Energy ring and perforating unit for unconventional reservoir perforation-fracturing integration

Abstract

The application provides an energy ring and a perforating unit for unconventional reservoir perforation and fracturing integration. The energy ring for unconventional reservoir perforation and fracturing integration comprises a shell in the shape of a ring, a central energy guide hole is arranged in the middle of the shell, a ring-shaped closed inner cavity is arranged around the central energy guide hole in the shell, an energy-gathering reaction filling body is arranged in the closed inner cavity, and the energy-gathering reaction filling body is arranged in multiple blocks along the circumferential direction of the energy-gathering reaction filling body. At least one energy guide groove is arranged at the first end of the shell. A plurality of flow guide holes are distributed on the outer circumferential side of the shell, and each energy-gathering reaction filling body is in communication with at least one flow guide hole. By adopting the application, the shell and the energy-gathering reaction filling body inside the shell form a functional synergistic overall structure of protection, energy storage, energy reaction release and energy guidance, so that the extension of micro cracks to the deep part of the formation is ensured, the dense area of the unconventional reservoir is broken through, and the collapse caused by the sudden rise and fall of the pressure in the hole is avoided.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well perforation equipment technology, specifically to an energy ring and perforation unit for unconventional reservoir perforation-fracturing integration. Background Technology

[0002] Perforated completion is the most widely used oil and gas well completion method, accounting for over 85% of all well completions. For unconventional reservoirs such as tight sandstone and shale, good perforation quality is not only the channel for oil and gas production, but also the foundation and key to the effective implementation of subsequent large-scale volumetric fracturing. Since the 1940s, shaped charge perforation technology has gradually become the mainstream perforation technology in oilfields both domestically and internationally due to its simple tools, efficient process, and reasonable cost.

[0003] The principle of shaped charge perforation technology is that after the perforating projectile detonates, the metal shaped charge liner forms a high-speed metal jet that penetrates the casing and cement sheath, creating a channel in the reservoir rock. However, currently used shaped charge perforation technologies, while creating the channel, also exert strong impact and compression on the surrounding rock, forming a compacted and fractured zone with a thickness of 6.4–12.7 mm, which can drastically reduce the permeability to 7%–20% of the original core. Furthermore, some rock debris and shaped charge liner residue can clog the channel, further increasing flow resistance. Therefore, existing shaped charge perforation technology urgently needs improvement to significantly alleviate or eliminate the problem of the compacted and fractured rock zone and the adverse effects of perforation residue and the metal jet on the channel, thereby increasing the permeability of the surrounding rock.

[0004] Patent document CN222279526U discloses a perforation projectile for fracturing perforation, comprising a projectile body with an energy ring at the open end. The energy ring can cause secondary combustion and explosion in the perforation channel after the projectile body enters the perforation channel, releasing energy to increase the channel volume, increase the number of fractures in the perforation channel, and clear the channel. Analysis revealed that this perforation projectile design suffers from problems such as uneven energy release spatial distribution, low high-pressure gas flow efficiency, and uncontrollable energy release rhythm. Specifically: 1) Its energy ring consists of an annular shell made of fluoropolymer material, filled with a thermite filling layer, and distributed in an integral layered manner. After detonation, the energy is concentrated in the central area of ​​the channel. The energy coverage of the formation at the edge of the near-wellbore zone is insufficient, resulting in microfractures developing only locally around the channel and unable to extend into the deep formation, making it difficult to break through the tight zone of unconventional reservoirs.

[0005] 2) Unconventional reservoirs require directional guidance of high-pressure gas to impact natural microfractures, but their energy loops lack dedicated flow guiding structures. During the perforation-fracturing process, high-pressure gas tends to escape disorderly from the perforation inlet or the sidewall of the channel, which not only wastes energy but also fails to act precisely on the target fracture, resulting in poor microfracture interweaving.

[0006] 3) Different types of unconventional reservoirs have significantly different requirements for energy release rhythm. However, the reaction layer of their energy loop is designed as an integral whole without segmented control mechanism. The energy release rate is fixed and cannot be dynamically adjusted according to the reservoir type, resulting in a mismatch between the transformation effect and the reservoir requirements. In some reservoirs, improper energy release can even cause pore collapse.

[0007] In summary, given the current societal emphasis on energy security, the need to vigorously promote the exploration and development of unconventional oil and gas resources such as shale and tight sandstone to resolve the traditional oil and gas supply-demand imbalance is becoming increasingly urgent. Addressing the challenges of unconventional reservoir development, this invention focuses on developing an integrated perforation-fracturing energy ring, effectively reducing the risk of secondary reservoir damage and improving overall development efficiency. Summary of the Invention

[0008] To solve at least one of the above technical problems, the present invention provides an energy ring and perforation unit for unconventional reservoir perforation-fracturing integration.

[0009] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell with a central energy-conducting hole at its center. An annular closed cavity surrounds the central energy-conducting hole within the shell, containing shaped charge reactors arranged in multiple pieces along its circumference. At least one energy-conducting groove is also provided at the first end of the shell, each groove directly opposite one of the shaped charge reactors. Multiple flow-guiding holes are distributed along the outer periphery of the shell, with each shaped charge reactor communicating with at least one flow-guiding hole.

[0010] The beneficial effects of this invention are: This invention, through its shell and internal shaped charge reaction filler, forms a synergistic structure that integrates protection, energy storage, energy reaction release, and energy guidance. This ensures that microfractures extend deep into the formation, thus breaking through the tight zone of unconventional reservoirs, and avoids collapse caused by sudden pressure rises and falls within the pores. Specifically: 1) The shell protects the shaped charge reactor filling material inside, preventing external rock debris from impacting and damaging the filling material, and also preventing the filling material from being prematurely triggered. 2) The guide hole provides a directional outflow channel for the high-pressure gas generated by the shaped charge reaction filler, which is concentrated and accurately applied to the target fracture, greatly enhancing the energy intensity of the formation at the edge of the near-wellbore zone. This ensures that the microfractures extend into the deep formation, thereby breaking through the tight zone of the unconventional reservoir. The microfractures have good interweaving properties and avoid the formation of compaction and fracture zones and the blockage of the channels by residues, thus improving the fracturing effect. 3) Through the energy-conducting groove, the energy of the high-speed metal jet is concentrated on the corresponding shaped charge reaction filler, providing the initial triggering conditions for the subsequent step-by-step energy release of the shaped charge reaction filler. At the same time, high-pressure gas is discharged through the flow guide hole, which is convenient to adapt to the energy release rhythm requirements of unconventional reservoirs and avoids collapse caused by sudden pressure rises and falls in the channel.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, the energy-concentrating reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their own circumference. The flow-conducting hole penetrates the fluoropolymer energy storage layer and communicates with the aluminothermic reaction layer. Each energy-conducting groove is directly opposite one of the aluminothermic reaction layers.

[0013] The energy-conducting groove allows the metal jet to act on the corresponding aluminothermic reaction layer, providing the initial triggering conditions for stepwise energy release. Furthermore, the aluminothermic reaction triggered by the aluminothermic agent provides the temperature for the decomposition of the fluoropolymer energy storage layer, enabling it to react accordingly, thus achieving synergistic energy release from both the fluoropolymer energy storage layer and the aluminothermic reaction layer. Simultaneously, the decomposition of the fluoropolymer energy storage layer allows it to neutralize the metallic Al generated in the aluminothermic reaction layer, transforming it into stable solid AlF3 and gaseous H2, preventing HF leakage. Moreover, AlF3 can assist in breaking up blockages, and H2 can enhance pore pressure, ensuring that microfractures extend deep into the formation, thereby breaking through the tight zone of unconventional reservoirs. The good interweaving of microfractures prevents the formation of compacted fracture zones and the blockage of pores by residual material, improving fracturing efficiency.

[0014] Furthermore, the thermite reaction layer includes multiple thermite filling blocks, which are arranged equidistantly along the circumference of the thermite reaction layer, and a detonating charge filling block is provided between each two adjacent thermite filling blocks; each thermite filling block is connected to at least one flow guide hole, and each detonating charge filling block is connected to at least one flow guide hole; each energy-conducting groove is directly opposite one of the thermite filling blocks.

[0015] By using thermite filler blocks as the core unit for energy release, their annular equidistant array distribution allows the energy release of the thermite reaction layer to spread uniformly along the circumference. Detonation charge filler blocks are placed between adjacent thermite filler blocks, which can prevent untriggered thermite filler blocks from reacting prematurely due to the energy influence of triggered thermite filler blocks, ensuring the independence of the reaction of each thermite filler block, realizing the sequential triggering of the thermite filler blocks, thereby forming a pulsed energy release, solving the problem of sudden rise and fall of channel pressure caused by concentrated energy release during traditional energy ring reactions.

[0016] Furthermore, the detonating charge filling block is a lead oxide-aluminum detonating charge column, in which the mass ratio of Pb3O4 to Al is 6:4-7:3.

[0017] By utilizing the stable release of heat and shock waves during the reaction of lead oxide and aluminum, the reliability of the detonation process is ensured. By limiting the mass ratio of Pb3O4 to Al to 6:4-7:3, the combustion rate and energy output intensity of the detonation charge can be controlled by adjusting the component ratio. When the mass ratio is close to 6:4, the combustion rate of the detonation charge is faster, suitable for shale reservoirs requiring rapid triggering of the thermite packing blocks; when the mass ratio is close to 7:3, the combustion rate is slower, suitable for tight sandstone reservoirs requiring slow energy release. Thus, the detonation charge packing blocks can adapt to the stimulation needs of different types of unconventional reservoirs, precisely controlling the energy release rhythm of the thermite reaction layer.

[0018] Furthermore, the inner wall of the energy-conducting groove is provided with a tungsten alloy energy-conducting coating; the thickness of the tungsten alloy energy-conducting coating is 0.3mm-0.5mm.

[0019] By utilizing the high temperature resistance and high energy reflectivity of tungsten alloy, the energy loss of the jet in the inner wall of the energy-conducting groove can be reduced during the impact of high-speed metal jets, thus preventing the inner wall of the energy-conducting groove from melting or deforming due to high-temperature jets. Setting the thickness of the tungsten alloy energy-conducting coating to 0.3-0.5mm ensures that the coating has sufficient adhesion stability and energy conduction performance to prevent it from falling off under the impact of the jet, while also preventing the internal space of the energy-conducting groove from shrinking due to excessive coating thickness. This ensures that the high-speed metal jet can pass smoothly and be directionally guided to the corresponding thermite filler block.

[0020] Furthermore, the fluoropolymer energy storage layer includes multiple energy storage cavities, which are uniformly arranged along the circumference of the fluoropolymer energy storage layer. A flow guide hole is provided between every two adjacent energy storage cavities. The energy storage cavities are filled with fluoropolymer particle fillers, which are a mixture of polytetrafluoroethylene nanoparticles and calcium fluoride particles.

[0021] The energy storage chamber provides an independent storage space, allowing the fluoropolymer particles to be evenly distributed circumferentially, avoiding uneven energy release caused by concentrated energy storage. Simultaneously, the inner ring side and the side near the guide hole of the energy storage chamber are first triggered by the reaction heat of the aluminothermic reaction layer, which promotes the full mixing of fluoropolymer decomposition products and aluminothermic reaction products, and fully converts them into solid AlF3 and gaseous H2, avoiding HF leakage. This fully promotes the AlF3 to assist in breaking up blockages and H2 to enhance pore pressure, ensuring that microfractures extend into the deep formation and thus break through the tight zone of unconventional reservoirs. The good microfracture interweaving avoids the formation of compacted fracture zones and the blockage of pores by residues, improving the fracturing effect.

[0022] Furthermore, in the fluoropolymer particle filler, the mass ratio of polytetrafluoroethylene nanoparticles to calcium fluoride particles is 3:1-5:1, the particle size of the polytetrafluoroethylene nanoparticles is 50nm-100nm, and the particle size of the calcium fluoride particles is 200nm-300nm.

[0023] Polytetrafluoroethylene (PTFE) nanoparticles with a particle size of 50-100 nm can rapidly decompose and release chemical energy under high temperature and pressure. Calcium fluoride (CFD) particles with a particle size of 200-300 nm can regulate the decomposition rate of PTFE nanoparticles. At the same time, the 3:1-5:1 mass ratio design can flexibly adjust the energy release intensity according to the density of unconventional reservoirs, ensuring that the energy release of the fluoropolymer energy storage layer and the energy release of the thermite reaction layer form a synergistic effect. This allows the explosive charge packing block to adapt to the transformation needs of different types of unconventional reservoirs and precisely control the energy release rhythm of the thermite reaction layer.

[0024] Furthermore, the energy storage cavity is a polytetrafluoroethylene composite material reinforced with glass fiber or carbon fiber.

[0025] Polytetrafluoroethylene (PTFE) provides fundamental properties such as temperature resistance, chemical corrosion resistance, and ease of molding, ensuring the energy storage and sealing compatibility of the energy storage cavity. When the reaction heat of the thermite reaction layer triggers melting, the products are essentially the same as the internal PTFE nanoparticles, which facilitates the breaking of blockages and enhances pore pressure, thereby improving the fracturing effect. The fiber reinforcement enhances the structural strength and impact resistance, making it suitable for the extreme working conditions of downhole perforation-fracturing, ensuring the overall structural stability of the fluoropolymer energy storage layer and preventing premature triggering.

[0026] Furthermore, the outer end of the guide hole is inclined towards the second end of the shell, and the axis of the guide hole forms an angle of 15°-30° with the end face of the shell; the diameter of the guide hole is 1.5mm-2.5mm.

[0027] By tilting the guide holes, high-temperature, high-pressure gas flows out and into the deeper formation, promoting the extension of microfractures into the formation. This angled arrangement facilitates adaptation to the development direction of natural microfractures in unconventional reservoirs, allowing the high-pressure gas flowing out of the guide holes to more precisely impact the natural microfractures, promoting their expansion and interweaving, and forming a more complete drainage channel. This aperture arrangement ensures that the high-pressure gas has sufficient flow rate and volume to provide adequate pressure to drive microfracture expansion, while avoiding weakening the structural strength of the energy ring due to excessively large apertures, thus preventing the energy ring from rupturing under downhole high-pressure environments. Therefore, the guide holes ensure both efficient flow guidance and structural stability of the energy ring, improving fracturing effectiveness.

[0028] Furthermore, the guide hole is also equipped with a biodegradable sealing component.

[0029] The biodegradable plugging component completely seals the flow channel during the perforation stage and before the high temperature and pressure are generated by the shaped charge reaction filler, preventing high-pressure gas from escaping prematurely and ensuring that energy is concentrated on the perforation channel and the formation of fractures. After entering the fracturing stage, the biodegradable plugging component gradually degrades under the action of high temperature and formation fluids, and the flow channel opens accordingly, allowing high-pressure gas to diffuse directionally into the deep formation through the flow channel, ensuring the formation of a microfracture network and improving the fracturing effect.

[0030] Furthermore, the shell includes a protective outer cylinder, a central inner cylinder in the middle of the protective outer cylinder, an annular first end plate between the first end of the central inner cylinder and the first end of the protective outer cylinder, and an annular second end plate between the second end of the central inner cylinder and the second end of the protective outer cylinder; the first end plate is integrally formed with the central inner cylinder, and the second end plate is integrally formed with the protective outer cylinder; the energy-conducting groove is provided on the first end plate.

[0031] During assembly, the energy-concentrating reaction filler is placed on the central inner cylinder, and then the protective outer cylinder is placed on the energy-concentrating reaction filler. The installation is convenient. The central inner cylinder, as the core support structure of the energy ring, provides a coaxial reference for each layer of the energy-concentrating reaction filler and the protective outer cylinder, ensuring the precise alignment of each functional layer and avoiding energy transfer obstruction caused by interlayer misalignment, thus ensuring high reliability.

[0032] Furthermore, the protective outer cylinder is made of ceramic matrix composite material, and the thickness of the protective outer cylinder is 1.2mm-2.0mm.

[0033] Utilizing the high temperature resistance, high pressure resistance, and impact resistance of ceramic matrix composites, it can prevent external formation rock debris from causing impact damage to the shaped charge reaction filler layers inside the energy ring during the detonation of the perforating projectile and the reaction of each layer inside the energy ring. At the same time, it can isolate the influence of internal high temperature on the external structure. Setting the thickness of the ceramic matrix composite layer to 1.2-2.0mm can ensure that the protective outer cylinder has sufficient structural strength to withstand complex downhole conditions, while avoiding redundancy in the overall volume of the energy ring due to excessive thickness.

[0034] The present invention provides a perforation unit, including a perforation projectile body, wherein an energy ring for unconventional reservoir perforation-fracturing integration is coaxially mounted at the jet outlet of the perforation projectile body.

[0035] It ensures that microfractures extend into the deep formation to break through the tight zone of unconventional reservoirs. The microfractures are well interwoven and avoid the formation of compaction and fracture zones and the blockage of pores by residues, thus improving the fracturing effect. It is easy to adapt to the energy release rhythm requirements of unconventional reservoirs and avoids collapse caused by sudden pressure rises and falls in the pores.

[0036] Furthermore, the outer wall of the jet outlet of the perforating projectile body is provided with an installation step, and an annular positioning sleeve is fixed to the first edge of the shell, and the annular positioning sleeve is fitted onto the installation step.

[0037] The annular positioning sleeve and the mounting steps on the outer wall of the jet outlet of the perforating projectile body form a precise fitting fit, providing positioning constraints for the coaxial installation of the energy ring and the perforating projectile body. This prevents the energy ring from shifting coaxially or rotating circumferentially at the jet outlet of the perforating projectile body, ensuring that the high-speed metal jet generated by the perforating projectile body can act perpendicularly on the energy ring and stably enter the energy guiding groove. This ensures that the shaped charge reaction filler (or thermite filler block) can be precisely triggered, providing installation positioning guarantee for the stable operation of the entire perforating unit. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the energy ring for the unconventional reservoir perforation-fracturing integration of the present invention.

[0039] Figure 2 This is a cross-sectional view of the energy ring used in the unconventional reservoir perforation-fracturing integration of the present invention.

[0040] Figure 3 This is an exploded view of the energy ring for the unconventional reservoir perforation-fracturing integration of the present invention.

[0041] Figure 4 This is a schematic diagram of the perforation unit of the present invention.

[0042] Figure 5 This is a longitudinal cross-sectional view of the perforation unit of the present invention.

[0043] Figure 6 This is a schematic diagram of the perforation projectile body.

[0044] In the accompanying drawings, the technical features represented by each reference numeral are as follows: 1-Shell; 2-Central energy guiding hole; 3-Energy guiding groove; 4-Flow guiding hole; 5-Thermite filling block; 6-Explosive charging filling block; 7-Energy storage cavity; 8-Fluoropolymer granule filling; 9-Protective outer cylinder; 10-Central inner cylinder; 11-First end plate; 12-Second end plate; 13-Annular positioning sleeve; 20 - Perforation projectile body; 21 - Mounting step. Detailed Implementation

[0045] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0046] See also: This invention Figure 1-6 .

[0047] Example 1, as Figure 1-3As shown: This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4.

[0048] principle: During installation, the first end of the casing 1 (i.e., the end where the energy-conducting groove 3 is located) is coaxially mounted at the jet outlet of the perforating projectile body 20. During perforation operations, the perforating projectile body 20 serves as an energy output source, and can generate a high-speed metal jet after being detonated downhole and ejected from the jet outlet. In this process, a portion of the high-speed metal jet is ejected from the central energy guiding hole 2 to achieve the perforation purpose; the high-speed metal jet at the edge acts on the shell 1, and the shell 1 is coaxially connected to the jet outlet to ensure that the metal jet can completely act on the energy ring and launch the energy ring as a whole into the perforation channel area. At the same time, the energy guiding groove 3 can constrain and guide the high-speed metal jet, so that the energy of the high-speed metal jet is concentrated on the corresponding shaped charge reaction filler, causing one or more of the shaped charge reaction fillers to be triggered first. After the triggered shaped charge reaction filler explodes, it will trigger the adjacent shaped charge reaction fillers in turn, so that the shaped charge reaction fillers release energy step by step; through the flow guiding hole 4, a directional outflow channel is provided for the high-pressure gas generated by the triggering of the shaped charge reaction filler, so that it can be concentrated and accurately act on the target crack.

[0049] Note: Both the shell 1 and the enclosed inner cavity can be polygonal annular or circular. Preferably, both the shell 1 and the enclosed inner cavity are circular, and the central energy-conducting hole 2 is circular.

[0050] By employing this invention, a synergistic integrated structure is formed through the shell 1 and its internal shaped charge reaction filler, providing protection, energy storage, energy reaction release, and energy guidance. This ensures that microfractures extend deep into the formation, thereby breaking through the tight zone of unconventional reservoirs, and avoids collapse caused by sudden pressure rises and falls within the pores; specifically: 1) The shell 1 protects the shaped charge reaction filler inside, preventing external rock debris from impacting and damaging the shaped charge reaction filler, and also preventing the shaped charge reaction filler from being prematurely triggered. 2) The high-pressure gas generated by the energy-concentrating reaction filler is provided with a directional outflow channel through the flow guide hole 4, so that it can be concentrated and accurately act on the target fracture, which greatly enhances the energy intensity of the formation at the edge of the near-wellbore zone, ensures that the microfractures extend into the deep formation and thus break through the tight zone of the unconventional reservoir. The microfractures have good interweaving properties and avoid the formation of compaction and fracture zones and the blockage of the channels by residues, thus improving the fracturing effect. 3) Through the energy-conducting groove 3, the energy of the high-speed metal jet is concentrated on the corresponding energy-concentrating reaction filler, providing the initial triggering conditions for the subsequent step-by-step energy release of the energy-concentrating reaction filler. At the same time, high-pressure gas is discharged through the flow guide hole 4, which is convenient to adapt to the energy release rhythm requirements of unconventional reservoirs and avoids collapse caused by sudden pressure rise and fall in the channel.

[0051] Example 2: An improvement based on Example 1.

[0052] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4.

[0053] Furthermore, the energy-concentrating reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their own circumference. The flow-guiding hole 4 penetrates the fluoropolymer energy storage layer and communicates with the aluminothermic reaction layer. Each energy-conducting groove 3 is directly opposite one of the aluminothermic reaction layers.

[0054] The reactions involved are as follows: 1) A typical aluminothermic reaction occurs in the aluminothermic reaction layer (Fe2O3 is the oxidant). The reaction conditions are: high temperature (>1500℃, triggered by the jet impact of the perforating projectile body 20) and a closed space with a sealed inner cavity.

[0055] Reaction equation: Fe₂O₃ + 2Al → Al₂O₃ + 2Fe The aluminothermic reaction releases a large amount of heat and liquid Fe, raising the temperature to over 2000℃, providing energy for the decomposition of the fluoropolymer energy storage layer, and simultaneously driving an initial increase in pore pressure.

[0056] Alternatively, V2O5 or Cr2O3 can be used as oxidants to replace the aluminothermic reaction, making them suitable for ultra-dense reservoirs.

[0057] 2) The fluoropolymer energy storage layer undergoes a fluoropolymer decomposition reaction. The reaction conditions are: high temperature (>800℃, aluminothermic reaction transfer), ultra-high pressure (>500MPa), and a closed space with a sealed inner cavity.

[0058] Reaction equation: -(C2H2F2) n -→nC2F4↑+nHF(g)+nC The fluoropolymer consists of polytetrafluoroethylene nanoparticles and calcium fluoride particles. The polytetrafluoroethylene nanoparticles decompose to release chemical energy, while the calcium fluoride particles slow down the decomposition rate, ensuring that energy is released synergistically with the aluminothermic reaction.

[0059] 3) After the fluoropolymer energy storage layer reacts, its products undergo a neutralization reaction with aluminum and HF with the aluminothermic reaction products (secondary energy release).

[0060] Reaction conditions: high temperature (>800℃), ultra-high pressure (>500MPa), and a closed environment within the pore.

[0061] Reaction equation: 2Al + 6HF(g) → AlF3 + 3H2↑ It neutralizes highly toxic HF and generates solid AlF3 and gaseous H2. Solid AlF3 can help break up blockages, while gaseous H2 can increase pore pressure, release additional energy, and improve fracturing effect.

[0062] The metal jet is directed onto the corresponding aluminothermic reaction layer via the energy-conducting groove 3, providing the initial triggering conditions for stepwise energy release. Furthermore, the aluminothermic reaction triggered by the aluminothermic agent provides the temperature for the decomposition of the fluoropolymer energy storage layer, enabling it to react accordingly, thus achieving synergistic energy release from both the fluoropolymer energy storage layer and the aluminothermic reaction layer. Simultaneously, the decomposition of the fluoropolymer energy storage layer allows it to neutralize with the metallic Al generated in the aluminothermic reaction layer, transforming it into stable solid AlF3 and gaseous H2, preventing HF leakage. Moreover, AlF3 can assist in breaking up blockages, and H2 can enhance pore pressure, ensuring that microfractures extend deep into the formation, thereby breaking through the tight zone of unconventional reservoirs. The good interweaving of microfractures prevents the formation of compacted fracture zones and the blockage of pores by residual material, improving fracturing efficiency.

[0063] Example 3: An improvement based on Example 2.

[0064] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers.

[0065] Furthermore, the thermite reaction layer includes a plurality of thermite filling blocks 5, which are arranged equidistantly along the circumference of the thermite reaction layer, and a detonating charge filling block 6 is provided between each two adjacent thermite filling blocks 5; each thermite filling block 5 is connected to at least one guide hole 4, and each detonating charge filling block 6 is connected to at least one guide hole 4; each energy-conducting groove 3 is directly opposite one of the thermite filling blocks 5.

[0066] Note: The thermite filler block 5 mainly consists of a mixture of Fe2O3 powder and Al powder. Fe2O3 powder is used as an oxidant. Alternatively, V2O5 or Cr2O3 can be used as the oxidant to suit ultra-dense reservoirs.

[0067] Using the thermite filler block 5 as the core unit for energy release, its annular equidistant array distribution allows the energy release of the thermite reaction layer to spread uniformly along the circumference. A detonating charge filler block 6 is provided between adjacent thermite filler blocks 5, which can prevent untriggered thermite filler blocks 5 from reacting prematurely due to the energy influence of triggered thermite filler blocks 5, ensuring the independence of the reaction of each thermite filler block 5, realizing the sequential triggering of the thermite filler blocks 5, thereby forming a pulsed energy release, solving the problem of sudden rise and fall of channel pressure caused by concentrated energy release during the reaction of traditional energy rings.

[0068] Example 4: An improvement based on Example 3.

[0069] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers. The thermite reaction layer includes a plurality of thermite filling blocks 5, which are arranged equidistantly along the circumference of the thermite reaction layer. A detonating charge filling block 6 is provided between each two adjacent thermite filling blocks 5. Each thermite filling block 5 is connected to at least one flow guide hole 4, and each detonating charge filling block 6 is connected to at least one flow guide hole 4. Each energy-conducting groove 3 is directly opposite one of the thermite filling blocks 5.

[0070] Furthermore, the detonating charge filling block 6 is a lead oxide-aluminum detonating charge column, in which the mass ratio of Pb3O4 to Al is 6:4-7:3.

[0071] Reaction involved: Detonation reaction, 3Pb3O4 + 8Al → 4Al2O3 + 9Pb Reaction conditions: High temperature (>500℃, the reaction is triggered by thermite filler block 5), and the separation space between thermite filler blocks 5. Combustion releases heat and Pb vapor, which is directionally transferred circumferentially along the separation space between the thermite filler blocks 5, controlling the triggering rhythm of each thermite filler block 5 and avoiding a sudden pressure rise caused by synchronous reaction.

[0072] By utilizing the stable release of heat and shock waves during the reaction of lead oxide and aluminum, the reliability of the detonation process is ensured. By limiting the mass ratio of Pb3O4 to Al to 6:4-7:3, the combustion rate and energy output intensity of the detonation charge can be controlled by adjusting the component ratio. When the mass ratio is close to 6:4, the combustion rate of the detonation charge is faster, suitable for shale reservoirs requiring rapid triggering of the thermite packing block 5; when the mass ratio is close to 7:3, the combustion rate is slower, suitable for tight sandstone reservoirs requiring slow energy release. Thus, the detonation packing block 6 can adapt to the stimulation needs of different types of unconventional reservoirs, precisely controlling the energy release rhythm of the thermite reaction layer.

[0073] Example 5: An improvement based on Example 3.

[0074] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers. The thermite reaction layer includes a plurality of thermite filling blocks 5, which are arranged equidistantly along the circumference of the thermite reaction layer. A detonating charge filling block 6 is provided between each two adjacent thermite filling blocks 5. Each thermite filling block 5 is connected to at least one flow guide hole 4, and each detonating charge filling block 6 is connected to at least one flow guide hole 4. Each energy-conducting groove 3 is directly opposite one of the thermite filling blocks 5.

[0075] Furthermore, the inner wall of the energy-conducting groove 3 is provided with a tungsten alloy energy-conducting coating; the thickness of the tungsten alloy energy-conducting coating is 0.3mm-0.5mm.

[0076] Preferably, the number of energy-conducting grooves 3 is one or two, and the energy-conducting grooves 3 are circular grooves with their diameter gradually decreasing from the outside to the inside.

[0077] By utilizing the high temperature resistance and high energy reflectivity of tungsten alloy, the energy loss of the jet in the inner wall of the energy-conducting groove 3 can be reduced during the impact of high-speed metal jets, thus preventing the inner wall of the energy-conducting groove 3 from melting or deforming due to high-temperature jets. The thickness of the tungsten alloy energy-conducting coating is set to 0.3-0.5mm, which can ensure that the coating has sufficient adhesion stability and energy conduction performance to prevent it from falling off under the impact of the jet, and also prevent the internal space of the energy-conducting groove 3 from shrinking due to excessive coating thickness, thus ensuring that the high-speed metal jet can pass smoothly and be directionally guided to the corresponding thermite filling block 5.

[0078] Example 6: An improvement based on Example 2.

[0079] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers.

[0080] Furthermore, the fluoropolymer energy storage layer includes multiple energy storage cavities 7, which are uniformly arranged along the circumference of the fluoropolymer energy storage layer. A flow guide hole 4 is provided between every two adjacent energy storage cavities 7. The energy storage cavities 7 are filled with fluoropolymer particle filler 8, which is a mixture of polytetrafluoroethylene nanoparticles and calcium fluoride particles.

[0081] Preferably, the sum of the number of thermite filler blocks 5 and the number of explosive charge filler blocks 6 is the number of energy storage cavities 7, and the number of energy storage cavities 7 is the same as the number of guide holes 4; preferably, there are 12.

[0082] The energy storage chamber 7 provides an independent storage space, allowing the fluoropolymer particles 8 to be evenly distributed circumferentially, avoiding uneven energy release caused by concentrated energy storage. Simultaneously, the inner ring side of the energy storage chamber 7 and the side near the guide hole 4 are first triggered by the reaction heat of the aluminothermic reaction layer, promoting the full mixing of fluoropolymer decomposition products and aluminothermic reaction products, and fully converting them into solid AlF3 and gaseous H2, avoiding HF leakage. This fully promotes the AlF3 to assist in breaking up blockages and H2 to enhance pore pressure, ensuring that microfractures extend into the deep formation, thereby breaking through the tight zone of unconventional reservoirs. The good microfracture interweaving avoids the formation of compacted fracture zones and the blockage of pores by residues, improving the fracturing effect.

[0083] Example 7: An improvement based on Example 6.

[0084] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers. The fluoropolymer energy storage layer includes multiple energy storage cavities 7, which are uniformly arranged along the circumference of the fluoropolymer energy storage layer. A flow guide hole 4 is provided between every two adjacent energy storage cavities 7. The energy storage cavities 7 are filled with fluoropolymer particle filler 8, which is a mixture of polytetrafluoroethylene nanoparticles and calcium fluoride particles.

[0085] Furthermore, in the fluoropolymer particle filler 8, the mass ratio of polytetrafluoroethylene nanoparticles to calcium fluoride particles is 3:1-5:1, the particle size of the polytetrafluoroethylene nanoparticles is 50nm-100nm, and the particle size of the calcium fluoride particles is 200nm-300nm.

[0086] Note: The mass ratio design of 3:1-5:1 is suitable for shale reservoirs where rapid activation of the thermite filler block 5 is required. When the mass ratio is close to 3:1, the calcium fluoride particles decompose quickly, which matches the mass ratio of Pb3O4 to Al which is close to 6:4. When the mass ratio is close to 5:1, the calcium fluoride particles decompose slowly, which matches the mass ratio of Pb3O4 to Al which is close to 7:3. This is suitable for tight sandstone reservoirs where energy needs to be released slowly.

[0087] Polytetrafluoroethylene (PTFE) nanoparticles with a particle size of 50-100 nm can rapidly decompose and release chemical energy under high temperature and pressure. Calcium fluoride (CFD) particles with a particle size of 200-300 nm can regulate the decomposition rate of PTFE nanoparticles. At the same time, the 3:1-5:1 mass ratio design can flexibly adjust the energy release intensity according to the density of unconventional reservoirs, ensuring that the energy release of the fluoropolymer energy storage layer and the energy release of the thermite reaction layer form a synergistic effect. This allows the explosive charge packing block 6 to adapt to the transformation needs of different types of unconventional reservoirs and precisely control the energy release rhythm of the thermite reaction layer.

[0088] Example 8: An improvement based on Example 6.

[0089] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, and an annular closed cavity surrounding the central energy-conducting hole 2 within the shell 1. The closed cavity contains a shaped charge reaction filler, which is arranged in multiple pieces along its circumference. At least one energy-conducting groove 3 is also provided at the first end of the shell 1, with each groove 3 directly opposite one of the shaped charge reaction fillers. Multiple flow-guiding holes 4 are distributed on the outer periphery of the shell 1, with each shaped charge reaction filler communicating with at least one flow-guiding hole 4. The shaped charge reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole 2, and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple pieces along their circumference. The flow-guiding holes 4 penetrate the fluoropolymer energy storage layer and communicate with the aluminothermic reaction layer, with each groove 3 directly opposite one of the aluminothermic reaction layers. The fluoropolymer energy storage layer includes multiple energy storage cavities 7, which are uniformly arranged along the circumference of the fluoropolymer energy storage layer. A flow guide hole 4 is provided between every two adjacent energy storage cavities 7. The energy storage cavities 7 are filled with fluoropolymer particle filler 8, which is a mixture of polytetrafluoroethylene nanoparticles and calcium fluoride particles.

[0090] Furthermore, the energy storage cavity 7 is a polytetrafluoroethylene composite material reinforced with glass fiber or carbon fiber.

[0091] Polytetrafluoroethylene (PTFE) provides basic properties such as temperature resistance, chemical corrosion resistance, and easy molding, ensuring the energy storage and sealing compatibility of energy storage chamber 7. When it is triggered by the reaction heat of the thermite reaction layer, the product is basically the same as the internal PTFE nanoparticles, which facilitates the breaking of blockages and enhances the pressure in the pores, thereby improving the fracturing effect. The fiber reinforcement improves the structural strength and impact resistance, making it suitable for the extreme working conditions of downhole perforation-fracturing, and ensuring that the overall structure of the fluoropolymer energy storage layer is stable and will not be prematurely triggered.

[0092] Example 9: An improvement based on Example 1.

[0093] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4.

[0094] Furthermore, the outer end of the guide hole 4 is inclined toward the second end of the housing 1, and the axis of the guide hole 4 forms an angle of 15°-30° with the end face of the housing 1; the diameter of the guide hole 4 is 1.5mm-2.5mm.

[0095] Note: The second end of the shell 1 is the end furthest from the energy-conducting groove 3.

[0096] By tilting the guide holes 4, high-temperature and high-pressure gas flows out through them and into the deeper formation, promoting the extension of microfractures into the deeper formation. This angled arrangement facilitates adaptation to the development direction of natural microfractures in unconventional reservoirs, allowing the high-pressure gas flowing out through the guide holes 4 to more precisely impact the natural microfractures, promoting their expansion and interweaving, and forming a more complete drainage channel. This aperture arrangement ensures that the high-pressure gas has sufficient flow rate and volume to provide sufficient pressure to drive the expansion of microfractures, while avoiding weakening the structural strength of the energy ring due to excessively large apertures, thus preventing the energy ring from rupturing under downhole high-pressure environments. Therefore, the guide holes 4 ensure both efficient flow guidance and structural stability of the energy ring, improving the fracturing effect.

[0097] Example 10: An improvement based on Example 1.

[0098] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4.

[0099] Furthermore, the guide hole 4 is also provided with a biodegradable sealing component.

[0100] Preferably, the biodegradable plugging component is a polylactic acid (PLA) plugging rod. The PLA plugging rod can degrade at the temperature of the aluminothermic reaction, leaving no solid residue after degradation. This avoids clogging the guide hole 4 or polluting the formation, and eliminates the need for additional exhaust gas / solid waste treatment equipment, which is beneficial to environmental protection.

[0101] The biodegradable plugging component completely seals the guide hole 4 during the perforation stage and before the high temperature and pressure are triggered by the shaped charge reaction filler, preventing high-pressure gas from escaping from the guide hole 4 prematurely and ensuring that energy is concentrated on the perforation channel and the formation of fractures. After entering the fracturing stage, the biodegradable plugging component gradually degrades under the action of high temperature and formation fluid, and the guide hole 4 opens accordingly, allowing high-pressure gas to diffuse directionally into the deep formation through the guide hole 4, ensuring the formation of a microfracture network and improving the fracturing effect.

[0102] Example 11: An improvement based on Example 1.

[0103] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4.

[0104] Furthermore, the housing 1 includes a protective outer cylinder 9, a central inner cylinder 10 is provided in the middle of the protective outer cylinder 9, an annular first end plate 11 is provided between the first end of the central inner cylinder 10 and the first end of the protective outer cylinder 9, and an annular second end plate 12 is provided between the second end of the central inner cylinder 10 and the second end of the protective outer cylinder 9; the first end plate 11 is integrally formed with the central inner cylinder 10, and the second end plate 12 is integrally formed with the protective outer cylinder 9; the energy-conducting groove 3 is provided on the first end plate 11.

[0105] Note: The protective outer cylinder 9 and the central inner cylinder 10 correspond to the first end and the second end of the shell 1, respectively. One-piece molding: It can be formed from the same blank through casting, stamping, forging, or machining, or it can be formed by welding.

[0106] During assembly, the energy-concentrating reaction filler is placed on the central inner cylinder 10, and then the protective outer cylinder 9 is placed on the energy-concentrating reaction filler. The installation is convenient. The central inner cylinder 10, as the core support structure of the energy ring, provides a coaxial reference for each layer of the energy-concentrating reaction filler and the protective outer cylinder 9, ensuring the precise alignment of each functional layer and avoiding the obstruction of energy transmission caused by interlayer misalignment, thus ensuring high reliability.

[0107] Example 12: An improvement based on Example 11.

[0108] This invention provides an integrated energy ring for perforation-fracturing in unconventional reservoirs, comprising an annular shell 1, a central energy-conducting hole 2 at the center of the shell 1, an annular closed cavity surrounding the central energy-conducting hole 2, and a shaped charge reaction filler arranged in multiple pieces along its circumference within the closed cavity; at least one energy-conducting groove 3 is also provided at the first end of the shell 1, each energy-conducting groove 3 facing one of the shaped charge reaction fillers; multiple flow guide holes 4 are distributed on the outer periphery of the shell 1, and each shaped charge reaction filler is connected to at least one flow guide hole 4. The shell 1 includes a protective outer cylinder 9, a central inner cylinder 10 in the middle of the protective outer cylinder 9, an annular first end plate 11 between the first end of the central inner cylinder 10 and the first end of the protective outer cylinder 9, and an annular second end plate 12 between the second end of the central inner cylinder 10 and the second end of the protective outer cylinder 9; the first end plate 11 is integrally formed with the central inner cylinder 10, and the second end plate 12 is integrally formed with the protective outer cylinder 9; the energy-conducting groove 3 is provided on the first end plate 11.

[0109] Furthermore, the protective outer cylinder 9 is made of ceramic matrix composite material, and the thickness of the protective outer cylinder 9 is 1.2mm-2.0mm.

[0110] Preferably, the central inner cylinder 10 is made of a nickel-based alloy material.

[0111] Utilizing the high temperature resistance, high pressure resistance, and impact resistance of ceramic matrix composite materials, it can prevent external formation rock debris from causing impact damage to the layers of the shaped charge reaction filler inside the energy ring during the detonation of the perforation projectile body 20 and the reaction of each layer inside the energy ring. At the same time, it can isolate the influence of internal high temperature on the external structure. The thickness of the ceramic matrix composite material layer is set to 1.2-2.0 mm, which can ensure that the protective outer cylinder 9 has sufficient structural strength to withstand complex downhole working conditions, and can also avoid redundancy in the overall volume of the energy ring due to excessive thickness.

[0112] Example 13, as Figure 4-6 As shown: The present invention provides a perforation unit, including a perforation projectile body 20, wherein an energy ring for integrated perforation-fracturing of unconventional reservoirs, one of embodiments one to twelve, is coaxially mounted at the jet outlet of the perforation projectile body 20.

[0113] It ensures that microfractures extend into the deep formation to break through the tight zone of unconventional reservoirs. The microfractures are well interwoven and avoid the formation of compaction and fracture zones and the blockage of pores by residues, thus improving the fracturing effect. It is easy to adapt to the energy release rhythm requirements of unconventional reservoirs and avoids collapse caused by sudden pressure rises and falls in the pores.

[0114] Example 14: An improvement based on Example 13.

[0115] The present invention provides a perforation unit, including a perforation projectile body 20, wherein an energy ring for integrated perforation-fracturing of unconventional reservoirs, one of embodiments one to twelve, is coaxially mounted at the jet outlet of the perforation projectile body 20.

[0116] Furthermore, the outer wall of the jet outlet of the perforating projectile body 20 is provided with an installation step 21, and an annular positioning sleeve 13 is fixed to the first end edge of the shell 1, and the annular positioning sleeve 13 is sleeved on the installation step 21.

[0117] Preferably, the annular positioning sleeve 13 is disposed on the outer edge of the first end plate 11.

[0118] The annular positioning sleeve 13 and the mounting step 21 on the outer wall of the jet outlet of the perforating projectile body 20 form a precise fitting fit, providing positioning constraints for the coaxial installation of the energy ring and the perforating projectile body 20. This prevents the energy ring from being offset from the same axis or rotating circumferentially at the jet outlet of the perforating projectile body 20, ensuring that the high-speed metal jet generated by the perforating projectile body 20 can act perpendicularly on the energy ring and stably enter the energy guiding groove 3. This ensures that the energy-concentrating reaction filler (or thermite filler block 5) can be precisely triggered, providing installation and positioning guarantees for the stable operation of the entire perforating unit.

[0119] Explanation of the technical effects of the above embodiments: A mathematical model equation describing the superposition effect of pulse pressure is introduced. This equation is used to quantitatively describe the time-space distribution characteristics of the pressure within the channel during the five-segment triggering process of the thermite filling block, as follows: The superposition effect of pulse pressure on the thermite packing block 5 satisfies the following equation: in: P c (t) represents the superimposed pressure (MPa) inside the duct at time t. P0 is the standard peak pressure (MPa) of a single thermite packing block 5, with a typical range of 70–100 MPa; n represents the total number of thermite filler blocks (5), with a typical range of 6–12. ti=(i-1)·Δt is the triggering time (s) of the i-th unit; Δt=d s / v b , is the unit trigger interval (s); d s The width (mm) of the explosive charge filling block 6 is typically 0.8–1.2 mm. v b The burning velocity (m / s) of the explosive charge filling block 6 is typically 500–800 m / s. α is the pressure rise rate coefficient (s) -1 Typical value range: 1.0–1.5 × 10⁻⁶ 6 ; β is the pressure decay rate coefficient (s) -1 Typical value range: 0.5–1.0×10 6 ; u(t-ti) is the unit step function, indicating that the i-th unit is triggered after time ti.

[0120] Equation derivation process: This equation is derived based on the following physical assumptions and system behavior: 1. The pressure response of a single thermite filler block 5 can be modeled as a "rapid rise-slow decay" pulse, simulated using an exponential function combination; 2. The total pressure is a linear superposition of the pressure pulses from each unit; 3. The triggering sequence is determined by the detonation propagation speed v. b and the width of the dividing space d s Decide; 4. The step function u(t-ti) ensures that each unit contributes stress only after it is triggered.

[0121] Derivation steps: Single unit pressure function: The total pressure is the sum of the contributions from all units: Example (using shale reservoirs as an example): Assumptions: n=8; P 0= 80MPa; d s =1.0mm=0.001m; v b =600m / s; α=1.2×10 6 s -1 β = 0.8 × 10 6 s -1 ,but: P can be drawn c The (t) curve shows the pulse superposition effect, with peak pressure reaching over 500MPa.

[0122] Technical effects: Quantitatively control the energy release rhythm to adapt to different reservoir types; Avoid sudden increases or decreases in pressure to prevent the channel from collapsing; By adjusting d s vb Optimize pulse sequences using parameters such as n; It provides a mathematical model foundation for digital design and simulation.

[0123] Working principle and process: 1. The jet triggers the first thermite filler block 5 → t1 = 0; 2. The detonation units are ignited sequentially → ti = (i-1)Δt; 3. Each unit contributes one pressure pulse; 4. Pulse superposition forms a smoothly rising high-voltage platform; 5. Final pressure P c (t) acts on the fracturing reservoir.

[0124] The principles of each stage are as follows: Phase 1: Pre-assembly Phase – Structural Positioning and Initial State (Ground Assembly, Before Downhole Deployment) Component assembly: The energy ring is precisely fitted coaxially with the mounting step of the perforation projectile body through the annular positioning sleeve 13, so as to achieve coaxial positioning of the energy ring and the perforation projectile body and ensure that the energy ring is directly opposite the jet outlet of the perforation projectile body.

[0125] Initial state: The energy storage chamber 7 is filled with fluoropolymer granules 8, and the granules are in a stable state; the guide hole 4 is completely sealed with a biodegradable plugging component to prevent impurities from entering during the well run; the thermite filling block 5 and the detonating charge filling block 6 in the thermite reaction layer are not triggered and are in a stable state at room temperature; the energy guiding groove faces the jet outlet of the perforating projectile body.

[0126] Phase 2: Perforation Triggering and Initial Energy Guidance Phase (Preset Downhole Depth, Time 0-10) -6 s) Jet generation: The perforating projectile body detonates underground, generating a high-speed metal jet of 2000-3000 m / s, which is ejected from the jet outlet.

[0127] Energy directional guidance: The metal jet impacts the energy-conducting groove 3, and the tungsten alloy energy-conducting coating reduces jet energy loss, directionally constrains and guides the jet to 1-2 corresponding thermite filling blocks 5 to avoid energy dispersion.

[0128] Initial energy release: The thermite filler block 5, covered by the jet, absorbs the high temperature of the jet (>1500℃), reaches the thermite reaction threshold, initiates the first exothermic reaction, and releases high temperature and shock wave.

[0129] Stage 3: Segmented Energy Release Stage of the Thermite Reaction Layer (10 -6 s-10 -5 s) Detonation triggering: The high temperature (>2000℃) and shock wave released by the first reacting thermite filler block 5 directly act on the detonation charge filler blocks 6 in the space separating them on both sides, igniting the detonation charge column.

[0130] Circumferential stepwise detonation: The detonating charge filling block 6 burns at a speed of 500-800 m / s, and transmits energy directionally along the circumferential direction of the partition space. The remaining thermite filling blocks 5 are triggered in sequence according to the order of "detonating charge filling block 6 → adjacent thermite filling block 5".

[0131] Pulse pressure superposition: The trigger interval for each thermite filling block is in the microsecond range (e.g., when the separation space width is 1.0 mm, the delay is approximately 1.67 × 10⁵). -6 (s), forming a "pulse-like superposition" energy release, with the pressure inside the channel gradually rising to over 500MPa; at the same time, the shell 1 resists the impact of strata rock debris, protecting the integrity of the internal structure of the energy ring.

[0132] Phase 4: Synergistic Energy Release Phase of Fluoropolymer Energy Storage Layer (10 -5 s-10 -4 s) Energy is transferred to the energy storage layer: the high temperature (>2000℃) and high pressure (>500MPa) released by the thermite filler block 5 are transferred to the fluoropolymer energy storage layer.

[0133] Decomposition of the reaction filling layer: In the fluoropolymer particle filling material 8 in the energy storage cavity 7, the 50-100nm polytetrafluoroethylene nanoparticles decompose rapidly under high temperature and pressure, releasing chemical energy and gaseous products (C2F4, HF, etc.), and the 200-300nm calcium fluoride particles regulate the decomposition rate to avoid sudden energy release.

[0134] Secondary neutralization reaction: HF (gaseous) produced by the decomposition of polytetrafluoroethylene comes into contact with metallic Al produced by the aluminothermic reaction, and a neutralization reaction occurs, neutralizing HF and releasing additional energy and H2 gas.

[0135] Pressure superposition: The superposition effect of "aluminothermic reaction energy + fluoropolymer decomposition energy" is formed in the channel, and ultra-high pressure gas (H2, COF2, etc.) continues to accumulate, and the pressure further rises to 800-1000MPa.

[0136] Phase 5: Directional fracturing and microfracture formation phase (10 -4 s-10 -3 s) Degradation of the biodegradable plug and opening of orifice 4: Under the influence of downhole temperature and formation fluid, the polylactic acid plug rod inside orifice 4 gradually degrades, approximately 10 -4 Complete degradation occurs within s, and the flow guide hole 4 opens.

[0137] Directional gas diffusion: Ultra-high pressure gas diffuses directionally into the deep formation through the guide hole 4, impacting the contaminated area near the wellbore and achieving contamination removal.

[0138] Microcrack network formation: High-pressure gas breaks through the tensile strength of the rock, inducing the main crack to extend along the guiding direction of the guide hole 4, while forming a fan-shaped microcrack network on the duct wall, eliminating the perforation compaction zone.

[0139] Operation completed: The energy ring maintains the structural support of shell 1 until fracturing is completed, and the system realizes the "integrated perforation-fracturing" function.

[0140] In the description of this invention, it should be understood that if descriptive terms indicating orientation, direction, or positional relationship appear, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of understanding this invention and simplifying the description, and does not indicate or imply that the part, element, or whole referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0141] Furthermore, if sequential descriptive terms such as "first," "second," etc., appear, their purpose in this specification is for ease of understanding or simplification. For example, to distinguish multiple technical features of the same type or function, which must be mentioned separately, this specification may use prefixes or suffixes to differentiate them. Therefore, they should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0142] In this invention, if descriptive terms describing structural relationships are used, such as "installation," "connection," "joining," and "fixation," they should be interpreted broadly unless otherwise explicitly specified and limited. For example, "installation," "connection," and "joining" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two components or the interaction between two components. "Fixation" can refer to an integral fixation or a detachable fixation using fasteners; it can be a direct fixation or a fixation through an intermediate medium. For those skilled in the art, the specific meaning of the above descriptive terms in this invention can be understood based on the specific circumstances, the context, and the coherence of the preceding and following text.

[0143] In this invention, if descriptive terms containing subordinate or connecting meanings appear, such as "above" or "below" the second feature, they should not be interpreted restrictively unless otherwise explicitly specified and limited. For example, "above" or "below" could mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Those skilled in the art can understand the specific meaning of the above descriptive terms in this invention based on the specific circumstances, the context, and the coherence of the preceding and following text.

[0144] Furthermore, "above," "on top of," and "above" the first feature in relation to the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0145] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments, examples, and features described in this specification, and such combinations or integrations should all fall within the scope of the present invention.

[0146] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Variations, modifications, substitutions, and modifications made by those skilled in the art to the above embodiments within the scope of information available through public channels and in conjunction with the technical teachings given in this application are still covered within the protection scope of this application.

Claims

1. An integrated energy ring for perforation-fracturing in unconventional reservoirs, characterized in that: The shell (1) is annular, with a central energy-conducting hole (2) in the middle. The shell (1) has an annular closed cavity surrounding the central energy-conducting hole (2). The closed cavity contains a condensing reaction filler, which is arranged in multiple pieces along its circumference. The first end of the shell (1) is also provided with at least one energy-conducting groove (3), with each energy-conducting groove (3) facing one of the condensing reaction fillers. The outer periphery of the shell (1) is provided with multiple flow-guiding holes (4), and each condensing reaction filler is connected to at least one flow-guiding hole (4).

2. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 1, characterized in that: The energy-concentrating reaction filler includes an aluminothermic reaction layer and a fluoropolymer energy storage layer. The aluminothermic reaction layer is arranged around the central energy-conducting hole (2), and the fluoropolymer energy storage layer is arranged around the aluminothermic reaction layer. Both the aluminothermic reaction layer and the fluoropolymer energy storage layer are arranged in multiple blocks along their own circumference. The flow-conducting hole (4) penetrates the fluoropolymer energy storage layer and communicates with the aluminothermic reaction layer. Each energy-conducting groove (3) is directly opposite one of the aluminothermic reaction layers.

3. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 2, characterized in that: The thermite reaction layer includes multiple thermite filling blocks (5), which are arranged equidistantly along the circumference of the thermite reaction layer. A detonating charge filling block (6) is provided between each two adjacent thermite filling blocks (5). Each thermite filling block (5) is connected to at least one flow guide hole (4), and each detonating charge filling block (6) is connected to at least one flow guide hole (4). Each energy-conducting groove (3) is directly opposite one of the thermite filling blocks (5).

4. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 3, characterized in that: The explosive charge filling block (6) is a lead oxide-aluminum explosive charge column, in which the mass ratio of Pb3O4 to Al is 6:4-7:

3.

5. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 3, characterized in that: The inner wall of the energy-conducting groove (3) is provided with a tungsten alloy energy-conducting coating; the thickness of the tungsten alloy energy-conducting coating is 0.3mm-0.5mm.

6. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 2, characterized in that: The fluoropolymer energy storage layer includes multiple energy storage cavities (7), which are uniformly arranged along the circumference of the fluoropolymer energy storage layer. A flow guide hole (4) is provided between every two adjacent energy storage cavities (7). The energy storage cavities (7) are filled with fluoropolymer particle filler (8), which is a mixture of polytetrafluoroethylene nanoparticles and calcium fluoride particles.

7. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 6, characterized in that: In the fluoropolymer particle filler (8), the mass ratio of polytetrafluoroethylene nanoparticles to calcium fluoride particles is 3:1-5:1, the particle size of polytetrafluoroethylene nanoparticles is 50nm-100nm, and the particle size of calcium fluoride particles is 200nm-300nm.

8. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 6, characterized in that: The energy storage cavity (7) is a polytetrafluoroethylene composite material reinforced with glass fiber or carbon fiber.

9. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 1, characterized in that: The outer end of the guide hole (4) is inclined toward the second end of the shell (1), and the axis of the guide hole (4) forms an angle of 15°-30° with the end face of the shell (1); the diameter of the guide hole (4) is 1.5mm-2.5mm.

10. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 1, characterized in that: The guide hole (4) is also provided with a biodegradable sealing component.

11. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 1, characterized in that: The shell (1) includes a protective outer cylinder (9), a central inner cylinder (10) is provided in the middle of the protective outer cylinder (9), an annular first end plate (11) is provided between the first end of the central inner cylinder (10) and the first end of the protective outer cylinder (9), and an annular second end plate (12) is provided between the second end of the central inner cylinder (10) and the second end of the protective outer cylinder (9); the first end plate (11) is integrally formed with the central inner cylinder (10), and the second end plate (12) is integrally formed with the protective outer cylinder (9); the energy-conducting groove (3) is provided on the first end plate (11).

12. The energy ring for integrated perforation-fracturing in unconventional reservoirs according to claim 11, characterized in that: The protective outer cylinder (9) is made of ceramic matrix composite material, and the thickness of the protective outer cylinder (9) is 1.2mm-2.0mm.

13. A perforation unit, comprising a perforation projectile body (20), characterized in that: An energy ring for unconventional reservoir perforation-fracturing integration, as described in any one of claims 1-12, is coaxially mounted at the jet outlet of the perforation projectile body (20).

14. The perforation unit according to claim 13, characterized in that: The outer wall of the jet outlet of the perforating projectile body (20) is provided with an installation step (21), and the first end edge of the shell (1) is fixed with an annular positioning sleeve (13), which is fitted onto the installation step (21).

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