A downhole perforating charge for oil and gas production

Abstract

The application discloses a downhole perforating bullet for oil and gas exploitation, and belongs to the field of perforating bullets. The melting type plugging mechanism is arranged, so that after the booster is ignited, the low-antimony lead-antimony alloy rod is melted at the same time when the main explosive is ignited. At this time, the pressure spring immediately releases the elastic force. The metal rod pushes the plugging piece to slide along the through sliding groove in a directional manner. The opening of the detonator mounting channel section is quickly covered. The plugging is completed before the energy leaks to the detonator mounting channel section. The problem that the detonation energy leaks through the detonator mounting channel section is solved. After the plugging, a sealed space is formed in the inner part of the shell body. The energy concentration of the main explosive and the booster drives the shaped charge liner to form a high-speed metal jet. The perforating depth and the perforating aperture of the perforating bullet are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of perforating charges, and more particularly to a downhole perforating charge for oil and gas exploitation. BACKGROUND

[0002] In the process of oil and gas exploration and development, perforating operation is a key process for connecting downhole oil and gas layers and wellbore. The core is to drive the shaped charge to form a high-speed metal jet by the high-temperature and high-pressure energy generated after the perforating charge is detonated, to break through the downhole casing, cement ring and penetrate into the oil and gas layer, thereby establishing a channel for oil and gas to flow from the formation to the wellbore.

[0003] However, in actual application, the internal energy sealing and utilization efficiency of the existing perforating charge always has technical bottlenecks, and the core problem is concentrated in the structural design defects of the detonator installation channel section: in order to realize the convenient disassembly and detonation signal conduction of the detonator, the detonator installation channel section needs to maintain a channel structure in communication with the outside of the shell. However, after the booster and main explosive are ignited, part of the high-temperature and high-pressure energy generated will leak out through the opening of the detonator installation channel section. This leakage path not only easily causes the energy inside the perforating charge to be wasted on the shaped charge, but also causes the metal jet formed by the shaped charge to have reduced speed and uneven density due to energy dispersion, thereby causing problems such as insufficient perforation depth and small hole diameter, which is difficult to meet the needs of deep wells, ultra-deep wells or tight oil and gas reservoirs for efficient establishment of perforation channels.

[0004] In order to alleviate the above-mentioned energy leakage problem, the prior art has attempted to use rigid plugging members (such as metal plugs) and flexible plugging members (such as rubber plugs) to pre-plug the detonator installation channel section, but such schemes have significant limitations: if the rigid plugging member is sealed too tightly, it will hinder the normal disassembly of the detonator, and even easily cause the detonator to be deformed during disassembly; although the flexible plugging member has a larger assembly redundancy, it facilitates the normal disassembly of the detonator, but its material is easily melted or carbonized in the high-temperature environment of 2000℃ or above generated by the detonation of the perforating charge, losing the plugging ability.

[0005] Therefore, the prior art lacks a sealing scheme that can achieve automatic sealing, effectively block energy leakage from the detonator installation channel section, and has a compact structure that adapts to the internal space of the perforating charge under the premise of not affecting the portability, disassembly and detonation function of the detonator, resulting in that the energy utilization rate of the perforating charge is always difficult to improve, which restricts its application effect in efficient oil and gas exploitation operations. Based on this, there is an urgent need to design a sealing mechanism that can automatically melt and trigger based on the high temperature characteristics of the perforating charge during detonation, quickly complete the sealing of the detonator installation channel section through elastic driving force, and has a simple and compact structure, to solve the technical problems of energy leakage and insufficient driving force of the shaped charge, and thereby improve the perforating performance of the perforating charge and the oil and gas well exploitation efficiency, so we propose a downhole perforating charge for oil and gas exploitation to solve the above problems. SUMMARY

[0006] 1. Technical problem to be solved:

[0007] In view of the problems existing in the prior art, the purpose of the present application is to provide a downhole perforating charge for oil and gas exploitation, which can automatically melt and trigger based on the high temperature characteristics of the perforating charge during detonation, quickly complete the sealing of the detonator installation channel section through elastic driving force, and has a simple structure, to solve the technical problems of energy leakage and insufficient driving force of the shaped charge, and thereby improve the perforating performance of the perforating charge and the oil and gas well exploitation efficiency.

[0008] 2. Technical scheme:

[0009] To solve the above problems, the present application adopts the following technical scheme.

[0010] A downhole perforating charge for oil and gas exploitation, comprising a shell, a filling cavity section, an installation cavity section and a detonator installation channel section are formed inside the shell, a shaped charge is fixedly installed in the filling cavity section by a pressure ring, and a fuse sealing mechanism is arranged in the installation cavity section.

[0011] The fuse sealing mechanism comprises a ring seat, the ring seat comprises an annular part and a U-shaped limiting part, the annular part is fixedly installed on the inner wall bottom of the installation cavity section by screws, an avoidance opening is formed on the annular part corresponding to the position of the U-shaped limiting part, a sealing piece is arranged inside the U-shaped limiting part, sliding fins are fixedly connected to the outer wall of the sealing piece on both sides, through-slots are formed on both sides of the U-shaped limiting part corresponding to the positions of the sliding fins, and the sealing piece is slidably connected to the U-shaped limiting part through the sliding fins and the through-slots on both sides.

[0012] The other two sides of the outer wall of the blocking sheet are provided with insertion holes one, the inner wall of the U-shaped limiting part is provided with insertion holes two, the insertion holes two and one of the insertion holes one at the corresponding position are connected by low-antimony lead-antimony alloy rods, the shell is provided with a spring channel at the position corresponding to the avoiding opening, the other insertion hole one is inserted with a metal rod, one end of the metal rod extends to the inside of the spring channel through the avoiding opening, the inner wall of the spring channel is provided with an internal thread structure, the spring channel outside the shell is threadedly connected with a cap, the inside of the cap is sleeved with a pressing spring, one end of the metal rod is provided with a contact end, and the two ends of the pressing spring are respectively in contact with the contact end and one side of the inner wall of the cap.

[0013] Further, the shell, the ring seat, the blocking sheet, the metal rod and the cap are made of the same material, the cross section of the blocking sheet and the detonator installation channel section is a circular structure, and the diameter of the outer wall of the blocking sheet is greater than the diameter of the inner wall of the detonator installation channel section.

[0014] Further, the pressing ring and the inner wall of the filling cavity section are fixedly installed by a plurality of rivets, the inside of the filling cavity section on one side of the shaped charge is filled with main explosive, and the inside gap of the installation cavity section is filled with booster.

[0015] Further, the shell bottom is provided with a wire pressing groove, the shell bottom on one side of the wire pressing groove is fixedly installed with a wire pressing ring, and the bottom of the detonator installation channel section is in communication with the inside of the wire pressing groove.

[0016] The preparation method of the low-antimony lead-antimony alloy rod comprises the following steps:

[0017] Step S1, raw material preparation

[0018] Raw material selection:

[0019] Lead (Pb): industrial pure lead (purity ≥ 99.9%) is selected to avoid impurities such as sulfur (S) and iron (Fe) (impurities will increase the brittleness of the alloy and easily break during supporting); the form can be selected as block or granular (granular melting is faster).

[0020] Antimony (Sb): industrial pure antimony (purity ≥ 99.8%) is selected, and impurities are also avoided; the form is preferably small block (large block antimony dissolves slowly, which is easy to cause composition segregation).

[0021] Proportioning calculation:

[0022] According to the weight of the demand, for example, 1000g alloy needs to be prepared, 900g pure lead + 100g pure antimony needs to be weighed (the error is controlled within ±0.5%, otherwise it will deviate from the "low antimony" characteristics, and the content of antimony is too high, which will increase the melting point, and too low will not be strong enough).

[0023] Step S2, melting equipment and container selection

[0024] Melting furnace: prefer small medium frequency induction furnace or resistance heating furnace (temperature controllable range 300-800℃, meet the needs of lead antimony melting); if the scale is very small, you can also use a graphite crucible heating device with temperature control (avoid using ordinary iron pot, iron will be dissolved into the alloy and affect the purity).

[0025] Melting container: use graphite crucible (high temperature resistant, not react with lead and antimony, avoid metal pollution), the crucible needs to be dried in advance (120℃ for 1-2 hours, remove moisture, prevent "explosion" during melting).

[0026] Step S3, sub-step melting

[0027] The melting point of lead (327℃) is much lower than that of antimony (630℃), if added at the same time, antimony will "sink to the bottom" because lead has not been melted, resulting in uneven dissolution, so it needs to be added in stages:

[0028] First, put the weighed pure lead into the graphite crucible, start the heating furnace, and heat to 350-400℃ (lead completely melts, becomes liquid, and has good flowability).

[0029] Keep the temperature at about 400℃, slowly add small pieces of pure antimony (add 3-5 times, wait for 1-2 minutes after each addition, to avoid the sudden cooling of antimony block causing the lead liquid to solidify).

[0030] After all the antimony blocks are added, raise the furnace temperature to 450-550℃ (at this temperature, antimony can be completely dissolved in the lead liquid, and the volatilization of lead is very low, the boiling point of lead is 1740℃, below 550℃ there is almost no obvious volatilization, to avoid the proportion of ingredients deviating).

[0031] Step S4, stirring and slag removal

[0032] Stirring: use a graphite rod (which does not react with the alloy) to slowly stir the molten alloy liquid clockwise, the stirring time is 5-8 minutes, and the rotating speed is controlled at 30-50 revolutions per minute (avoid stirring too fast to cause air to be drawn in, increase oxidation), the purpose is to mix the lead and antimony molecules thoroughly, to prevent "segregation" (i.e. local antimony content is too high or too low, causing the melting point of some areas to be too high, and some areas to be insufficient in strength).

[0033] Deslagging: Lead and antimony will be oxidized at high temperature (PbO, Sb2O3 is generated), these oxides will float on the surface of the alloy liquid to form a "slag layer", which needs to be removed with a graphite spoon (if the slag layer is mixed into the alloy, it will reduce the tensile strength of the metal rod, and the support will be easily broken).

[0034] Step S5, casting and subsequent processing

[0035] Casting:

[0036] After deslagging, the uniform alloy liquid is slowly poured into a preheated metal mold (the mold material can be cast iron or 45 steel, the mold cavity needs to match the diameter of the final metal rod, for example, a 3mm diameter metal rod, the mold cavity is designed to be 3.5mm, leaving a processing allowance), the mold is preheated to avoid rapid solidification of the alloy liquid due to cold, resulting in shrinkage, cracks and other defects.

[0037] Cooling and demolding: naturally cooled to room temperature (about 1-2 hours, not recommended for water cooling to avoid large temperature difference causing internal stress of the alloy), and then demolded to obtain a "lead-antimony alloy rod blank".

[0038] Subsequent plastic processing: If the rod blank diameter is too large or the surface is not flat, it can be adjusted by low-temperature hot rolling (heated to 200-300°C, rolled to the target diameter) or drawing (drawn to the required size with a metal drawing machine), which can also refine the alloy grains and further improve the room temperature strength, which is beneficial to the support of the sealing sheet.

[0039] Step S6, performance verification

[0040] After the metal rod is made, two key indicators, melting point detection and strength detection, are performed to avoid subsequent failure:

[0041] Melting point detection: Take a small amount of alloy sample and use a differential scanning calorimeter (DSC) to measure the melting point, which should be in the range of 280-320°C, meeting the melting point requirements of low-antimony lead-antimony alloy rods, ensuring that the low-antimony lead-antimony alloy rod can be quickly melted and broken when the booster or main explosive ignites and explodes.

[0042] Strength detection: Take a section of the metal rod (50mm long) and use a universal testing machine to measure the room temperature tensile strength, which needs to reach 25-35MPa to ensure that it can support the sealing sheet without deforming prematurely.

[0043] The low-antimony lead-antimony alloy rod prepared through the above process can meet the core requirements of "stable support at room temperature and easy melting and breaking during explosion".

[0044] 3. Beneficial effects:

[0045] Compared with the prior art, the advantages of the present application are:

[0046] (1) The scheme, relying on the exclusive design of low-antimony lead-antimony alloy rod and the filling structure of booster, realizes the precise triggering of stable support at room temperature and instantaneous melting of detonation, the melting point of low-antimony lead-antimony alloy rod is 280-320℃, the tensile strength at room temperature is 25-35MPa, the low-antimony lead-antimony alloy rod can stably connect the sealing sheet and the U-shaped limiting part at room temperature, avoids the displacement of the sealing sheet to block the installation channel of the detonator, when the detonator ignites the booster, the booster fills the gap of the installation cavity section and fully wraps the alloy rod, the detonation high temperature above 2000℃ can instantaneously melt the low-antimony lead-antimony alloy rod, there is no melting delay or room temperature fracture risk, and the sealing action and energy release are started synchronously;

[0047] (2) The scheme, after the booster is ignited, the low-antimony lead-antimony alloy rod is melted at the same time as the main explosive is ignited, at this time, the pressure spring immediately releases the elastic force, the sealing sheet is pushed by the metal rod and slides along the through sliding groove, the opening of the detonator installation channel section is quickly covered, the sealing is completed before the energy leaks to the detonator installation channel section, and the problem of detonation energy leakage through the detonator installation channel section is solved;

[0048] (3) The scheme, the cross section of the sealing sheet is circular and the diameter is greater than the inner diameter of the detonator installation channel section, the opening of the detonator installation channel section can be completely covered, the gap leakage caused by size mismatch is avoided, the materials of the shell, the ring seat, the sealing sheet, the metal rod and the cap are consistent and high-temperature resistant, the melting of the components caused by detonation high temperature is avoided to cause sealing failure, at the same time, a sealed space is formed in the shell after sealing, the energy of the main explosive and the booster is concentrated to drive the shaped charge to form a high-speed metal jet, and the perforating depth and perforating aperture of the perforating bomb are improved. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a whole structure schematic diagram of the application;

[0050] Figure 2 It is an installation structure schematic diagram of the internal melting type sealing mechanism of the installation cavity section of the application (the installation cavity section of the shell has been truncated for easy viewing);

[0051] Figure 3 It is a Figure 2 schematic diagram of a partial area structure of the application;

[0052] Figure 4 It is a cross section structure schematic diagram of the shell of the application;

[0053] Figure 5 It is a Figure 4 schematic diagram of a partial area structure of the application;

[0054] Figure 6 It is a Figure 5 schematic diagram of a partial area structure of the application.

[0055] Explanation of reference numerals in the drawings:

[0056] 1, fuse type plugging mechanism; 2, ring seat; 201, annular part; 2011, avoiding opening; 202, U-shaped limiting part; 2021, through sliding groove; 2022, jack two; 3, plugging piece; 301, sliding fin; 302, jack one; 4, low-antimony lead-antimony alloy rod; 5, metal rod; 6, cap; 7, pressure spring;

[0057] 8, shell; 801, filling cavity section; 802, mounting cavity section; 803, detonator mounting channel section; 804, spring channel; 805, wire pressing groove; 9, pressure ring; 10, shaped charge; 11, main explosive; 12, booster. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the specification of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0059] Embodiment 1: please refer to Figures 1-6 A downhole perforating bullet for oil and gas exploitation comprises a shell 8, the shell 8 is internally provided with a filling cavity section 801, a mounting cavity section 802 and a detonator mounting channel section 803, the filling cavity section 801 is internally fixedly installed with a shaped charge 10 through a pressure ring 9, and the mounting cavity section 802 is internally provided with a fuse type plugging mechanism 1.

[0060] The fuse type plugging mechanism 1 comprises a ring seat 2, the ring seat 2 comprises an annular part 201 and a U-shaped limiting part 202, the annular part 201 is fixedly installed on the inner wall bottom of the mounting cavity section 802 through a screw, and the annular part 201 is provided with an avoiding opening 2011 at a position corresponding to the U-shaped limiting part 202, the U-shaped limiting part 202 is internally provided with a plugging piece 3, and the plugging piece 3 is fixedly connected with sliding fins 301 on both sides of the outer wall, the U-shaped limiting part 202 is provided with through sliding grooves 2021 on both sides at positions corresponding to the sliding fins 301, and the plugging piece 3 is slidably connected with the U-shaped limiting part 202 through the sliding fins 301 and the through sliding grooves 2021 on both sides;

[0061] The other two sides of the outer wall of the blocking sheet 3 are provided with the insertion hole one 302, the inner wall of the U-shaped limiting part 202 is provided with the insertion hole two 2022, the insertion hole two 2022 and one of the insertion hole one 302 at the corresponding position are connected through the low-antimony lead-antimony alloy rod 4, the shell 8 at the position corresponding to the avoiding opening 2011 is provided with the spring channel 804, the other insertion hole one 302 is inserted with the metal rod 5, one end of the metal rod 5 extends to the inside of the spring channel 804 through the avoiding opening 2011, the inner wall of the spring channel 804 is provided with the internal thread structure, the spring channel 804 on the outer side of the shell 8 is threadedly connected with the cap 6, the cap 6 is sleeved with the pressing spring 7 inside, one end of the metal rod 5 is provided with the contact end, the two ends of the pressing spring 7 are respectively in contact with the contact end and one side of the inner wall of the cap 6;

[0062] The materials of the shell 8, the ring seat 2, the blocking sheet 3, the metal rod 5 and the cap 6 are the same, the cross sections of the blocking sheet 3 and the detonator installation channel section 803 are circular structures, and the diameter of the outer wall of the blocking sheet 3 is greater than the diameter of the inner wall of the detonator installation channel section 803;

[0063] The connecting position between the pressure ring 9 and the inner wall of the filling cavity section 801 is fixedly installed through a plurality of rivets, the inside of the filling cavity section 801 at one side of the shaped charge cup 10 is filled with the main explosive 11, and the inside of the installation cavity section 802 is filled with the booster 12, and the bottom of the booster 12 is filled to the top opening of the detonator installation channel section 803;

[0064] The bottom of the shell 8 is provided with the wire pressing groove 805, and the bottom of the shell 8 at one side of the wire pressing groove 805 is fixedly installed with a wire pressing ring, and the bottom of the detonator installation channel section 803 is in communication with the inside of the wire pressing groove 805.

[0065] The working principle of the oil and gas exploitation downhole perforating bullet is as follows:

[0066] First, the detonator outer wall is sleeved with a sealing ring and inserted into the inside of the detonator installation channel section 803, so that the bottom of the detonator can be in contact with the booster 12, which facilitates ignition of the booster 12, and the wire at the top of the detonator is pressed on the wire pressing groove 805 through the wire pressing ring, so as to fix the wire at the top of the detonator;

[0067] When the detonator is triggered and ignited, the booster 12 inside the installation cavity section 802 is ignited first, the booster 12 is ignited to generate high-temperature and high-pressure explosion gas flow, which melts the low-antimony lead-antimony alloy rod 4 at the same time, and also rapidly ignites the main explosive 11, at this time, the high-temperature and high-pressure explosion gas flow generated by the booster 12 and the main explosive 11 further melts the low-antimony lead-antimony alloy rod 4, at the same time, the high-temperature and high-pressure explosion gas flow also explodes the shaped charge cup 10, so that the shaped charge cup 10 forms a high-speed metal jet, which facilitates penetrating through the downhole casing or the cement sheath and deep into the oil and gas layer;

[0068] In the process of melting the low-antimony lead-antimony alloy rod 4, when one side of the blocking piece 3 loses the support of the low-antimony lead-antimony alloy rod 4, the pressure spring 7 inside the cap 6 releases its elastic force, pushes the blocking piece 3 to the position of the detonator installation channel section 803 at the connection between the detonator installation channel section 803 and the installation cavity section 802 through the metal rod 5, seals the opening of the detonator installation channel section 803 at the connection between the detonator installation channel section 803 and the installation cavity section 802, forms a sealed state inside the shell 8, avoids the high temperature and high pressure energy generated when the booster 12 and the main explosive 11 ignite from leaking outside the shell 8 through the detonator installation channel section 803, or the remaining part of the detonator being pushed out after the sealing ring on the outer wall of the detonator is melted and then leaking outside the shell 8 through the detonator installation channel section 803, and is beneficial to the high temperature and high pressure energy generated when the booster 12 and the main explosive 11 ignite being concentrated inside the shell 8, and then the shaped charge cup 10 being shot out at high speed.

[0069] In view of the above embodiment 1, further description is made, please refer to Figure 3 、 Figure 5 and Figure 6 By the sliding fin 301 and the through sliding groove 2021, the blocking piece 3 is conveniently oriented and slid inside the U-shaped limiting part 202, the opening of the detonator installation channel section 803 at the connection between the detonator installation channel section 803 and the installation cavity section 802 is sealed, the structure design that the outer wall diameter of the blocking piece 3 is greater than the inner wall diameter of the detonator installation channel section 803 avoids the blocking piece 3 being too small to seal the opening of the detonator installation channel section 803, the materials of the shell 8, the ring seat 2, the blocking piece 3, the metal rod 5 and the cap 6 are the same, which makes the ring seat 2, the blocking piece 3 and the metal rod 5 not easy to be melted inside the shell 8, avoids the ring seat 2, the blocking piece 3 and the metal rod 5 being melted by the high temperature and high pressure energy generated when the booster 12 and the main explosive 11 ignite, and makes the opening of the detonator installation channel section 803 lose the sealing effect;

[0070] The design of the jack one 302 and the jack two 2022 is to improve the stability of the plug-in connection of the low-antimony lead-antimony alloy rod 4, the metal rod 5 and the blocking piece 3, reduce the phenomenon of loosening at the connection, and also facilitate the installation of the low-antimony lead-antimony alloy rod 4 and the metal rod 5;

[0071] The contact end provided at one end of the metal rod 5 is to increase the contact area and facilitate contact with the pressure spring 7;

[0072] The inside gap of the installation cavity section 802 is filled with the booster 12, and the structure design that the bottom of the booster 12 is filled to the top opening of the detonator installation channel section 803 can make the booster 12 fill the inside gap of the ring seat 2 and fully wrap the low-antimony lead-antimony alloy rod 4, increase the contact area with the low-antimony lead-antimony alloy rod 4, and after the booster 12 is ignited, the low-antimony lead-antimony alloy rod 4 can be fused, and the sensitivity of the low-antimony lead-antimony alloy rod 4 is improved.

[0073] The above merely describes the preferred embodiments of the present application; however, the protection scope of the present application is not limited to this. Any person skilled in the art, according to the technical solution and the improvement concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, and should be covered within the protection scope of the present application.

Claims

1. A downhole perforating charge for use in oil and gas exploration comprising a shell (8) characterised in that: The shell (8) is internally provided with a filling cavity section (801), a mounting cavity section (802) and a detonator mounting channel section (803), the drug cover (10) is fixedly installed in the filling cavity section (801) by a compression ring (9), and the fuse type plugging mechanism (1) is arranged in the mounting cavity section (802). The fuse type plugging mechanism (1) comprises a ring seat (2), the ring seat (2) comprises an annular part (201) and a U-shaped limiting part (202), the annular part (201) is fixedly installed on the inner wall bottom of the mounting cavity section (802) by screws, an avoiding opening (2011) is formed in the annular part (201) at the position corresponding to the U-shaped limiting part (202), the U-shaped limiting part (202) is internally provided with a plugging piece (3), and the outer wall of the plugging piece (3) is fixedly connected with sliding fins (301) on both sides, through-slots (2021) are formed in the U-shaped limiting part (202) on both sides at positions corresponding to the sliding fins (301), and the plugging piece (3) is slidably connected in the U-shaped limiting part (202) through the sliding fins (301) and the through-slots (2021). The outer wall of the plugging piece (3) is additionally provided with two plug holes (302) on both sides, one side of the inner wall of the U-shaped limiting part (202) is provided with a plug hole (2022), the plug hole (2022) and one of the plug holes (302) at the corresponding position are connected through a low-antimony lead-antimony alloy rod (4), the shell (8) is provided with a spring channel (804) at the position corresponding to the avoiding opening (2011), the other plug hole (302) is inserted with a metal rod (5), one end of the metal rod (5) extends to the inside of the spring channel (804) through the avoiding opening (2011), the inner wall of the spring channel (804) is provided with an internal thread structure, the spring channel (804) on the outside of the shell (8) is threadedly connected with a cap (6), the cap (6) is sleeved with a pressure spring (7) inside, one end of the metal rod (5) is provided with a contact end, and the pressure spring (7) is in contact with the contact end and one side of the inner wall of the cap (6) respectively.

2. The downhole perforating charge for use in oil and gas exploration according to claim 1, characterized in that: The shell (8), the ring seat (2), the plugging piece (3), the metal rod (5) and the cap (6) are all made of the same material, the cross section of the plugging piece (3) and the detonator mounting channel section (803) is a circular structure, and the diameter of the outer wall of the plugging piece (3) is greater than the diameter of the inner wall of the detonator mounting channel section (803).

3. The downhole perforating projectile of claim 1, wherein: The compression ring (9) is fixedly installed at the connection between the compression ring (9) and the inner wall of the filling cavity section (801), the main explosive (11) is filled in the filling cavity section (801) on one side of the drug cover (10), the gap in the mounting cavity section (802) is filled with the booster (12), and the bottom of the booster (12) is filled to the top opening of the detonator mounting channel section (803).

4. The downhole perforating charge of claim 1 wherein: The shell (8) bottom is provided with a wire pressing groove (805), and a wire pressing ring is fixedly installed on one side of the shell (8) bottom at one side of the wire pressing groove (805). The detonator mounting channel section (803) bottom is communicated with the wire pressing groove (805) inside.

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