Tungsten copper lead powder, small diameter perforating charge case based on the powder and preparation method

Abstract

The application discloses a small-diameter perforating charge cup, which comprises a conical cup body, the cup body is hollow, the top of the inner surface and the top of the outer surface of the cup body are spherical caps, the middle part of the inner surface and the middle part of the outer surface of the cup body are circular table surfaces, the lower part of the inner surface of the cup body is a convex circular table surface, the bottom of the inner surface of the cup body is a convex circular table surface, the side of the bottom of the outer surface of the cup body is a cylindrical surface, the wall thickness of the cup body gradually increases from top to bottom, the inner surface of the cup body is smoothly connected, and the top of the outer surface of the cup body and the middle part of the outer surface of the cup body are smoothly connected. The application further discloses tungsten-copper-lead powder. The application further discloses a preparation method of the tungsten-copper-lead powder. The application further discloses a preparation method of the small-diameter perforating charge cup. The small-diameter perforating charge cup solves the problems of small far-end perforating aperture and low penetration depth of the existing small-diameter perforator in a large-casing deformed well.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well perforation projectile manufacturing technology, specifically relating to a small-diameter perforation projectile shroud. This invention also relates to tungsten-copper-lead powder, a method for preparing tungsten-copper-lead powder, and a method for preparing a small-diameter perforation projectile shroud. Background Technology

[0002] The shaped charge liner for oil and gas well perforation projectiles is a key component used in perforation projectile explosive devices, especially in shaped charge systems. Its function is to convert the explosive energy into a metal jet to penetrate the target. The shaped charge liner is usually made of metal, and as the core component of the perforation projectile, its shape, material, and structural parameters have a significant impact on the formation and penetration capability of the jet.

[0003] Traditional Type 40 perforating guns (model DP16RDX3-1XF) are typically used in operations without formation accidents, especially with 60 or 73mm tubing. These perforating guns were originally designed to establish a flow channel between the oil and gas reservoir and the wellbore under normal reservoir conditions, enabling oil and gas extraction. However, when used in wells with 140mm large casing, the penetration depth of the traditional Type 40 perforating gun is insufficient due to the higher steel grade of the casing (e.g., TP140V), the thicker well wall (from 5mm to 12.7mm), and the larger perforation gap. It cannot effectively penetrate the distal end of the casing, resulting in a smaller perforated diameter, which affects subsequent fracturing operations.

[0004] Furthermore, due to the limited containment diameter of the 40mm perforation gun, increasing the diameter of the liner would reduce the height of the liner or increase the cone angle of the liner, which would be detrimental to penetration depth; while reducing the diameter of the liner would limit the increase in aperture and charge, which is difficult to balance in a space-constrained situation. Summary of the Invention

[0005] The purpose of this invention is to provide a small-diameter perforation ammunition cover, which solves the problems of small perforation diameter and low penetration depth of existing small-diameter perforators in large casing deformation wells.

[0006] A second objective of this invention is to provide tungsten-copper-lead powder.

[0007] A third objective of this invention is to provide a method for preparing tungsten-copper-lead powder.

[0008] The fourth objective of this invention is a method for preparing a small-diameter perforated ammunition shroud.

[0009] The first technical solution adopted in this invention is a small-diameter perforation ammunition liner, comprising a conical liner body, the liner body being hollow inside, the top of the inner surface and the top of the outer surface of the liner being spherical, the middle of the inner surface and the middle of the outer surface of the liner being frustum-shaped, the lower part of the inner surface of the liner being a convex frustum-like surface, the bottom of the inner surface of the liner being a convex frustum-like surface, and the bottom side of the outer surface of the liner being a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped shroud is tangent to the top spherical surface of the outer surface of the drug-shaped shroud. The side of the middle part of the inner surface of the drug-shaped shroud is tangent to the top spherical surface of the inner surface of the drug-shaped shroud, the side of the lower part of the inner surface of the drug-shaped shroud, and the side of the bottom of the inner surface of the drug-shaped shroud. The wall thickness of the drug-shaped shroud gradually increases from top to bottom. The inner surface of the drug-shaped shroud transitions smoothly, and the top and middle parts of the outer surface of the drug-shaped shroud transition smoothly.

[0010] The features of this invention are: The cone angle at the middle of the inner surface is 56°36′-58°36′, and the cone angle at the middle of the outer surface is 57°27′-59°27′. The cone angle at the middle of the outer surface is 51′ larger than the cone angle at the middle of the inner surface.

[0011] The ratio of the bottom diameter at the top of the inner surface, the bottom diameter at the middle of the inner surface, the bottom diameter at the bottom of the inner surface, and the bottom diameter at the bottom of the inner surface is 0.426:1:1.449:1.894. The ratio of the height of the top of the inner surface, the height of the middle of the inner surface, the height of the bottom of the inner surface, and the height of the bottom of the inner surface is 0.241:1:0.876:1.397.

[0012] The second technical solution adopted in this invention is a tungsten-copper-lead powder, which is composed of the following raw material powders in the following mass percentages: 30%~50% tungsten powder, 30%~50% electrolytic copper powder, and 15%~25% lead powder, and the sum of the mass percentages of the above components is 100%.

[0013] The third technical solution adopted in this invention is a method for preparing tungsten-copper-lead powder, comprising the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 0.2~2 hours to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

[0014] The features of this invention are: The sieving operations in steps S3-S5 all use a 20-mesh Taylor sieve, the mixing machine is a double-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

[0015] The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 1~5 hours; The mixing process in step S5 is as follows: pour the sieved powder into the mixer, set the mixing speed to 34.2 rpm, and the mixing time to 3~7 hours.

[0016] The fourth technical solution adopted in this invention is a method for preparing a small-diameter perforation ammunition cover, comprising the following steps: The prepared tungsten-copper-lead powder is poured into the female mold of the pressure mold. The female mold rotates at a speed of 500-600 rpm. During the rotation of the female mold, the male mold of the pressure mold is pressed into the female mold. The pressure is applied to 2 MPa while the female mold drives the male mold to rotate synchronously. The pressure application time is 6 seconds. After the pressure application is completed, the mold is demolded to obtain the drug-formed liner.

[0017] The features of this invention are: The female mold of the pressing mold matches the outer surface of the drug-shaped cover, and the male mold of the pressing mold matches the inner surface of the drug-shaped cover.

[0018] The beneficial effects of this invention are: The tungsten-copper-lead powder, the small-diameter perforation projectile liner based on the powder, and the preparation method provided by this invention employ a multi-segment composite internal structure. After detonation, this structure forms jets that are approximately two segments with different length-to-diameter ratios, acting on the casing and the formation respectively. The jet at the casing forms a larger aperture, while the jet at the formation forms a deeper penetration depth. This achieves effective control over the casing aperture and formation penetration depth. Furthermore, the use of tungsten-copper-lead powder results in higher uniformity. The pressed liner effectively avoids density differences in the axial and arc directions of the liner, increasing the stability of the jet formed by the liner and preventing deflection of the jet during its journey, which would affect the stability of the perforation projectile. This improves the penetration capability and aperture size of the perforation projectile under high-gap conditions, achieving the goal of a large distal aperture and deep formation penetration. This addresses the problems faced by small-diameter perforating guns in the construction and application of large-casing deformed wells, such as inability to penetrate the distal end of the perforation, small average casing aperture, and shallow penetration depth of oil and gas reservoirs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the small-diameter perforation ammunition cover of the present invention; Figure 2 This is a schematic diagram of the inner surface structure of the present invention; Figure 3 This is a schematic diagram of the outer surface structure of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] The small-diameter perforation ammunition cover provided by this invention, such as Figure 1 As shown, it includes a cone-shaped propellant liner body, the interior of which is hollow, as... Figure 2 and Figure 3 As shown, the top of both the inner and outer surfaces of the shaped charge liner are spherical to form a larger aperture on the casing. The middle of both the inner and outer surfaces of the shaped charge liner are frustum surfaces, which reduces the influence of the high clearance on the aperture during the jet perforation process and achieves the purpose of increasing the aperture of the far end casing under gravity. The lower part of the inner surface of the shaped charge liner is a convex frustum surface, and the bottom of the inner surface of the shaped charge liner is a convex frustum surface, which has a velocity gradient and continuous jet effective jet quality, used to form a large perforation depth in the formation. The bottom side of the outer surface of the shaped charge liner is a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped shroud is tangent to the top spherical surface of the outer surface of the drug-shaped shroud. The side of the middle part of the inner surface of the drug-shaped shroud is tangent to the top spherical surface of the inner surface of the drug-shaped shroud, the side of the lower part of the inner surface of the drug-shaped shroud, and the side of the bottom of the inner surface of the drug-shaped shroud. The wall thickness of the drug-shaped shroud gradually increases from top to bottom. The inner surface of the drug-shaped shroud transitions smoothly, and the top and middle parts of the outer surface of the drug-shaped shroud transition smoothly.

[0022] The cone angle at the middle of the inner surface is 56°36′-58°36′, and the cone angle at the middle of the outer surface is 57°27′-59°27′. The cone angle at the middle of the outer surface is 51′ larger than the cone angle at the middle of the inner surface.

[0023] The ratio of the bottom diameter at the top of the inner surface, the bottom diameter at the middle of the inner surface, the bottom diameter at the bottom of the inner surface, and the bottom diameter at the bottom of the inner surface is 0.426:1:1.449:1.894. The ratio of the height of the top of the inner surface, the height of the middle of the inner surface, the height of the bottom of the inner surface, and the height of the bottom of the inner surface is 0.241:1:0.876:1.397.

[0024] After detonation, the shaped charge liner forms approximately two jets with different aspect ratios that act on the casing and the formation respectively, thus achieving effective control over the casing aperture and the formation penetration depth.

[0025] The tungsten-copper-lead powder provided by the present invention is composed of the following raw material powders in the following mass percentages: 35%~45% tungsten powder, 35%~45% electrolytic copper powder, and 15%~25% lead powder, the sum of the mass percentages of the above components being 100%.

[0026] The grade of tungsten powder is CTP45-250; Tungsten powder particle size distribution: +100 mesh: 15%~35%, 100~200 mesh: 30%~50%, 200~325 mesh: 15%~35%, -325 mesh: 5%~15%, Fisher particle size: 45~60μm; Loose packing density of tungsten powder: 7.5~9.5 g / m³ 3 The flow rate of tungsten powder is 10s / 50g, the purity of tungsten powder is ≥99.9%, the oxygen content of tungsten powder is ≤0.1%, and the microstructure of tungsten powder is quasi-spherical or spherical.

[0027] The appearance requirements for electrolytic copper powder are as follows: When viewed with the naked eye, electrolytic copper powder should be light rose red, uniform and loose, with a metallic luster, uniform in color, and free of visible mechanical impurities. The purity of electrolytic copper powder is ≥99.6%. Electrolytic copper powder particle size requirements: Electrolytic copper powder is generally analyzed using the sieves in Table 1; Table 1. Analytical Indicators of Electrolytic Copper Powder Sieve

[0028] The required loose powder ratio for electrolytic copper powder is 1.8~2.3 g / cm³. 3 Oxygen content of electrolytic copper powder: ≤0.15%; Microstructure of electrolytic copper powder: dendritic.

[0029] Appearance of lead powder: When observed with the naked eye, lead powder should be light silver-gray, uniform and loose, with a metallic luster, uniform color, and no visible mechanical impurities.

[0030] Lead powder composition: lead ≥ 99.7%, oxygen ≤ 0.15%; Lead powder particle size: The powder is usually analyzed by laser particle size analysis as shown in Table 2. In special cases such as equipment failure or special requirements, sieve analysis is used.

[0031] Table 2 Laser Particle Size Analysis

[0032] (2) Sieve analysis index: -200 mesh ≥80%.

[0033] Lead powder per unit volume: 4.5~6 g / cm³ 3 Lead powder microstructure: nearly spherical.

[0034] The method for preparing tungsten-copper-lead powder provided by the present invention includes the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 0.2~2 hours to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

[0035] The fractional paraffin wax is 0.05%-1% of the weight of the premixed powder, and 5-20ml of solvent oil is added per kilogram of premixed powder. The fractional paraffin wax acts as both a binder and a lubricant. After being heated and melted, the fractional paraffin wax becomes a liquid and is evenly coated on the surface of the tungsten, copper, and lead powder. The solvent oil will gradually evaporate and dry. The tungsten, copper, and lead powder coated with fractional paraffin wax has good flowability, pressing properties, and formability, and plays a positive role in the bonding, lubrication, and forming of the drug liner preform.

[0036] The sieving operations in steps S3-S5 all use a 20-mesh Taylor sieve, the mixing machine is a double-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

[0037] The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 1~5 hours; The mixing process in step S5 is as follows: pour the sieved powder into the mixer, set the mixing speed to 34.2 rpm, and the mixing time to 3~7 hours.

[0038] The method for preparing a small-diameter perforation ammunition cover provided by the present invention includes the following steps: Tungsten-copper-lead powder is poured into the female mold of the shroud mold. The female mold rotates at a speed of 500-600 rpm. During the rotation of the female mold, the male mold of the shroud mold is pressed into the female mold. The pressure is increased to 2 MPa while the female mold drives the male mold to rotate synchronously. The pressure time is 6 seconds. After the pressure is completed, the mold is demolded to obtain the shroud.

[0039] The female mold of the pressing mold matches the outer surface of the drug-shaped cover, and the male mold of the pressing mold matches the inner surface of the drug-shaped cover.

[0040] Example 1 The small-diameter perforation ammunition cover proposed in this embodiment, such as Figure 1 As shown, it includes a cone-shaped propellant liner body, the interior of which is hollow, as... Figure 2 and Figure 3As shown, the top of both the inner and outer surfaces of the shaped charge liner are spherical to form a larger aperture on the casing. The middle of both the inner and outer surfaces of the shaped charge liner are frustum surfaces, which reduces the influence of the high clearance on the aperture during the jet perforation process and achieves the purpose of increasing the aperture of the far end casing under gravity. The lower part of the inner surface of the shaped charge liner is a convex frustum surface, and the bottom of the inner surface of the shaped charge liner is a convex frustum surface, which has a velocity gradient and continuous jet effective jet quality, used to form a large perforation depth in the formation. The bottom side of the outer surface of the shaped charge liner is a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped shroud is tangent to the top spherical surface of the outer surface of the drug-shaped shroud. The side of the middle part of the inner surface of the drug-shaped shroud is tangent to the top spherical surface of the inner surface of the drug-shaped shroud, the side of the lower part of the inner surface of the drug-shaped shroud, and the side of the bottom of the inner surface of the drug-shaped shroud. The wall thickness of the drug-shaped shroud gradually increases from top to bottom. The inner surface of the drug-shaped shroud transitions smoothly, and the top and middle parts of the outer surface of the drug-shaped shroud transition smoothly.

[0041] Example 2 The small-diameter perforation ammunition cover proposed in this embodiment, such as Figure 1 As shown, it includes a cone-shaped propellant liner body, the interior of which is hollow, as... Figure 2 and Figure 3 As shown, the top of both the inner and outer surfaces of the shaped charge liner are spherical to form a larger aperture on the casing. The middle of both the inner and outer surfaces of the shaped charge liner are frustum surfaces, which reduces the influence of the high clearance on the aperture during the jet perforation process and achieves the purpose of increasing the aperture of the far end casing under gravity. The lower part of the inner surface of the shaped charge liner is a convex frustum surface, and the bottom of the inner surface of the shaped charge liner is a convex frustum surface, which has a velocity gradient and continuous jet effective jet quality, used to form a large perforation depth in the formation. The bottom side of the outer surface of the shaped charge liner is a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped shroud is tangent to the top spherical surface of the outer surface of the drug-shaped shroud. The side of the middle part of the inner surface of the drug-shaped shroud is tangent to the top spherical surface of the inner surface of the drug-shaped shroud, the side of the lower part of the inner surface of the drug-shaped shroud, and the side of the bottom of the inner surface of the drug-shaped shroud. The wall thickness of the drug-shaped shroud gradually increases from top to bottom. The inner surface of the drug-shaped shroud transitions smoothly, and the top and middle parts of the outer surface of the drug-shaped shroud transition smoothly.

[0042] The cone angle at the middle of the inner surface is 56°36′-58°36′, and the cone angle at the middle of the outer surface is 57°27′-59°27′. The cone angle at the middle of the outer surface is 51′ larger than the cone angle at the middle of the inner surface.

[0043] Example 3 The small-diameter perforation ammunition cover proposed in this embodiment, such as Figure 1 As shown, it includes a cone-shaped propellant liner body, the interior of which is hollow, as... Figure 2 and Figure 3As shown, the top of both the inner and outer surfaces of the shaped charge liner are spherical to form a larger aperture on the casing. The middle of both the inner and outer surfaces of the shaped charge liner are frustum surfaces, which reduces the influence of the high clearance on the aperture during the jet perforation process and achieves the purpose of increasing the aperture of the far end casing under gravity. The lower part of the inner surface of the shaped charge liner is a convex frustum surface, and the bottom of the inner surface of the shaped charge liner is a convex frustum surface, which has a velocity gradient and continuous jet effective jet quality, used to form a large perforation depth in the formation. The bottom side of the outer surface of the shaped charge liner is a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped shroud is tangent to the top spherical surface of the outer surface of the drug-shaped shroud. The side of the middle part of the inner surface of the drug-shaped shroud is tangent to the top spherical surface of the inner surface of the drug-shaped shroud, the side of the lower part of the inner surface of the drug-shaped shroud, and the side of the bottom of the inner surface of the drug-shaped shroud. The wall thickness of the drug-shaped shroud gradually increases from top to bottom. The inner surface of the drug-shaped shroud transitions smoothly, and the top and middle parts of the outer surface of the drug-shaped shroud transition smoothly.

[0044] The cone angle at the middle of the inner surface is 56°36′-58°36′, and the cone angle at the middle of the outer surface is 57°27′-59°27′. The cone angle at the middle of the outer surface is 51′ larger than the cone angle at the middle of the inner surface.

[0045] The ratio of the bottom diameter at the top of the inner surface, the bottom diameter at the middle of the inner surface, the bottom diameter at the bottom of the inner surface, and the bottom diameter at the bottom of the inner surface is 0.426:1:1.449:1.894. The ratio of the height of the top of the inner surface, the height of the middle of the inner surface, the height of the bottom of the inner surface, and the height of the bottom of the inner surface is 0.241:1:0.876:1.397.

[0046] Example 4 The tungsten-copper-lead powder used to manufacture any of the small-diameter perforated ammunition shrouds in Examples 1-3 is composed of the following raw material powders in mass percentage: 40% tungsten powder, 40% electrolytic copper powder, and 20% lead powder, with the sum of the mass percentages of the above components being 100%.

[0047] Example 5 The tungsten-copper-lead powder used to manufacture any of the small-diameter perforated ammunition shrouds in Examples 1-3 is composed of the following raw material powders in mass percentage: 35% tungsten powder, 45% electrolytic copper powder, and 20% lead powder, with the sum of the mass percentages of the above components being 100%.

[0048] Example 6 The tungsten-copper-lead powder used to manufacture any of the small-diameter perforated ammunition shrouds in Examples 1-3 is composed of the following raw material powders in mass percentage: 45% tungsten powder, 40% electrolytic copper powder, and 15% lead powder, with the sum of the mass percentages of the above components being 100%.

[0049] Example 7 The tungsten-copper-lead powder used to manufacture any of the small-diameter perforated ammunition shrouds in Examples 1-3 is composed of the following raw material powders in mass percentage: 40% tungsten powder, 35% electrolytic copper powder, and 25% lead powder, with the sum of the mass percentages of the above components being 100%.

[0050] Example 8 The preparation method of any of the tungsten-copper-lead powders in Examples 4-7 includes the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 1 hour to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; The amount of sliced ​​paraffin is 0.1% of the weight of the premixed powder, and 15ml of solvent oil is added for every kilogram of premixed powder.

[0051] S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

[0052] The sieving operations in steps S3-S5 all use a 20-mesh Taylor sieve, the mixing machine is a double-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

[0053] The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 2 hours. The mixing process in step S5 is as follows: the sieved powder is poured into the mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 5 hours.

[0054] Example 9 The preparation method of any of the tungsten-copper-lead powders in Examples 4-7 includes the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 0.2 hours to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; The amount of sliced ​​paraffin is 0.05% of the weight of the premixed powder, and 5 ml of solvent oil is added for every kilogram of premixed powder.

[0055] S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

[0056] The sieving operations in steps S3-S5 all use a 20-mesh Taylor sieve, the mixing machine is a double-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

[0057] The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 1 hour; The mixing process in step S5 is as follows: the sieved powder is poured into the mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 3 hours.

[0058] Example 10 The preparation method of any of the tungsten-copper-lead powders in Examples 4-7 includes the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 2 hours to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; The amount of sliced ​​paraffin is 1% of the weight of the premixed powder, and 20ml of solvent oil is added for every kilogram of premixed powder.

[0059] S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

[0060] The sieving operations in steps S3-S5 all use a 20-mesh Taylor sieve, the mixing machine is a double-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

[0061] The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 5 hours. The mixing process in step S5 is as follows: the sieved powder is poured into the mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 7 hours.

[0062] Example 11 The preparation method of any small-diameter perforation ammunition cover in Examples 1-3 includes the following steps: Pour the tungsten-copper-lead powder prepared in any of Examples 8-10 into the female mold of the pressure mold. The female mold rotates at 500 rpm. During the rotation of the female mold, the male mold of the pressure mold is pressed into the female mold. During the synchronous rotation of the female mold and the male mold, the pressure is increased to 2 MPa and the pressure time is 6 seconds. After the pressure is completed, the mold is demolded to obtain the drug-formed cover.

[0063] The female mold of the pressing mold matches the outer surface of the drug-shaped cover, and the male mold of the pressing mold matches the inner surface of the drug-shaped cover.

[0064] Example 12 The preparation method of any small-diameter perforation ammunition cover in Examples 1-3 includes the following steps: Pour the tungsten-copper-lead powder prepared in any of Examples 8-10 into the female mold of the pressure mold. The female mold rotates at 600 rpm. During the rotation of the female mold, the male mold of the pressure mold is pressed into the female mold. During the synchronous rotation of the female mold and the male mold, the pressure is increased to 2 MPa and the pressure time is 6 seconds. After the pressure is completed, the mold is demolded to obtain the drug-formed cover.

[0065] The female mold of the pressing mold matches the outer surface of the drug-shaped cover, and the male mold of the pressing mold matches the inner surface of the drug-shaped cover.

[0066] Example 13 The preparation method of any small-diameter perforation ammunition cover in Examples 1-3 includes the following steps: Pour the tungsten-copper-lead powder prepared in any of Examples 8-10 into the female mold of the pressure mold. The female mold rotates at 550 rpm. During the rotation of the female mold, the male mold of the pressure mold is pressed into the female mold. During the synchronous rotation of the female mold and the male mold, the pressure is increased to 2 MPa and the pressure time is 6 seconds. After the pressure is completed, the mold is demolded to obtain the drug-formed cover.

[0067] The female mold of the pressing mold matches the outer surface of the drug-shaped cover, and the male mold of the pressing mold matches the inner surface of the drug-shaped cover.

[0068] Comparative Example 1 The shaped charge hood proposed in this comparative example includes a cone-shaped shaped charge hood body, which is hollow inside. The top of the inner surface and the top of the outer surface of the shaped charge hood are both flat, the bottom of the inner surface and the middle of the outer surface of the shaped charge hood are both frustum surfaces, the bottom side of the outer surface of the shaped charge hood is a cylindrical surface, the inner surface of the shaped charge hood has a smooth transition, and the top and middle of the outer surface of the shaped charge hood have a smooth transition.

[0069] Comparative Example 2 The shaped charge hood proposed in this comparative example includes a conical shaped charge hood body, which is hollow inside. The top of both the inner and outer surfaces of the shaped charge hood are spherical caps. The middle of both the inner and outer surfaces of the shaped charge hood are frustum-shaped surfaces. The bottom of the inner surface of the shaped charge hood is a convex frustum-like surface. The bottom side of the outer surface of the shaped charge hood is a cylindrical surface. The inner surface of the shaped charge hood has a smooth transition, and the top and middle of the outer surface of the shaped charge hood have a smooth transition.

[0070] Comparative Example 3 The tungsten-copper powder used in this comparative example for manufacturing any small-diameter perforated ammunition shroud of Examples 1-3 is composed of the following raw material powders in mass percentage: 80% tungsten powder and 20% electrolytic copper powder, the sum of the mass percentages of the above components being 100%.

[0071] Table 3. Test data of average penetration depth and aperture of various comparative charge liner types under the condition of casing-assisted well.

[0072] Table 3 shows the average penetration depth and aperture test data of each comparative shaped charge liner under the casing variation well condition. As can be seen from the table, by increasing the upper cone angle of the shaped charge liner and extending the lower arc structure, the jet converges at the upper part of the shaped charge liner to form a coarser jet, thereby forming a larger aperture at the casing. At the same time, the double R curve structure at the lower end of the shaped charge liner solves the problem of jet "chasing" that is easy to form when the subsequent jet structure design is unreasonable, and avoids the jet accumulation to form a large pestle. Through reasonable structural design, a reasonable velocity gradient of the shaped charge liner is achieved.

[0073] Meanwhile, by combining double arcs and straight cones, the wall thickness variation of the shaped charge liner satisfies the trend that the contribution rate of the shaped charge liner to the jet gradually increases from the top to the bottom of the liner, thereby improving the energy utilization rate after the explosive detonation and forming two jets with large diameter differences, so as to achieve the purpose of larger orifice and deeper perforation depth at the perforation sleeve.

Claims

1. A small-diameter perforation ammunition cover, characterized in that, The device includes a cone-shaped shaped charge body, which is hollow inside. The top of the inner surface and the top of the outer surface of the shaped charge are both spherical caps. The middle part of the inner surface and the middle part of the outer surface of the shaped charge are both frustum surfaces. The lower part of the inner surface of the shaped charge is a convex frustum-like surface. The bottom part of the inner surface of the shaped charge is a convex frustum-like surface. The bottom side of the outer surface of the shaped charge is a cylindrical surface. The side of the middle part of the outer surface of the drug-shaped cover is tangent to the top spherical surface of the outer surface of the drug-shaped cover. The side of the middle part of the inner surface of the drug-shaped cover is tangent to the top spherical surface of the inner surface of the drug-shaped cover, the side of the lower part of the inner surface of the drug-shaped cover, and the side of the bottom of the inner surface of the drug-shaped cover. The wall thickness of the drug-shaped cover gradually increases from top to bottom. The inner surface of the drug-shaped cover has a smooth transition, and the top and middle parts of the outer surface of the drug-shaped cover have a smooth transition.

2. The small-diameter perforation ammunition cover according to claim 1, characterized in that, The cone angle at the middle of the inner surface is 56°36′-58°36′, and the cone angle at the middle of the outer surface is 57°27′-59°27′. The cone angle at the middle of the outer surface is 51′ larger than the cone angle at the middle of the inner surface.

3. The small-diameter perforation ammunition cover according to claim 2, characterized in that, The ratio of the bottom diameter of the top of the inner surface, the bottom diameter of the middle of the inner surface, the bottom diameter of the lower part of the inner surface, and the bottom diameter of the inner surface is 0.426:1:1.449:1.

894. The ratio of the height of the top of the inner surface, the height of the middle of the inner surface, the height of the lower part of the inner surface, and the height of the bottom of the inner surface is 0.241:1:0.876:1.

397.

4. A tungsten-copper-lead powder for manufacturing the shaped charge liner according to claims 1-3, characterized in that, The following raw material powders are prepared in the following proportions by mass. Composition: 35%~45% tungsten powder, 35%~45% electrolytic copper powder, 15%~25% lead powder, the sum of the mass percentages of the above components is 100%.

5. The method for preparing the tungsten-copper-lead powder according to claim 4, characterized in that, Includes the following steps: S1: Pour tungsten powder, electrolytic copper powder, and lead powder into a mixer and premix for 0.2~2 hours to obtain premixed powder. S2: Weigh out sliced ​​paraffin wax and solvent oil, place them in a 90℃ oven to fully dissolve them, and obtain a mixed solvent; S3: Pour the mixed solvent into the premixed powder, stir, and sieve to obtain the initial sieve powder; S4: Pour the initial sieved powder into the mixer, mix, sieve, spread the sieved powder on a plastic film, and let it dry; S5: Sift the dried powder and then pour it into a mixer to mix it to obtain tungsten-copper-lead powder.

6. The method for preparing tungsten-copper-lead powder according to claim 5, characterized in that, The sliced ​​paraffin wax is 0.05%-1% of the weight of the premixed powder, and 5-20ml of solvent oil is added to each kilogram of premixed powder.

7. The method for preparing tungsten-copper-lead powder according to claim 5, characterized in that, The sieving operations in steps S3-S5 are all performed using a 20-mesh Taylor sieve, the mixing machine is a dual-motion mixing machine, and the solvent oil is No. 120 non-oxidizing solvent oil.

8. The method for preparing tungsten-copper-lead powder according to claim 5, characterized in that, The mixing process in step S4 is as follows: the initial sieved powder is poured into the double motion mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 1~5 hours. The mixing process in step S5 is as follows: the sieved powder is poured into the mixer, the mixing speed is set to 34.2 rpm, and the mixing time is 3~7 hours.

9. The method for preparing the small-diameter perforation ammunition shroud according to any one of claims 1-3, characterized in that, Includes the following steps: The tungsten-copper-lead powder prepared according to any one of claims 5-8 is poured into the female mold of the pressure mold. The female mold rotates at a speed of 500-600 rpm. During the rotation of the female mold, the male mold of the pressure mold is pressed into the female mold. During the synchronous rotation of the female mold and the male mold, the pressure is increased to 2 MPa and the pressure time is 6 seconds. After the pressure is completed, the mold is demolded to obtain the drug-formed cover.

10. The method for preparing a small-diameter perforated ammunition shroud according to claim 9, characterized in that, The female mold of the pressing mold matches the outer surface of the drug shaped cover, and the male mold of the pressing mold matches the inner surface of the drug shaped cover.

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