Layered combustion composite perforating bullet

Abstract

The utility model relates to the technical field of perforating bullets, in particular to a layered combustion composite perforating bullet which comprises a perforating bullet body, main explosive, a shaped charge liner and a containing bin body, the perforating bullet body is of a barrel-shaped structure with openings in the top end and the bottom end, and the opening diameter of the top end of the perforating bullet body is smaller than that of the bottom end of the perforating bullet body. The top of the perforating bullet body is expanded from top to bottom, an opening in the top end of the perforating bullet body is composed of a hemispherical groove formed in the upper surface of the perforating bullet body and a cylindrical through hole extending downwards from the bottom of the groove, and an inner cavity of the perforating bullet body is filled with the main explosive. The combustion duration and the combustion velocity gradient of the propellant powder in each combustion chamber are controlled by utilizing the density of the propellant powder in each combustion chamber and the regular hexagonal through holes in the partition plate; continuous pulse is further realized; and the effects of continuous fracturing, fracture forming and pore channel cleaning are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of perforating charges, in particular to a layered combustion composite perforating charge. Background Art

[0002] A conventional composite perforating charge is composed of a perforating charge, a front chamber and a kind of propellant. It has a simple structure. Its working principle is that after the perforating charge explodes, it shoots a hole in the underground rock formation. At the same time, the generated heat directly ignites the propellant, and relies on the instantaneously generated high-temperature and high-pressure gas to fracture the hole, making the hole produce cracks, so as to improve the permeability and recovery rate of oil. However, because the propellant is single and the burning speed is fixed, there is no time difference in combustion, the burning time is short, the pulse time acting on the hole also lasts for a short time, and the fracturing and crevice-forming effects are not particularly ideal. Especially for the strata with relatively firm geological structures, the fracturing effect cannot be achieved.

[0003] The Chinese patent document with the publication number of CN103696743A discloses a liner, a perforating charge casing and an ultra-deep penetration perforating charge. This perforating charge adopts a small-charge loading structure. Compared with the structural design of large charge loading, by adopting a small-charge loading combined with the overall structural optimization design, the perforating effect of ultra-deep penetration is achieved, which can greatly improve the operation safety of perforating equipment. However, it does not disclose how to make the combustion have a time difference, so as to increase the pulse time acting on the hole and improve the fracturing and crevice-forming effects.

[0004] In summary, how to design a layered combustion composite perforating charge to make the combustion have a time difference, so as to increase the pulse time acting on the hole and improve the fracturing and crevice-forming effects has become a problem to be solved at present. Content of the Utility Model

[0005] The purpose of the utility model is to provide a layered combustion composite perforating charge to solve the above problems.

[0006] To achieve the above purpose, the following technical solutions are provided:

[0007] A layered combustion composite perforating charge, comprising: a perforating charge body, main charge, liner, and a receiving chamber. The perforating charge body is a cylindrical structure with openings at both the top and bottom ends, and the opening diameter at the top end is smaller than that at the bottom end. The top of the perforating charge body is provided with a gradually increasing diameter from top to bottom. The opening at the top end of the perforating charge body is composed of a hemispherical groove formed on its upper surface and a cylindrical through-hole extending downward from the bottom of the groove. The main charge is filled in the inner cavity of the perforating charge body, and its outer wall is in contact with the inner side wall of the perforating charge body. The top of the main charge is correspondingly located below the cylindrical through-hole. The side wall of the liner abuts against the perforating charge body, and a semi-closed cavity is formed between it and the perforating charge body. The main charge is correspondingly located in the semi-closed cavity. The receiving chamber is an annular sleeve structure, fixed to the bottom of the perforating charge body, and the receiving chamber is filled with propellant.

[0008] Preferably, the top surface of the receiving chamber is recessed downward to form a first groove, and the bottom end of the perforating charge body is limited in the first groove. The side wall at the top of the receiving chamber is inclined away from the perforating charge body.

[0009] Preferably, two inner and outer layers of partitions are provided along the circumferential direction in the inner cavity of the receiving chamber. The top and bottom ends of the partitions are in contact with the receiving chamber. The two partitions divide the inner cavity of the receiving chamber into a first combustion chamber, a second combustion chamber, and a third combustion chamber. The first combustion chamber, the second combustion chamber, and the third combustion chamber are arranged in sequence radially outward along the inner cavity of the receiving chamber. The first combustion chamber, the second combustion chamber, and the third combustion chamber are respectively filled with a first propellant, a second propellant, and a third propellant. The densities of the first propellant, the second propellant, and the third propellant increase in sequence.

[0010] Preferably, the bottom plate of the receiving chamber has a thickness of 1.5 mm, and the bottom plate of the receiving chamber is provided with a circular through-hole with a diameter of 2 mm along its radial direction. The partition has a thickness of 2 mm and is provided with a regular hexagonal through-hole with an inscribed circle diameter of 1.5 mm.

[0011] The beneficial effects of the present utility model are as follows:

[0012] 1. The present utility model controls the combustion duration and combustion speed gradient of the propellants in each combustion chamber by using the density of the propellants in each combustion chamber and the regular hexagonal through-holes on the partitions, further realizing the functions of uninterrupted pulses, continuous fracturing, creating fractures, and cleaning the hole channels.

[0013] 2. When the present utility model is in use, first, different propellants are respectively filled into the corresponding three combustion chambers, then the bottom plate of the receiving chamber is bonded to the lower end surface of its main body with high-temperature glue. Finally, the perforating charge body is coated with high-temperature glue and pressed into the receiving chamber. The entire operation process is simple, convenient, safe, and reliable. Brief Description of the Drawings

[0014] Figure 1 is a schematic structural view of the present utility model;

[0015] Figure 2 is a schematic structural view of the bottom plate of the accommodation bin;

[0016] Figure 3 is a schematic structural view of the partition board;

[0017] Figure 4 is a schematic structural view of the perforating charge projectile in the embodiment of the present utility model;

[0018] In the figure:

[0019] 1 - perforating charge projectile;

[0020] 2 - main charge;

[0021] 3 - liner;

[0022] 4 - accommodation bin, 401 - first groove, 402 - circular through - hole; 403 - first propellant, 404 - second propellant, 405 - third propellant;

[0023] 5 - partition board, 501 - regular hexagon through - hole. Detailed Embodiments

[0024] Next, the technical solutions in the schematic diagrams in the embodiments of the present utility model will be clearly and completely described in combination with the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present utility model.

[0025] Such as Figures 1-3As shown in the figure, a layered combustion composite perforating charge includes: a perforating charge body 1, a main charge 2, a liner 3, and a receiving chamber body 4. The perforating charge body 1 is a cylindrical structure with openings at both the top and bottom ends, and the opening diameter at the top end is smaller than that at the bottom end. The top of the perforating charge body 1 is provided with a gradually expanding diameter from top to bottom. The opening at the top end of the perforating charge body 1 is composed of a hemispherical groove opened on its upper surface and a cylindrical through-hole extending downward from the bottom of the groove. The main charge 2 is loaded into the inner cavity of the perforating charge body 1, and its outer wall is in contact with the inner side wall of the perforating charge body 1. The top of the main charge 2 is correspondingly located below the cylindrical through-hole. The side wall of the liner 3 abuts against the perforating charge body 1, and a semi-closed cavity is formed between it and the perforating charge body 1. The main charge 2 is correspondingly located in the semi-closed cavity. The receiving chamber body 4 is an annular sleeve structure, fixed to the bottom of the perforating charge body 1, and the receiving chamber body 4 is loaded with propellant;

[0026] In some embodiments, the top surface of the receiving chamber body 4 is recessed downward to form a first groove 401. The bottom end of the perforating charge body 1 is limited in the first groove 401, and the side wall at the top of the receiving chamber body 4 is inclined away from the perforating charge body 1;

[0027] In some embodiments, two inner and outer layers of partitions 5 are provided along the circumference in the inner cavity of the receiving chamber body 4. The top and bottom ends of the partitions 5 are in contact with the receiving chamber body 4. The two layers of partitions 5 divide the inner cavity of the receiving chamber body 4 into a first combustion chamber, a second combustion chamber, and a third combustion chamber. The first combustion chamber, the second combustion chamber, and the third combustion chamber are arranged in sequence radially outward along the inner cavity of the receiving chamber body 4. The first combustion chamber, the second combustion chamber, and the third combustion chamber are respectively loaded with a first propellant 403, a second propellant 404, and a third propellant 405. The densities of the first propellant 403, the second propellant 404, and the third propellant 405 increase in sequence;

[0028] In some embodiments, the bottom plate thickness of the receiving chamber body 4 is 1.5 mm, and a circular through-hole 402 with a diameter of 2 mm is provided along the radial direction of the bottom plate of the receiving chamber body 4. The thickness of the partition 5 is 2 mm, and a regular hexagonal through-hole 501 with an inscribed circle diameter of 1.5 mm is provided;

[0029] In this embodiment, the first propellant 403, the second propellant 404, and the third propellant 405 are loose-packed propellant, aluminum powder-containing low-density propellant, and aluminum powder-containing high-density propellant in sequence. The perforating charge body 1 is cold-extruded from 20# steel. During the pressing process of the charge, the fluidity of the explosive is increased, and two grooves are also provided along the radial direction on the inner cavity conical surface, so that the charge column can be tightly combined with the inner surface of the projectile, solving the problem of the separation of the charge column from the projectile due to stress reasons;

[0030] The main charge 2 uses PBX-16, and its main component is RDX. This explosive has the characteristics of stable performance, high detonation velocity, large power, high temperature resistance, etc.;

[0031] The liner 3 adopts a high-tungsten formula, with additional metal powders such as copper, bismuth, molybdenum and a binder. The angle of the liner 3 uses an optimized three-cone variable-wall liner 3, and the variable cone angles are 39°-42°-45° in sequence; the bus length of the liner 3 is increased, and compared with conventional perforating charges, there is a significant improvement in penetration depth and aperture;

[0032] The accommodation chamber 4 is made of aluminum alloy casting. The regular hexagon through-hole 501 is a hole for the transfer of gunpowder combustion, used to transfer the flame from the first combustion chamber to the second combustion chamber and from the second combustion chamber to the third combustion chamber; the circular through-hole 402 on the bottom plate of the accommodation chamber 4 is the launch hole, and the high-temperature and high-pressure gas generated after the combustion of the propellant flows out therefrom;

[0033] The particle size of the loose-packed propellant is larger than the particle size of the circular through-hole 402. Since the loose-packed propellant has a lower density, a relatively higher sensitivity and is located in the innermost combustion chamber, it is the propellant that is first ignited after the perforating charge explodes; when the perforating charge explodes, the heat generated first ignites it, and the high-temperature and high-pressure gas generated first rushes into the hole channel, realizing the first fracturing of the hole channel. At the same time, the flame generated by the combustion of the propellant in the first combustion chamber is transmitted to the second combustion chamber through the regular hexagon through-hole 501, igniting the low-density propellant with aluminum powder added, continuing the first wave of pulses, and continuously realizing the second fracturing of the hole channel. When the propellant in the second combustion chamber burns, the flame continues to be transmitted to the third combustion chamber through the regular hexagon through-hole 501, and the propellant in the third combustion chamber burns; the high-temperature and high-pressure gas generated finally completes the fracturing of the hole channel, making the cracks in the hole channel continue to widen; at the same time, due to the presence of aluminum powder in the propellants in the second and third combustion chambers, which has its own combustion performance, the temperature after combustion continues to increase, cleaning the hole channel twice successively, making the hole channel after perforation smoother and more conducive to the flow of oil in the hole channel, thereby improving the oil recovery rate.

Claims

1. A layered combustion composite perforating bullet, characterized in that: include: A perforating bullet body, a main charge explosive, a charge liner and a storage tank body. The perforating bullet body is a cylindrical structure with openings at both ends, and the opening diameter at the top is smaller than the opening diameter at the bottom. The top of the perforating bullet body is expanded from top to bottom. The opening at the top of the perforating bullet body is composed of a hemispherical groove opened on its upper surface and a cylindrical through hole extending downward from the bottom of the groove. The main charge explosive is filled in the inner cavity of the perforating bullet body, and its outer wall is in contact with the inner wall of the perforating bullet body. The top of the main charge explosive is correspondingly located under the cylindrical through hole. The side wall of the charge liner abuts against the perforating bullet body and forms a semi-enclosed cavity with the perforating bullet body. The main charge explosive is correspondingly located in the semi-enclosed cavity. The storage tank body is an annular sleeve structure. The storage tank body is fixed to the bottom of the perforating bullet body and is filled with propellant.

2. A layered combustion composite perforating bullet according to claim 1, characterized in that: The top surface of the storage body is sunken downward to form a first groove, the bottom end of the perforating bullet body is limitedly disposed in the first groove, and the side wall of the top of the storage body is inclined away from the perforating bullet body.

3. The layered combustion composite perforating charge according to claim 2, characterized in that: An inner and outer layer of partitions are provided in the inner cavity of the accommodating warehouse body along its circumference, and the top and bottom ends of the partitions are in contact with the accommodating warehouse body. The two layers of partitions divide the inner cavity of the accommodating warehouse body into a first combustion chamber, a second combustion chamber and a third combustion chamber. The first combustion chamber, the second combustion chamber and the third combustion chamber are arranged radially outward in sequence in the inner cavity of the accommodating warehouse body. The first combustion chamber, the second combustion chamber and the third combustion chamber are respectively filled with a first propellant, a second propellant and a third propellant, and the densities of the first propellant, the second propellant and the third propellant increase in sequence.

4. A layered combustion composite perforating charge according to claim 3, characterized in that: The bottom plate of the storage bin body has a thickness of 1.5 mm, and a circular through hole with a diameter of 2 mm is opened in the radial direction of the bottom plate of the storage bin body. The partition has a thickness of 2 mm and a regular hexagonal through hole with an circumscribed circle diameter of 1.5 mm is opened.

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