Delayed detonation device for oil and gas well perforation, detonation method of delayed detonation device and oil and gas well perforation device

Abstract

The invention discloses a delayed detonation device for oil and gas well perforation, a detonation method of the delayed detonation device and an oil and gas well perforation device. The delayed detonation device comprises a shell which is arranged in a perforation of an oil and gas well in a penetrating manner; a cavity is formed in the shell; a mechanical timing module, a locking piece and a releasing mechanism are sequentially arranged in the cavity, and the mechanical timing module regulates and controls the locking piece so that the locking piece can lock or release the releasing mechanism; the mechanical timing module can delay preset time to open the locking piece, so that the releasing mechanism is in a releasing state, and the releasing mechanism transmits explosion to the perforating gun detonating tube through the lower connecting port. By means of the mechanical timing delay detonation device, the dual guarantee of manual controllability under the conventional condition and automatic detonation under the extreme condition is achieved, the safety and success rate of perforation operation are improved, and the mechanical timing delay detonation device has important application value and popularization significance.

Description

Technical Field

[0001] This invention belongs to the technical field of oil and gas well monitoring devices, specifically relating to a delayed detonation device and its detonation method for oil and gas well perforation, and an oil and gas well perforation device. Background Technology

[0002] In oil and gas well completion operations, perforation is a crucial step connecting the wellbore to the oil and gas reservoir, and its reliability directly affects well productivity and operational safety. Currently, the widely used tubing-transmitted perforation (TCP) primarily relies on hydraulic, mechanical impact, or cable-based electrical signal triggering. Under normal conditions, these methods can meet operational requirements, but their limitations are increasingly apparent in deep wells, ultra-deep wells, and high-temperature, high-pressure well environments. For example, hydraulic triggering requires stable differential pressure support, but it is difficult to establish pressure when well leakage or packer failure occurs; mechanical impact methods rely on drop bars or balls, but in high-inclination or long horizontal sections, they are easily affected by friction and well fluid resistance, leading to a decrease in triggering success rate; while cable-based electrical signals are flexible, the high temperatures downhole can cause cable or electronic component failure, resulting in insufficient reliability.

[0003] More seriously, when the perforating gun fails to detonate downhole, the entire gun string containing the pyrotechnic device must typically be retrieved, a complex operation posing significant safety hazards. This not only impacts the construction schedule but also increases well control risks. While redundant designs (such as dual detonators or multi-stage detonation chains) exist in the industry to improve reliability, they haven't fundamentally solved the problem of excessive reliance on external conditions. Therefore, there is an urgent need for a new perforation detonation method that can be manually triggered under normal conditions, while automatically completing detonation within a preset time using an internal delay mechanism under extreme conditions without relying on external power or pressure. This would improve the safety and success rate of TCP perforation operations in complex well conditions.

[0004] Chinese patent document CN223044134U mainly relates to equipment improvements in the perforation gun casing processing stage. The focus is on achieving metal shavings recovery and cleaning during the perforation gun casing processing by setting up a processing workbench, chip collection box, exhaust fan, and hoses. Its advantages include improved processing efficiency and reduced environmental pollution. However, this technology is limited to the perforation gun manufacturing stage and does not address the reliability or safety of detonation during underground use. In contrast, the delayed detonation device of this application is geared towards practical underground scenarios, solving the problem of automatically and reliably detonating the perforation gun under high temperature, high pressure, and conditions where manual pressurization is impossible. Therefore, it is more practical and has greater safety value in terms of functional application.

[0005] Chinese patent document CN223177511U focuses on the ease of operation of perforating guns in confined spaces. By improving the perforating gun connector, protective cover, and threaded connection structure, it makes the gun more stable and reliable during installation and use, suitable for downhole environments with limited operating space. Although its structural optimization helps improve construction convenience, this technology still mainly focuses on improving the perforating gun body structure and installation reliability, without addressing the improvement of the detonation method.

[0006] Analysis of the aforementioned patent documents primarily focuses on improvements to the perforating gun's manufacturing process and optimization of its structural installation convenience. While these improvements have led to advancements in manufacturing and usage, they have not resolved the issue of the perforating gun's detonation reliability under extreme downhole conditions. Under conditions of high temperature and pressure, or where manual pressurization is impossible, traditional triggering methods are highly prone to failure, resulting in perforation misfires or safety hazards. Summary of the Invention

[0007] Therefore, the present invention provides a delayed detonation device and detonation method for perforation of oil and gas wells, and an oil and gas well perforation device, which can solve the problem that traditional triggering methods are prone to failure under conditions such as high temperature and high pressure or when artificial pressurization is not possible, resulting in perforation misfire or safety hazards.

[0008] To address the aforementioned problems, the present invention provides a delayed detonation device for perforation in oil and gas wells, comprising:

[0009] The outer casing is inserted into the perforation of an oil and gas well; the upper and lower ends of the outer casing are provided with ports: an upper connecting port and a lower connecting port; the upper connecting port is used to connect to the wellhead of the oil and gas well, and the lower connecting port is used to connect to the detonating cord of the perforation gun; a cavity is formed inside the outer casing;

[0010] The cavity is sequentially provided with a mechanical timing module, a locking element, and a release mechanism. The mechanical timing module controls the locking element to lock or release the release mechanism. The mechanical timing module can delay the locking element for a preset time to open the locking element so that the release mechanism is in the released state. The release mechanism transmits detonation to the detonating tube of the perforating gun through the lower connection port.

[0011] In some embodiments, a flow channel is formed within the cavity to connect the upper connection port and the lower connection port. The cavity is also provided with a trigger unit, which is located between the mechanical timing module and the upper connection port. The trigger unit includes a flow-blocking component and a piston that abut against each other. The flow-blocking component is located in the flow channel, and the fluid in the flow channel exerts pressure on the flow-blocking component. When the pressure is greater than a preset value, the flow-blocking component drives the piston to move.

[0012] In some embodiments, the mechanical timing module includes a spring-gear type delay assembly and a hydraulically damped delay assembly; the spring-gear type delay assembly includes a spring, a gear reducer, and a cam mechanism; the spring provides power, which is transmitted to the cam mechanism via the gear reducer mechanism; the hydraulically damped assembly includes a hydraulic cylinder that houses the piston; the triggering unit triggers the spring and triggers fluid flow in the hydraulic cylinder to cause the mechanical timing module to delay the opening of the locking element.

[0013] In some embodiments, the release mechanism includes a compression spring and a striker, the compression spring abutting against the striker and the locking member acting on the striker; when the locking member unlocks the striker, the compression spring pushes the striker.

[0014] In some embodiments, the locking element includes a first locking element comprising a shear pin disposed between the piston and the housing for locking the piston.

[0015] In some embodiments, the locking member further includes a second locking member, which includes a fork pawl that holds the firing pin and cooperates with the mechanical timing module; when the mechanical timing module finishes timing, the fork pawl disengages from the firing pin.

[0016] To address the aforementioned problems, the present invention provides a detonation method utilizing the delayed detonation device described above, comprising:

[0017] In the first detonation mode, pressure is increased into the cavity through the upper connection port until the mechanical timing module is activated. The mechanical timing module delays for a preset time to adjust the locking element, so that the release mechanism is in the release state for detonation.

[0018] In some implementations, when the mechanical timing module is started, the pressure inside the cavity is simultaneously released to put the cavity into a negative pressure state.

[0019] In some embodiments, when the locking element includes a shear pin, the operation method further includes a second detonation method, in which pressure is increased into the cavity through the upper connection port until the shear pin is broken, and the piston moves to push the release mechanism to detonate.

[0020] To address the aforementioned problems, the present invention provides an oil and gas well perforation device, including the delayed detonation device as described above, or a delayed detonation device operating according to the aforementioned detonation method.

[0021] The present invention has the following beneficial effects:

[0022] The delayed detonation device proposed in this application innovates from the perspective of detonation mechanism and operational safety assurance. In particular, under extreme working conditions where manual triggering is not possible, it achieves automatic detonation through mechanical timing, effectively avoiding misfires and safety hazards, and making up for key problems that existing technologies cannot solve.

[0023] This invention, through a mechanical timed delay detonation device, achieves dual protection: manual control under normal conditions and automatic detonation under extreme conditions. It not only improves the safety and success rate of perforation operations but also makes up for the shortcomings of existing technologies, and has significant application value and promotion significance. Attached Figure Description

[0024] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] Figure 1 This is a cross-sectional view of an oil and gas well perforation device according to an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional schematic diagram of the mechanical timing module according to an embodiment of the present invention;

[0027] Figure 3 This is a cross-sectional view of the release mechanism according to an embodiment of the present invention;

[0028] Figure label:

[0029] 1. Upper connecting end; 2. Housing; 3. Inner liner; 4. Mechanical timing module; 5. Shear pin; 6. Shift fork pawl; 7. Piston; 8. Flow control assembly; 9. Compression spring; 10. Strike pin; 12. Spring-driven gear delay assembly; 13. Hydraulic damping delay assembly; 14. Sealing ring; 15. Lower connecting end. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] It should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0032] See also Figures 1 to 3 As shown, according to an embodiment of the present invention, a delayed detonation device for perforation of oil and gas wells includes:

[0033] The outer casing 2 is inserted into the perforation of the oil and gas well; the upper and lower ends of the outer casing 2 are provided with ports: an upper connecting port and a lower connecting port; the upper connecting port is used to connect to the wellhead of the oil and gas well, and the lower connecting port is used to connect to the detonating cord of the perforation gun; a cavity is formed inside the outer casing 2;

[0034] The cavity is sequentially provided with a mechanical timing module 4, a locking element, and a release mechanism. The mechanical timing module 4 regulates the locking element to lock or release the release mechanism. The mechanical timing module can delay the locking element for a preset time to open the locking element so that the release mechanism is in the released state. The release mechanism transmits detonation to the detonating tube of the perforating gun through the lower connection port.

[0035] The present invention uses a mechanical timing module to delay the unlocking and release mechanism. The output end of the mechanical timing module 4 is connected to a locking component, which can automatically release the lock on the release mechanism when the preset time limit is reached, thereby enabling detonation.

[0036] This invention employs standardized upper and lower connection ports, allowing for convenient connection in series with tubing-transmitted perforating gun strings. Its overall materials and sealing design meet the requirements of high-temperature and high-pressure well conditions, with a temperature resistance of over 220℃ and a pressure resistance of 150–200 MPa, making it suitable for perforation operations in harsh environments such as deep wells and ultra-high-temperature, high-pressure wells.

[0037] For details, please refer to Figure 1 As shown, an upper connection port is provided at the top of the upper connection end 1 of the outer shell 2, and a lower connection port is provided at the bottom of the lower connection end 15. The interior is a cavity structure, and more specifically, an inner liner 3 is provided inside the cavity. The mechanical timing module 4, the locking element and the release mechanism are all set in the inner liner 3 to improve the sealing performance.

[0038] In some embodiments, a flow channel is formed within the cavity to connect the upper connection port and the lower connection port. A trigger unit is also provided within the cavity, positioned between the mechanical timing module 4 and the upper connection port. The trigger unit includes an abutting flow-blocking component 8 and a piston 7. The flow-blocking component 8 is located within the flow channel, and the fluid in the flow channel exerts pressure on the flow-blocking component 8. When the pressure exceeds a preset value, the flow-blocking component 8 drives the piston 7 to move, thereby triggering the mechanical timing module 4 to open the locking element.

[0039] A trigger unit is installed inside the cavity. Specifically, the trigger unit can be a flow-blocking component 8 and a piston 7 that are connected vertically. The mechanical timing module 4 is connected to the piston 7 to receive the fluid pressure signal in the well and start the timing. The flow-blocking component 8 is installed above the piston 7. When the flow-blocking component 8 is subjected to the action of the fluid, it will create a pressure difference that drives the piston 7 to move.

[0040] A through-hole is provided on the flow-blocking component 8. When the through-hole is not blocked, no pressure difference will be generated, preventing the piston 7 from moving. By blocking the through-hole using a ball-throwing method, the piston 7 can be moved.

[0041] In some embodiments, the mechanical timing module 4 includes a spring-gear delay assembly 12 and a hydraulic damping delay assembly 13; the spring-gear delay assembly 12 includes a spring, a gear reduction mechanism and a cam mechanism; the spring provides power, which is transmitted to the cam mechanism via the gear reduction mechanism; the hydraulic damping assembly 13 includes a hydraulic cylinder that houses the piston 7; the triggering unit triggers the spring and triggers the fluid flow of the hydraulic cylinder to delay the opening of the locking member by the mechanical timing module (4).

[0042] The mechanical timing module 4 installed inside the outer casing 2 of this invention adopts a passive mechanical delay structure, and can be a combination of a spring-loaded gear delay component 12 and a hydraulically damped delay component 13. The locking component is connected to the output end of the mechanical timing module 4, which can automatically release the locking of the release mechanism when the preset time limit is reached, thereby triggering the detonation.

[0043] The delayed detonation function of this invention relies on a purely mechanical structure, eliminating the need for delay powder or electronic timing devices. Compared to traditional gunpowder delay fuses, this device eliminates the risk of inaccurate delays or premature extinguishing due to temperature and pressure variations in pyrotechnic devices. Compared to electronic timing devices, this device has a simple and reliable structure, requires no downhole power supply or signal transmission, and can withstand long-term high-temperature and high-pressure environments in the mine while maintaining stable function. In particular, the spring-loaded gear-type delay component 12 provides a relatively constant mechanical delay basis, while the hydraulically damped delay component 13 can further fine-tune the delay length, allowing the total delay time accuracy to be controlled within ±5%, significantly better than the accuracy level of existing delay powder devices. Furthermore, through a reasonable structural design, the delay time can be flexibly adjusted within the range of several seconds to tens of minutes as needed, exhibiting greater adaptability.

[0044] The innovative aspect of this device lies in its integration of a mechanical clockwork timing mechanism and a hydraulic delay mechanism, enabling long-delay, high-precision detonation control even in the absence of power downhole. It also employs a dual safety locking system with a shear pin 5 and a ratchet, providing redundant safety features during the downhole and pressurization phases to prevent premature or accidental detonation. Furthermore, the device simplifies on-site operations through ball-launcher triggering and wellhead pressure control, exhibits good compatibility with existing TCP perforation technology, and possesses broad practical value and promising prospects for widespread adoption.

[0045] In some embodiments, the release mechanism includes a compression spring 9 and a striker 10, the compression spring 9 abutting against the striker 10, and the locking member acting on the striker 10; when the locking member unlocks the striker 10, the compression spring 9 pushes the striker 10.

[0046] In a more specific configuration, the firing pin 10 is positioned in the lower axial channel of the inner liner 3 and is pushed downwards by a compression spring 9 to point towards the detonating primer 11. During the delay period, the firing pin 10 is held in a ready-to-fire position by a locking element; when the locking element is unlocked, the compression spring 9 immediately releases its elastic force, driving the firing pin 10 to strike downwards at high speed, igniting the detonating primer 11. The detonating primer 11 is ignited by the instantaneous impact of the firing pin 10, and its flame or shock wave is transmitted through the lower output interface to the detonating cord connected thereto, detonating the perforated ammunition below. This device uses a non-electric detonation method where the mechanical firing pin 10 strikes the primer, which is highly reliable and unaffected by the downhole electromagnetic environment.

[0047] In some embodiments, the locking element includes a first locking element, which includes a shear pin 5 disposed between the piston 7 and the housing 2 for locking the piston 7.

[0048] In the initial assembly state of the device, the shear pin 5 is connected between the piston 7 and the outer casing 2 or the fixed seat, mechanically locking the piston 7 and the connected timing module in a standby position. Only when the pressure at the wellhead reaches a preset threshold will the shear pin 5 be sheared to release the piston. By precisely designing the shear force value of the shear pin 5, it can be ensured that vibrations or unexpected pressure fluctuations during the downhole process will not trigger the detonation, and the detonation action will only be initiated under the expected pressure conditions.

[0049] In some embodiments, the locking member further includes a second locking member, which includes a fork pawl 6 that holds the firing pin 10 and cooperates with the mechanical timing module 4; when the mechanical timing module 4 finishes timing, the fork pawl 6 disengages from the firing pin 10.

[0050] The second locking element adopts a fork and pawl structure 6, which can unlock the slider mechanism at a set time. During the delay, the fork and pawl 6 cooperates with the mechanical timing module 4 to keep the striker 10 in the ready-to-fire position; when the mechanical timing module 4 finishes timing, the fork and pawl 6 automatically disengages from the striker 10. Preferably, the fork and pawl 6 is connected to the tail of the striker 10 or its connecting part, and always blocks the movement of the striker 10 before receiving the unlocking signal from the timing module. When the timing ends, the fork / pawl is quickly rotated or slid away by a spring or cam mechanism, thereby releasing the striker 10.

[0051] To address the aforementioned problems, the present invention provides an operation method for the delayed detonation device as described above, comprising:

[0052] In the first detonation mode, pressure is increased into the cavity through the upper connection port until the mechanical timing module 4 is activated. The mechanical timing module 4 delays for a preset time to adjust the locking element, so that the release mechanism is in the release state for detonation.

[0053] The delayed detonation device of the present invention has two detonation operation modes: normal detonation mode and delayed detonation mode.

[0054] The first detonation mode described above is a delayed detonation mode. The timing module is activated by pressurizing and shearing the locking pin. Then, the wellhead is quickly depressurized to create negative pressure conditions in the wellbore. When the predetermined delay time (e.g., 5 to 10 minutes) after depressurization ends, the mechanical timing module 4 unlocks the firing pin 10 to ignite the primer 11, detonating the perforating projectile to complete the perforation.

[0055] In some implementations, when the mechanical timing module 4 is started, the pressure inside the cavity is simultaneously released so that the cavity is in a negative pressure state.

[0056] The negative pressure created in the wellbore by the delayed detonation mode helps improve the flow of oil and gas after perforation.

[0057] In some embodiments, when the locking element includes a shear pin 5, the operation method further includes a second detonation method, in which pressure is increased into the cavity through the upper connection port until the shear pin 5 is disengaged, and the piston 7 moves to push the release mechanism to detonate.

[0058] The second detonation method described above is the normal detonation mode. During operation, pressure is applied to the tubing through the upper connection port until the shear pin 5 cuts. The piston 7 immediately pushes the firing pin 10 to unlock and directly ignites the primer 11, thereby instantly detonating the perforating gun (i.e., the wellbore is always pressurized without any special delay). The normal mode is used for perforation operations that do not require negative pressure conditions.

[0059] The two detonation modes mentioned above can be selected by the operations engineer by controlling the wellhead pressurization / depressurization program, thus achieving the dual function of one device.

[0060] To address the aforementioned problems, the present invention provides an oil and gas well perforation device, including the delayed detonation device as described above, or a delayed detonation device operating according to the aforementioned control method.

[0061] See Figure 1 As shown, the oil and gas well perforation device includes a housing 2, an upper connecting end 1 and a lower connecting end 15 at both ends, and an inner liner 3 disposed inside the housing 2. A delayed detonation component cavity is formed inside the inner liner 3, and a mechanical timing module 4 is installed in the cavity. The mechanical timing module 4 is connected to a piston 7 to receive the well fluid pressure signal to start the timing.

[0062] A flow-blocking component 8 is provided above the piston 7, which is sealed off by the ball-throwing seat. The flow-blocking component 8 allows fluid to pass through when the ball is not thrown, and after the ball is thrown and sealed off, a pressure difference is formed to drive the piston 7 to move.

[0063] The oil and gas well perforation device also includes a dual locking mechanism for locking and releasing the striker 10, consisting of a shear pin 5 and a fork pawl 6, as well as a detonating primer located below the striker 10 and a lower output port that engages with the primer. Sealing rings 14 are provided between the outer casing 2, the inner liner 3, and all moving parts to ensure pressure sealing.

[0064] The mechanical timing module 4 includes a spring-loaded gear-type delay assembly 12 and a hydraulically damped delay assembly 13. The spring-loaded gear-type delay assembly 12, composed of a pre-loaded spring through a gear reduction mechanism, provides the mechanical delay power and precisely sets the delay time. The hydraulically damped delay assembly 13 includes micro-flow holes filled with damping fluid and a piston structure, used for fluid damping adjustment of the spring release speed. The combination of these two components ensures that the delay time remains precisely controllable even under high pressure and high temperature conditions downhole, achieving delay times on the order of minutes with minimal environmental influence, significantly improving the reliability and accuracy of delayed detonation.

[0065] Piston 7 is located in the upper cavity of the inner liner 3 and can sense the fluid pressure from the upper wellhead after the ball-seat sealing assembly is closed. The lower end of piston 7 is connected to the input end of mechanical timing module 4, and the upper end is temporarily fixed by shear pin 5. When the fluid pressure applied at the wellhead reaches the set value, piston 7 overcomes the resistance of shear pin 5 and moves downward a certain distance, pushing mechanical timing module 4 to start timing. At the same time, the movement of piston 7 causes the damping fluid in the hydraulic damping assembly to flow slowly through the annular gap, thereby realizing time delay control. This structure allows the time delay process to start timing from the trigger event of wellhead pressure application.

[0066] An annular space is provided between the outer shell 2 and the inner liner 3 to accommodate components such as the mechanical timing module 4, shear pin 5, pawl fork 6, and compression spring 9. This ensures that the timing module and the firing pin 10 will not rotate or shift when subjected to downhole impacts or fluid scouring, guarantees that the firing pin 10 is aligned with the primer, and ensures that all transmission components are coaxial, thereby improving detonation reliability.

[0067] The upper and lower connection ports adopt standardized snap-type / conical surface seals; the lower output interface is equipped with a limited deep shoulder and anti-misalignment conical surface, which is compatible with hollow bullet type or segmented combination perforation gun detonation system, and achieves seamless compatibility with continuous tubing or cable perforation process.

[0068] The load-bearing and corrosion-resistant components are made of high-temperature and high-pressure resistant materials such as Inconel 718 and 17-4PH; the seals are made of oil-resistant and temperature-resistant elastomers such as FKM / FFKM; the device is suitable for temperatures ≥150-180 ℃, pressure ≤100 MPa, and continuous working time ≥30h.

[0069] The shear force of the shear pin 5 can be configured in stages (e.g., 3-15 kN); the stroke and spring preload of the firing pin 10 are adjustable (e.g., 2-6 mm, 50-200 N); the mechanical delay can be set in the range of seconds to hours (preferably 1-48 h).

[0070] The device can be equipped with mechanical status indicators to display statuses such as "wound / unwound" and "unlocked / unlocked," so that the ground can identify process nodes through pressure-time / displacement curves or visual windows.

[0071] It will be readily understood by those skilled in the art that the above embodiments can be freely combined and superimposed without conflict.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A delayed detonation device for perforation in oil and gas wells, characterized in that, include: The outer shell (2) is inserted into the perforation of the oil and gas well; the upper and lower ends of the outer shell (2) are provided with ports: an upper connecting port and a lower connecting port; the upper connecting port is used to connect to the wellhead of the oil and gas well, and the lower connecting port is used to connect to the detonating tube of the perforation gun; a cavity is formed inside the outer shell (2); The cavity is provided with a mechanical timing module (4), a locking element and a release mechanism in sequence. The mechanical timing module (4) controls the locking element so that the locking element locks or releases the release mechanism. The mechanical timing module (4) can delay the opening of the locking element for a preset time so that the release mechanism is in the release state. The release mechanism transmits the detonation to the perforating gun detonating tube through the lower connection port.

2. The delayed detonation device according to claim 1, characterized in that: The cavity has a flow channel that connects the upper connection port and the lower connection port. The cavity is also provided with a trigger unit, which is located between the mechanical timing module (4) and the upper connection port. The trigger unit includes a flow-blocking component (8) and a piston (7) that abut against each other. The flow-blocking component (8) is located in the flow channel. The fluid in the flow channel exerts pressure on the flow-blocking component (8). When the pressure is greater than a preset value, the flow-blocking component (8) drives the piston (7) to move, so that the piston (7) triggers the mechanical timing module (4) to open the locking member.

3. The delayed detonation device according to claim 2, characterized in that: The mechanical timing module (4) includes a spring-gear type delay assembly (12) and a hydraulic damping type delay assembly (13); the spring-gear type delay assembly (12) includes a spring, a gear reduction and a cam mechanism; the spring provides power, which is transmitted to the cam mechanism via the gear reduction mechanism; the hydraulic damping type assembly (13) includes a hydraulic cylinder that houses the piston (7); the triggering unit triggers the spring and triggers the fluid flow of the hydraulic cylinder to delay the opening of the locking member by the mechanical timing module (4).

4. The delayed detonation device according to claim 2 or 3, characterized in that: The release mechanism includes a compression spring (9) and a striker (10). The compression spring (9) abuts against the striker (10), and the locking member acts on the striker (10). When the locking member unlocks the striker (10), the compression spring (9) pushes the striker (10).

5. The delayed detonation device according to claim 4, characterized in that: The locking element includes a first locking element, which includes a shear pin (5) disposed between the piston (7) and the outer casing (2) for locking the piston (7).

6. The delayed detonation device according to claim 4 or 5, characterized in that: The locking component also includes a second locking component, which includes a fork pawl (6) that holds the striker (10) and cooperates with the mechanical timing module (4). When the mechanical timing module (4) finishes timing, the fork pawl (6) disengages from the striker (10).

7. A detonation method using the delayed detonation device as described in any one of claims 1-6, characterized in that, include: In the first detonation mode, the pressure is increased into the cavity through the upper connection port until the mechanical timing module (4) is activated. The mechanical timing module (4) delays for a preset time to adjust the locking element, so that the release mechanism is in the release state for detonation.

8. The method according to claim 7, characterized in that: When the mechanical timing module (4) is started, the pressure inside the cavity is simultaneously released so that the cavity is in a negative pressure state.

9. The method according to claim 7 or 8, characterized in that: When the locking element includes a shear pin (5), the method further includes a second detonation method, which pressurizes the cavity through the upper connection port until the shear pin (5) is broken, and the piston (7) moves to push the release mechanism to detonate.

10. A perforation device for oil and gas wells, characterized in that, Includes a delayed detonation device as described in any one of claims 1-6, or a delayed detonation device operated in accordance with the method described in any one of claims 7-9.

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