Perforating bullet for fracturing perforation

Abstract

The perforating bullet comprises a perforating bullet body, an energy ring is arranged at the opening end of the perforating bullet body, the energy ring can conduct secondary burning and explosion on a perforation channel after the perforating bullet body is shot into the perforation channel, the energy ring comprises a shell made of fluoropolymer materials and a thermite filling layer, the shell is arranged in an annular shape, and the thermite filling layer is arranged in the shell. The shell is filled with the thermite filling layer, and the outer wall of the opening end of the perforating bullet body is sleeved with the shell. According to the utility model, the energy ring is arranged at the opening end of the perforating bullet body, so that during normal perforation, secondary detonation and energy release are carried out on the interior of a perforation channel, and the effects of increasing the volume of the channel, increasing cracks of the perforation channel and cleaning the channel are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of fracturing and perforating, in particular to a perforating bullet for fracturing and perforating. Background Art

[0002] In recent years, the development of unconventional shale oil and gas, coalbed methane, etc. has become a hot spot for global energy development and a top priority for China's future energy strategy. Unconventional oil and gas resources are mainly obtained by drilling horizontal wells and performing hydraulic sand fracturing to form porous reservoirs to ensure production. Hydraulic fracturing must be carried out by "fracture perforation" to achieve the purpose of reservoir transformation. According to the research results and construction cases of unconventional hydraulic fracturing completion at home and abroad for many years, the uniform large aperture of "fracture perforation" will improve the distribution of fracturing fluid, reduce pressure friction, and more effectively distribute proppants, while the different sizes of casing holes will produce sand bridges and sand screening. The tip of the "mouse tail-shaped" perforation channel is more likely to be blocked, and the effective hole depth becomes shorter. The pollution of the rock debris compaction zone around the channel is not conducive to sand addition, and it also increases the hydraulic pressure fracture pressure and increases the fracturing cost.

[0003] Generally speaking, the composite material of PTFE filled with inorganic or metal particles is very stable and is an important engineering material. Because the FC (fluorine-carbon) bond is very strong (bond energy 431-515kJ / mol), it is generally believed that PTFE is very stable and usually does not react with other materials. However, the small molecular fluorocarbon gas (such as tetrafluoroethylene, hexafluoropropylene, octafluorobutene, etc.) decomposed by PTFE at high temperatures above 500℃ is active and can react with Al to generate AlF3 (aluminum trifluoride) high exothermic redox reaction. The unit mass calorific value of PTFE / Al energetic reaction material is 8.53MJ / kg, which is 2.0 times the calorific value of the explosive TNT reaction, and the adiabatic reaction temperature is more than 4000K. The density of PTFE / Al is usually not less than 2.0g / cm3, while that of TNT is 1.7g / cm3, so the unit volume calorific value of PTFE / Al is higher, at least 2.4 times that of TNT. Compared with explosives, propellants or pyrotechnics, PTFE / Al is less dangerous and its hazard level is Class 4.1 combustible solid.

[0004] To this end, a perforating bullet for fracturing perforation is proposed. Utility Model Content

[0005] The purpose of the utility model is to provide a perforating bullet for fracturing perforation, so as to solve or at least alleviate one or more of the above-mentioned problems and other problems existing in the prior art.

[0006] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0007] A perforating bullet for fracturing perforation comprises a perforating bullet body. An energy ring is arranged at the open end of the perforating bullet body. The energy ring can perform secondary combustion and explosion on the perforating channel after the perforating bullet body is shot into the perforating channel.

[0008] In a perforating bullet for fracturing perforation according to the utility model, the energy ring includes an outer shell made of fluoropolymer material and a thermite filling layer, the outer shell is arranged in a ring shape, the thermite filling layer is filled inside the outer shell, and the outer shell is sleeved on the outer wall of the open end of the perforating bullet body.

[0009] In a perforating bullet for fracturing perforation according to the utility model, the cross section of the shell is pentagonal.

[0010] In a perforating bullet for fracturing perforation according to the utility model, the thickness between the inner wall and the outer wall of the shell is 2mm-8mm.

[0011] In a perforating bullet for fracturing perforation according to the utility model, the shell is a polytetrafluoroethylene shell.

[0012] In a perforating bullet for fracturing perforation according to the utility model, the thermite filling layer is a filling layer formed by mixing aluminum powder and ferric oxide powder.

[0013] The utility model has at least the following beneficial effects:

[0014] The utility model realizes secondary deflagration in the perforating channel during normal perforation by installing an energy ring at the open end of the perforating bullet body, releases energy, and achieves the effects of increasing the channel volume, increasing the cracks in the perforating channel, and cleaning the channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of the utility model.

[0017] Description of Figure Numbers:

[0018] 1. Perforating gun; 2. Detonating cord; 3. Magazine; 4. Perforating bullet body; 5. Casing; 6. Thermite filling layer. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiment of the utility model more clear, the following is a further detailed description of the embodiment of the utility model in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0020] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the embodiments of the present invention.

[0021] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be the internal connection of two components; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0022] Please refer to Figure 1 As shown, in the embodiment of the utility model,

[0023] A perforating bullet for fracturing perforation comprises a perforating bullet body 4. An energy ring is arranged at the open end of the perforating bullet body 4. The energy ring can perform secondary combustion and explosion on the perforating channel after the perforating bullet body 4 is shot into the perforating channel.

[0024] Specifically, the energy ring includes an outer shell 5 made of fluoropolymer material and a thermite filling layer 6. The outer shell 5 is arranged in a ring shape, and the thickness between the inner wall and the outer wall of the outer shell 5 is 2mm-8mm. The thermite filling layer 6 is filled inside the outer shell 5, and the outer shell 5 is mounted on the outer wall of the open end of the perforating bullet body 4.

[0025] Furthermore, in order to make the shell 5 fit tightly on the perforating charge body 4 , the cross section of the shell 5 is set to be pentagonal, and the outer wall of the shell 5 is inclined in the same direction as the outer wall of the perforating charge body 4 .

[0026] In this embodiment, the outer shell 5 is a polytetrafluoroethylene shell, and the thermite filling layer 6 is a filling layer composed of a mixture of aluminum powder and ferric oxide powder.

[0027] In some embodiments, the shell 5 may also be made of other fluoropolymers besides polytetrafluoroethylene, and the thermite filling layer 6 may also be composed of aluminum powder and metal powders such as V2O5, Cr2O3, MnO2, etc.

[0028] The mechanism of energy ring perforation is: an energy ring is made of high energy density nano new material of PTFE / Al and assembled with the perforating bullet body 4, and then the perforating bullet body 4 is installed in the clip 3 on the perforating gun 1, and then the detonating cord 2 is ignited, and the perforating bullet body 4 is detonated underground to form a high-speed metal jet, especially the umbrella-shaped jet tail, which will hit the energy ring head-on at a speed of 2000-3000m / S. Under the impact of high pressure and high temperature, the energy ring structure is decomposed into tiny particles to form active particles, and at the same time, it is brought into the perforating channel by the umbrella-shaped tail of the jet. The nanoparticles excited under the instantaneous ultra-high pressure of more than 500MPa will undergo continuous physical and chemical violent reactions in the closed channel, resulting in rapid combustion and explosion, releasing kinetic energy, a large amount of chemical energy and ultra-high pressure gas. Continuous deflagration occurs in the confined space of the downhole perforation channel, forming a secondary pulse pressure shock wave, which effectively removes pollution in the near-wellbore area, breaks up the dense area, opens the blocked perforation tip and induces the formation of fan-shaped micro-fracture areas, while creating micro-fractures on the perforation wall.

[0029] The fluorine polymerization reaction of fluoropolymer and aluminum is

[0030] (1) AI2O3+-(C2H2F2) N -(C X H Y F Z )+HF(g)

[0031] (2)–(C2H2F2)-C X H Y F Z +HF(g)+C

[0032] (3)C X H Y F Z -HF(g)+C

[0033] (4) 2AI = 6HF-2AIF3 + 3H2

[0034] Thermite reaction is a redox reaction that can produce temperatures above 2000°C; the fluorination reaction of aluminum, iron or other metal ions with fluoropolymers can generate greater energy.

[0035] The energy released by the energy ring is almost entirely in the perforation channel, which not only expands the depth and capacity of the perforation channel, but also maintains the integrity and consistency of the perforation entrance aperture and ensures that the expansion of the perforating gun will not increase further. The energy ring does not affect the perforating performance of the perforating bullet, does not change the existing perforating gun system, and does not cause safety problems for the perforating gun.

[0036] The above description shows and describes several preferred embodiments of the utility model, but as before, it should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the utility model concept of this article through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A perforating bullet for fracturing perforation, characterized in that: It comprises a perforating bullet body (4), wherein an energy ring is arranged at the open end of the perforating bullet body (4), and the energy ring can perform secondary combustion and explosion on the perforating channel after the perforating bullet body (4) is shot into the perforating channel.

2. The perforating bullet for fracturing perforation according to claim 1, characterized in that: The energy ring comprises an outer shell (5) made of fluoropolymer material and a thermite filling layer (6); the outer shell (5) is arranged in a ring shape; the thermite filling layer (6) is filled inside the outer shell (5); and the outer shell (5) is sleeved on the outer wall of the open end of the perforating bullet body (4).

3. The perforating bullet for fracturing perforation according to claim 2, characterized in that: The cross section of the shell (5) is pentagonal.

4. The perforating bullet for fracturing perforation according to claim 3, characterized in that: The thickness between the inner wall and the outer wall of the outer shell (5) is 2 mm to 8 mm.

5. The perforating bullet for fracturing perforation according to claim 4, characterized in that: The shell (5) is a polytetrafluoroethylene shell.

6. The perforating bullet for fracturing perforation according to claim 2, characterized in that: The thermite filling layer (6) is a filling layer formed by mixing aluminum powder and ferric oxide powder.

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