CN117967254B

CN117967254B - Perforating gun

Info

Publication number: CN117967254B
Application number: CN202410371943.9A
Authority: CN
Inventors: 戴鹏; 代超
Original assignee: Xi'an Ruitong Energy Technology Co ltd
Current assignee: Xi'an Ruitong Energy Technology Co ltd
Priority date: 2024-03-29
Filing date: 2024-03-29
Publication date: 2024-06-07
Anticipated expiration: 2044-03-29
Also published as: CN117967254A

Abstract

The invention relates to the technical field of equipment for shooting through an underground soil layer, and particularly discloses a perforating gun, wherein a plate group comprises two arc plates which are spaced along the circumferential direction of a bullet frame pipe, a limit frame is arranged on the inner wall of the bullet frame pipe, the arc plates are slidably arranged on the limit frame, an oil chamber is formed between the arc plates and the limit frame, a fixing piece is connected with the bullet frame pipe and provided with a buffer chamber, a piston plate is slidably matched in the buffer chamber, the piston plate is elastically connected with the fixing piece, the side wall of the buffer chamber is provided with oil holes, a grading transmission assembly is connected with the arc plates, and when first-stage pressure pulse is generated in the perforating gun, the impact force drives one arc plate in the plate group to move through the grading transmission assembly; when a second-stage pressure pulse is generated in the perforating gun, the impact force drives another arc-shaped plate in the plate group to move through the grading transmission assembly. According to the perforating gun, multiple impact pressures can be sequentially eliminated through the arrangement of the grading transmission assembly, the arc plate and the piston plate, and the explosion is avoided.

Description

Perforating gun

Technical Field

The invention relates to the technical field of equipment for penetrating an underground soil layer, in particular to a perforating gun.

Background

Perforating guns are a combination of equipment and kits for perforating hydrocarbon wells. The energy-accumulating perforating gun is widely used, and the energy accumulating phenomenon of the fried flower is used for generating energy accumulating jet flow to shoot the stratum. In the related art, some perforating guns adopt a multi-stage pulse perforating technology, and high-temperature and high-pressure gas generated by the multi-combination gunpowder echelon combustion is extruded along perforation tunnels in a pulse loading mode to impact a stratum, so that the repeated action time of the high-pressure gas on the stratum is prolonged, the perforation tunnels are extended and expanded in a crack mode, and the purposes of blocking removal, joint making, joint extending and joint expanding are achieved, so that the purposes of increasing oil and injection are achieved.

Chinese patent publication No. CN203614083U discloses a multistage pulse directional perforator, wherein when the perforating gun barrel of the perforator is in an inclined or horizontal posture, under the action of gravity of a balancing weight, a multistage pulse perforating bullet rack rotates to enable perforating bullets to be in a preset angle, so that directional perforation is realized. When the gun is ignited, the perforating bullet is detonated by the detonating cord and perforated, a primary pressure peak value is generated at the same time, and then the gun is subjected to echelon generation of a secondary pressure peak value and a tertiary pressure peak value under the action of two-stage gunpowder propellant, so that multistage pulse perforation is realized. However, in practice, the perforator still has the disadvantage of: when perforating the multi-stage pulse perforating, the perforating gun bears multiple impact pressures, the impact pressure generated by each stage of pulse is very large, and after the perforating gun impacts multiple times, the gun barrel has the risk of firing.

Disclosure of Invention

The invention provides a perforating gun, which aims to solve the problem that the gun barrel is at risk of explosion after the perforating gun is subjected to multiple impacts in the related art.

The perforating gun comprises a gun body, a bullet frame tube, plate groups, fixing pieces and a grading transmission assembly, wherein the gun body is in a circular tube shape, the bullet frame tube is coaxially arranged in the gun body, a plurality of perforating bullets penetrate through the tube wall of the bullet frame tube, the gun body is provided with blind holes corresponding to the perforating bullets one by one, the plate groups are uniformly distributed along the circumferential direction of the bullet frame tube and positioned in the bullet frame tube, the plate groups comprise two arc plates which are spaced along the circumferential direction of the bullet frame tube, the inner wall of the bullet frame tube is provided with a limiting frame, the arc plates are slidably arranged on the limiting frame along the radial direction of the bullet frame tube, and an oil chamber is formed between the arc plates and the limiting frame; the fixing piece is connected with the spring frame pipe, the fixing piece is provided with buffer chambers corresponding to the oil chambers one by one, a piston plate is slidably matched in the buffer chambers, the piston plate is elastically connected with the fixing piece, and the side wall of the buffer chamber is provided with oil holes for communicating the buffer chambers with the oil chambers; the grading transmission assembly is arranged in the fixing piece and connected with the arc-shaped plates, and when first-stage pressure pulse is generated in the perforating gun, impact force drives one arc-shaped plate in the plate group to move towards the outer side of the bullet frame pipe through the grading transmission assembly; when a second-stage pressure pulse is generated in the perforating gun, the impact force drives the other arc-shaped plate in the plate group to move towards the outer side of the bullet frame tube through the grading transmission assembly.

Preferably, the grading transmission assembly comprises a connecting rod and a locking mechanism, the number of the plate groups is two, the two arc plates in the plate groups are divided into a first arc plate and a second arc plate, the second arc plate is provided with a sliding groove, and the extending direction of the sliding groove is consistent with the sliding direction of the second arc plate; the connecting rods are four and mutually hinged to form four hinge shafts, wherein two opposite hinge shafts are respectively connected with the two first arc plates in a rotating way, and the other two hinge shafts are respectively matched in the two sliding grooves in a sliding way; the oil hole that the second arc corresponds is internal to be matched with and is blocked up the piece, the mounting include with bullet frame pipe coaxial fixed section of thick bamboo, locking mechanism locates the inboard of fixed section of thick bamboo, the blocking up the piece with locking mechanism connects, when producing first-stage pressure pulse in the perforating gun, locking mechanism receives the impact force, drives the blocking up the piece is opened the oil hole.

Preferably, the locking mechanism comprises a sliding plate, a stop block and a bearing plate, the blocking piece comprises two inserting rods, the sliding plate is respectively in sliding fit with the buffer chambers corresponding to the two second arc plates, a first spring is connected between the sliding plate and the piston plate, and the inserting rods are connected with the sliding plate; the sliding plate is provided with two protruding blocks protruding out of the buffer chamber, the two blocking blocks are in one-to-one correspondence with the two protruding blocks, the blocking blocks are slidably arranged on the fixed cylinder, and the blocking blocks are used for blocking the corresponding protruding blocks; the bearing plate is arranged in the fixed cylinder and is elastically and slidably connected with the fixed cylinder, and the stop block is connected with the bearing plate through a wedge structure, so that when the bearing plate slides, the stop block can be driven to slide through the wedge structure, and the stop block is enabled to avoid the convex block.

Preferably, the wedge structure comprises a first inclined plane arranged on the stop block and a second inclined plane arranged on the bearing plate, and the second inclined plane is matched with the first inclined plane.

Preferably, the connecting rod comprises two sub-connecting rods which are mutually overlapped and slidingly connected, wherein one sub-connecting rod is elastically and slidingly connected with an inserting block, the other sub-connecting rod is provided with a slot, and in an initial state, the inserting block of one of the two adjacent connecting rods is extruded by the sub-connecting rod of the other connecting rod, and the inserting block is inserted into the slot.

Preferably, the fixing piece and the grading transmission assembly form a multi-stage buffer device, and the multi-stage buffer device is arranged at two ends of the spring frame pipe respectively.

Preferably, a detonating cord is arranged in the gun body, and each perforating bullet is connected with the detonating cord.

Preferably, the two ends of the gun body are respectively in threaded connection with a gun head and a gun tail.

By adopting the technical scheme, the invention has the beneficial effects that:

1. The invention realizes multiple buffering by the graded transmission component, the arc-shaped plate and the piston plate, and the buffering times correspond to the times of pressure pulses, so that the impact pressure can be cleared up during each pulse, the damage of the gun body is reduced, and the explosion is avoided.

2. The insert and socket of the present invention unlocks the two sub-links when the second stage pressure pulse is about to end. Therefore, when third-stage pressure pulse is generated in the perforating gun, the whole length of the connecting rod can be prolonged, so that length compensation is performed for the outward movement of the first arc-shaped plate and the second arc-shaped plate, third buffering of the first arc-shaped plate and the second arc-shaped plate is ensured, third impact force digestion is realized, and the gun body is protected.

Drawings

Fig. 1 is a schematic perspective view of a perforating gun of the present invention.

Fig. 2 is a perspective cross-sectional view of a perforating gun of the present invention.

Fig. 3 is an enlarged schematic view of the present invention at a in fig. 2.

Fig. 4 is a partial structural schematic view of the spring carrier tube to first arcuate plate portion of the present invention.

Fig. 5 is a schematic perspective view of a first arcuate plate to shaft portion of the present invention.

Fig. 6 is a schematic partial structure of a portion from a buffer chamber to a bearing plate corresponding to a second arcuate plate of the present invention.

Fig. 7 is a schematic perspective view of a piston plate to sled portion corresponding to the second arcuate plate of the present invention.

Fig. 8 is a perspective view of a stopper of the present invention.

Fig. 9 is a schematic perspective view of a pusher of the present invention.

Fig. 10 is a perspective cross-sectional view of a connecting rod portion of the present invention.

Reference numerals:

1. A gun body; 11. a gun head; 12. a gun tail; 13. detonating cord; 14. a blind hole; 2. a spring frame tube; 21. perforating charges; 3. an arc-shaped plate; 31. an oil chamber; 32. a first arcuate plate; 321. a first support plate; 33. a second arcuate plate; 331. a second support plate; 3311. a chute; 4. a limit frame; 5. a fixed cylinder; 51. a buffer chamber; 511. an oil hole; 512. a piston plate; 5121. a second spring; 52. a fixing frame; 521. a stop block; 5211. a first inclined surface; 6. a connecting rod; 61. a hinge shaft; 62. a sub-link; 621. inserting blocks; 6211. a third spring; 622. a slot; 7. a rod; 8. a slide plate; 81. a first spring; 82. a bump; 9. a pressure bearing plate; 91. a return spring; 92. a pushing block; 921. and a second inclined plane.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

The perforating gun of the present invention is described below in conjunction with fig. 1-10.

In a first embodiment, as shown in fig. 1 to 9, the perforating gun of the present invention includes a gun body 1, a bullet frame tube 2, a plate set, a fixing member and a grading transmission assembly, the gun body 1 is in a circular tube shape, two ends of the gun body 1 are respectively connected with a gun head 11 and a gun tail 12 in a threaded manner, the gun head 11 and the gun tail 12 are both in a circular ring structure coaxial with the gun body 1, and the interior of the gun head 11 can be closed. The bullet rack tube 2 is coaxially arranged in the gun body 1, a plurality of perforation bullets 21 which are distributed at equal intervals along the axial direction of the bullet rack tube 2 are arranged on the bullet rack tube 2, each perforation bullet 21 extends along the radial direction of the bullet rack tube 2 and penetrates through the whole tube wall of the bullet rack tube 2, and the extending directions of two adjacent perforation bullets 21 are mutually perpendicular. The explosion-proof cable 13 is arranged in the gun body 1, the explosion-proof cable 13 is positioned outside the bullet frame tube 2 and spirally arranged around the bullet frame tube 2, a detonator connected with the explosion-proof cable 13 can be arranged in the gun body 1, the explosion-proof cable 13 can be ignited by the detonator, one end of the explosion-proof cable 13 can also penetrate out from the peripheral wall of the gun body 1, and the explosion-proof cable 13 can be ignited outside. Each charge 21 is connected to a detonating cord 13. The gun body 1 is provided with blind holes 14 corresponding to the perforating bullets 21 one by one, the orifices of the blind holes 14 face the outer side of the gun body 1, and the blind holes 14 are formed in such a way that through holes can be machined in the gun body 1 in advance, and the deep parts of the through holes are sealed by adopting a blocking cover bonding mode or a gasket welding mode and the like, so that the blind holes 14 are formed.

The plate group has a plurality ofly and is located bullet frame pipe 2, and a plurality of plate groups are along bullet frame pipe 2's circumference evenly distributed, and the plate group includes along bullet frame pipe 2's circumference two arc 3 that are spaced apart, and arc 3 extends along bullet frame pipe 2's axial, and bullet frame pipe 2's inner wall is equipped with spacing frame 4, and spacing frame 4 is cylindric and extends along bullet frame pipe 2's axial wholly, and perforating bullet 21 runs through spacing frame 4. The arc plate 3 is arranged on the limit frame 4 along the radial sliding of the spring frame tube 2, and the space between the arc plate 3 and the limit frame 4 forms an oil chamber 31. The fixing piece comprises a fixing cylinder 5, and the fixing cylinder 5 is coaxially connected with the spring frame tube 2. The fixed cylinder 5 is provided with buffer chambers 51 corresponding to the oil chambers 31 one by one on the peripheral wall, the buffer chambers 51 extend along the axial direction of the spring frame tube 2, piston plates 512 are slidably matched in the buffer chambers 51, and the piston plates 512 are elastically connected with the fixed cylinder 5. The side wall of the buffer chamber 51 is provided with an oil hole 511, and the oil hole 511 communicates the buffer chamber 51 with the corresponding oil chamber 31.

The graded transmission assembly is arranged in the fixed cylinder 5 and is connected with the plurality of arc plates 3, and when in use, the perforating gun is vertically inserted into the underground stratum. Then, the detonating cord 13 is ignited, the detonating cord 13 sequentially ignites the plurality of perforating charges 21, the perforating charges 21 generate high-pressure jet flow, and the jet flow is ejected from the blind hole 14 and a deep hole is punched in the stratum, so that the inflow of underground petroleum is facilitated. At the same time, a first stage pressure pulse is generated within the perforating gun. The generated first impact force drives one arc plate 3 in the plate group to move towards the outer side of the spring frame tube 2 through the grading transmission assembly, the arc plate 3 extrudes buffer oil in the oil chamber 31, the buffer oil flows into the buffer chamber 51 through the oil hole 511 to press the piston plate 512 to slide, and the buffer of the arc plate 3 is realized through elastic force acting on the piston plate 512 and friction force in the buffer oil, so that the first impact force is digested. Next, after a millisecond-level time interval, a second-level pressure pulse is generated in the perforating gun to generate a second impact force, and the second impact force drives another arc plate 3 in the plate group to move towards the outer side of the bullet rack tube 2 through the grading transmission assembly, the movement process of the arc plate 3 is the same as that of the arc plate 3, and the oil liquid and the piston plate 512 corresponding to the arc plate 3 realize the digestion of the second impact force.

Thus, the present embodiment achieves multiple buffering by the step drive assembly, arcuate plate 3 and piston plate 512 corresponding to the number of pressure pulses, with each pulse being able to dissipate the impact pressure, reducing damage to the gun body 1 and avoiding firing. In addition, the percussion pressure in the perforating gun can also release the proper amount of pressure outwards through the opened blind hole 14.

The step transmission assembly comprises a connecting rod 6 and a locking mechanism, the number of the plate groups is two, two arc plates 3 in the plate groups are divided into a first arc plate 32 and a second arc plate 33, the first arc plate 32 is provided with a first support plate 321, and the second arc plate 33 is provided with a second support plate 331. The second support plate 331 is provided with a chute 3311, the extending direction of the chute 3311 is consistent with the sliding direction of the second arc plate 33, and two ends of the chute 3311 are closed. The connecting rods 6 are four and hinged to each other so as to form four hinge shafts 61, wherein two opposite hinge shafts 61 are respectively connected with the two first arc plates 32 in a rotating way, and the other two hinge shafts 61 are respectively matched in the two slide grooves 3311 in a sliding way. The oil hole 511 that the second arc 33 corresponds is fitted with the stifled piece in, and the stifled piece includes along the inserted bar 7 of the axial extension of bullet frame pipe 2, and the inboard of fixed section of thick bamboo 5 is located to locking mechanism, and inserted bar 7 is connected with locking mechanism, and when producing first order pressure pulse in the perforating gun, locking mechanism receives the impact force, drives stifled piece and opens oil hole 511.

The locking mechanism comprises a sliding plate 8, a stop block 521 and a bearing plate 9, the blocking piece comprises an inserting rod 7, the sliding plate 8 is two and is respectively in sliding fit in the buffer chambers 51 corresponding to the two second arc plates 33, and the sliding plate 8 is positioned on one side of the piston plate 512, which is away from the oil hole 511. A first spring 81 is connected between the slide plate 8 and the piston plate 512, and one end of the plunger 7 passes through the piston plate 512 and is fixedly connected with the slide plate 8. The wall body of the buffer chamber 51 adjacent to the axle center of the fixed cylinder 5 is provided with an avoidance groove, the avoidance groove extends along the axial direction of the spring frame pipe 2, two ends of the avoidance groove are closed, the sliding plate 8 is provided with a convex block 82 protruding out of the buffer chamber 51, and the convex block 82 is in sliding fit with the avoidance groove. Two fixing frames 52 adjacent to the two protruding blocks 82 are arranged in the fixing barrel 5, two check blocks 521 are arranged on the two fixing frames 52 in a sliding mode, and the sliding direction of the check blocks 521 is perpendicular to the axial direction of the spring frame tube 2. The two stoppers 521 are in one-to-one correspondence with the two protrusions 82, the stoppers 521 are located on one side of the corresponding protrusions 82 away from the oil hole 511, and in an initial state, the protrusions 82 are abutted against the stoppers 521, and the stoppers 521 are used for stopping the corresponding protrusions 82. The bearing plate 9 is disposed in the fixed cylinder 5 and is elastically slidably connected with the fixed cylinder 5, specifically, the sliding direction of the bearing plate 9 is consistent with the axial direction of the spring frame tube 2, and the bearing plate 9 is connected with the fixed cylinder 5 through the return spring 91. The stop block 521 is connected with the bearing plate 9 through a wedge structure, so that when the bearing plate 9 slides, the stop block 521 can be driven to slide through the wedge structure, and the stop block 521 is enabled to avoid the convex block 82.

The wedge structure includes a first sloped surface 5211 and a second sloped surface 921, the first sloped surface 5211 being disposed on the stop 521. The bearing plate 9 has a push block 92, and the second inclined surface 921 is provided on the push block 92, and in the initial state, the second inclined surface 921 is matched with the first inclined surface 5211.

The piston plate 512 corresponding to the first arcuate plate 32 is connected to the inner wall of the buffer chamber 51 by the second spring 5121.

When the first-stage pressure pulse is generated in the perforating gun, the plunger 7 seals the oil hole 511 corresponding to the second arc plate 33, so that the buffer oil in the oil chamber 31 corresponding to the second arc plate 33 cannot flow into the buffer chamber 51, and the impact force cannot push the second arc plate 33 to move. The first arc plate 32 is pushed by the impact force to move outwards, and the first arc plate 32 buffers the first impact force. When the first arc plate 32 moves, the connecting rod 6 is driven to do plane motion, and meanwhile the hinge shaft 61 in the chute 3311 slides to a limit position, namely, one end of the chute 3311 close to the axle center of the spring frame tube 2.

At the same time, the first impact force also acts on the bearing plate 9, and pushes the bearing plate 9 to slide towards the outer side of the spring frame tube 2, the bearing plate 9 slides along the second inclined plane 921 through the pushing block 92, and under the action of the first inclined plane 5211, the stop block 521 slides and avoids the convex block 82. When the first stage pressure pulse is completed, the stop 521 is completely offset from the bump 82. At the same time, after the first stage pressure pulse is completed, the first arcuate plate 32 moves outwardly to the extreme position.

Next, the gun generates a second stage pressure pulse, the second impact force acting on both the second arcuate plate 33 and the first arcuate plate 32, but now the first arcuate plate 32 is in the outwardly displaced limit position and cannot continue to move outwardly. The second arc plate 33 starts to squeeze the buffer oil in the oil chamber 31 under the action of the second impact force, the buffer oil pushes the plunger 7 to separate the plunger 7 from the oil hole 511, the buffer oil flows into the buffer chamber 51 through the oil hole 511 and acts on the piston plate 512, and thus, the second arc plate 33, the buffer oil and the piston plate 512 form a secondary buffer for the second impact force.

When the second arc plate 33 moves, the second support plate 331 moves along the sliding chute 3311, the chute wall of one end of the sliding chute 3311 close to the axis of the spring frame tube 2 moves along the hinge shaft 61, the hinge shaft 61 pulls the two first arc plates 32 towards the inner side of the spring frame tube 2 under the action of each connecting rod 6, and finally the two first arc plates 32 and the two second arc plates 33 are enclosed together to form a circular structure, and meanwhile, the plane shape of the four connecting rods 6 is square.

In general, the perforating gun continuously generates three pulses in the whole perforating process, and the third-stage pressure pulse also generates a third impact force, so that the second embodiment is provided for eliminating the third impact force.

In the second embodiment, with continued reference to fig. 2 to 10, the link 6 includes two sub-links 62, each sub-link 62 is stepped, the two sub-links 62 are inserted in pairs and stacked on each other, and the two sub-links 62 are slidably connected. One of the sub-links 62 is provided with a receiving groove, an insert block 621 is slidably fitted in the receiving groove in the axial direction of the spring holder tube 2, and the insert block 621 is connected with the sub-link 62 through a third spring 6211. The other sub-link 62 is provided with a slot 622, and the slot 622 penetrates the sub-link 62 in the axial direction of the spring holder tube 2. In the initial state, the insert block 621 of one of the adjacent two links 6 is pressed by the sub link 62 of the other, and the insert block 621 is inserted into the slot 622.

When the perforating gun performs the first stage pressure pulse, since only the first arc plate 32 moves and the second arc plate 33 does not move, all the first arc plate 32 and the second arc plate 33 can enclose an elliptic structure, and at this time, the deflection degree of two adjacent connecting rods 6 is deepened, and the insert block 621 is still extruded by the sub connecting rod 62. When the second stage pressure pulse is about to end, the planar shapes of the four connecting rods 6 form a square, at this time, the two adjacent connecting rods 6 are mutually perpendicular, the sub-connecting rods 62 no longer block the insert block 621, the insert block 621 ejects the slot 622 under the action of the third spring 6211, and at this time, the two sub-connecting rods 62 in each connecting rod 6 are unlocked.

When third-stage pressure pulses are generated in the perforating gun, third impact force uniformly acts on the first arc-shaped plate 32 and the second arc-shaped plate 33, the first arc-shaped plate 32 and the second arc-shaped plate 33 simultaneously move outwards, and the two sub-connecting rods 62 of each connecting rod 6 are away from each other, so that the length of the connecting rod 6 is increased, and the outward movement of the first arc-shaped plate 32 and the second arc-shaped plate 33 is adapted. Subsequently, the first arc plate 32 and the second arc plate 33 respectively squeeze the respective buffer oil, and the first arc plate 32 and the second arc plate 33 realize buffering and resolving of the third impact force again through the buffer oil and the piston plate 512, so that the gun body 1 is protected.

The fixing piece and the grading transmission component form a multistage buffering device, and the multistage buffering device is two and is respectively arranged at two ends of the spring frame pipe 2.

The arrangement of two multi-stage buffering devices enables the buffering of impact force to be more uniform.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. The utility model provides a perforating gun, includes and is tubular body of a gun (1) and coaxial locating bullet frame pipe (2) in body of a gun (1), wear to be equipped with a plurality of perforating charges (21) on the pipe wall of bullet frame pipe (2), body of a gun (1) be equipped with blind hole (14) of perforating charges (21) one-to-one, its characterized in that still includes:

the plate sets are arranged in the spring frame tubes (2) and uniformly distributed along the circumference of the spring frame tubes (2), each plate set comprises two arc plates (3) which are spaced along the circumference of the spring frame tubes (2), a limiting frame (4) is arranged on the inner wall of each spring frame tube (2), each arc plate (3) is slidably arranged on each limiting frame (4) along the radial direction of each spring frame tube (2), and an oil chamber (31) is formed between each arc plate (3) and each limiting frame (4);

The fixing piece is connected with the spring frame tube (2), the fixing piece is provided with buffer chambers (51) corresponding to the oil chambers (31) one by one, piston plates (512) are slidably matched in the buffer chambers (51), the piston plates (512) are elastically connected with the fixing piece, and oil holes (511) for communicating the buffer chambers (51) with the oil chambers (31) are formed in the side walls of the buffer chambers (51);

The grading transmission assembly is arranged in the fixing piece and connected with the arc-shaped plates (3), and when first-stage pressure pulse is generated in the perforating gun, impact force drives one arc-shaped plate (3) in the plate group to move towards the outer side of the bullet frame tube (2) through the grading transmission assembly; when a second-stage pressure pulse is generated in the perforating gun, the impact force drives the other arc-shaped plate (3) in the plate group to move towards the outer side of the bullet rack tube (2) through the grading transmission assembly;

The step transmission assembly includes:

The number of the connecting rods (6) is two, two arc plates (3) in the plate group are divided into a first arc plate (32) and a second arc plate (33), the second arc plate (33) is provided with a sliding groove (3311), and the extending direction of the sliding groove (3311) is consistent with the sliding direction of the second arc plate (33); the connecting rods (6) are four and mutually hinged so as to form four hinge shafts (61), wherein two opposite hinge shafts (61) are respectively connected with the two first arc plates (32) in a rotating way, and the other two hinge shafts (61) are respectively matched in the two sliding grooves (3311) in a sliding way;

The locking mechanism is matched with a blocking piece in an oil hole (511) corresponding to the second arc-shaped plate (33), the fixing piece comprises a fixing cylinder (5) coaxial with the elastic frame pipe (2), the locking mechanism is arranged on the inner side of the fixing cylinder (5), the blocking piece is connected with the locking mechanism, and when a first-stage pressure pulse is generated in the perforating gun, the locking mechanism is under the action of impact force to drive the blocking piece to open the oil hole (511);

The locking mechanism includes:

The sliding plate (8) comprises inserting rods (7), the sliding plates (8) are respectively in sliding fit with the buffer chambers (51) corresponding to the two second arc-shaped plates (33), a first spring (81) is connected between the sliding plates (8) and the piston plate (512), and the inserting rods (7) are connected with the sliding plates (8);

The sliding plate (8) is provided with two protruding blocks (82) protruding out of the buffer chamber (51), the two protruding blocks (521) are in one-to-one correspondence with the two protruding blocks (82), the blocking blocks (521) are slidably mounted on the fixed cylinder (5), and the blocking blocks (521) are used for stopping the corresponding protruding blocks (82);

The bearing plate (9), the bearing plate (9) is arranged in the fixed cylinder (5) and is elastically and slidably connected with the fixed cylinder (5), and the stop block (521) is connected with the bearing plate (9) through a wedge structure, so that when the bearing plate (9) slides, the stop block (521) can be driven to slide through the wedge structure, and the stop block (521) is prevented from avoiding the convex block (82);

The connecting rod (6) comprises two sub-connecting rods (62) which are mutually overlapped and connected in a sliding way, one sub-connecting rod (62) is elastically connected with an inserting block (621) in a sliding way, the other sub-connecting rod (62) is provided with an inserting groove (622), in the initial state, the inserting block (621) of one of the two adjacent connecting rods (6) is extruded by the sub-connecting rod (62) of the other connecting rod, and the inserting block (621) is inserted into the inserting groove (622).

2. A perforating gun as claimed in claim 1, characterized in that the wedge-shaped structure comprises a first bevel (5211) provided on the block (521) and a second bevel (921) provided on the bearing plate (9), the second bevel (921) cooperating with the first bevel (5211).

3. Perforating gun as claimed in claim 1, characterized in that the fixing element and the step transmission assembly form a multi-stage buffer device, two of which are arranged at the two ends of the cartridge carrier tube (2).

4. Perforating gun as claimed in claim 1, characterized in that a detonating cord (13) is provided in the gun body (1), each perforating charge (21) being connected to the detonating cord (13).

5. Perforating gun as claimed in claim 1, characterized in that the two ends of the gun body (1) are respectively screwed with a gun head (11) and a gun tail (12).