阅读说明：本技术 泄压装置及射孔枪 (Pressure relief device and perforating gun ) 是由 刘洪涛 窦益华 耿海龙 金衍 黎丽丽 单锋 王克林 魏波 何剑锋 杨能 周建平 于 2020-04-23 设计创作，主要内容包括：本发明提供一种泄压装置及射孔枪,涉及油气井开采技术领域,用于解决射孔枪的胀枪、炸枪问题。泄压装置包括腔体、活塞体、弹力件和连接件,腔体具有柱状内腔,柱状内腔的第一端设有用于与射孔枪本体上的装弹孔连通的连通口,柱状内腔的侧壁上设有泄压孔和通孔,通孔设置在连通口与泄压孔之间；活塞体和弹力件安装在柱状内腔中,且弹力件的第一端与活塞体的第二端相抵,弹力件的第二端与柱状内腔的第二端相抵,以使活塞体的第一端封堵连通口；活塞体上设有凹坑,连接件穿设在通孔和凹坑中；当活塞体承受的压力大于预定压力且小于或等于射孔枪本体的抗内压极限值时,活塞体剪断连接件和压缩弹力件,使连通口与泄压孔连通以进行泄压。(The invention provides a pressure relief device and a perforating gun, relates to the technical field of oil and gas well exploitation, and is used for solving the problems of gun expansion and gun explosion of the perforating gun. The pressure relief device comprises a cavity, a piston body, an elastic piece and a connecting piece, wherein the cavity is provided with a columnar inner cavity, a communication port for communicating with a bullet loading hole in the perforating gun body is arranged at the first end of the columnar inner cavity, a pressure relief hole and a through hole are arranged on the side wall of the columnar inner cavity, and the through hole is arranged between the communication port and the pressure relief hole; the piston body and the elastic piece are arranged in the columnar inner cavity, the first end of the elastic piece is abutted against the second end of the piston body, and the second end of the elastic piece is abutted against the second end of the columnar inner cavity so that the first end of the piston body blocks the communication opening; the piston body is provided with a pit, and the connecting piece penetrates through the through hole and the pit; when the pressure born by the piston body is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the connecting piece and the compression elastic piece are sheared by the piston body, so that the communication port is communicated with the pressure relief hole to relieve the pressure.)

1. A pressure relief device is characterized by comprising a cavity, a piston body, an elastic piece and a connecting piece, wherein the cavity is provided with a columnar inner cavity, a communication port for communicating with a bullet loading hole in a perforating gun body is formed in the first end of the columnar inner cavity, a pressure relief hole and a through hole are formed in the side wall of the columnar inner cavity, and the through hole is formed between the communication port and the pressure relief hole;

the piston body and the elastic piece are arranged in the columnar inner cavity, the first end of the elastic piece is abutted against the second end of the piston body, and the second end of the elastic piece is abutted against the second end of the columnar inner cavity, so that the first end of the piston body blocks the communication opening;

a pit is arranged on the piston body, and the connecting piece penetrates through the through hole and the pit; when the pressure born by the piston body is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the connecting piece is sheared by the piston body and the elastic piece is compressed, so that the communication opening is communicated with the pressure relief hole to relieve the pressure; when the elasticity of the elastic piece is larger than the pressure borne by the piston body, the elastic piece pushes the piston body to move towards the communication opening, so that the first end of the piston body blocks the communication opening.

2. The pressure relief device according to claim 1, wherein said pressure relief holes are plural in number, and said plural pressure relief holes are arranged at intervals along a circumferential direction of said columnar cavity.

3. The pressure relief device according to claim 1 or 2, wherein the number of the through holes and the number of the pits are plural, the plural through holes are arranged at intervals along the circumferential direction of the columnar inner cavity, the plural pits are arranged at intervals along the circumferential direction of the piston body, and the plural through holes and the plural pits are arranged in one-to-one correspondence.

4. The pressure relief device of claim 1, wherein said connector is a pin, said pin being in clearance fit with said through hole.

5. The pressure relief device of claim 1 or 4, wherein said recess is a receptacle and said connector is a clearance fit with said receptacle.

6. The pressure relief device of claim 1 or 4, wherein said recess is a notch extending from a middle portion of said piston body to said second end of said piston body.

7. The pressure relief device according to claim 1, wherein said second end of said piston body defines a first receiving groove for receiving said first end of said resilient member.

8. The pressure relief device according to claim 1, wherein a sealing cover is disposed at a second end of said cylindrical cavity, said sealing cover having a second receiving groove for receiving a second end of said resilient member.

9. The pressure relief device according to claim 1, wherein a sealing ring is sleeved outside the piston body, and the outer peripheral surface of the sealing ring is used for contacting with the inner side surface of the cylindrical inner cavity.

10. Perforating gun, characterized in that it comprises a perforating gun body and a pressure relief device according to any of claims 1-9, the communication port of the pressure relief device being in communication with a charge hole in the perforating gun body.

Technical Field

The invention relates to the technical field of oil and gas field exploitation, in particular to a pressure relief device and a perforating gun.

Background

In oil and gas field production, cementing is usually performed by running a casing into the oil and gas well and then perforating with a perforating gun. In the process of perforation operation, a perforating gun is connected below a tubing string, the perforating gun is lowered to a preset depth in a casing through the tubing string, the perforating gun is aligned to the casing, then shaped charges in the perforating gun are detonated, the casing is penetrated through by the shaped charges, and therefore an oil-gas flow channel between an oil-gas well and a reservoir stratum is established.

High-temperature and high-pressure gas can be generated after the shaped charge is exploded, and the high-temperature and high-pressure gas is discharged through perforation holes in the perforating gun, so that pressure relief is realized. However, the pressure relief is slow due to the small size of the perforation hole, high-temperature and high-pressure gas is gathered in the perforating gun, and when the pressure of the high-temperature and high-pressure gas is greater than the internal pressure resistance limit value of the perforating gun, the perforating gun is easy to expand and explode.

Disclosure of Invention

The invention provides a pressure relief device and a perforating gun, and aims to solve the problems of gun expansion and gun explosion of the perforating gun.

On one hand, the invention provides a pressure relief device which comprises a cavity, a piston body, an elastic piece and a connecting piece, wherein the cavity is provided with a columnar inner cavity, a communication port used for being communicated with a bullet loading hole in a perforating gun body is arranged at the first end of the columnar inner cavity, a pressure relief hole and a through hole are arranged on the side wall of the columnar inner cavity, and the through hole is arranged between the communication port and the pressure relief hole; the piston body and the elastic piece are arranged in the columnar inner cavity, the first end of the elastic piece is abutted against the second end of the piston body, and the second end of the elastic piece is abutted against the second end of the columnar inner cavity so that the first end of the piston body blocks the communication opening; the piston body is provided with a pit, and the connecting piece penetrates through the through hole and the pit; when the pressure born by the piston body is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the connecting piece and the compression elastic piece are sheared by the piston body, so that the communication port is communicated with the pressure relief hole to relieve the pressure; when the elasticity of the elastic piece is larger than the pressure born by the piston body, the elastic piece pushes the piston body to move towards the communication opening, so that the first end of the piston body blocks the communication opening.

In the pressure relief device, the number of the pressure relief holes is multiple, and the pressure relief holes are arranged at intervals along the circumferential direction of the columnar inner cavity.

In the pressure relief device, the number of the through holes and the number of the pits are multiple, the through holes are arranged at intervals along the circumferential direction of the columnar inner cavity, the pits are arranged at intervals along the circumferential direction of the piston body, and the through holes and the pits are arranged in a one-to-one correspondence manner.

In the above pressure relief device, the connecting member is a pin, and the pin is in clearance fit with the through hole.

In the above-described pressure relief device, the recess is a receptacle, and the connecting member is in clearance fit with the receptacle.

In the above pressure relief device, the recess is a slot extending from the middle of the piston body to the second end of the piston body.

In the above pressure relief device, the second end of the piston body is provided with a first receiving groove, and the first receiving groove is used for receiving the first end of the elastic member.

In the pressure relief device, the second end of the columnar inner cavity is provided with the sealing cover, the sealing cover is provided with the second accommodating groove, and the second accommodating groove is used for accommodating the second end of the elastic piece.

In the pressure relief device, the piston body is sleeved with the sealing ring, and the outer peripheral surface of the sealing ring is used for contacting with the inner side surface of the columnar inner cavity.

On the other hand, the invention also provides a perforating gun which comprises a perforating gun body and the pressure relief device, wherein a communication port of the pressure relief device is communicated with the bullet loading hole in the perforating gun body.

When the pressure relief device provided by the invention is used, the communication port of the pressure relief device is communicated with the bullet loading hole on the perforating gun body, and the first end of the piston body is enabled to plug the communication port under the action of the elasticity of the elastic piece because the elastic piece in the pressure relief device is abutted against the second end of the piston body. When the perforating gun is put into the casing for perforating operation, the first end of the piston body seals the communication port, so that perforating liquid in the casing can be prevented from entering the perforating gun body through the communication port, and the influence of the perforating liquid on the normal work of the perforating gun is avoided. After the shaped charges in the perforating gun body are detonated, high-temperature and high-pressure gas generated by explosion acts on the perforating gun body to enable the perforating gun body to bear pressure, and meanwhile, the high-temperature and high-pressure gas acts on the first end of the piston body through the communication port to enable the piston body to bear the same pressure. Because the connecting piece has certain strength, when the pressure born by the piston body is less than or equal to the preset pressure, the connecting piece can not be sheared by the piston body, the first end of the piston body can still block the communication opening, and at the moment, the high-temperature and high-pressure gas in the perforating gun body is discharged through the perforation hole on the perforating gun body.

When the pressure born by the piston body is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the connecting piece is sheared by the piston body, the elastic piece is compressed to move towards the pressure relief hole, when the piston body moves to the preset position, the communication port is communicated with the pressure relief hole, at the moment, one part of high-temperature and high-pressure gas in the perforating gun body is discharged through the perforation hole, and the other part of high-temperature and high-pressure gas is discharged out of the pressure relief device through the communication port and the pressure relief hole, so that the rapid pressure relief is realized. Because the pressure born by the perforating gun body is the same as the pressure born by the piston body, and the pressure born by the piston body is less than or equal to the internal pressure resistance limiting value of the perforating gun body, the pressure born by the perforating gun body is less than or equal to the internal pressure resistance limiting value of the perforating gun body, so that the perforating gun does not have the problems of gun expansion and gun explosion. After the high-temperature and high-pressure gas in the perforating gun body is exhausted, the elastic force of the elastic piece is larger than the pressure borne by the piston body, and under the elastic force action of the elastic piece, the elastic piece can push the piston body to move towards the communication opening, so that the first end of the piston body can block the communication opening again, perforating liquid in the sleeve can be prevented from entering the perforating gun body through the communication opening, and the perforating liquid is prevented from influencing the normal work of the perforating gun.

Therefore, after the shaped charge in the perforating gun body is detonated, high-temperature and high-pressure gas generated by explosion can be decompressed together through the pressure relief device and the perforation hole, and compared with the prior art in which the pressure is relieved only through the perforation hole, the pressure relief speed is obviously improved, so that the perforating gun can be prevented from being damaged due to the high-temperature and high-pressure gas generated by the explosion of the shaped charge, the problems of gun expansion and gun explosion of the perforating gun can be effectively solved, the perforating operation is ensured to be smoothly carried out, the success rate of the perforating operation is improved, and the period of the perforating operation is shortened.

Drawings

Fig. 1 is a schematic structural view of a pressure relief device according to an embodiment of the present invention when closed;

fig. 2 is a schematic structural view of the pressure relief device according to the embodiment of the present invention when opened;

fig. 3 is a cross-sectional view taken along the line a-a in fig. 1.

Description of reference numerals:

10-a cavity; 11-a cylindrical lumen;

12-a communication port; 13-pressure relief holes;

14-a through hole; 15-sealing the cover;

20-a piston body; 21-pits;

22-a sealing ring; 30-a spring;

40-connecting piece.

Detailed Description

High-temperature high-pressure gas can be generated after the shaped charge in the perforating gun explodes and is discharged through the perforation hole on the perforating gun, so that pressure relief is realized. However, the pressure relief is slow due to the small size of the perforation hole, high-temperature and high-pressure gas is gathered in the perforating gun, and when the pressure of the high-temperature and high-pressure gas is greater than the internal pressure resistance limit value of the perforating gun, the perforating gun is easy to expand and explode. In view of this, the embodiment of the present invention provides a pressure relief device, which performs rapid pressure relief on a perforating gun through the pressure relief device and a perforation hole, so that pressures inside and outside the perforating gun are rapidly balanced, thereby preventing the problems of gun expansion and gun explosion.

In order to make the aforementioned objects, features and advantages of the embodiments of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the production of oil and gas fields, cementing is usually performed by running a casing into the well and then perforating with a perforating gun to establish a flow path between the well and the reservoir. The perforating gun comprises a perforating gun body and a pressure relief device, wherein a loading hole and a perforating hole are formed in the perforating gun body, the loading hole is used as a filling hole of a shaped charge, and is used for a communication hole communicated with the pressure relief device, an internal thread is usually arranged in the loading hole, an external thread is arranged on the outer surface of a cavity where a communication port of the pressure relief device is located, and the pressure relief device and the perforating gun body can be connected through the matching of the internal thread and the external thread. When the perforating gun is used for perforating operation, the shaped charge is firstly loaded into the perforating gun body through the charge hole, and then the communication port of the pressure relief device is communicated with the charge hole. After detonation of the shaped charges, the shaped charges are ejected from the perforations and the casing is then fired through, thereby establishing a flow path between the well and the reservoir. High-temperature and high-pressure gas generated after the shaped charge explodes is partially discharged through the perforation hole, and the other part is discharged through the charge hole by the pressure relief device, so that the pressure is quickly relieved, the pressure inside and outside the perforating gun is quickly balanced, and the problems of gun expansion and gun explosion are prevented.

Fig. 1 is a schematic structural view of a pressure relief device according to an embodiment of the present invention when closed; fig. 2 is a schematic structural view of the pressure relief device according to the embodiment of the present invention when opened; fig. 3 is a cross-sectional view taken along the line a-a in fig. 1.

As shown in fig. 1, 2 and 3, the pressure relief device according to the embodiment of the present invention includes a cavity 10, a piston body 20, an elastic member 30 and a connecting member 40, wherein the cavity 10 has a cylindrical inner cavity 11, a first end of the cylindrical inner cavity 11 is provided with a communication port 12 for communicating with a loading hole on a perforating gun body, a side wall of the cylindrical inner cavity 11 is provided with a pressure relief hole 13 and a through hole 14, and the through hole 14 is disposed between the communication port 12 and the pressure relief hole 13. The piston body 20 and the elastic member 30 are installed in the cylindrical cavity 11, and a first end of the elastic member 30 abuts against a second end of the piston body 20, and a second end of the elastic member 30 abuts against a second end of the cylindrical cavity 11, so that the first end of the piston body 20 blocks the communication port 12. The piston body 20 is provided with a recess 21, and the connecting member 40 is inserted into the through hole 14 and the recess 21. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the piston body 20 shears the connecting piece 40 and the compression elastic piece 30, so that the communication port 12 is communicated with the pressure relief hole 13 for pressure relief. When the elastic force of the elastic member 30 is greater than the pressure received by the piston body 20, the elastic member 30 pushes the piston body 20 to move toward the communication opening 12 so that the first end of the piston body 20 blocks the communication opening 12.

In the embodiment, the cavity 10 is a housing having an inner cavity, and the shape of the cavity 10 may be a cylinder, or may be other shapes, such as a rectangular parallelepiped, a sphere, and the like. Preferably, the chamber 10 is cylindrical in shape. The inner cavity of the cavity 10 is a columnar inner cavity 11, and the columnar inner cavity 11 is columnar. For example, the cylindrical cavity 11 may be a cylindrical cavity or a polygonal cylindrical cavity. Preferably, the cylindrical cavity 11 is a cylindrical cavity.

Since the cylindrical inner cavity 11 is an inner cavity of the cavity 10, a side wall of the cylindrical inner cavity 11 is a side wall of the cavity 10, and an inner side surface of the cylindrical inner cavity 11 is an inner side surface of the cavity 10. The cylindrical cavity 11 has opposite first and second ends in a length direction. For example, as shown in fig. 1 and 2, the first end of the cylindrical cavity 11 is the upper end of the cylindrical cavity 11, and the second end of the cylindrical cavity 11 is the lower end of the cylindrical cavity 11.

Wherein, the first end of the columnar inner cavity 11 is provided with a communication port 12, and the communication port 12 is respectively communicated with the columnar inner cavity 11 and a charging hole on the perforating gun body. The side wall of the columnar inner cavity 11 is provided with a pressure relief hole 13 and a through hole 14, that is, the side wall of the cavity 10 is provided with the pressure relief hole 13 and the through hole 14, and the pressure relief hole 13 is communicated with the columnar inner cavity 11. The communication port 12 communicates with the relief hole 13 through the columnar inner chamber 11 to perform relief.

The piston body 20 and the elastic member 30 are installed in the cylindrical inner chamber 11. Wherein the shape of the piston body 20 matches the shape of the cylindrical bore 11, i.e. the piston body 20 is also cylindrical in shape. The piston body 20 has opposite first and second ends in a length direction. For example, as shown in fig. 1 and 2, a first end of the piston body 20 is an upper end of the piston body 20, and a second end of the piston body 20 is a lower end of the piston body 20. The elastic member 30 is a member that can deform along its length direction under the action of an external force by its elasticity and recover to its original shape after the external force is removed, and may be a coil spring, a spring plate, an elastic ring, an elastic column, or the like. The resilient member 30 has opposite first and second ends in the length direction. For example, as shown in fig. 1 and 2, the first end of the elastic member 30 is an upper end of the elastic member 30, and the second end of the elastic member 30 is a lower end of the elastic member 30.

Because the first end of the elastic member 30 abuts against the second end of the piston body 20 and the second end of the elastic member 30 abuts against the second end of the cylindrical inner cavity 11, the elastic member 30 is in a compressed state, and under the elastic force of the elastic member 30, the first end of the piston body 20 can block the communication port 12, thereby blocking the communication between the communication port 12 and the pressure relief hole 13.

The recess 21 provided in the piston body 20 means that a recessed structure recessed from the outer peripheral surface to the inside is provided on the outer peripheral surface of the piston body 20, and the recess 21 is the recessed structure. A connecting member 40 is inserted through the through hole 14 and the recess 21, and the connecting member 40 is used to connect the piston body 20 and the chamber 10 together. The predetermined pressure is the maximum amount of pressure that piston body 20 can withstand when piston body 20 is under pressure and connector 40 is not sheared by piston body 20. The limit value of the internal pressure resistance of the perforating gun body refers to the maximum value of the pressure which can be borne by the perforating gun body when the perforating gun body bears the pressure and the perforating gun body cannot expand or explode. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the piston body 20 shears the connecting piece 40 and the compression elastic piece 30, so that the communication port 12 is communicated with the pressure relief hole 13 for pressure relief.

Wherein the chamber body 10 and the piston body 20 are made of a metal material to prevent damage when subjected to high pressure. The elastic member 30 can be a spring with a predetermined elastic coefficient or other elastic members according to actual needs, and the first end of the piston body 20 can be sealed off from the communication opening 12 only by the elastic force of the elastic member 30. The connecting element 40 can be made in a predetermined thickness and a predetermined length according to actual needs to provide the pressure relief device with a suitable predetermined pressure. It will be appreciated that different gun bodies have different internal pressure resistance limits and that different thicknesses and lengths of the connector 40 may be selected for different gun bodies to provide a predetermined pressure at the pressure relief device that is less than the internal pressure resistance limit of the gun body.

When the pressure relief device provided by the invention is used, the communication port 12 of the pressure relief device is communicated with the bullet loading hole on the perforating gun body, and the elastic piece 30 in the pressure relief device is abutted against the second end of the piston body 20, so that the first end of the piston body 20 blocks the communication port 12 under the action of the elastic force of the elastic piece 30. When the perforating gun is put into a casing for perforating operation, the first end of the piston body 20 blocks the communication port 12, so that perforating fluid in the casing can be prevented from entering the perforating gun body through the communication port 12, and the perforating fluid is prevented from influencing the normal operation of the perforating gun. After the shaped charges in the perforating gun body are detonated, high-temperature and high-pressure gas generated by explosion acts on the perforating gun body to enable the perforating gun body to bear pressure, and simultaneously acts on the first end of the piston body 20 through the communication port 12 to enable the piston body 20 to bear the same pressure. Because the connecting piece 40 has certain strength, when the pressure born by the piston body 20 is less than or equal to the preset pressure, the connecting piece 40 can not be sheared by the piston body 20, the first end of the piston body 20 can still block the communication opening 12, and the high-temperature and high-pressure gas in the perforating gun body is discharged through the perforation holes on the perforating gun body.

When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the piston body 20 shears the connecting piece 40 and compresses the elastic piece 30 to move towards the pressure relief hole 13, when the piston body 20 moves to the preset position, the communication port 12 is communicated with the pressure relief hole 13, at the moment, part of high-temperature and high-pressure gas in the perforating gun body is exhausted through the perforation hole, and the other part of high-temperature and high-pressure gas is exhausted out of the pressure relief device through the communication port 12 and the pressure relief hole 13, so that the rapid pressure relief is realized. Because the pressure born by the perforating gun body is the same as the pressure born by the piston body 20, and the pressure born by the piston body 20 is less than or equal to the internal pressure resistance limit value of the perforating gun body, the pressure born by the perforating gun body is less than or equal to the internal pressure resistance limit value of the perforating gun body, so that the perforating gun does not have the problems of gun expansion and gun explosion. After the high-temperature and high-pressure gas in the perforating gun body is exhausted, the elastic force of the elastic member 30 is greater than the pressure borne by the piston body 20, and under the elastic force of the elastic member 30, the elastic member 30 can push the piston body 20 to move towards the communication opening 12, so that the first end of the piston body 20 can block the communication opening 12 again, perforating fluid in the sleeve can be prevented from entering the perforating gun body through the communication opening 12, and the perforating fluid is prevented from influencing the normal work of the perforating gun.

Therefore, after the shaped charge in the perforating gun body is detonated, high-temperature and high-pressure gas generated by explosion can be decompressed together through the pressure relief device and the perforation hole, and compared with the prior art in which the pressure is relieved only through the perforation hole, the pressure relief speed is obviously improved, so that the perforating gun can be prevented from being damaged due to the high-temperature and high-pressure gas generated by the explosion of the shaped charge, the problems of gun expansion and gun explosion of the perforating gun can be effectively solved, the perforating operation is ensured to be smoothly carried out, the success rate of the perforating operation is improved, and the period of the perforating operation is shortened.

The casing is filled with perforating liquid in order to control the pressure difference between the reservoir and the oil-gas well during perforating operation by using the pressure of the perforating liquid and prevent the problems of blowout, perforating blockage, reservoir damage and the like during perforating operation. In order to avoid the influence of perforating fluid on the normal operation of the perforating gun, the perforating fluid needs to be prevented from entering the perforating gun body in the whole perforating operation process. In the process of discharging high-temperature and high-pressure gas in the perforating gun body, the high-temperature and high-pressure gas is continuously and quickly discharged, so that perforating fluid cannot enter the perforating gun body. Before and after the high-temperature and high-pressure gas in the perforating gun body is exhausted, the first end of the piston body 20 can be used for plugging the communication opening 12 under the action of the elastic force of the elastic piece 30, and perforating liquid can be prevented from entering the perforating gun body.

The predetermined position in the above embodiment is a position at which the piston body 20 is moved to communicate the communication port 12 with the relief hole 13. That is, when the piston body 20 is moved to this position, the first end of the piston body 20 no longer blocks the communication port 12 and the piston body 20 no longer seals with the inner side of the cylindrical inner chamber 11, thereby communicating the communication port 12 with the relief hole 13.

In a possible embodiment, the inner side of the cylindrical inner cavity 11 is provided with a step surface close to the first end of the cylindrical inner cavity 11, through which the communication opening 12 extends. The first end of the piston body 20 abuts against the stepped surface by the elastic force of the elastic member 30, so that the first end of the piston body 20 closes the communication port 12. At this time, the through hole 14 and the recess 21 are located on the same plane, and the piston body 20 and the chamber 10 can be coupled together by inserting the coupling member 40 into the through hole 14 and the recess 21.

In the above embodiment, after the piston body 20 is moved to the predetermined position, the communication port 12 communicates with the relief hole 13. In a possible embodiment, the number of the pressure relief holes 13 is multiple, and the multiple pressure relief holes 13 are arranged at intervals along the circumference of the cylindrical inner cavity 11. Like this at the in-process of pressure release, the pressure release speed of a plurality of pressure release holes 13 is faster, can guarantee that the perforating gun can not take place to damage because of the high temperature high-pressure gas that the shaped charge explosion produced, and the time that pressure relief device bore pressure simultaneously is shorter for pressure relief device's life-span is longer.

Preferably, the plurality of pressure relief holes 13 are uniformly spaced along the circumference of the cylindrical inner cavity 11. Therefore, in the pressure relief process, the pressure born by the cavity 10 is more uniform, so that the service life of the pressure relief device is longer. For example, the number of the pressure relief holes 13 is four, and the four pressure relief holes 13 are uniformly spaced along the circumferential direction of the columnar inner cavity 11.

In the above embodiment, in order to ensure that the first end of the piston body 20 always blocks the communication port 12 and prevent perforating fluid from entering the perforating gun body when the pressure applied to the piston body 20 is less than or equal to the predetermined pressure, the elastic member 30 is disposed between the second end of the piston body 20 and the second end of the cylindrical cavity 11, and the connecting member 40 is disposed and the connecting member 40 is inserted into the through hole 14 and the recess 21 corresponding to the through hole 14. In a possible embodiment, the number of the through holes 14 and the number of the pits 21 are both multiple, the multiple through holes 14 are arranged at intervals along the circumferential direction of the cylindrical inner cavity 11, the multiple pits 21 are arranged at intervals along the circumferential direction of the piston body 20, and the multiple through holes 14 and the multiple pits 21 are arranged in a one-to-one correspondence. For example, the number of the through holes 14 and the number of the dimples 21 are four, four through holes 14 are uniformly spaced along the circumferential direction of the cylindrical inner cavity 11, four dimples 21 are uniformly spaced along the circumferential direction of the piston body 20, and four through holes 14 and four dimples 21 are arranged in one-to-one correspondence.

The number of the through holes 14 and the pits 21 is set to be a plurality, and different numbers of connecting pieces 40 are selectively installed according to different preset pressures to connect the piston body 20 and the cavity 10 together, so that the pressure relief device can have different preset pressures, and can be suitable for different perforating gun bodies.

For example, a connecting member 40 is inserted into the through hole 14 and the recess 21, and when the piston body 20 is subjected to a pressure greater than a first predetermined pressure and less than or equal to a first internal pressure resistance limit value, the piston body 20 shears the connecting member 40, thereby achieving rapid pressure relief. The two connecting pieces 40 are respectively arranged in the through holes 14 and the pits 21 in a penetrating way, and when the pressure born by the piston body 20 is greater than a second preset pressure and less than or equal to a second internal pressure resistance limit value, the piston body 20 can simultaneously shear the two connecting pieces 40, so that the rapid pressure relief is realized. The three connecting pieces 40 are respectively arranged in the through holes 14 and the pits 21 in a penetrating way, and when the pressure born by the piston body 20 is greater than a third preset pressure and less than or equal to a third internal pressure resistance limit value, the piston body 20 can simultaneously shear the three connecting pieces 40, so that the rapid pressure relief is realized. Wherein the first predetermined pressure is less than the second predetermined pressure, the second predetermined pressure is less than the third predetermined pressure, the first internal pressure resistance limit value is less than the second internal pressure resistance limit value, and the second internal pressure resistance limit value is less than the third internal pressure resistance limit value.

From the above, it will be appreciated that a connector 40 is provided which allows a pressure relief device having a first predetermined pressure to be adapted to a body of a perforating gun having a first internal pressure resistance limit. The two connections 40 are arranged such that the pressure relief device has a second predetermined pressure suitable for use with a body of a perforating gun having a second internal pressure resistance limit. Three connections 40 are provided to allow the pressure relief device to have a third predetermined pressure for a body of a perforating gun having a third internal pressure resistance limit, and so on.

The structure of the connecting member 40 is various, for example, the connecting member 40 may be a pin, and the pin is loosely fitted to the through hole 14. A pin passes through the through hole 14 and extends into the recess 21 to connect the piston body 20 with the chamber 10. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the side wall of the pit 21 is abutted against the plug pin, and then the plug pin is sheared. When the piston body 20 shears the pin, a portion of the pin remains in the through-hole 14. The pin is a clearance fit in the through hole 14 so that the sheared pin can be easily removed from the through hole 14.

In one possible embodiment, the recess 21 is a socket and the connector 40 is a clearance fit with the socket. A connector 40 passes through the through hole 14 and extends into the receptacle to connect the piston body 20 with the chamber 10. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the hole wall of the jack is abutted against the connecting piece 40, and then the connecting piece 40 is sheared. When the piston body 20 shears the connector 40, a portion of the connector 40 may remain in the socket. The connector 40 is a clearance fit with the socket so that the sheared connector 40 can be easily removed from the socket.

The insertion hole may be a blind hole or a through hole penetrating the piston body 20. When the insertion hole is a through hole penetrating the piston body 20, the connecting member 40 firstly penetrates the through hole 14 at one side of the cylindrical cavity 11, then penetrates the through hole, and finally penetrates the through hole 14 at the other side of the cylindrical cavity 11 to connect the piston body 20 and the chamber 10 together.

In the above embodiment, the recess 21 is a receptacle, but is not limited thereto. The recess 21 may also be a catching groove extending from the middle of the piston body 20 to the second end of the piston body 20, that is, the catching groove communicates with the second end of the piston body 20. Connecting piece 40 passes through hole 14 and extends into the snap groove to connect piston body 20 and chamber 10 together. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the groove wall of the clamping groove far away from the second end of the piston body 20 is abutted against the connecting piece 40, and then the connecting piece 40 is cut off. After the piston body 20 shears the connector 40, the sheared connector 40 may be expelled from the snap groove through the second end of the piston body 20 and out of the cylindrical bore 11 through the relief hole 13 as the piston body 20 is moved to a predetermined position.

In the above embodiment, the connecting member 40 is a latch, but is not limited thereto. The connecting member 40 may also be a bolt, the through hole 14 is a bolt hole, the recess 21 is a socket, the bolt is in threaded fit with the bolt hole, and the bolt is in clearance fit with the socket. The bolts first pass through and are threadedly coupled with the bolt holes and then extend into the insertion holes to couple the piston body 20 and the chamber 10 together. When the pressure born by the piston body 20 is greater than the preset pressure and less than or equal to the limit value of the internal pressure resistance of the perforating gun body, the hole wall of the insertion hole is abutted against the bolt, and the bolt is sheared. When the piston body 20 shears the bolt, a portion of the bolt will remain in the bolt hole and another portion of the bolt will remain in the receptacle. The bolt is in threaded engagement with the bolt hole so that the sheared bolt can be conveniently unscrewed from the bolt hole. The bolt is in clearance fit with the jack, so that the sheared bolt can be conveniently taken out of the jack.

In the above embodiment, the resilient member 30 is installed between the second end of the piston body 20 and the second end of the cylindrical bore 11. In order to improve the stability of the elastic member 30 and prevent the elastic member 30 from shaking, in a possible embodiment, the second end of the piston body 20 is provided with a first receiving groove for receiving the first end of the elastic member 30. The first end of the elastic member 30 is accommodated in the first accommodating groove, the first end of the elastic member 30 abuts against the groove bottom of the first accommodating groove, and the groove wall of the first accommodating groove can prevent the elastic member 30 from moving radially, so that the stability of the elastic member 30 is improved.

In the above embodiment, the cavity 10 may be formed by casting, forging, or metal injection molding, and the cavity 10 with both ends open may be formed first, and then the second end of the cylindrical inner cavity 11 is closed. For example, the first end and the second end of the cylindrical cavity 11 are both provided with openings, wherein the opening at the first end of the cylindrical cavity 11 is a communication port 12, and the opening at the second end of the cylindrical cavity 11 is closed by a sealing cover 15, that is, the second end of the cylindrical cavity 11 is provided with the sealing cover 15. The cover 15 is provided with a second receiving groove for receiving a second end of the resilient member 30. The second end of the elastic member 30 is accommodated in the second accommodating groove, the second end of the elastic member 30 abuts against the groove bottom of the second accommodating groove, and the groove wall of the second accommodating groove can prevent the elastic member 30 from moving radially, so that the stability of the elastic member 30 is improved.

Wherein the cap 15 is detachably coupled to the second end of the cylindrical inner chamber 11 so that the cap 15 can be removed from the second end of the cylindrical inner chamber 11 when installing or replacing the piston body 20 and the elastic member 30, and then the piston body 20 and the elastic member 30 are put into the cylindrical inner chamber 11 or the piston body 20 and the elastic member 30 are taken out from the cylindrical inner chamber 11. Wherein, can dismantle the connection and can choose threaded connection or other connection methods of dismantling for use according to actual need.

In a possible embodiment, the piston body 20 is provided with a sealing ring 22 in a jacket manner, the outer circumferential surface of the sealing ring 22 being intended to be in contact with the inner side of the cylindrical interior 11. The sealing ring 22 is sleeved outside the piston body 20, the sealing ring 22 can move along with the piston body 20, and the outer peripheral surface of the sealing ring 22 is always in contact with and sealed with the inner side surface of the columnar inner cavity 11 in the moving process, so that perforating fluid is prevented from entering the perforating gun body from a gap between the piston body 20 and the inner side surface of the columnar inner cavity 11. The number of the sealing rings 22 may be plural, and the plural sealing rings 22 are provided at intervals in the axial direction of the piston body 20. The plurality of sealing rings 22 arranged at intervals have a better sealing effect on the gap between the piston body 20 and the inner side surface of the cylindrical inner cavity 11. For example, the number of the seal rings 22 is two, and the two seal rings 22 are provided at intervals in the axial direction of the piston body 20.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.