A perforating gun

Abstract

The present invention relates to the technical field of oil production, and specifically discloses a perforating gun, wherein a bullet rack tube is coaxially arranged in a gun barrel and is provided with a plurality of bullet holes for installing perforating bullets, a detonating cord is wound around the outer side of the bullet rack tube and connected to each perforating bullet, a limit frame is fixedly arranged on the outer side of the bullet rack tube and a bullet hole cover is arranged therein, a closing piece is elastically slidably assembled in the limit frame along the radial direction of the bullet rack tube, a through hole connected to the bullet hole is arranged in the central area of ​​the closing piece, and a non-return structure is connected between the closing piece and the gun barrel to prevent the closing piece from returning to its original position after movement. The perforating gun of the present invention utilizes the blasting energy of the perforating bullet to displace the closing piece, thereby preventing perforating bullet fragments from entering the annular space between the gun barrel and the bullet rack tube, thereby avoiding the fragments from being stuck between the bullet rack tube and the gun barrel, and ensuring the smooth use of the perforating gun.

Description

Technical Field

[0001] The invention relates to the technical field of oil extraction, and in particular to a perforating gun. Background Art

[0002] The perforating gun is an important tool used for well completion or cementing in petroleum engineering, and is mainly used for perforating operations in oil and gas wells. It uses the principle of efficient concentrated energy blasting and the high-energy metal jet emitted by the perforating bullet to penetrate the wellbore, cement ring and formation, establish a channel for oil and gas production, and allow oil and gas to flow from the formation into the wellbore for oil and gas extraction. This operation process is called the "finishing touch" of oil and gas exploration and is carried out after drilling, logging, cementing and other processes.

[0003] The Chinese patent document with the authorization announcement number CN117868756B discloses a perforator, including a casing, a detonating cord and two positioning plates, an ammunition rack is arranged between the two positioning plates, the ammunition rack includes a plurality of coaxially arranged frames, each frame is provided with a bullet hole for loading a perforating bullet, the detonating cord is used to connect with a plurality of perforating bullets loaded on the ammunition rack, and the casing is sleeved on the outer peripheral side of the ammunition rack. Under normal conditions, the casing seals the ammunition rack and the perforating bullets therein, and after the detonating cord is ignited, the perforating bullets can be detonated, so that the perforating bullet jets are fired in all directions, achieving the effect of perforating the well wall, and the holes formed are convenient for oil and gas to flow from the formation into the wellbore.

[0004] However, after the perforating gun is used, some fragments of the perforating bullet may remain in the interlayer between the ammunition rack and the casing. These fragments are likely to get stuck in the casing, hindering the subsequent axial removal of the casing. In addition, the presence of the fragments of the perforating bullet increases the friction between the ammunition rack and the casing, thereby causing wear and affecting the service life of the perforating gun. Summary of the invention

[0005] The present invention provides a perforating gun, aiming to solve the problem in the related art that part of fragments of the perforating bullet may remain in the interlayer between the ammunition rack and the casing, thereby affecting the smooth use of the perforating gun.

[0006] The perforating gun of the present invention comprises a gun barrel, a loading mechanism and a protection assembly, wherein the loading mechanism comprises a bullet rack tube and a detonating cord, the bullet rack tube is coaxially arranged in the gun barrel and is provided with a plurality of bullet holes for installing perforating bullets, the detonating cord is wound around the outside of the bullet rack tube and is connected to each of the perforating bullets, the protection assembly is separately arranged at the plurality of bullet holes, the protection assembly comprises a limit frame and a closing member, the limit frame is fixedly arranged on the outside of the bullet rack tube and the bullet hole cover is arranged therein, the closing member is elastically slidably assembled in the limit frame along the radial direction of the bullet rack tube, a through hole connected to the bullet hole is provided in the central area of ​​the closing member, and a non-return structure is connected between the closing member and the gun barrel to prevent the closing member from returning to its original position after moving.

[0007] The effect is that the present invention utilizes the blasting energy of the perforating bullet to make the sealing member slide outward, thereby isolating the annular space between the gun barrel and the bullet rack tube from the internal space of the bullet rack tube, and the sealing member can block the fragments of the perforating bullet and prevent them from entering the annular space, thereby avoiding the fragments from being stuck between the bullet rack tube and the gun barrel, making the subsequent axial movement of the gun barrel smoother. In addition, since there is no fragment left between the bullet rack tube and the gun barrel, the friction effect thereof is almost eliminated, thereby reducing wear and ensuring the service life of the perforating gun.

[0008] Preferably, the non-return structure includes a guide member arranged on the closing member, a flexible ring sleeved on the outer circumference of the guide member, a guide hole opened on the gun barrel, and a flexible ring arranged in the guide hole, wherein the outer diameter of the flexible ring is larger than the inner diameter of the flexible ring, and when the closing member slides away from the bomb rack tube, the guide member can extend into the guide hole, and the flexible ring is squeezed over the flexible ring, and the flexible ring is used to limit the retreat of the flexible ring.

[0009] Preferably, the gun barrel is provided with a blocking mechanism corresponding to the through holes one by one, the blocking mechanism comprising a displacement seat body, a matching piece and a blocking door, the displacement seat body is slidably assembled on the gun barrel along the radial direction of the bullet holder tube and is provided with an exit hole for passing the perforating bullet jet; the matching piece is arranged on the displacement seat body and slidably fitted in the guide hole, the matching piece is used to contact the guide member when the guide member extends into the guide hole, and slide outward under the push of the guide member; there are two blocking doors and both are slidably assembled on the displacement seat body, and a guiding structure is connected between the blocking door and the gun barrel, so that when the displacement seat body slides outward, the guiding structure guides the two blocking doors to approach each other until the exit hole is blocked.

[0010] The effect is that the fragments of the perforating bullet can be blocked by the blocking door on the inner side of the barrel, that is, the fragments can be retained in the penetration hole, the through hole and the bullet holder tube, thereby preventing the fragments from spreading outward and entering the wellbore, thereby avoiding the fragments from contaminating the oil and gas in the wellbore, causing wear or damage to the equipment in the wellbore, and also avoiding the formation of safety hazards in the wellbore, ensuring the safety of work.

[0011] Preferably, the outer wall of the gun barrel is provided with a groove, the blocking door has a protrusion extending into the groove, the guide structure includes an inclined guide groove opened on the groove wall and a guide rod fixed on the protrusion, the guide rod is slidably fitted in the guide groove, the guide grooves in the two guide structures are symmetrically arranged in an eight-shaped shape, and when the blocking door moves outward, the guide rod slides in the guide groove to make the two blocking doors approach each other.

[0012] The effect is that the outward movement of the guide groove and the blocking door forms a linkage. When the blocking door moves outward, it is used to control the moving direction of the guide rod, thereby prompting the two blocking doors to approach each other until the two blocking doors block the outlet hole and close the outlet hole.

[0013] Preferably, launching holes corresponding to the through holes are arranged on the wall of the gun barrel, and the displacement seat body forms a retaining ring portion at the through hole, and the retaining ring portion fits in the corresponding launching hole. When the displacement seat body slides outward, the retaining ring portion slides in the launching hole to maintain the connection state between the launching hole and the through hole.

[0014] Preferably, the plurality of bullet holes are divided into a plurality of hole groups arranged at intervals along the axial direction of the bullet rack tube, the hole group includes two opposite bullet holes, the two bullet holes in the hole group can be equipped with a single perforating bullet, and the axial directions of the bullet holes in two adjacent hole groups are arranged at an angle; a rotatable bullet rack is provided in the bullet rack tube, the bullet rack includes a limiting structure corresponding to the hole groups one by one, the limiting structure includes an annular portion for limiting the position of the perforating bullet and a blocking portion connected to the annular portion, and when the bullet rack rotates, the blocking portion can block one of the bullet holes in the hole group.

[0015] The effect is that when the perforating gun is placed horizontally, the sealing part can seal the bullet holes above which the perforating bullet fragments have been cleared through the rotation of the bullet rack, so as to prevent the fragments from flowing back into these bullet holes again; after that, the perforating gun is turned 180 degrees, so that all the fragments fall into the inner space of the bullet rack tube, and the bullet rack tube is tilted so that the fragments can flow out along the bullet rack tube, so as to achieve the purpose of cleaning, which is simple and convenient, and has a good cleaning effect.

[0016] Preferably, the starting end of the bomb rack forms a rotating handle that is rotatably fitted in the bomb rack tube.

[0017] The effect is that the rotating handle is easy to hold to drive the bomb rack to rotate.

[0018] Preferably, two ends of the gun barrel are respectively threadedly connected with a gun head and a gun tail.

[0019] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0020] The present invention utilizes the blasting energy generated at the moment of the perforating bullet blasting to drive the sealing member to slide outward until it abuts against the gun barrel. At this time, a part of the sealing member enters the annular space, and the other part is retained in the limit frame, thereby isolating the space from the bullet support tube to the through hole portion from the annular space between the bullet support tube and the gun barrel. Fragments after the perforating bullet blasting cannot enter the annular space under the obstruction of the sealing member, thereby avoiding the fragments from being stuck between the bullet support tube and the gun barrel, making the subsequent axial movement of the gun barrel smoother. In addition, since there is no fragment left between the bullet support tube and the gun barrel, the friction effect thereof is almost eliminated, thereby reducing wear and ensuring the service life of the perforating gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the appearance of the perforating gun of the present invention.

[0022] Figure 2 It is a cross-sectional schematic diagram of the perforating gun of the present invention.

[0023] Figure 3 The present invention Figure 2 A magnified schematic diagram of center A.

[0024] Figure 4 It is a structural schematic diagram of the concealed gun barrel rear bullet rack tube to the blocking mechanism of the present invention.

[0025] Figure 5 It is a local structural schematic diagram of a gun barrel portion of the present invention.

[0026] Figure 6 It is a three-dimensional schematic diagram of the bomb rack tube to the bomb rack part of the present invention.

[0027] Figure 7 It is a schematic diagram of the structure when the sealing member of the present invention enters the annular space.

[0028] Reference numerals:

[0029] 100. Perforating bullets;

[0030] 1. Gun barrel; 11. Gun head; 12. Gun tail; 13. Groove; 131. Guide groove; 14. Launch hole;

[0031] 2. Protective assembly; 21. Limiting frame; 22. Closing member; 221. Through hole; 222. Tension spring;

[0032] 3. Bullet rack tube; 31. Bullet hole;

[0033] 4. Detonating cord;

[0034] 5. Annular space;

[0035] 61. guide member; 62. flexible ring; 63. guide hole; 64. flexible ring;

[0036] 7. Locking mechanism; 71. Displacement seat; 711. Through hole; 712. Guide rail; 713. Stop ring; 72. Matching piece; 73. Locking door;

[0037] 8. bomb rack; 81. annular portion; 82. sealing portion; 83. rotating handle; 831. annular ring; 832. connecting rod structure. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0039] Combine the following Figures 1 to 7 The perforating gun of the present invention is described.

[0040] like Figure 1 , Figure 2 , Figure 3 and Figure 7 As shown, the perforating gun of the present invention comprises a gun barrel 1 , a loading mechanism and a protection component 2 .

[0041] The two ends of the gun barrel 1 are respectively threadedly connected with a gun head 11 and a gun tail 12 , and the gun head 11 and the gun tail 12 are used to seal the inner space of the gun barrel 1 to prevent external impurities from entering the inner space of the gun barrel 1 .

[0042] The loading mechanism includes a bullet rack tube 3 and a detonating cord 4. The bullet rack tube 3 is coaxially arranged in the barrel 1 and forms an annular space 5 with the barrel 1. The bullet rack tube 3 is provided with a plurality of hole groups arranged at equal intervals along its axial direction. The hole group includes two opposite bullet holes 31. The two bullet holes 31 in the hole group can be equipped with a single perforating bullet 100. The axial directions of the bullet holes 31 in two adjacent hole groups are perpendicular to each other. The detonating cord 4 is spirally wound on the outside of the bullet rack tube 3 and connected to each perforating bullet 100 to detonate the perforating bullet 100.

[0043] There are multiple protection components 2 and they are arranged at multiple bullet holes 31. The protection components 2 include a limit frame 21 and a closure member 22. The limit frame 21 is fixedly arranged on the outside of the bullet rack tube 3 and covers the bullet holes 31 therein. The closure member 22 is slidably assembled in the limit frame 21 along the radial direction of the bullet rack tube 3. The closure member 22 is connected to the limit frame 21 through a tension spring 222. The central area of ​​the closure member 22 is provided with a through hole 221 connected to the bullet hole 31. A non-return structure is connected between the closure member 22 and the gun barrel 1 to prevent the closure member 22 from returning to its original position after moving. In this embodiment, the shape of the closure member 22 can be an arc plate, an arc block, etc. that matches the limit frame 21.

[0044] After the perforating bullet 100 is detonated, the metal jet impacts outward along the bullet hole 31 and the through hole 221, thereby punching holes in the well wall to form holes, which facilitates the introduction of oil and gas from the formation into the wellbore. At the same time, under the action of the blasting energy of the perforating bullet 100, the sealing member 22 slides outward until it abuts against the barrel 1. Under the action of the non-return structure, the sealing member 22 is locked in the current position and cannot return to its original position. At this point, a portion of the sealing member 22 is retained in the limiting frame 21, and the other portion enters the annular space 5 and isolates the through hole 221 from the annular space 5. The fragments of the perforating bullet 100 after blasting cannot enter the annular space 5 due to the obstruction of the sealing member 22, but are retained in the bullet rack tube 3 or the through hole 221, thereby avoiding the fragments from being stuck between the bullet rack tube 3 and the barrel 1, making the subsequent axial movement of the barrel 1 smoother. In addition, since there are no fragments between the bullet rack tube 3 and the barrel 1, the friction effect thereof is almost eliminated, thereby reducing wear and tear and ensuring the service life of the perforating gun.

[0045] Continue to refer Figures 3 to 5 The non-return structure includes a guide member 61, a flexible ring 62, a guide hole 63 and a flexible ring 64. The guide member 61 and the guide hole 63 both extend along the radial direction of the bomb rack tube 3 and are arranged opposite to each other. The guide member 61 is fixed on the closure member 22, the guide hole 63 is opened on the gun barrel 1, the flexible ring 62 is sleeved on the outer periphery of the guide member 61, and the flexible ring 64 is coaxially arranged in the guide hole 63. It can be understood that the flexible ring 64 and the hole wall of the guide hole 63 are fixed together. The outer diameter of the flexible ring 62 is slightly larger than the inner diameter of the flexible ring 64. In this embodiment, the shape of the guide member 61 can be columnar, rod-shaped, etc., and the material of the flexible ring 62 and the flexible ring 64 can be rubber, silicone, etc.

[0046] When the closure member 22 slides outward, it drives the guide member 61 to slide toward the side away from the magazine tube 3, and the guide member 61 gradually extends into the guide hole 63 and drives the flexible ring 62 to squeeze over the flexible ring 64. When the closure member 22 abuts against the gun barrel 1, the flexible ring 64 is used to limit the retreat of the flexible ring 62, thereby limiting the return movement of the closure member 22.

[0047] In other embodiments, the above-mentioned flexible ring 62 can be replaced by a pin with a ball head, which is slidably assembled on the guide member 61 and connected to the guide member 61 through a spring, and the flexible ring 64 is replaced by a groove 13 matching the pin. The groove 13 is opened on the hole wall of the guide hole 63. When the guide member 61 extends into the guide hole 63, the pin can be stuck in the groove 13, thereby limiting the return movement of the guide member 61 and the closing member 22.

[0048] Under normal working conditions, the fragments of the perforating bullet 100 after blasting may also rush out of the barrel 1 through the hole 221 and enter the external wellbore, thereby possibly contaminating the oil and gas and other resources introduced into the wellbore and affecting the quality of the product. In addition, when the fragments flow in the wellbore, they may cause wear or damage to the equipment in the wellbore and affect the operation of the equipment. The presence of fragments in the wellbore also poses certain safety hazards.

[0049] To this end, continue to refer to Figure 1 , Figure 3 , Figure 4 and Figure 7 The gun barrel 1 is provided with a blocking mechanism 7 corresponding to the through hole 221. The blocking mechanism 7 includes a displacement seat body 71, a matching piece 72 and a blocking door 73. The displacement seat body 71 is slidably mounted on the outer side of the gun barrel 1 along the radial direction of the bullet holder tube 3 and is provided with an outlet hole 711 for the jet of the perforating bullet 100. The matching piece 72 is fixed on the displacement seat body 71 and slidably matched in the guide hole 63. The matching piece 72 is used to contact the guide member 61 when the guide member 61 extends into the guide hole 63, and slide outward under the push of the guide member 61. In this embodiment, the matching piece 72 can be in the shape of a column, a rod, etc. There are two blocking doors 73 and both are slidably mounted on the displacement seat body 71. Specifically, the displacement seat body 71 is provided with a guide rail 712 extending along the axial direction of the gun barrel 1, and the blocking door 73 is provided with a guide block slidably matched on the guide rail 712. Under normal conditions, the two blocking doors 73 are located on both sides of the outlet hole 711. A guide structure is connected between the blocking door 73 and the barrel 1. When the fitting 72 slides outward, it pushes the displacement seat 71 to slide outward, and the guide structure guides the two blocking doors 73 to approach each other until the two blocking doors 73 block the through hole 711. In this way, the fragments of the perforating bullet 100 can be blocked by the blocking door 73 on the inner side of the barrel 1, that is, these fragments can be retained in the through hole 711, the through hole 221 and the bullet holder tube 3, avoiding these fragments from spreading outward and entering the wellbore, thereby avoiding the problems of the fragments contaminating the oil and gas in the wellbore, causing wear or damage to the equipment in the wellbore, and also avoiding the formation of safety hazards in the wellbore, ensuring the safety of work.

[0050] Among them, the outer wall of the gun barrel 1 is provided with a groove 13 extending along its axial direction, the groove 13 is opposite to the middle area of ​​the blocking door 73, the blocking door 73 has a protrusion extending into the groove 13, the guide structure includes an inclined guide groove 131 opened on the groove wall of the groove 13 and a guide rod fixed on the protrusion, the guide rod is slidably fitted in the guide groove 131, and the guide grooves 131 in the two guide structures are symmetrically arranged in an eight-shaped shape. When the displacement seat body 71 drives the blocking door 73 to move outward, the guide rod slides in the guide groove 131 to make the two blocking doors 73 approach each other. When the two blocking doors 73 stop against each other, the two blocking doors 73 block the middle through hole 711 to make it closed.

[0051] Continue to refer Figure 3 and Figure 7 The barrel 1 is provided with a launch hole 14 corresponding to the through hole 711. It can be understood that the launch hole 14 is connected to the through hole 711 corresponding to the outside and the through hole 221 corresponding to the inside. From the inside to the outside, the projectile hole 31, the through hole 221, the launch hole 14, and the launch hole 711 together form a launch channel for the jet of the perforating bullet 100, which is convenient for the jet of the perforating bullet 100 to pass through. The displacement seat body 71 forms a retaining ring portion 713 at the through hole 711. The retaining ring portion 713 fits in the corresponding launch hole 14. When the displacement seat body 71 slides outward, the retaining ring portion 713 slides in the launch hole 14 to maintain the connection state between the launch hole 14 and the through hole 711. Such arrangement ensures that when the displacement seat body 71 moves outward, the through hole 711 and the launching hole 14 maintain a one-way connection, and the retaining ring portion 713 encloses the area between the two, thereby preventing the debris inside the barrel 1 from spreading to the surroundings from the sandwich area between the launching hole 14 and the through hole 711, thereby preventing the debris from flowing out of the barrel 1 from the sandwich area and flowing into the wellbore, thereby ensuring the blocking effect of the debris.

[0052] In order to ensure the smooth pouring of the fragments from the hole 711 to the inner area of ​​the bomb rack tube 3, continue to refer to Figure 2 and Figure 6 A rotatable bullet rack 8 is provided in the bullet rack tube 3. The bullet rack 8 includes limiting structures corresponding to the hole groups one by one. The limiting structure includes an annular portion 81 that limits the position of the perforating bullet 100 and a blocking portion 82 connected to the annular portion 81 through a connecting rod. The blocking portion 82 is an arc that matches the tube wall of the bullet rack tube 3. It can be understood here that the annular portions 81 of two adjacent limiting structures are connected by a connecting shaft.

[0053] refer to Figures 1 to 7When perforating is completed and the perforating gun is taken out of the wellbore, the perforating gun can be placed horizontally so that two adjacent hole groups are arranged in a fork shape. At this time, the blocking door 73 blocks the through hole 711, and a closed space is formed from the through hole 711 to the inner area of ​​the bullet rack tube 3. The fragments in the two upper bullet holes 31 in the two adjacent hole groups will fall into the bullet rack tube 3, and part of them may continue to fall into the two lower bullet holes 31. Then, the bullet rack 8 is rotated, and the two blocking parts 82 in the adjacent limiting structure can gradually close the two upper bullet holes 31 to prevent the fragments from returning to the two bullet holes 31 again. Then, the perforating gun is turned over 180 degrees as a whole, so that the positions of the upper and lower bullet holes 31 are reversed. At this time, the two bullet holes 31 at the bottom are blocked by the blocking portion 82, and the fragments cannot enter. The fragments in the two bullet holes 31 at the top will fall into the bullet rack tube 3 under the action of gravity. At this point, all the fragments have entered the bullet rack tube 3. If the bullet rack tube 3 is slightly tilted, the fragments can flow out along the bullet rack tube 3 to achieve the purpose of cleaning. It should be noted that at this time, the gun head 11 or the gun tail 12 has been removed in advance to make way for the discharge of the fragments. It is worth noting that the above-mentioned bullet hole 31 is not limited to the body of the bullet hole 31. The area inside the hole between the bullet hole 31 and the corresponding through hole 711 can be regarded as the interval included in the bullet hole 31. When the discharge of fragments is completed, the displacement seat body 71 can be pressed to move the displacement seat body 71 toward the axis of the barrel 1, the blocking door 73 is reset and the through hole 711 is reopened, the matching piece 72 presses the guide piece 61 to move back, and the flexible ring 62 on the guide piece 61 squeezes over the flexible ring 64. After the flexible ring 62 completely passes over the flexible ring 64, the tension spring 222 pulls the closing piece 22 and the guide piece 61 to reset. At this point, the reset of each component on the perforating gun is realized, which is convenient for the reuse of the perforating gun.

[0054] Continue to refer Figure 2 and Figure 6 The starting end of the bomb rack 8 forms a rotating handle 83 that rotates and fits in the bomb rack tube 3. It can be understood that the rotating handle 83 is similar to the rotating handle of a valve. The outer side is a circular ring body 831 that rotates and fits on the inner wall of the bomb rack tube 3, and the inner side is a star-shaped connecting rod structure 832. The connecting rod structure 832 not only supports and connects the circular ring body 831, but also does not hinder the flow of fragments, which is conducive to the discharge of fragments. The connecting rod structure 832 is connected to the annular portion 81 through a connecting shaft.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0057] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A perforating gun, comprising a gun barrel and a loading mechanism, wherein the loading mechanism comprises a charge rack tube and a detonating cord, wherein the charge rack tube is coaxially arranged in the gun barrel and is provided with a plurality of charge holes for loading perforating charges, and the detonating cord is wound around the outer side of the charge rack tube and connected to each of the perforating charges, wherein: The gun also includes a protection assembly disposed at a plurality of the bullet holes, the protection assembly including a limit frame and a closing piece, the limit frame being fixedly disposed on the outside of the bullet rack tube and the bullet hole cover being disposed therein, the closing piece being elastically slidably assembled in the limit frame along the radial direction of the bullet rack tube, a through hole communicating with the bullet hole being disposed in the central region of the closing piece, and a non-return structure being connected between the closing piece and the gun barrel for preventing the closing piece from returning to its original position after being moved; The non-return structure includes a guide member provided on the closing member, a flexible ring sleeved on the outer periphery of the guide member, a guide hole provided on the gun barrel, and a flexible ring provided in the guide hole. The outer diameter of the flexible ring is greater than the inner diameter of the flexible ring. When the closing member slides away from the bomb rack tube, the guide member can extend into the guide hole, and the flexible ring squeezes over the flexible ring. The flexible ring is used to limit the retreat of the flexible ring. Under the action of the blasting energy of the perforating bullet, the closing piece slides outward until it hits the gun barrel. Under the action of the non-return structure, the closing piece is locked in the current position and cannot return to its original position. A part of the closing piece remains in the limit frame, and the other part enters the annular space and isolates the through hole from the annular space. The fragments after the perforating bullet is exploded cannot enter the annular space due to the obstruction of the closing piece, but are retained in the bullet rack tube or the through hole, thereby preventing the fragments from being stuck between the bullet rack tube and the gun barrel.

2. The perforating gun according to claim 1, characterized in that: The gun barrel is provided with a blocking mechanism corresponding to the through holes one by one, the blocking mechanism comprising a displacement seat body, a matching piece and a blocking door, the displacement seat body is slidably assembled on the gun barrel along the radial direction of the bullet holder tube and is provided with an outlet hole for the perforating bullet jet to pass through; the matching piece is arranged on the displacement seat body and slidably matched in the guide hole, the matching piece is used to contact the guide piece when the guide piece extends into the guide hole, and slide outward under the push of the guide piece; There are two blocking doors which are slidably assembled on the displacement seat body, and a guiding structure is connected between the blocking door and the gun barrel, so that when the displacement seat body slides outward, the guiding structure guides the two blocking doors to approach each other until the penetration hole is blocked.

3. The perforating gun according to claim 2, characterized in that: The outer wall of the gun barrel is provided with a groove, and the blocking door has a protrusion extending into the groove. The guide structure includes an inclined guide groove opened on the groove wall and a guide rod fixed on the protrusion. The guide rod is slidably fitted in the guide groove. The guide grooves in the two guide structures are symmetrically arranged in an eight-shaped shape. When the blocking door moves outward, the guide rod slides in the guide groove to make the two blocking doors approach each other.

4. The perforating gun according to claim 2, characterized in that: The barrel wall of the gun barrel is provided with launching holes corresponding to the through holes one by one, and the displacement seat body forms a retaining ring portion at the through holes, and the retaining ring portion is fitted in the corresponding launching hole. When the displacement seat body slides outward, the retaining ring portion slides in the launching hole to maintain the connection state between the launching hole and the through hole.

5. The perforating gun according to claim 1, characterized in that: The plurality of projectile holes are divided into a plurality of hole groups arranged at intervals along the axial direction of the bullet rack tube, the hole group includes two opposing projectile holes, the two projectile holes in the hole group can be equipped with a single perforating bullet, and the axial directions of the projectile holes in two adjacent projectile holes groups are arranged at an angle; A rotatable bullet rack is provided in the bullet rack tube, and the bullet rack includes a limiting structure corresponding to the hole groups one by one. The limiting structure includes an annular portion that limits the position of the perforating bullet and a blocking portion connected to the annular portion. When the bullet rack rotates, the blocking portion can block one of the bullet holes in the hole group.

6. The perforating gun according to claim 5, characterized in that The starting end of the bomb rack forms a rotating handle which is rotatably fitted in the bomb rack tube.

7. The perforating gun according to claim 1, characterized in that: The two ends of the gun barrel are respectively threadedly connected with a gun head and a gun tail.

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