Repeated perforating bullet for same hole

Abstract

The invention discloses a same-hole repeated perforating bullet. The problem that an existing perforating bullet is poor in same-hole repeated perforation penetration performance is mainly solved. The invention is characterized in that the shaped charge liner (3) comprises an outer generatrix (31) and an inner generatrix (32), the outer generatrix (31) is a straight line, the inner generatrix (32) is divided into four sections, the top of the liner is a first curve section (321), and a second straight line section (322), a third straight line section (323) and a fourth straight line section (324) are sequentially arranged downwards along the top of the liner. The same-hole repeated perforation bullet can effectively improve the same-hole repeated perforation penetration depth, and the same-hole repeated perforation penetration depth can be improved by more than 60%.

Description

Technical Field

[0001] The invention relates to the technical field of oil field production engineering, in particular to a same-hole repeated perforating bullet. Background Art

[0002] At present, the average penetration depth of perforating bullets equipped with 102mm perforating guns on sandstone targets is 350mm. In the existing technology, the penetration depth of perforating bullets is generally improved by increasing the charge, changing the charging method and increasing the blasting height, but these methods are limited in effect and have many disadvantages. Increasing the charge will inevitably increase the risk of gun explosion; and increasing the blasting height also has shortcomings. The most favorable blasting height is a range. When the blasting height increases beyond this range, the jet will produce radial dispersion and swing. When it swings to a certain extent, it will break, affecting the penetration performance of the jet. The same-hole repeated perforation technology is a new research direction for improving the penetration depth of perforating bullets in recent years. Experiments show that under the condition that other conditions remain unchanged, the same-hole repeated perforation technology is used with conventional perforating bullets, and the penetration depth is increased by about 20%. At present, there is no research in China on effectively improving the secondary penetration performance of the same-hole repeated perforation. Summary of the invention

[0003] In order to overcome the problem of poor penetration performance of repeated perforating in the same hole by existing perforating bullets, the present invention provides a repeated perforating bullet for the same hole, which can effectively improve the penetration of repeated perforating in the same hole, and the penetration of repeated perforating in the same hole can be improved by more than 60%.

[0004] The technical solution of the present invention is: a same-hole repeated perforating bullet, including a shell, a charge liner is arranged inside the shell, and a charge is arranged in a cavity between the shell and the charge liner. The charge liner includes an outer busbar and an inner busbar, the outer busbar is a straight line, and the inner busbar is four sections, wherein the top of the liner is a first curved section, and the second straight section, the third straight section, and the fourth straight section are arranged downward along the top of the liner.

[0005] The included angle β between the outer generatrix of the medicine liner and the axis is 42° to 54°.

[0006] The angle α1 between the second straight line segment of the inner busbar of the medicine liner and the axis is 42° to 50°, the angle α2 between the third straight line segment and the axis is 38° to 46°, and the angle α3 between the fourth straight line segment and the axis is 36° to 46°.

[0007] The radius of the first curved section of the inner busbar of the medicine liner is 2.2 to 3 mm.

[0008] The busbars in the shell are sequentially divided into a first straight line segment of the shell, a second straight line segment of the shell, a third curved line segment of the shell, a fourth straight line segment of the shell, and a fifth straight line segment of the shell from the top of the shell to the bottom of the shell.

[0009] The angle γ1 between the first straight line segment of the shell and the axis is 50° to 80°, the angle γ2 between the second straight line segment of the shell and the axis is 100° to 130°, and the angle γ3 between the fourth straight line segment of the shell and the axis is 18° to 30°.

[0010] The present invention has the following beneficial effects: by adopting the above scheme, the charge liner structure and shell structure of the present invention are used, which not only has sufficient penetration speed, but is not easy to break, and maximizes the good shape and speed of the jet when it hits the target, and effectively improves the penetration depth of repeated perforation in the same hole. Comparative tests have shown that when a conventional perforating bullet is used for a single perforation and the perforating bullet of the present invention is used for a secondary perforation, the penetration depth of repeated perforation in the same hole can be increased by more than 60% on average. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the present invention;

[0012] Figure 2 It is a schematic diagram of the liner;

[0013] Figure 3 is a schematic diagram of the shell.

[0014] In the figure, 1 is the shell, 2 is the charge, 3 is the liner, 31 is the outer busbar, and 32 is the inner busbar. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings:

[0016] Depend on Figures 1 to 3 As shown, a same-hole repeated perforating bullet comprises a shell 1, a charge liner 3 is arranged inside the shell 1, and a charge 2 is arranged in the cavity between the shell 1 and the charge liner 3. The charge liner 3 comprises an outer busbar 31 and an inner busbar 32, wherein the outer busbar 31 is a straight line, and the angle β between the outer busbar 31 and the axis is 42° to 54°. The inner busbar 32 of the charge liner is divided into four sections, wherein the top of the liner is the first curved section 321, and the second straight section 322, the third straight section 323, and the fourth straight section 324 are arranged along the top of the liner, and a tangent transition is adopted between the curves and the straight lines. The radius of the first curved section 32 of the inner busbar 32 of the charge liner is 2.2 to 3 mm, the angle α1 between the second straight section 322 of the inner busbar 32 and the axis is 42° to 50°, the angle α2 between the third straight section 323 and the axis is 38° to 46°, and the angle α3 between the fourth straight section 324 and the axis is 36°-46°.

[0017] The inner busbar of the shell 1 is composed of a plurality of straight lines and arcs with different slopes, which are the first straight line segment 11, the second straight line segment 12, the third curved line segment 13, the fourth straight line segment 14, and the fifth straight line segment 15 from the top to the bottom of the shell. The angle γ1 between the first straight line segment 11 and the axis of the shell is 50° to 80°, the angle γ2 between the second straight line segment 12 and the axis of the shell is 100° to 130°, the angle γ3 between the fourth straight line segment 14 and the axis of the shell is 18° to 30°, and the arc radius of the third curved line segment 13 of the shell is 10 to 20 mm. The outer diameter of the shell 1 is 50 to 56 mm. This structure of the shell 1 and the liner 3 makes the liner wall thickness change from nonlinear to linear along the axial direction, so that the thickness of the explosive along the normal line of the liner generatrix is ​​different, which effectively improves the energy utilization rate of the explosive. At the same time, the top of the perforating bullet shell has sufficient thickness, and the thickness of each part of the top is basically consistent, which can reduce the interference between bullets and weaken the destructive effect of sparse waves, thereby improving the penetration depth of the perforating bullet.

[0018] Embodiment 1:

[0019] Perforating bullet size: outer diameter 52mm, height 60mm;

[0020] The outer diameter of the liner is 44mm and the height is 50mm;

[0021] The angle β of the outer generatrix of the liner is 58°; the radius of the first arc of the inner generatrix is ​​2.4 mm, and the angles α1, α2, and α3 between the second to fourth straight line segments and the axis are 47°, 44°, and 42°, respectively.

[0022] Along the axial direction, from the top to the bottom of the perforating bullet shell, the angles γ1, γ2, and γ3 between the straight line and the shell axis are 34°, 54°, and 12° respectively. The arc radius is 12mm, and the inner diameter of the large opening at the lower end of the shell is 50mm.

[0023] The main charge of the perforating bullet is RDX, with a charge weight of 42g.

[0024] Repeated perforation tests were carried out on standard Berea sandstone targets in a same-hole repeated perforation test device (rated confining pressure 20MPa, rated pore pressure 10MPa, rated well pressure 10MPa, control accuracy 5%). The single penetration result was 386mm, and the same-hole repeated perforation result was 600mm. The same-hole repeated perforation penetration depth was increased by 63.0%.

[0025] Embodiment 2:

[0026] The size of the perforating bullet is 52mm in outer diameter and 60mm in height.

[0027] The outer diameter of the medicine cover is 45mm and the height is 50mm.

[0028] The angle β of the outer mother line of the liner is 56°; the radius of the first arc of the inner mother line is 2.8 mm, and the angles α1, α2, and α3 between the second to fourth straight line segments and the axis are 48°, 46°, and 44°, respectively.

[0029] Along the axial direction, from the top to the bottom of the perforating bullet shell, the angles γ1, γ2, and γ3 between the straight line and the shell axis are 32°, 58°, and 14° respectively. The arc radius is 10mm, and the inner diameter of the shell wide mouth is 52mm.

[0030] The main charge of the perforating bullet is RDX, with a charge weight of 42g.

[0031] Repeated perforation tests were carried out on standard Berea sandstone targets in a same-hole repeated perforation test device (rated confining pressure 20MPa, rated pore pressure 10MPa, rated well pressure 10MPa, control accuracy 5%). The single penetration result was 354mm, and the same-hole repeated perforation result was 575mm. The same-hole repeated perforation penetration depth was increased by 62.4%.

Claims

1. A same-hole repeated perforating bullet, comprising a shell (1), a charge liner (3) is arranged inside the shell (1), and a charge (2) is arranged in a cavity between the shell (1) and the charge liner (3), characterized in that: The medicine-type cover (3) comprises an outer busbar (31) and an inner busbar (32), wherein the outer busbar (31) is a straight line, and the inner busbar (32) is divided into four sections, wherein the top of the cover is a first curved section (321), and downward along the top of the cover are a second straight section (322), a third straight section (323), and a fourth straight section (324).

2. The same-hole repeated perforating bullet according to claim 1, characterized in that: The included angle β between the outer generatrix (31) of the medicine liner (3) and the axis is 42° to 54°.

3. The same-hole repeated perforating bullet according to claim 2, characterized in that: The angle α1 between the second straight segment (322) of the inner busbar (32) of the medicine liner and the axis is 42° to 50°, the angle α2 between the third straight segment (323) and the axis is 38° to 46°, and the angle α3 between the fourth straight segment (324) and the axis is 36° to 46°.

4. The same-hole repeated perforating bullet according to claim 3, characterized in that: The radius of the first curved section (32) of the inner busbar (32) of the medicine liner is 2.2-3 mm.

5. The same-hole repeated perforating bullet according to claim 1, characterized in that: The busbar inside the shell (1) is, from the top of the shell to the bottom of the shell, a first straight line segment (11) of the shell, a second straight line segment (12) of the shell, a third curved line segment (13) of the shell, a fourth straight line segment (14) of the shell, and a fifth straight line segment (15) of the shell.

6. The same-hole repeated perforating bullet according to claim 1, characterized in that: The included angle γ1 between the first straight line segment (11) of the shell and the axis is 50° to 80°, the included angle γ2 between the second straight line segment (12) of the shell and the axis is 100° to 130°, and the included angle γ3 between the fourth straight line segment (14) of the shell and the axis is 18° to 30°.

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