Self-liquid-filling ball-throwing pressure conversion device for perforation and perforation pipe string

Abstract

The utility model relates to a pressure conversion device, in particular to a self-liquid-filling ball-throwing pressure conversion device for perforation and a perforation pipe string, and solves the technical problem that the purchase cost is high due to high processing difficulty and high processing precision requirement of the conventional pressure tapping detonating device. According to the self-liquid-filling ball-throwing pressure conversion device for perforation, a channel communicating the inside and the outside of the shell is established through the conical hole and the communicating hole, when the self-liquid-filling ball-throwing pressure conversion device is put into a well, the channel guarantees communication with an annulus in the well, when the self-liquid-filling ball-throwing pressure conversion device is pressed and detonated, the annulus in the well can be isolated through cooperation of the plugging ball and the conical hole, and the safety of the device is improved. Pressure is transmitted to the pressure electronic control unit or the pressure exploder through the pressure transmitting hole to complete detonation, the plugging ball is dissolved in the pulling-out process, a channel established by the conical hole and the communicating hole communicates the interior and the exterior of the shell again, and the whole device is simple in structure and convenient to machine.

Description

Technical Field

[0001] The utility model relates to a pressure conversion device, in particular to a self-priming liquid ball-throwing pressure conversion device for perforation and a perforation string. Background Technique

[0002] During the oil and gas exploitation process, the pressure initiation device used is applicable not only to vertical wells but also to pressurized initiation under various well conditions such as heavy oil wells, highly deviated wells, and horizontal wells. By applying pressure at the wellhead to act on the pressure initiation device, its piston moves rapidly after shearing the shear pin or breaking through the pressure limit under the combined action of the pressure applied at the wellhead and the well fluid pressure, strikes the initiator to generate detonation, and then detonates the perforating gun string connected to the pressure initiation device.

[0003] During the process of the existing pressure initiation device being lowered into the well, since the entire pipe string is closed and its interior is not connected to the well annulus, in the event of a blowout, it is impossible to carry out circulating kill well to stop the blowout, presenting certain safety hazards. During the process of lowering into the well, it is necessary to manually inject perforating fluid into the pipe string, which is time-consuming and laborious. Secondly, when the pipe string is retrieved from the well, the perforating fluid in the pipe string will gush out from the pipe string and spill onto the wellhead ground, causing pollution. To solve the above problems, the prior art provides a pressure opening and initiation device with through holes provided on its outer shell for connecting the inside and outside of the pipe string. When this device is pressurized for initiation, the through holes are blocked by its own piston to ensure that the pressure will not leak out to the well annulus; after the pressurized initiation is completed, the piston shears the shear pin and moves downward, and the through holes on the outer shell connect the inside and outside of the pipe string. During the operation of retrieving the pipe string, the perforating fluid flows from the inside of the pipe string into the wellbore through the through holes of the outer shell and will not gush out to the wellhead ground. However, compared with the traditional pressure initiation device, this pressure opening and initiation device has a large processing difficulty and high processing precision requirements, resulting in a high procurement cost. How to transform the pressure initiation device at a low cost so that it can be connected to the well annulus during the process of being lowered into the well, be isolated from the well annulus during the pressurized initiation, and be connected to the well annulus again during the retrieval has become a major problem encountered by oilfield operation units. Summary of the Utility Model

[0004] The purpose of the utility model is to solve the problem that the existing pressure opening and initiation device has a large processing difficulty and high processing precision requirements, resulting in a high procurement cost. The design idea is to transform the pressure initiation device at a low cost so that it can be connected to the well annulus during the process of being lowered into the well, be isolated from the well annulus during the pressurized initiation, and be connected to the well annulus again during the retrieval, and to provide a self-priming liquid ball-throwing pressure conversion device for perforation and a perforation string.

[0005] To achieve the above purpose, the utility model provides the following technical solutions:

[0006] A self-priming ball-throwing pressure conversion device for perforation, characterized in that it includes a housing and a plugging ball;

[0007] The top end of the housing is used to connect with the oil pipe, and the bottom end is used to connect with a pressure initiator or a pressure electronic control unit;

[0008] A plugging seat is arranged inside the housing. A conical hole is opened at the center of the top of the plugging seat, and the large hole of the conical hole faces the top end of the housing; a communication hole is opened on the outer wall of the housing, and the conical hole is communicated with the outside of the housing through the communication hole;

[0009] A pressure transmission hole for communicating the upper and lower ends of the housing is axially penetrated through the plugging seat;

[0010] The plugging ball is used to cooperate with the conical hole to plug the conical hole, and the plugging ball is made of a material soluble in chloride ions.

[0011] Furthermore, the housing includes a large-diameter section arranged near the top end and a small-diameter section arranged near the bottom end; an external thread is arranged on the small-diameter section, which is used for threaded connection with a pressure initiator;

[0012] The plugging seat is arranged inside the large-diameter section and is located at the bottom of the large-diameter section. An internal thread is arranged on the inner wall of the large-diameter section above the plugging seat, which is used for threaded connection with the oil pipe.

[0013] Furthermore, a blind hole is axially opened at the bottom of the conical hole, and the communication hole is radially opened along the outer wall of the housing and is communicated with the blind hole;

[0014] There are multiple pressure transmission holes arranged around the blind hole, and the top openings of the pressure transmission holes are located on the conical surface of the conical hole.

[0015] Furthermore, the material soluble in chloride ions for making the plugging ball is an aluminum-magnesium alloy material.

[0016] Meanwhile, the present invention also provides a perforation string, which includes a deeper short joint, an oil pipe and a perforating gun, characterized in that it further includes the above-mentioned self-priming ball-throwing pressure conversion device for perforation, a battery pack, an electronic delay initiation device, an electronic selected initiation device, a setting tool, a bridge plug and a pressure electronic control unit;

[0017] The deeper short joint, the oil pipe, the self-priming ball-throwing pressure conversion device for perforation, and the pressure electronic control unit are connected in sequence from top to bottom;

[0018] The battery pack is connected to the tail end of the pressure electronic control unit. There are multiple perforating guns, and the electronic delay initiation device is connected between adjacent perforating guns. The perforating gun at the top is connected to the tail end of the battery pack, and the tail end of the perforating gun at the bottom is connected to the electronic selective initiation device. The top end of the setting tool is connected to the tail end of the electronic selective initiation device, and the tail end is connected to the bridge plug.

[0019] Among them, the pressure electronic control unit is electrically connected to the battery pack, the battery pack is electrically connected to the electronic selective initiation device, and the electronic selective initiation device is electrically connected to the setting tool and each electronic delay initiation device.

[0020] Meanwhile, the present utility model also provides another perforating string, which includes a deeper short joint, a tubing, a perforating gun, and a pressure initiator. The special feature lies in that: it further includes the above-mentioned self-priming liquid ball-throwing pressure conversion device for perforating.

[0021] The deeper short joint, the tubing, the self-priming liquid ball-throwing pressure conversion device for perforating, the pressure initiator, and the perforating gun are connected in sequence from top to bottom.

[0022] The pressure initiator includes a housing, a piston, a firing pin, a shear assembly, and an initiator.

[0023] The housing includes an axially penetrating first joint and a second joint. The right end of the first joint is sealingly arranged inside the left end of the second joint, and the initiator is coaxially arranged inside the second joint; the piston is sealingly arranged inside the first joint and the second joint.

[0024] The shear assembly is arranged between the outside of the piston and the inside of the first joint and the second joint for fixing the position of the piston, and the shear assembly can be fractured under force.

[0025] The firing pin is detachably installed at one end of the piston close to the initiator.

[0026] Further, the shear assembly includes a shear sleeve and shear pins.

[0027] A first joint step surface is arranged inside the first joint, and a second joint step surface is arranged inside the second joint. The large-diameter section of the first joint step surface faces the second joint, and the large-diameter section of the second joint step surface faces the first joint. Moreover, the large-diameter sections of the first joint step surface and the second joint step surface together form an installation cavity.

[0028] The piston is located inside the installation cavity, the shear sleeve is located between the inner wall of the installation cavity and the outer wall of the piston, and the piston and the shear sleeve are connected by a plurality of shear pins.

[0029] The outer diameter of the piston is less than or equal to the inner diameter of the corresponding small-diameter section of the second joint step surface.

[0030] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0031] (1) The self-priming liquid and ball throwing pressure conversion device for perforation provided by the present utility model establishes a passage connecting the inside and outside of the communication housing through the tapered hole and the communication hole. When lowering into the well, this passage ensures communication with the annulus in the well. When pressurizing for detonation, through the cooperation of the plugging ball and the tapered hole, the annulus in the well can be isolated. In this way, during the process of lowering and retrieving, there will be no situation of perforating fluid gushing out, realizing environmentally friendly and green operation. Moreover, the entire device has a simple structure, is convenient to process, and has a low cost.

[0032] (2) When the perforating string provided by the present utility model is lowered into the well, the passage formed by the tapered hole, the blind hole, and the communication hole of the self-priming liquid and ball throwing pressure conversion device for perforation connects the inside and outside of the perforating string, ensuring communication with the annulus in the well. When pressurizing for detonation, through the cooperation of the plugging ball and the tapered hole, the annulus in the well is isolated, and the pressure is transmitted to the pressure initiator through the pressure transmission hole. The shear assembly of the pressure initiator is stressed and fractured, and the piston moves downward to make the firing pin strike the initiator to complete the detonation of the perforating gun. When retrieving, magnesium chloride or potassium chloride is put into the well, the plugging ball dissolves, and the passage connects the inside and outside of the housing again, and there will be no blowout or well kick during retrieval.

[0033] (3) When the perforating string provided by the present utility model is lowered into the well, the passage formed by the tapered hole, the blind hole, and the communication hole of the self-priming liquid and ball throwing pressure conversion device for perforation connects the inside and outside of the perforating string, ensuring communication with the annulus in the well. When pressurizing for detonation, through the cooperation of the plugging ball and the tapered hole, the annulus in the well is isolated. Through the cooperation of multiple perforating guns and the electronic delay detonation device, within the delay time after the electronic delay detonation device is activated, the corresponding perforating gun can be moved to the formation at the corresponding depth. Because there are multiple electronic delay detonation devices and multiple perforating guns, perforation of different depth formations can be carried out at different times. In this way, multi-stage perforation operation can be completed. Compared with the traditional operation mode where only one perforation can be carried out in one trip into the well, the flexibility of the perforation operation is greatly improved. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of an embodiment of the self-priming liquid and ball throwing pressure conversion device for perforation of the present utility model;

[0035] Figure 2 It is a schematic structural diagram of the first embodiment of the perforating string of the present utility model;

[0036] Figure 3 It is a schematic structural diagram of the second embodiment of the perforating string of the present utility model;

[0037] Figure 4 It is a schematic structural diagram of the pressure initiator in the second embodiment of the perforating string of the present utility model.

[0038] The description of the reference numerals is as follows:

[0039] 01 - Self - filling liquid ball - throwing pressure conversion device for perforation, 1 - Housing, 1001 - Large - diameter section, 1002 - Small - diameter section; 2 - Plugging seat, 3 - Blind hole, 4 - Communication hole, 5 - Pressure - transmitting hole, 6 - Plugging ball, 7 - Tapered hole, 8 - Longer short joint, 9 - Oil pipe, 10 - Pressure initiator, 101 - First joint, 102 - Piston, 103 - Second joint, 104 - Firing pin, 105 - Initiator, 106 - Shearing sleeve, 1061 - Shearing pin; 11 - Perforating gun, 12 - Battery pack, 13 - Electronic delay initiation device, 14 - Electronic selective initiation device, 15 - Setting tool, 16 - Packer, 17 - Pressure electronic control unit. Detailed implementation manners

[0040] The present utility model will be further described below in conjunction with the accompanying drawings and exemplary embodiments.

[0041] Referring to Figure 1 , the self - filling liquid ball - throwing pressure conversion device for perforation of the present utility model includes a housing 1 and a plugging ball 6. The plugging ball 6 is made of an aluminum - magnesium alloy material soluble in chloride ions. The housing 1 includes a large - diameter section 1001 disposed near the top end and a small - diameter section 1002 disposed near the bottom end. An external thread is provided on the small - diameter section 1002 for threaded connection with the pressure initiator 10 or the pressure electronic control unit 17. An internal thread for threaded connection with the oil pipe 9 is provided on the inner wall of the large - diameter section 1001 above the plugging seat 2.

[0042] A tapered hole 7 for cooperating with the plugging ball 6 is opened at the center of the top of the plugging seat 2. The plugging ball 6 is used to cooperate with the tapered hole 7 to plug the tapered hole 7. The large hole of the tapered hole 7 faces the top end of the housing 1. A blind hole 3 is axially opened at the bottom of the tapered hole 7, and a communication hole 4 communicating with the blind hole 3 is radially opened on the outer wall of the housing 1. The tapered hole 7 is communicated with the wellbore annulus outside the housing 1 through the communication hole 4. A pressure - transmitting hole 5 for communicating the upper and lower ends of the housing 1 is axially penetrated on the plugging seat 2. In order to ensure the pressure - transmitting effect, a plurality of pressure - transmitting holes 5 are provided and are all arranged around the blind hole 3, and the top opening of the pressure - transmitting hole 5 is located on the conical surface of the tapered hole 7.

[0043] Example 1 of the perforating string:

[0044] As Figure 2 shown, the perforating string includes a longer short joint 8, an oil pipe 9, a self - filling liquid ball - throwing pressure conversion device 01 for perforation, a pressure electronic control unit 17, a battery pack 12, a perforating gun 11, an electronic delay initiation device 13, an electronic selective initiation device 14, a setting tool 15, and a packer 16.

[0045] Among them, the deeper short joint 8, the tubing 9, the self-priming liquid ball throwing pressure conversion device 01 for perforation and the pressure electronic control unit 17 are connected in sequence from top to bottom. The battery pack 12 is connected to the tail end of the pressure electronic control unit 17, and the battery pack 12 is electrically connected to the pressure electronic control unit 17. In this embodiment, there are three perforating guns 11 and two electronic delay initiation devices 13. The perforating gun 11 at the top is connected to the tail end of the battery pack 12. The tail end of the perforating gun 11 at the bottom is connected to the electronic selective initiation device. The electronic delay initiation device 13 is connected between adjacent perforating guns 11. The top end of the setting tool 15 is connected to the tail end of the electronic selective initiation device 14, and the tail end is connected to the bridge plug 16. The battery pack 12 is electrically connected to the electronic selective initiation device 14, and the electronic selective initiation device 14 is electrically connected to the setting tool 15 and each electronic delay initiation device 13.

[0046] The pressure electronic control unit 17 can adopt a pressure sensor. When pressure is applied for initiation, since the plugging ball 6 seals the connection with the well annulus, the pressure can only be transmitted from the pressure transfer hole 5 to the pressure electronic control unit 17. When the starting pressure is reached, the pressure electronic control unit 17 sends an electrical signal to the battery pack 12 to activate the battery pack 12. After the battery pack 12 is activated, it supplies power to the electronic selective initiation device 14 to start the electronic selective initiation device 14. The electronic selective initiation device 14 is used to control the start of the setting tool 15 and the electronic delay initiation device 13. In this embodiment, the setting tool 15 adopts a gunpowder setting tool. When the battery pack 12 supplies power to the setting tool 15, the setting gunpowder in the setting tool 15 will be activated, and then the bridge plug 16 is set in the well by the acting force generated by the setting gunpowder, and the well plugging can be completed. Due to the plugging effect of the bridge plug 16, the oil and gas seeping out from the formation after perforation will not flow to the well bottom.

[0047] The usage method of the perforating string in this embodiment is as follows:

[0048] S1 Lower the perforating string into the well;

[0049] S2 When the deeper short joint 8 detects that it has reached the designated formation, throw the plugging ball 6 from the wellhead. The plugging ball 6 falls into the conical hole 7 of the self-priming liquid ball throwing pressure conversion device 01 for perforation, and pressure is applied from the wellhead. The pressure is transmitted from the pressure transfer hole 5 to the pressure electronic control unit 17;

[0050] S3 After the pressure electronic control unit 17 reaches the starting pressure, it activates the battery pack 12. The battery pack 12 supplies power to the electronic selective initiation device 14, and the electronic selective initiation device 14 starts;

[0051] The S4 electronic selection initiation detonator 14 activates the setting gunpowder in the setting tool 15 to start the setting tool 15. The setting tool 15 sets the bridge plug 16 in the well. After the setting is completed, the bridge plug 16 is disengaged from the setting tool 15;

[0052] The S5 electronic selection initiation detonator 14 activates multiple electronic delay detonators 13 respectively;

[0053] The activated electronic delay detonator 13 fires the perforating gun 11 connected thereto after delaying to a predetermined time. During the delay period, the corresponding perforating gun 11 is moved to the designated depth formation to complete the perforation of the corresponding depth formation;

[0054] Repeat step S6 until the perforation of all corresponding depth formations is completed;

[0055] Magnesium chloride or calcium chloride is put into the wellhead. The plugging ball 6 dissolves by itself, and then the perforating string is recovered from the wellhead.

[0056] In this usage method, through the cooperation of multiple electronic delay detonators 13 and multiple perforating guns 11, since the delay time of the electronic delay detonator 13 can be freely set, the perforation operation of different depth formations can be realized at different times, so that the multi-stage perforation operation can be completed. Compared with the traditional operation form that can only perform one perforation in one trip downhole, the flexibility of the perforation operation is greatly improved.

[0057] After the entire perforating string is lowered into the well, when the S4 electronic selection initiation detonator 14 has activated all the electronic delay detonators 13 respectively, if there is a problem in the well and it is not suitable to continue the perforation operation, at this time, because all the perforating guns 11 are in a state of waiting to be fired and the entire perforating string cannot be lifted out, there will be certain problems. Therefore, another usage method is provided:

[0058] Lower the perforating string into the well;

[0059] When the deeper sub-section 8 detects that it has reached the designated formation, the plugging ball 6 is put into the wellhead. The plugging ball 6 falls into the conical hole 7 of the self-priming liquid ball throwing pressure conversion device 01 for perforation, and pressure is applied from the wellhead. The pressure is transmitted from the pressure transmission hole 5 to the pressure electronic control unit 17;

[0060] After the pressure electronic control unit 17 reaches the starting pressure, it activates the battery pack 12. The battery pack 12 continuously supplies power to the corresponding S4 electronic selection initiation detonator 14 within a preset time period, and the S4 electronic selection initiation detonator 14 starts;

[0061] The S4 electronic selective initiation detonator 14 activates the setting gunpowder in the setting tool 15 to start the setting tool 15. The setting tool 15 sets the bridge plug 16 in the well. After the setting is completed, the bridge plug 16 is disengaged from the setting tool 15, and then the battery pack 12 is in the standby state;

[0062] S5 Move the perforating string until one of the perforating guns 11 moves to the corresponding depth formation. Apply pressure from the wellhead. After the pressure electronic control unit 17 reaches the starting pressure, it activates the battery pack 12. The battery pack 12 continuously supplies power to the electronic selective initiation detonator 14 within a preset time period. The electronic selective initiation detonator 14 starts the electronic delay detonator 13 connected to the perforating gun 11. After delaying to a predetermined time, it detonates the perforating gun 11 to complete the perforation of the corresponding depth formation. Then the battery pack 12 is in the standby state again;

[0063] S6 Repeat step S5 until all perforations of the corresponding depth formations are completed;

[0064] S7 Pour magnesium chloride or calcium chloride from the wellhead. The plugging ball 6 dissolves by itself, and then the perforating string is recovered from the wellhead.

[0065] After adopting this method, only one corresponding perforating gun 11 is detonated by one pressure application. If there is a problem in the well during perforation, the perforating string can be recovered in time.

[0066] Perforating string embodiment two:

[0067] As Figure 3 shown, the perforating string includes a deeper short joint 8, a tubing 9, a self-priming liquid ball-drop pressure conversion device 01 for perforation, a pressure initiator 10, and a perforating gun 11, which are connected in sequence from top to bottom. The deeper short joint 8 is used to measure the lowering depth of the entire perforating string.

[0068] The structure of the pressure initiator 10 is as Figure 4 shown. It includes a housing, a piston 102, a firing pin 104, a shear assembly, and an initiator 105.

[0069] The housing includes an axially penetrating first joint 101 and a second joint 103. The right end of the first joint 101 is threadedly connected and sealed inside the left end of the second joint 103. And a sealing ring is provided at the sealed connection between the two to ensure the sealing effect. The initiator 105 is coaxially arranged inside the second joint 103. The piston 102 is sealed inside the first joint 101 and the second joint 103. A firing pin 104 is detachably installed at one end of the piston 102 close to the initiator 105.

[0070] The shear assembly is arranged between the outside of the piston 102 and the inside of the first joint 101 and the second joint 103 for fixing the position of the piston 102. In this embodiment, the shear assembly includes a shear sleeve 106 and shear pins 1061. In order to fix the position of the piston 102 through the shear assembly, a first joint step surface is provided inside the first joint 101, and a second joint step surface is provided inside the second joint 103. Moreover, the large-diameter section of the first joint step surface faces the second joint 103, while the large-diameter section of the second joint step surface faces the first joint 101. In this way, the two large-diameter sections are arranged oppositely, and the large-diameter section of the first joint step surface and the large-diameter section of the second joint step surface together form an installation cavity.

[0071] The piston 102 is located in the installation cavity. The shear sleeve 106 is sleeved on the outer wall of the piston 102 and is located between the inner wall of the installation cavity and the outer wall of the piston 102. The piston 102 and the shear sleeve 106 are connected by a plurality of shear pins 1061. The shear pins 1062 can be broken under force. The outer diameter of the piston 102 is less than or equal to the inner diameter of the corresponding small-diameter section of the second joint step surface. In this way, after the shear pins 1061 are cut off under force, the piston 102 can move towards the detonator 105 direction and will not be affected by the second joint step surface, and then the firing pin 104 can smoothly impact the detonator 105.

[0072] When the entire perforating string is lowered into the well, the passage formed by the conical hole 7, the blind hole 3 and the communication hole 4 of the self-priming liquid ball throwing pressure conversion device 01 for perforating connects the inside and outside of the device, ensuring communication with the wellbore annulus. When pressure is applied for detonation, the conical hole 7 is blocked by the plugging ball 6 to isolate the wellbore annulus. The pressure is transmitted from the pressure transmission hole 5 to the piston 102, and the piston 102 transmits the pressure to the shear pins 1061. The shear pins 1061 are cut off under force, so that the piston 102 breaks away from the shear sleeve 106 and moves towards the detonator 105 direction, and the firing pin 104 impacts the detonator 105 to detonate the perforating gun 11. When retrieving, by injecting magnesium chloride or potassium chloride into the well, the plugging ball 6 dissolves automatically when encountering chloride ions, so that the passage formed by the conical hole 7, the blind hole 3 and the communication hole 4 reconnects the inside and outside of the device, preventing blowout or well kick.

[0073] The usage method of the perforating string in this embodiment is as follows:

[0074] S1 Lower the perforating string into the well;

[0075] S2 When the deeper sub 8 detects that it has reached the designated formation, the plugging ball 6 is dropped from the wellhead. The plugging ball 6 falls into the conical hole 7 of the self-priming liquid ball throwing pressure conversion device 01 for perforating;

[0076] S3 Apply pressure from the wellhead. The pressure is transmitted from the pressure transmission hole 5 to the piston 102, and the piston 102 transmits the pressure to the shear assembly;

[0077] The S4 shearing component is fractured under force, and then the piston 102 drives the firing pin 104 to impact the initiator 105, triggering the perforating gun 11 to complete the perforation of the formation at the specified depth;

[0078] After the perforation of the formation at this depth is completed, magnesium chloride or calcium chloride is put into the well, the plugging ball 6 dissolves by itself, and then the perforating string is recovered from the wellhead.

[0079] The embodiments described above are only descriptions of the specific implementation manners of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A self-priming liquid ball-drop pressure conversion device for perforation, characterized in that: It includes a housing (1) and a plugging ball (6); The top end of the housing (1) is used to connect with an oil pipe (9), and the bottom end is used to connect with a pressure initiator (10) or a pressure electronic control unit (17); A plugging seat (2) is arranged inside the housing (1). A conical hole (7) is opened at the center of the top of the plugging seat (2), and the large hole of the conical hole (7) faces the top end of the housing (1); A communication hole (4) is opened on the outer wall of the housing (1), and the conical hole (7) is communicated with the outside of the housing (1) through the communication hole (4); A pressure transmission hole (5) for communicating the upper and lower ends of the housing (1) is axially penetrated on the plugging seat (2); The plugging ball (6) is used to cooperate with the conical hole (7) to plug the conical hole (7), and the plugging ball (6) is made of a material soluble in chloride ions.

2. The self-priming liquid ball-drop pressure conversion device for perforation according to claim 1, wherein: The housing (1) includes a large-diameter section (1001) arranged near the top end and a small-diameter section (1002) arranged near the bottom end; An external thread is arranged on the small-diameter section (1002), which is used for threaded connection with the pressure initiator (10); The plugging seat (2) is arranged inside the large-diameter section (1001) and is located at the bottom of the large-diameter section (1001). An internal thread is arranged on the inner wall of the large-diameter section (1001) above the plugging seat (2), which is used for threaded connection with the oil pipe (9).

3. The self-priming ball-throwing pressure conversion device for perforation according to claim 1 or 2, characterized in that: A blind hole (3) is axially opened at the bottom of the conical hole (7), and the communication hole (4) is radially opened along the outer wall of the housing (1) and is communicated with the blind hole (3); There are multiple pressure transmission holes (5) arranged around the blind hole (3), and the top openings of the pressure transmission holes (5) are located on the conical surface of the conical hole (7).

4. The self-priming liquid ball-throwing pressure conversion device for perforation according to claim 1, characterized in that: The material soluble in chloride ions for making the plugging ball (6) is an aluminum-magnesium alloy material.

5. A perforating string, comprising a deeper short joint (8), a tubing (9) and a perforating gun (11), characterized in that: It also includes a self-priming ball pressure conversion device (01) for perforating, a battery pack (12), an electronic delay initiation device (13), an electronic selective initiation device (14), a setting tool (15), a bridge plug (16) and a pressure electronic control unit (17) as described in any one of claims 1-4; The deeper short joint (8), the oil pipe (9), the self-priming ball pressure conversion device (01) for perforating, and the pressure electronic control unit (17) are connected in sequence from top to bottom; The battery pack (12) is connected to the tail end of the pressure electronic control unit (17). There are multiple perforating guns (11), and the electronic delay initiation device (13) is connected between adjacent perforating guns (11). The perforating gun (11) at the top is connected to the tail end of the battery pack (12). The tail end of the perforating gun (11) at the bottom is connected to the electronic selective initiation device (14). The top end of the setting tool (15) is connected to the tail end of the electronic selective initiation device (14), and the tail end is connected to the bridge plug (16); Among them, the pressure electronic control unit (17) is electrically connected to the battery pack (12), the battery pack (12) is electrically connected to the electronic selective initiation device (14), and the electronic selective initiation device (14) is electrically connected to the setting tool (15) and each electronic delay initiation device (13).

6. A perforating string, comprising a deeper short joint (8), a tubing (9), a perforating gun (11), and a pressure initiator (10), characterized in that: It also includes a self-priming ball pressure conversion device (01) for perforating as described in any one of claims 1-4; The deeper short joint (8), the oil pipe (9), the self-filling liquid ball pressure conversion device for perforating (01), the pressure detonator (10) and the perforating gun (11) are connected in sequence from top to bottom; The pressure detonator (10) comprises a housing, a piston (102), a firing pin (104), a shearing assembly and a detonator (105); The housing comprises a first joint (101) and a second joint (103) which are axially connected, the right end of the first joint (101) is sealedly arranged inside the left end of the second joint (103), and the detonator (105) is coaxially arranged inside the second joint (103); the piston (102) is sealedly arranged inside the first joint (101) and the second joint (103); The shearing assembly is arranged between the outside of the piston (102) and the inside of the first joint (101) and the second joint (103), and is used to fix the position of the piston (102). The shearing assembly can be broken when subjected to force. The firing pin (104) is detachably mounted on one end of the piston (102) close to the detonator (105).

7. The perforating string according to claim 6, characterized in that: The shear assembly comprises a shear sleeve (106) and a shear pin (1061); A first joint step surface is provided inside the first joint (101), a second joint step surface is provided inside the second joint (103), the large diameter section of the first joint step surface faces the second joint (103), the large diameter section of the second joint step surface faces the first joint (101), and the large diameter section of the first joint step surface and the large diameter section of the second joint step surface together form a mounting cavity; The piston (102) is located in the installation cavity, the shear sleeve (106) is located between the inner wall of the installation cavity and the outer wall of the piston (102), and the piston (102) and the shear sleeve (106) are connected via a plurality of shear pins (1061); The outer diameter of the piston (102) is smaller than or equal to the inner diameter of the small diameter section corresponding to the step surface of the second joint.

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