cleaning liquid from entering the oil pipe through the valve body 1, thereby meeting the operation requirements of back washing in later period, and ensuring the normal operation of oil pumping, pressure reduction and back washing.

Specifically, the accommodating chamber 103 is a cylindrical chamber provided along the circumferential direction of the valve body 1.

Further, as shown in fig. 3 and fig. 4, the air inlet hole 101 and the check valve 5 are located at the same height, and the air inlet hole 101 and the check valve 5 are arranged relatively to the accommodating chamber 103, so that the natural gas can directly enter the valve body 1 through the check valve 5 after entering the accommodating chamber 103 from the air inlet hole 101, the natural gas is prevented from being excessively retained in the accommodating chamber 103, the external discharge efficiency of the natural gas is improved, and the gas pressure in the oil jacket annular space is effectively and quickly reduced.

Further, as shown in fig. 3 and 4, the height of the piston 2 is smaller than the height difference between the pressing hole 102 and the air inlet hole 101 in the vertical direction, so that when the piston 2 blocks the pressing hole 102, the air inlet hole 101 and the accommodating chamber 103 are in a communication state.

Further, as shown in fig. 3 to 5, a plurality of second anti-back rings 201 are disposed on an outer wall of the piston 2, each second anti-back ring 201 is disposed along a circumferential direction of the piston 2, the second anti-back rings 201 are continuously arranged on the piston 2 from top to bottom at intervals, a first anti-back ring 4 is fixedly disposed on an inner wall of the accommodating chamber 103 opposite to the outer wall of the piston 2, the first anti-back ring 4 is disposed along the circumferential direction of the accommodating chamber 103, and the first anti-back ring 4 and each second anti-back ring 201 are matched with each other, so that the first anti-back ring 4 is unidirectionally anti-back downward. After the piston 2 moves downwards to the lower part of the accommodating chamber 103, the first check ring 4 and the second check ring 201 are matched with each other, so that the piston 2 is limited, the situation that the piston 2 moves upwards to reset due to the fact that the gas pressure in the oil sleeve annulus is greater than the gas pressure in the oil pipe can be effectively avoided, and the stability of the piston 2 for plugging the air inlet 101 is guaranteed.

The first anti-back ring 4 is of a circular ring structure, the inner edge of the first anti-back ring 4 forms a limiting head, and the second anti-back rings 201 form a zigzag structure which is continuously arranged from top to bottom at intervals.

Specifically, the bottom surface of the first anti-back-off ring 4 is a plane extending along the horizontal direction, and the top surface is a slope surface gradually inclining downwards from the inner wall of the valve body 1 to the outer wall of the piston 2; the top surface of the second anti-back-off ring 201 is a plane extending along the horizontal direction, the bottom surface of the second anti-back-off ring 201 is a slope surface gradually inclining upwards from the outer wall of the piston 2 to the inner wall of the valve body 1, when the gas lift circulation valve is closed, the outer edge of the first anti-back-off ring 4 is clamped between two adjacent second anti-back-off rings 201, and the bottom surface of the first anti-back-off ring 4 abuts against the top surface of the second anti-back-off ring 201 located below in the two adjacent second anti-back-off rings 201, so that the piston 2 is limited.

As shown in fig. 3 and 4, a plurality of first sealing rings 6 are fixedly embedded on the upper outer wall and the upper inner wall of the piston 2, and each first sealing ring 6 is tightly attached to the inner wall of the accommodating chamber 103. The lower part of the accommodating chamber 103 is provided with a plurality of second sealing rings 7 corresponding to the inner walls of two opposite sides of the outer wall and the inner wall of the piston 2, and when the gas lift circulating valve is closed, each second sealing ring 7 is closely attached to the outer wall and the inner wall of the lower part of the piston 2.

As shown in fig. 3 and 4, a shear pin 3 is arranged between the piston 2 and the inner wall of the accommodating chamber 103, the shear pin 3 is located above each first sealing ring 6, one end of the shear pin 3 is fixedly embedded in the inner wall of the upper portion of the piston 2, the other end of the shear pin 3 is fixedly embedded in the inner wall of the upper portion of the accommodating chamber 103, and the piston 2 is fixed on the upper portion of the accommodating chamber 103 through the shear pin 3, so that the piston 2 blocks the pressurizing hole 102; a gap is reserved between the outer wall of the piston 2 above the shearing pin 3 and the inner wall of the accommodating chamber 103, the gap between the piston 2 and the accommodating chamber 103 is pressed through the pressing hole 102, the shearing pin 3 is sheared through pressing, and the piston 2 moves downwards to the lower part of the accommodating chamber 103 under the action of the self gravity and the pressure of liquid entering the accommodating chamber 103 through the pressing hole 102, so that the piston 2 blocks the air inlet hole 101.

In an embodiment of the present invention, as shown in fig. 3 and 4, a mounting plate 104 connected to an inner wall of the valve body 1 is disposed inside the valve body 1, the mounting plate 104 is a cylindrical structure, an outer edge of the mounting plate 104 is connected to the inner wall of the valve body 1, the accommodating chamber 103 is located between the inner wall of the valve body 1 and an outer wall of the mounting plate 104, the pressing hole 102 is located above the mounting plate 104, and the air inlet hole 101 is located below the mounting plate 104. The piston 2 is conveniently mounted by the mounting plate 104.

In another embodiment of the present invention, the top of the valve body 1 is a detachable structure connected by a screw, and after the top of the valve body 1 is detached, the upper portion of the accommodating chamber 103 is directly communicated with the outside, so that the piston 2 is conveniently installed.

As shown in fig. 3 and 4, an external thread is arranged on the outer wall of the upper part of the valve body 1, and the upper part of the valve body 1 is connected with an oil pipe through the external thread; the inner wall of the lower part of the valve body 1 is provided with internal threads, and the lower part of the valve body 1 is connected with an oil pipe through the internal threads.

The working principle of the gas lift circulating valve is as follows: the gas lift circulation valve is connected to an oil pipe of the electric pump production pipe column and extends into the oil sleeve annulus to a depth of about 200 meters along with the oil pipe. When the gas lift circulating valve is opened, the piston 2 is fixed on the upper part of the accommodating chamber 103 through the shearing pin 3, the pressurizing hole 102 is blocked through the piston 2, gas in the oil sleeve annulus sequentially enters the valve body 1 through the air inlet 101, the accommodating chamber 103 and the check valve 5 and is discharged to the ground through an oil pipe communicated with the valve body 1, and the gas pressure in the oil sleeve annulus is reduced; when the gas lift circulating valve is closed, the reverse well washing and later-stage well repairing (reverse circulation well killing fluid) can be carried out, the pressure in the oil pipe is increased to 15MPa so as to cut off the shearing pin 3, the piston 2 moves downwards to the lower part of the accommodating cavity 103 under the action of the pressure in the oil pipe, the air inlet hole 101 is sealed, the piston 2 is limited through the first stop ring 4 and the second stop ring 201, the reverse well washing and well repairing can be completed, the content of natural gas in the oil sleeve annulus is low at the moment, the outward discharge is not needed, and after the content of the natural gas in the oil sleeve annulus is increased, the gas lift circulating valve can be lifted to the ground along with the electric pump production pipe column for replacement, so that the natural gas in the oil sleeve annulus can achieve the outward discharge effect again.

The gas lift circulating valve has the characteristics and advantages that:

firstly, an accommodating chamber 103 is formed in the cylinder wall of a valve body 1, a pressurizing hole 102 communicated with the accommodating chamber 103 and a one-way valve 5 communicated with the accommodating chamber 103 in a one-way mode to the interior of the valve body 1 from the accommodating chamber 103 are arranged on the inner wall of the valve body 1, an air inlet 101 communicated with the accommodating chamber 103 is arranged on the outer wall of the valve body 1, a piston 2 for plugging the pressurizing hole 102 is arranged in the accommodating chamber 103, gas in the oil sleeve annulus can enter the interior of the valve body 1 through the air inlet 101, the accommodating chamber 103 and the one-way valve 5 in sequence and is discharged to the ground through an oil pipe connected with the valve body 1, so that the purpose of reducing the pressure in the oil sleeve annulus is achieved, the potential safety hazards of cable penetrator breakdown and natural gas leakage are effectively prevented, the safety of wellhead operation is improved, and no need of operators to control and detect the pressure in the oil sleeve annulus, effectively saves manpower and material resources and reduces the production cost.

Second, this gas lift circulation valve well piston 2 can move down in holding chamber 103 to carry out the shutoff to inlet port 101, thereby avoided the backwash well in-process washing liquid to enter into oil pipe through valve body 1 in, satisfy the operation requirement of later stage backwash well, guaranteed the normal clear of backwash well work.

Third, be provided with first anti-backing ring 4 on the inner wall of accommodation chamber 103 in this gas lift circulation valve, be provided with a plurality of second anti-backing rings 201 on the outer wall of piston 2, piston 2 moves the back downwards, is in the chucking state each other between first anti-backing ring 4 and the second anti-backing ring 201, can play spacing effect to piston 2, prevents that piston 2 from shifting up the circumstances of reseing and taking place, guarantees that piston 2 has good stability to the shutoff of inlet port 101.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the protection scope of the invention.

Claims

1. A gas lift circulating valve is arranged on an oil pipe close to a wellhead in an electric pump production string and extends into an oil sleeve annulus along with the oil pipe, and is characterized by comprising a valve body (1) and a piston (2), wherein the valve body (1) is of a cylindrical structure arranged in the vertical direction, an accommodating chamber (103) is formed in the cylinder wall of the valve body (1), a pressurizing hole (102) communicated with the accommodating chamber (103) and a check valve (5) communicated with the inside of the valve body (1) in a one-way mode from the accommodating chamber (103) are formed in the inner wall of the valve body (1), an air inlet hole (101) communicated with the accommodating chamber (103) is formed in the outer wall of the valve body (1), and the piston (2) is arranged in the accommodating chamber (103);

when the gas lift circulating valve is opened, the piston (2) seals the pressurizing hole (102), and the oil sleeve annulus is communicated with the interior of the valve body (1) sequentially through the air inlet hole (101), the accommodating chamber (103) and the one-way valve (5);

when the gas lift circulating valve is closed, the piston (2) moves in the accommodating chamber (103) and seals the air inlet hole (101).

2. The gas lift circulation valve according to claim 1, wherein the accommodation chamber (103) is a cylindrical chamber disposed along a circumferential direction of the valve body (1), the pressing hole (102) is located at an upper portion of the accommodation chamber (103), and the air intake hole (101) and the check valve (5) are located at a lower portion of the accommodation chamber (103).

3. Gas lift circulation valve according to claim 2, wherein the gas inlet hole (101) and the non return valve (5) are located at the same height, and the gas inlet hole (101) and the non return valve (5) are located opposite to the receiving chamber (103).

4. The gas lift circulation valve according to claim 2, wherein the piston (2) is a cylindrical structure arranged along a vertical direction, and the height of the piston (2) is smaller than the height difference between the pressing hole (102) and the air inlet hole (101) in the vertical direction, so that when the piston (2) blocks the pressing hole (102), the air inlet hole (101) and the accommodating chamber (103) are in a communication state.

5. The gas lift circulation valve according to claim 2, wherein the piston (2) is fixed to the upper part of the housing chamber (103) by means of a shear pin (3) so that the piston (2) blocks the pressing hole (102); shearing the shearing pin (3), and moving the piston (2) to the lower part of the accommodating chamber (103) so that the piston (2) seals the air inlet hole (101).

6. The gas lift circulation valve according to claim 5, wherein a plurality of second anti-back-off rings (201) are continuously arranged on the outer wall of the piston (2) from top to bottom at intervals, a first anti-back-off ring (4) is fixedly arranged on the inner wall of the accommodating chamber (103) opposite to the outer wall of the piston (2), and the first anti-back-off ring (4) and each second anti-back-off ring (201) are mutually matched so that the first anti-back-off ring (4) is unidirectionally prevented from backing off downwards.

7. The gas lift circulation valve according to claim 6, wherein the first anti-back-off ring (4) is an annular structure, the inner edge of the first anti-back-off ring (4) forms a limiting head, and the plurality of second anti-back-off rings (201) form a zigzag structure which is continuously arranged from top to bottom at intervals.

8. The gas lift circulation valve according to claim 1, wherein a plurality of first sealing rings (6) are fixedly embedded in both the upper outer wall and the upper inner wall of the piston (2), and each first sealing ring (6) is in close contact with the inner wall of the accommodating chamber (103).

9. The gas lift circulation valve according to claim 1, wherein a plurality of second sealing rings (7) are provided on the inner walls of both sides of the receiving chamber (103) corresponding to the outer and inner walls of the piston (2), each second sealing ring (7) corresponding to a lower outer wall and a lower inner wall of the piston (2) being in close contact when the gas lift circulation valve is closed.

10. The gas lift circulation valve according to claim 1, wherein an outer thread is provided on an outer wall of an upper portion of the valve body (1), an inner thread is provided on an inner wall of a lower portion of the valve body (1), and the upper portion and the lower portion of the valve body (1) are respectively connected to the oil pipe by a thread.