Safe pressure transmitting device for oil and gas well perforation

Abstract

The invention belongs to the field of oil and gas well perforation, and discloses a safe pressure transmission device for oil and gas well perforation, which comprises a perforating gun, a detonation assembly and a delay assembly, a plurality of perforating bullets are arranged on the inner side of the perforating gun in a surrounding mode, a damping liquid flow channel is fixed to the inner side of the perforating gun, a large piston is arranged on the inner side of the damping liquid flow channel in a sealed sliding fit mode, a buffer cylinder is coaxially arranged on the inner side of the large piston, and a plurality of partition grooves are fixed to the bottom of the buffer cylinder. The inner side of the connecting pipe is in sealing sliding fit with a detonating assembly; the delay assembly comprises a supporting cylinder, a guide frame and a spring. A delay device is arranged at the bottom of the large piston, the multiple detonating assemblies are distinguished through the delay device, so that only one detonating assembly can be triggered when the large piston descends every time, the delay device is changed through the counter-acting force of explosion of a single ammunition chamber, and then the detonating assemblies sequentially form the effect of delayed explosion clockwise or anticlockwise. And each ammunition chamber is enabled to be accurately detonated according to a preset time sequence.

Description

Technical Field

[0001] The present disclosure belongs to the field of perforating oil and gas wells, and particularly relates to a safety pressure transmission device for perforating oil and gas wells. Background Art

[0002] In the perforating operation of oil and gas wells, a pressure initiation device is a key safety initiation device triggered by changes in the downhole environmental pressure. Its core use is to accurately control the detonation timing of perforating charges under preset pressure conditions (such as the pressure difference between the wellbore and the formation, annulus pressurization, or liquid column pressure threshold);

[0003] At the same time, the pressure initiation device uses the well pressure as a trigger signal. When the pressure reaches the set value, the mechanical structure and energy transfer mechanism inside the device interact to detonate the explosive and complete the perforating operation.

[0004] However, when the piston safety pressure transmission device is applied to a continuous multi-directional shaped charge perforator such as the one with the application number CN101832123A, since the central axes of multiple perforating charges are in the same plane, when one ammunition chamber is detonated, the pressure at the bottom of the perforator suddenly increases and the reaction force during the explosion easily triggers the pressure transmission device again, resulting in the situation where multiple ammunition chambers are accidentally detonated simultaneously. At the same time, the reaction force of the explosion easily damages the original flow channel, making it difficult to achieve the effect of sequentially delayed explosions in a given order. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present disclosure is to provide a safety pressure transmission device for perforating oil and gas wells, which solves the problems in the prior art due to...

[0006] The purpose of the present disclosure can be achieved through the following technical solutions:

[0007] A safety pressure transmission device for perforating oil and gas wells includes: a perforating gun, a detonation assembly, and a delay assembly;

[0008] A plurality of perforating charges are arranged around the inner side of the perforating gun. A damping liquid flow channel is fixed on the inner side of the perforating gun. A large piston is hermetically and slidably fitted inside the damping liquid flow channel. A plurality of connecting pipes are arranged around the outer side of the damping liquid flow channel. The positions of the connecting pipes correspond to the positions of the perforating charges. The end of the connecting pipe is fixed with a perforating charge. A buffer cylinder is coaxially arranged inside the large piston. A plurality of partition grooves are fixed at the bottom of the buffer cylinder. Liquid inlets are opened at the upper ends of the plurality of partition grooves. A detonation assembly is hermetically and slidably fitted inside the connecting pipe;

[0009] The delay component includes a support cylinder, a guide frame and a spring. A support cylinder is coaxially arranged outside the damping liquid flow channel, and a support plate is fixed to the bottom of the support cylinder. A drainage hole is penetrated through the upper end of the support plate. A guide frame is slidably arranged on the outer wall of the support cylinder, and a guide groove is penetrated through the inner side of the guide frame. A spring is fixed to the lower end surface of the support plate.

[0010] In some disclosures, a through groove is opened inside the perforating gun, and a support shell is fixed inside the through groove. A reinforcing rib is fixed to one side of the support shell close to the connecting pipe.

[0011] In some disclosures, the structure of the large piston is an annular structure, and an annular groove is opened at the bottom end of the large piston. The diameter of the annular groove is the same as the outer diameter of the guide frame.

[0012] In some disclosures, a clamping groove is penetrated through the bottom end of the connecting pipe close to the large piston, and a slider is slidably arranged inside the clamping groove.

[0013] In some disclosures, a bent pipe is fixed between the partition groove and the corresponding connecting pipe. A communication structure is formed between the partition groove and the connecting pipe through the bent pipe, and the bent pipe is in sealed sliding fit with the slider.

[0014] In some disclosures, the detonation component includes a small piston, a guide rod, a sliding groove, a convex block and a firing pin. A small piston is in sealed sliding fit inside the connecting pipe. A guide rod penetrating through the small piston is arranged on the small piston. The moving path of the small piston is the same as the moving path of the guide rod. A sliding groove is opened at the lower end of the small piston. A convex block is slidably connected to the lower end of the sliding groove. The shape of the convex block is adapted to the shape of the clamping groove. A firing pin is fixed to one side of the small piston away from the large piston.

[0015] In some disclosures, when the small piston moves directly above the clamping groove, the convex block just fits into the clamping groove. At this time, the detonation component is in a self-locking state. When the convex block contracts upward and the small piston leaves the clamping groove, the detonation component is in an active state.

[0016] In some disclosures, buffer pads are fixed to both sides of the small piston. The outer wall of the buffer pad is in sealed fit with the inner wall of the connecting pipe, and the material of the buffer pad is rubber.

[0017] In some disclosures, a limiting groove is opened at the position corresponding to the spring on the lower end surface of the support plate. When the spring is compressed to the limit position, the lower end surface of the support plate fits with the upper end surface of the partition groove. A cylindrical block is arranged on the outer wall of the support cylinder, and the moving path of the cylindrical block is the same as the moving path of the guide groove.

[0018] In some disclosures, a corrugated pipe is fixed directly below the support plate, and the corrugated pipe is slidably connected to the upper end surface of the partition groove.

[0019] The explanations for the nouns, conjunctions, or adjectives involved in the above technical solutions are as follows:

[0020] Fixed connection means that after the parts or components are fixed, there is no relative movement between them;

[0021] Rotational connection means that the connection between parts allows the parts to rotate relative to each other;

[0022] Threaded connection is a detachable fixed connection, which has the advantages of simple structure, reliable connection, convenient installation and disassembly, etc., and is widely used in the fields of mechanical engineering and connection structures;

[0023] Sliding connection means that the connection between parts allows the parts to slide relative to each other.

[0024] Advantages of the present disclosure:

[0025] 1. A delay device is provided at the bottom of the large piston. The delay device is used to distinguish multiple detonation components so that only one detonation component can be triggered each time the large piston descends. The reaction force generated by the explosion of a single ammunition chamber is used to change the delay device, and then the detonation components are sequentially detonated with a time delay in a clockwise or counterclockwise direction, ensuring that each ammunition chamber detonates precisely according to the predetermined sequence.

[0026] 2. At the same time, the cooperation between the detonation component and the delay device can achieve self-locking after the explosion, reducing the interference of the triggered unit to other ammunition chambers, and effectively solving the problems of mis-triggering and flow channel damage during the delayed detonation of multi-directional shaped charge perforating bullets. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 is the internal structure schematic diagram of the embodiment of the present disclosure;

[0029] Figure 2 is the overall structure schematic diagram of the embodiment of the present disclosure;

[0030] Figure 3 is the schematic diagram of the damping liquid flow channel and the perforating bullet explosion structure of the embodiment of the present disclosure;

[0031] Figure 4 is the overall internal structure schematic diagram of the damping liquid flow channel of the embodiment of the present disclosure;

[0032] Figure 5It is a schematic diagram of the overall structure of the detonation component according to an embodiment of the present disclosure;

[0033] Figure 6 It is a schematic diagram of the overall structure of the delay component according to an embodiment of the present disclosure;

[0034] Figure 7 It is a schematic cross-sectional structure diagram of the damping liquid flow channel according to an embodiment of the present disclosure.

[0035] In the figure: 1, perforating gun; 101, through groove; 102, reinforcing rib; 2, perforating charge; 3, support shell; 4, damping liquid flow channel; 41, connecting pipe; 411, clamping groove; 412, slider; 5, large piston; 51, annular groove; 6, buffer cylinder; 61, partition groove; 62, liquid inlet; 7, detonation component; 71, small piston; 72, guiding rod; 73, sliding groove; 74, convex block; 75, firing pin; 711, buffer pad; 8, delay component; 81, support cylinder; 82, guiding frame; 83, spring; 811, support plate; 812, drainage hole; 813, cylindrical block; 814, limiting groove; 815, corrugated pipe; 821, guiding groove; 9, elbow pipe. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.

[0037] Please refer to Figures 1 to 7 , a safety pressure transmission device for perforating an oil and gas well, including: a perforating gun 1, a detonation component 7 and a delay component 8;

[0038] A plurality of perforating charges 2 are arranged around the inner side of the perforating gun 1. A damping liquid flow channel 4 is fixed to the inner side of the perforating gun 1. A large piston 5 is hermetically and slidably fitted to the inner side of the damping liquid flow channel 4. A plurality of connecting pipes 41 are arranged around the outer side of the damping liquid flow channel 4. The positions of the connecting pipes 41 correspond to the positions of the perforating charges 2. The end of the connecting pipe 41 is fixed with a perforating charge 2. A buffer cylinder 6 is coaxially arranged inside the large piston 5. A plurality of partition grooves 61 are fixed to the bottom of the buffer cylinder 6. Liquid inlets 62 are opened at the upper ends of the plurality of partition grooves 61. A detonation component 7 is hermetically and slidably fitted to the inner side of the connecting pipe 41;

[0039] The delay component 8 includes a support cylinder 81, a guide frame 82, and a spring 83. A support cylinder 81 is coaxially arranged outside the damping liquid flow channel 4. The support cylinder 81 has a bottom plate 811 fixed to its bottom. A drainage hole 812 is provided through the upper end of the bottom plate 811. A guide frame 82 is slidably arranged on the outer wall of the support cylinder 81, and a guide groove 821 is provided through the inner side of the guide frame 82. A spring 83 is fixed to the lower end surface of the bottom plate 811.

[0040] During use, the perforating charge 2 is arranged around the end of the damping liquid flow channel 4. When in use, when the perforating gun 1 moves downward to a specified position, the pressure at the bottom of the perforating gun 1 increases. Thus, the pressure difference on both sides of the large piston 5 drives the large piston 5 to slide vertically downward along the damping liquid flow channel 4. The partition groove 61 is composed of multiple sealing grooves, and each sealing groove is provided with a liquid inlet 62 at its upper end. At this time, the position of the drainage hole 812 before explosion coincides with the position of the liquid inlet 62 at the upper end of one of the partition grooves 61, so that the damping liquid inside the damping liquid flow channel 4 will pass through the drainage hole 812 and the liquid inlet 62 and enter one of the partition grooves 61. When one of the partition grooves 61 is filled with damping liquid, it pushes the detonating component 7 corresponding to this partition groove to contract upward, and thus move out of the connecting pipe 41. As a result, the detonating component 7 changes from a self-locking state to an active state. At this time, the large piston 5 continues to slide downward, and further transmits the damping liquid pressure in the damping liquid flow channel 4 to each connecting pipe 41. The detonating components 7 in the remaining connecting pipes 41 are in a self-locking state, so that the damping liquid in the damping liquid flow channel 4 during the downward pressing process will push the detonating component 7 in the active state to slide outward until it contacts the perforating charge 2, triggering the detonation of the perforating charge 2 and realizing precise perforation. During this process, the large piston 5 is located at one end of the connecting pipe 41 away from the perforating charge 2 and blocks the remaining connecting pipes 41 to prevent the shock wave of the explosion from affecting the damping liquid in other connecting pipes 41. This not only effectively reduces the risk of simultaneous misdetonation of multiple perforating charges 2, but also significantly improves the safety and reliability of the perforation operation, ensuring the stable production of the oil and gas well.

[0041] However, when the perforating charge 2 explodes, the generated shock wave will drive the detonating assembly 7 to slide along the connecting pipe 41 towards the end close to the large piston 5 until the detonating assembly 7 slides to its original position and further self-locks. At the same time, the pressure at the bottom of the large piston 5 increases instantaneously during the explosion, causing the large piston 5 to slide vertically upwards. Meanwhile, the damping liquid in the connecting pipe 41 flows back and pushes the large piston 5 to reset. At the same time, when the large piston 5 moves upwards, the pressure exerted by the large piston 5 on the support plate 811 weakens, causing the spring 83 to gradually return to its original state, and the elastic force generated by the restoration of the spring 83 drives the support plate 811 and the support cylinder 81 to move upwards, causing the cylindrical block 813 to slide along the guiding groove 821. During the sliding process of the cylindrical block 813, it will drive the support plate 811 to rotate and change the position of the drainage hole 812 to ensure that the drainage hole 812 coincides with the liquid inlet 62 on another partition groove 61 during the next perforation. After the explosion, as the pressure generated by the explosion weakens, the pressure difference originally exerted on the large piston 5 at its current position is restored, causing the large piston 5 to descend again. At this time, due to the change in the position of the drainage hole 812, when the large piston 5 descends again, it will trigger the liquid inlet 62 corresponding to the next partition groove 61, allowing the damping liquid to enter the new partition groove 61, further driving the corresponding detonating assembly 7 into an active state, repeating the above perforation process, ensuring that each perforating charge 2 is detonated precisely in sequence, and achieving the sequential cyclic detonation of the perforating charges 2 and the automatic reset of the detonating assembly 7 of the device.

[0042] Please refer to Figure 1 , a through groove 101 is provided inside the perforating gun 1, and a support shell 3 is fixed inside the through groove 101. A reinforcing rib 102 is fixed on one side of the support shell 3 close to the connecting pipe 41. The reinforcing rib 102 is closely combined with the connecting pipe 41 and the support shell 3 to form a stable structure, effectively dispersing the high-pressure impact force during perforation, further ensuring the stability and durability of the perforating gun 1 under complex well conditions, enhancing the stability on the outside, being beneficial to reducing deformation due to the high-pressure impact during the perforation process, and ensuring the overall rigidity of the perforating gun 1.

[0043] Please refer to Figure 4 and Figure 6 , the large piston 5 has an annular structure, and an annular groove 51 is provided at the bottom end of the large piston 5. The diameter of the annular groove 51 is the same as the outer diameter of the guiding frame 82. When the lower end surface of the large piston 5 fits with the upper end surface of the support plate 811, the guiding frame 82 is located inside the annular groove 51, ensuring the precise alignment of the large piston 5 and the support plate 811, and avoiding interference between the large piston 5 and the guiding frame 82 during the descending process of the large piston 5 by providing the annular groove 51, ensuring smooth movement.

[0044] A clamping groove 411 is provided through the bottom end of the connecting pipe 41 close to the large piston 5, and a slider 412 is slidably provided inside the clamping groove 411.

[0045] Please refer to Figure 4 and Figure 7 A bent pipe 9 is fixed between the partition groove 61 and the corresponding connecting pipe 41, and a communication structure is formed between the partition groove 61 and the connecting pipe 41 through the bent pipe 9, and the bent pipe 9 is in sealed sliding fit with the slider 412.

[0046] During use, when drainage is carried out, when the drainage hole 812 coincides with the liquid inlet 62 on the partition groove 61, the large piston 5 moves downward at this time, so that the damping liquid in the partition groove 61 passes through the bent pipe 9 communicated with the partition groove 61, and pushes the slider 412 at the upper end of the bent pipe 9 to move upward until the upper end surface of the convex block 74 fits with the lower end surface of the small piston 71. At this time, the outer wall of the convex block 74 fits with the inner wall of the connecting pipe 41, and the damping liquid in the damping liquid flow channel 4 will move outward during the downward movement of the large piston 5. Therefore, when the outer wall of the convex block 74 fits with the inner wall of the connecting pipe 41, it will push the small piston 71 to slide outward. The slider 412 is used to push the convex block 74 to fit with the piston 71, thereby releasing the self-locking state of the detonation assembly 7. The self-locking is realized through the clamping structure, so that the structure is simple, and the corresponding small piston can be automatically unlocked during the downward movement of the large piston 5. And when the small piston 71 moves to directly above the card slot 411, the convex block 74 can be embedded in the card slot 411 under the influence of gravity, so that the detonation assembly 7 is self-locked, making the response rapid. And because the card slot 411 is located at one end of the connecting pipe 41 close to the large piston 5, after the detonation, the end of the connecting pipe 41 far from the detonation point is more likely to remain intact and the sealing performance of the small piston 71 can be maintained.

[0047] Please refer to Figures 4 to 5 The detonation assembly 7 includes a small piston 71, a guide rod 72, a sliding groove 73, a convex block 74 and a firing pin 75. The inner side of the connecting pipe 41 is in sealed sliding fit with the small piston 71, and a guide rod 72 passing through the small piston 71 is arranged on the small piston 71. The moving path of the small piston 71 is the same as the moving path of the guide rod 72. A sliding groove 73 is opened at the lower end of the small piston 71. The lower end of the sliding groove 73 is slidably connected with the convex block 74, and the shape of the convex block 74 is adapted to the shape of the card slot 411. A firing pin 75 is fixed on one side of the small piston 71 away from the large piston 5.

[0048] When the small piston 71 moves to directly above the card slot 411, the convex block 74 is just embedded in the card slot 411. At this time, the detonation assembly 7 is in a self-locked state. When the convex block 74 contracts upward, the small piston 71 leaves the card slot 411. At this time, the detonation assembly 7 is in a movable state.

[0049] When in use, the small piston 71 slides along the inner wall of the guide rod 72 and the connecting tube 41, and the upper end of the small piston 71 is constrained by the guide rod 72 to avoid mechanical interference caused by excessive displacement. At the same time, when the guide rod 72 moves outward, the firing pin 75 collides with the perforating bullet 2, thereby detonating the perforating bullet 2. The center axis of the perforating bullet 2 and the center of gravity of the small piston 71 are in the same plane, so that when the perforating bullet 2 is detonated, the impact force of the perforating bullet 2 drives the small piston 71 to slide to the side close to the card slot 411, and the damping force in the connecting tube 41 at this time is reduced. The liquid is sent into the damping liquid flow channel 4. During this process, the retreat path of the small piston 71 is locked twice by the guide rod 72 and the card slot 411 to avoid accidental displacement caused by impact vibration, and the directional reflux of the damping liquid synchronously offsets the pressure fluctuation caused by the explosion, maintaining the pressure balance in the connecting pipe 41, and after the support plate 811 rotates, the drainage hole 812 is staggered with the liquid inlet 62 during detonation. At this time, the partition groove 61 corresponding to the detonation point forms a non-connected structure with the damping liquid flow channel 4, so that the self-locking of the detonating assembly 7 will not be released when the remaining perforating bullets 2 are detonated.

[0050] Please refer to Figure 5 , cushion pads 711 are fixed on both sides of the small piston 71, and the outer wall of the cushion pad 711 is sealed with the inner wall of the connecting pipe 41, and the cushion pad 711 is made of rubber. When in use, the rubber material can reduce the detonation, and the adaptive deformation ability of the rubber material automatically compensates the sealing gap when the small piston 71 retreats, ensuring the dynamic sealing integrity of the damping liquid return path during the reset process of the small piston 71, preventing pressure loss or external impurities from invading the flow channel, and absorbing the vibration energy of the small piston 71 when sliding through the deformation of the rubber.

[0051] A limiting groove 814 is provided at the position of the lower end surface of the support plate 811 corresponding to the spring 83. When the spring 83 is compressed to the limit position, the lower end surface of the support plate 811 fits with the upper end surface of the partition groove 61. A cylindrical block 813 is provided on the outer wall of the support tube 81, and the moving path of the cylindrical block 813 is the same as the moving path of the guide groove 821.

[0052] The spring 83 can be engaged in the limiting groove 814, reducing the height occupied by the spring, which is beneficial to improving the sealing between the support plate 811 and the partition groove 61, reducing the gap between the support plate 811 and the partition groove 61 after the support plate 811 is lowered, and improving the sealing of the device. The shape of the guide groove 821 is wavy. When the cylindrical block 813 slides along the guide frame 813, it will slide along the inner wall of the guide groove 821, and then relative rotation will occur.

[0053] Please refer to Figure 4 and Figure 6 A corrugated tube 815 is fixed directly below the support plate 811 , and the corrugated tube 815 is slidably connected to the upper end surface of the partition groove 61 .

[0054] The corrugated tube 815 is hermetically connected to the support plate 811. When the support plate 811 is lifted upward, the seal between the bottom of the support plate 811 and the remaining liquid inlet 62 is still maintained.

[0055] The following further describes a safety pressure transmission device for oil and gas well perforation provided by the present invention in conjunction with the accompanying drawings and embodiments.

[0056] During use, the perforating charges 2 are arranged around the inner side of the perforating gun 1, and the detonation assembly 7 is in a self-locking state before the perforating gun 1 reaches the designated position. At the same time, the ammunition of the perforating charges 2 is located on the side close to the connecting pipe 41. When the perforating gun 1 descends to a suitable position, the pressure at the bottom of the perforating gun 1 increases, so that the pressure difference on both sides of the large piston 5 drives the large piston 5 to slide vertically downward along the damping liquid flow channel 4. The position of the drainage hole 812 on the support plate 811 coincides with the liquid inlet 62 at the upper end of the partition groove 61 corresponding to the point to be detonated, so that the damping liquid in the damping liquid flow channel 4 enters the partition groove 61 and drives the slider 412 to move upward through the elbow pipe 9, so that the convex block 74 contracts into the sliding groove 73 until the upper end surface of the convex block 74 fits against the lower end surface of the small piston 71. At this time, the self-locking state of the small piston 71 corresponding to the partition groove 61 is released, and the small piston 71 is pushed to move towards the side close to the perforating charges 2 until the firing pin 75 on the small piston 71 makes a rigid impact on the perforating charges 2 and detonates the ammunition on the perforating charges 2.

[0057] At the same time, the impact force generated by the explosion drives the small piston 71 to slide towards the side close to the large piston 5, and the pressure received by the large piston 5 changes, so that the pressure difference on both sides of the large piston 5 changes, so that the downward pressure of the large piston 5 weakens. During the backward movement of the small piston 71, the damping liquid located in the connecting pipe 41 is sent back into the damping liquid flow channel 4 and pushes the large piston 5 to slide upward. At this time, the support plate 811 drives the support cylinder 81 to move upward under the influence of the elastic restoring force of the spring 83. When the cylindrical block 813 slides along the guiding frame 82 during the movement, the support cylinder 81 rotates until the drainage hole 812 coincides with the next liquid inlet 62, so as to achieve the effect of sequentially forming delayed explosions clockwise.

[0058] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0059] The above has shown and described the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure will have various changes and improvements, and these changes and improvements all fall within the scope of the present disclosure claimed.

Claims

1. A safety pressure transmission device for perforating oil and gas wells, characterized in that, Comprising: A perforating gun (1), a detonating assembly (7) and a delay assembly (8); A plurality of perforating charges (2) are disposed around the inner side of the perforating gun (1). A damping liquid flow channel (4) is fixed to the inner side of the perforating gun (1). A large piston (5) is in sealed sliding fit with the inner side of the damping liquid flow channel (4). A plurality of connecting pipes (41) are disposed around the outer side of the damping liquid flow channel (4). The position of the connecting pipes (41) corresponds to the position of the perforating charges (2). The end of the connecting pipe (41) is fixed with a perforating charge (2). A buffer cylinder (6) is coaxially disposed inside the large piston (5). A plurality of partition grooves (61) are fixed to the bottom of the buffer cylinder (6). Liquid inlets (62) are formed at the upper ends of the plurality of partition grooves (61). A detonating assembly (7) is in sealed sliding fit with the inner side of the connecting pipe (41); The delay assembly (8) includes a support cylinder (81), a guiding frame (82) and a spring (83). A support cylinder (81) is coaxially disposed on the outer side of the damping liquid flow channel (4). A support plate (811) is fixed to the bottom of the support cylinder (81). A drainage hole (812) is formed through the upper end of the support plate (811). A guiding frame (82) is slidably disposed on the outer wall of the support cylinder (81). A guiding groove (821) is formed through the inner side of the guiding frame (82). A spring (83) is fixed to the lower end surface of the support plate (811).

2. The safety pressure transmission device for oil and gas well perforation according to claim 1, characterized in that, A through groove (101) is formed in the inner side of the perforating gun (1). A support shell (3) is fixed inside the through groove (101). A reinforcing rib (102) is fixed to the side of the support shell (3) close to the connecting pipe (41).

3. The safety pressure transmission device for oil and gas well perforation according to claim 1, characterized in that, The large piston (5) has an annular structure. An annular groove (51) is formed at the bottom end of the large piston (5). The diameter of the annular groove (51) is the same as the outer diameter of the guiding frame (82).

4. A safety pressure transmission device for oil and gas well perforation according to claim 3, characterized in that, A clamping groove (411) is formed through the bottom end of the connecting pipe (41) close to the large piston (5). A sliding block (412) is slidably disposed inside the clamping groove (411).

5. The safety pressure transmission device for oil and gas well perforation according to claim 4, wherein, A bent pipe (9) is fixed between the partition groove (61) and the corresponding connecting pipe (41). A communication structure is formed between the partition groove (61) and the connecting pipe (41) through the bent pipe (9). The bent pipe (9) is in sealed sliding fit with the sliding block (412).

6. The safety pressure transmission device for oil and gas well perforation according to claim 1, characterized in that, The detonating assembly (7) includes a small piston (71), a guiding rod (72), a sliding groove (73), a convex block (74) and a firing pin (75). A small piston (71) is in sealed sliding fit with the inner side of the connecting pipe (41). A guiding rod (72) passing through the small piston (71) is provided on the small piston (71). The moving path of the small piston (71) is the same as the moving path of the guiding rod (72). A sliding groove (73) is formed at the lower end of the small piston (71). A convex block (74) is slidably connected to the lower end of the sliding groove (73). The shape of the convex block (74) is adapted to the shape of the clamping groove (411). A firing pin (75) is fixed to the side of the small piston (71) away from the large piston (5).

7. A safety pressure transmission device for perforating oil and gas wells according to claim 6, characterized in that, When the small piston (71) moves directly above the card slot (411), the convex block (74) just fits into the card slot (411). At this time, the detonation assembly (7) is in a self-locking state. When the convex block (74) contracts upward, the small piston (71) leaves the card slot (411), and at this time, the detonation assembly (7) is in an active state.

8. A safety pressure transmission device for perforating oil and gas wells according to claim 7, characterized in that, Buffer pads (711) are fixed on both sides of the small piston (71). The outer wall of the buffer pad (711) is in sealing fit with the inner wall of the connecting pipe (41), and the material of the buffer pad (711) is rubber.

9. The safety pressure transmission device for oil and gas well perforation according to claim 1, characterized in that, A limiting groove (814) is provided at the position corresponding to the spring (83) on the lower end surface of the support plate (811). When the spring (83) is compressed to the limit position, the lower end surface of the support plate (811) fits with the upper end surface of the partition groove (61). A cylindrical block (813) is provided on the outer wall of the support cylinder (81), and the moving path of the cylindrical block (813) is the same as the moving path of the guiding groove (821).

10. A safety pressure transmission device for oil and gas well perforation according to claim 9, characterized in that, A corrugated pipe (815) is fixed directly below the support plate (811), and the corrugated pipe (815) is slidably connected to the upper end surface of the partition groove (61).

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