Pressure relief device and oil well blind pipe section using same

Abstract

The utility model relates to the field of oil well development, in particular to a pressure relief device and an oil well blind pipe section using the same. The pressure relief device comprises an oil pipe connector, a pressure relief base and a pressure relief jackscrew, the oil pipe connector is provided with a pressure equalizing cavity communicated with the blind pipe section of the oil well, the pressure relief base is arranged on the radial circumferential surface of the oil pipe connector, and a first-stage pressure relief hole is formed in the side wall, at the mounting position of the pressure relief base, of the oil pipe connector; second-stage pressure relief holes are formed in the circumferential face of the pressure relief base, the pressure relief jackscrew is assembled in the pressure relief base, and the pressure equalizing cavity, the first-stage pressure relief holes and the second-stage pressure relief holes are communicated. The cavity is formed in the oil pipe connector, so that the pressure entering the pressure relief device from the blind pipe section of the oil well can be buffered and equalized and then is released to the outside through the pressure relief base, the pressure relief jackscrew can be prevented from being rushed out under the direct action of the pressure in the blind pipe section during pressure relief operation, safety accidents are prevented, and the service life of the pressure relief device is prolonged. And the safety of pressure relief operation is ensured.

Description

Technical Field

[0001] The utility model relates to the field of oilfield exploitation, in particular to a pressure relief device and an oil well blind pipe section using the device. Background Art

[0002] During the process of oilfield development, there are a large number of process transformation operations and pipeline network maintenance operations. Inevitably, there are some blind pipe sections in the pipeline network during the operation. The pressure in these blind pipe sections cannot be released, so that workers can only operate under pressure when operating on these blind pipe sections. Generally, the clamp at the distal connection of the blind pipe section is loosened under pressure to release the pressure, or the plug is removed under pressure to release the pressure of the blind pipe section. Although both of these pressure relief methods can achieve the pressure relief of the blind pipe section, since the pressure in the blind pipe section is greater than the external pressure, when the clamp is loosened or the plug is removed under pressure, the clamp or the plug will fly out quickly under the action of the pressure in the blind pipe section, posing a great potential safety hazard.

[0003] In order to solve the potential safety hazard existing in the operation under pressure, the Chinese utility model patent with the authorization announcement number CN201778729U discloses an anti-freezing plug as shown in Figure 1 Figure 1, which includes a plug 2. The plug 2 is provided with a central hole 5. A pressure relief small gate 1 is installed on the upper end face of the plug 2. A filling plug body 3 is fixed on the lower end face of the plug 2. A pressure relief channel 4 is provided in the axial direction of the filling plug body 3. The pressure relief channel 4 is communicated with the central hole 5 and the pressure relief small gate 1. When installing the plug 2, the pressure relief small gate 1 is opened to release the pressure, then the filling plug body 3 is inserted into the gate. After connecting the plug 2 with the gate, the pressure relief small gate 1 is closed, and the installation construction is completed. When disassembling the plug, the pressure relief small gate 1 is opened to release the pressure, and then the disassembly construction can be carried out. However, the axis direction of the pressure relief small gate 1 and the plug 2 in the above technical solution is parallel. During the pressure relief operation, the pressure between the gate and the plug will act on the pressure relief small gate 1 through the pressure relief channel 4 and the central hole 5. At this time, the operating components in the pressure relief small gate 1 are very likely to be directly affected by the pressure and be flushed out, also posing a potential safety hazard. Content of the Utility Model

[0004] The purpose of the utility model is to provide a pressure relief device to solve the problem of low safety caused by the need for operation under pressure of the existing blind pipe; at the same time, the purpose of the utility model is also to provide an oil well blind pipe section using the above pressure relief device to solve the problem of low safety during the maintenance operation of the existing oil well blind pipe section.

[0005] To achieve the above purpose, a pressure relief device of the utility model adopts the following technical solution:

[0006] A pressure relief device includes a tubing connector, a pressure relief base, and a pressure relief set screw. The tubing connector is provided with a pressure equalizing cavity communicating with the blind pipe section of the oil well. The pressure relief base is arranged on the radial outer peripheral surface of the tubing connector. A first-stage pressure relief hole is provided on the side wall of the tubing connector at the installation position of the pressure relief base. A second-stage pressure relief hole is provided on the peripheral surface of the pressure relief base. The pressure relief set screw is assembled in the pressure relief base. The pressure equalizing cavity, the first-stage pressure relief hole, and the second-stage pressure relief hole are communicated with each other.

[0007] The beneficial effects of the above technical solution are as follows: The pressure relief device of the present utility model is an innovative invention. Specifically, in combination with the actual application scenario, during the oilfield development process, when carrying out pipeline network maintenance operations, there are inevitably some blind pipe sections in the pipeline network, and the pressure in these blind pipe sections cannot be relieved. Therefore, operations on these blind pipe sections can only be carried out under pressure. By installing the pressure relief device on the side wall of the blind pipe section of the oil well and arranging a pressure equalizing cavity communicating with the blind pipe section of the oil well inside the tubing connector, when performing pressure relief operations on the blind pipe section of the oil well, the pressure gas in the blind pipe section of the oil well can change the flow direction of the gas after entering the pressure relief device, and the pressure gas can expand in the pressure equalizing cavity to reduce the pressure in advance. The space in the blind pipe section of the oil well is communicated with the outside through the pressure equalizing cavity, the first-stage pressure relief hole, the pressure relief base, and the second-stage pressure relief hole, changing the action path of the pressure gas in the blind pipe section of the oil well and avoiding safety accidents caused by the pressure gas in the blind pipe section of the oil well directly acting on the pressure relief set screw and flushing out the pressure relief set screw, greatly improving the safety of the pressure relief operation.

[0008] Further, the tubing connector includes a large-diameter section and a small-diameter section, and the pressure relief base is arranged at 1 / 3 of the small-diameter section close to one end of the large-diameter section.

[0009] Beneficial effects: The tubing connector is installed on the blind pipe section of the oil well through the end of the large-diameter section far from the small-diameter section. The setting of the large-diameter section can improve the connection stability at the joint and avoid the problem that the tubing connector is flushed out by the pressure gas during the normal operation of the blind pipe section of the oil well due to insufficient connection strength, improving the connection stability of the pressure relief device; at the same time, the setting of the small-diameter section reduces the material consumption during the production stage of the pressure relief device and reduces the production cost of the pressure relief device; and, the pressure relief base is arranged at 1 / 3 of the small-diameter section close to one end of the large-diameter section. When in use, the main acting force of the pressure gas in the blind pipe section of the oil well is along the axial direction of the tubing connector when it enters the pressure equalizing cavity. Such a setting can change the acting direction of the pressure gas entering the blind pipe section of the oil well in the pressure equalizing cavity, and the space for the pressure gas to expand increases, thereby further improving the pressure equalizing effect of the pressure equalizing cavity.

[0010] Further, the axial length of the small-diameter section is greater than the axial length of the large-diameter section.

[0011] Beneficial effects: The axial length of the small-diameter section is greater than that of the large-diameter section, which increases the volume of the pressure equalizing cavity while avoiding an increase in the production cost of the tubing connector.

[0012] Further, the pressure relief set screw is divided into an insertion section and an operation section, and the axial length of the insertion section is greater than or equal to the axial length of the pressure relief base.

[0013] Beneficial effects: The axial length of the insertion section is greater than or equal to the axial length of the pressure relief base, which can make the insertion section of the pressure relief set screw completely fill the pressure relief base, improving the sealing effect of the pressure relief set screw on the pressure relief base.

[0014] Further, a conical head for plugging the primary pressure relief hole is provided at one end of the insertion section away from the operation section.

[0015] Beneficial effects: The setting of the conical head enables the pressure relief set screw to more easily plug the primary pressure relief hole. At the same time, the primary pressure relief hole can align the pressure relief set screw through the conical surface of the conical head, avoiding skew when the pressure relief set screw adjusts its position in the pressure relief base.

[0016] Further, the outer peripheral surface of the operation section is a regular polygon.

[0017] Beneficial effects: Setting the outer peripheral surface of the operation section as a regular polygon facilitates the staff to adjust the length of the insertion section extending into the pressure relief base through the operation section, thereby completing the adjustment of the size of the pressure relief channel, that is, enabling the adjustment of the pressure relief speed.

[0018] Further, the pressure relief base is connected to the tubing connector by welding or threading.

[0019] Beneficial effects: When the pressure in the blind pipe section of the oil well is low, the pressure relief base is connected to the tubing connector by threading, which is convenient for disassembling the pressure relief base and the tubing connector and can be reused; when the pressure in the blind pipe section of the oil well is high, the pressure relief base is connected to the tubing connector by welding, which improves the structural strength of the connection between the pressure relief base and the tubing connector and ensures the safety of the pressure relief device during use.

[0020] Further, the secondary pressure relief hole is arranged near the connection position of the pressure relief base and the tubing connector.

[0021] Beneficial effects: The axial length that the pressure relief set screw can adjust in the pressure relief base can be shortened, that is, the fixed length of the pressure relief set screw and the pressure relief base is extended, improving the connection stability between the pressure relief set screw and the pressure relief base.

[0022] Further, the angle between the axis of the secondary pressure relief hole and the horizontal plane is 30 - 45 degrees.

[0023] To achieve the above object, the following technical solution is adopted for the blind pipe section of the oil well of the present utility model:

[0024] The blind pipe section of the oil well includes a blind pipe section. A pressure relief device is arranged on the radial peripheral surface of the blind pipe section. The pressure relief device is connected to the blind pipe section by means of snap connection or welding. The pressure relief device includes a tubing connector, a pressure relief base, and a pressure relief set screw. The tubing connector is provided with a pressure equalizing cavity communicating with the blind pipe section of the oil well. The pressure relief base is arranged on the radial outer peripheral surface of the tubing connector. A primary pressure relief hole is provided on the side wall of the tubing connector at the installation position of the pressure relief base. A secondary pressure relief hole is provided on the peripheral surface of the pressure relief base. The pressure relief set screw is assembled in the pressure relief base. The pressure equalizing cavity, the primary pressure relief hole, and the secondary pressure relief hole are communicated.

[0025] The beneficial effects of the above technical solution are as follows: The blind pipe section of the oil well of the present utility model is improved on the basis of the existing blind pipe section. Specifically, in combination with the actual application scenario, during the oilfield development process, when carrying out pipeline network maintenance operations, there are inevitably some blind pipe sections in the pipeline network, and the pressure in these blind pipe sections cannot be discharged. Therefore, operations on these blind pipe sections can only be carried out under pressure. By installing the pressure relief device on the side wall of the blind pipe section of the oil well and providing a pressure equalizing cavity communicating with the blind pipe section of the oil well in the tubing connector, when carrying out pressure relief operations on the blind pipe section of the oil well, the gas flow direction can be changed after the gas in the blind pipe section of the oil well enters the pressure relief device, and the pressure gas can expand in the pressure equalizing cavity to reduce the pressure in advance. The space in the blind pipe section of the oil well is communicated with the outside through the pressure equalizing cavity, the primary pressure relief hole, the pressure relief base, and the secondary pressure relief hole, changing the action path of the pressure gas in the blind pipe section of the oil well and avoiding safety accidents caused by the direct action of the pressure gas in the blind pipe section of the oil well on the pressure relief set screw and flushing out the pressure relief set screw, greatly improving the safety of the pressure relief operation.

[0026] Further, the tubing connector includes a large diameter section and a small diameter section, and the pressure relief base is arranged at 1 / 3 of the small diameter section close to the large diameter section.

[0027] Beneficial effects: The tubing connector is installed on the blind tubing section of the oil well through one end of the large-diameter section away from the small-diameter section. The setting of the large-diameter section can improve the connection stability at the joint, avoiding the problem that the tubing connector is flushed out by the pressure gas during the normal operation of the blind tubing section of the oil well due to insufficient connection strength, and improving the connection stability of the pressure relief device. At the same time, the setting of the small-diameter section reduces the material consumption of the pressure relief device during the production stage and lowers the production cost of the pressure relief device. Moreover, the pressure relief base is set at 1 / 3 of the end of the small-diameter section close to the large-diameter section. During use, when the pressure gas in the blind tubing section of the oil well enters the pressure equalizing cavity, its main acting force is along the axial direction of the tubing connector. Such a setting can make the pressure gas entering the blind tubing section of the oil well change its acting direction in the pressure equalizing cavity, thereby further improving the pressure equalizing effect of the pressure equalizing cavity.

[0028] Further, the axial length of the small-diameter section is greater than the axial length of the large-diameter section.

[0029] Beneficial effects: The axial length of the small-diameter section is greater than the axial length of the large-diameter section, increasing the volume of the pressure equalizing cavity while avoiding an increase in the production cost of the tubing connector.

[0030] Further, the pressure relief set screw is divided into an insertion section and an operation section, and the axial length of the insertion section is greater than or equal to the axial length of the pressure relief base.

[0031] Beneficial effects: The axial length of the insertion section being greater than or equal to the axial length of the pressure relief base can make the insertion section of the pressure relief set screw completely fill the pressure relief base, improving the sealing effect of the pressure relief set screw on the pressure relief base.

[0032] Further, a conical head for plugging the first-stage pressure relief hole is provided at one end of the insertion section away from the operation section.

[0033] Beneficial effects: The setting of the conical head can make it easier for the pressure relief set screw to plug the first-stage pressure relief hole. At the same time, the first-stage pressure relief hole can align the pressure relief set screw through the conical surface of the conical head, avoiding deflection when the pressure relief set screw adjusts its position in the pressure relief base.

[0034] Further, the outer peripheral surface of the operation section is a regular polygon.

[0035] Beneficial effects: Setting the outer peripheral surface of the operation section as a regular polygon facilitates the staff to adjust the length of the insertion section extending into the pressure relief base through the operation section, thereby completing the adjustment of the size of the pressure relief channel, that is, enabling the adjustment of the pressure relief speed.

[0036] Further, the pressure relief base is connected to the tubing connector by welding or threading.

[0037] Beneficial effects: When the pressure in the blind pipe section of the oil well is relatively low, the thread connection method is selected to connect the pressure relief base and the tubing connector, which facilitates the disassembly of the pressure relief base and the tubing connector and enables repeated use; when the pressure in the blind pipe section of the oil well is relatively high, the welding method is selected to connect the pressure relief base and the tubing connector, which improves the structural strength of the connection between the pressure relief base and the tubing connector and ensures the safety of the pressure relief device during use.

[0038] Further, the secondary pressure relief hole is arranged near the connection position between the pressure relief base and the tubing connector.

[0039] Beneficial effects: The axial length that the pressure relief screw can be adjusted within the pressure relief base can be shortened, that is, the fixed length of the pressure relief screw and the pressure relief base is extended, improving the connection stability between the pressure relief screw and the pressure relief base.

[0040] Further, the included angle between the axis of the secondary pressure relief hole and the horizontal plane is 30 - 45 degrees. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of an anti-freezing plug in the prior art;

[0042] Figure 2 is a schematic structural diagram of a specific embodiment 1 of a pressure relief device of the present invention;

[0043] Figure 3 is a side view of a specific embodiment 1 of a pressure relief device of the present invention;

[0044] Figure 4 is a specific embodiment 1 of a pressure relief device of the present invention Figure 3 is a sectional view taken along A - A in

[0045] Figure 5 is a specific embodiment 1 of a pressure relief device of the present invention Figure 3 is a sectional view taken along B - B in

[0046] Figure 6 is a top view of a specific embodiment 1 of a pressure relief device of the present invention;

[0047] Figure 7 is a schematic structural diagram of a pressure relief screw in a specific embodiment of a pressure relief device of the present invention;

[0048] Figure 8 is a front view of a pressure relief screw in a specific embodiment of a pressure relief device of the present invention;

[0049] Figure 9 is a bottom view of the operation section of a pressure relief screw in a specific embodiment of a pressure relief device of the present invention;

[0050] In the figure: 1 - pressure relief small gate valve, 2 - plug, 3 - filling plug body, 4 - pressure relief channel, 5 - central hole, 6 - clamp groove, 7 - tubing connector, 8 - primary pressure relief hole, 9 - pressure relief base, 10 - secondary pressure relief hole, 11 - pressure relief set screw, 12 - conical head, 13 - extending section, 14 - operating section, 15 - pressure equalizing cavity. Specific embodiments

[0051] The features and performance of the present utility model will be further described in detail below in conjunction with embodiments.

[0052] The principle of the solution of the pressure relief device of the present utility model is as follows:

[0053] A pressure relief device provided by the present utility model is installed on the pipe wall of the blind pipe section of the oil well so that the pressure relief device is communicated with the blind pipe section of the oil well. Its installation method can be selected as a snap connection or a welded connection according to the pressure in the blind pipe section of the oil well. The structure of the blind pipe section of the oil well is prior art, so it will not be elaborated here.

[0054] In the prior art, the general methods for pressure relief of the blind pipe section are to loosen the clamp at the distal connection of the blind pipe section under pressure for pressure relief, or to remove the plug under pressure to relieve the pressure of the blind pipe section. Although both of these pressure relief methods can achieve pressure relief of the blind pipe section, since the pressure in the blind pipe section is greater than the external pressure, when the clamp is loosened or the plug is removed under pressure, the clamp or the plug will fly out quickly under the action of the pressure in the blind pipe section, posing a great safety hazard. The present utility model installs the pressure relief device on the side wall of the blind pipe section of the oil well, and a pressure equalizing cavity 15 communicated with the blind pipe section of the oil well is arranged in the tubing connector 7. The pressure equalizing cavity 15 buffers the pressure in the blind pipe section of the oil well by guiding the gas to turn and expand when performing the pressure relief operation on the blind pipe section of the oil well. The space in the blind pipe section of the oil well is communicated with the outside through the pressure equalizing cavity 15, the primary pressure relief hole 8, the pressure relief base 9, and the secondary pressure relief hole 10 in the tubing connector 7, changing the pressure action path of the blind pipe section of the oil well, avoiding the safety accident caused by the pressure in the blind pipe section directly acting on the pressure relief set screw 11 and flushing out the pressure relief set screw 11, and greatly improving the safety of the pressure relief operation.

[0055] Based on the above solution principle, Embodiment 1 of the pressure relief device of the present utility model is as follows:

[0056] As Figure 2-6As shown in the figure, the pressure relief device includes a tubing connector 7, a pressure relief base 9, and a pressure relief set screw 11. A pressure equalizing cavity 15 is provided inside the tubing connector 7. The pressure relief base 9 is arranged on the circumferential surface of the tubing connector 7 by welding. An initial pressure relief hole 8 is provided on the circumferential surface of the tubing connector 7 at the position corresponding to the pressure relief base 9. A secondary pressure relief hole 10 is provided on the circumferential surface of the pressure relief base 9. The pressure relief set screw 11 is assembled in the pressure relief base.

[0057] The structure of the tubing connector 7 can be referred to Figure 2-6 , which includes a large diameter section and a small diameter section. The pressure relief base 9 is arranged on the circumferential surface of the small diameter section of the tubing connector 7, and the pressure relief base 9 is arranged at 1 / 3 of the small diameter section near one end of the large diameter section. One end of the small diameter section away from the large diameter section is blocked. With this setting, the tubing connector 7 is installed on the oil well blind pipe section through the end of the large diameter section away from the small diameter section. The setting of the large diameter section can improve the connection stability at the joint, avoiding the problem that the tubing connector 7 is flushed out by pressure during the normal operation of the oil well blind pipe section due to insufficient connection strength, and improving the connection stability of the pressure relief device. At the same time, the setting of the small diameter section reduces the material consumption of the pressure relief device during the production stage and reduces the production cost of the pressure relief device. And, the pressure relief base 9 is arranged at 1 / 3 of the small diameter section near one end of the large diameter section. During use, when the pressure in the oil well blind pipe section enters the tubing connector 7, its main acting force is along the axial direction of the tubing connector 7. This setting can change the acting direction of the pressure entering the oil well blind pipe section in the pressure equalizing cavity 15, thereby further improving the pressure equalizing effect of the pressure equalizing cavity 15.

[0058] The structure of the pressure relief set screw 11 can be referred to Figure 7-9 , which includes a conical head 12, an insertion section 13, and an operation section 14. The outer circumferential surface of the operation section 14 is a regular hexagon. After the pressure relief set screw 11 is assembled in the pressure relief base, the initial pressure relief hole 8 is blocked by the conical head 12, and the insertion section blocks the secondary pressure relief hole 10, simultaneously completing the blocking of the initial pressure relief hole 8 and the secondary pressure relief hole 10. And, according to the requirements of the actual working conditions, the axial length of the pressure relief set screw 11 inserted into the pressure relief base 9 can be adjusted to open the initial pressure relief hole 8 and the secondary pressure relief hole 10, and at the same time, the opening degrees of the initial pressure relief hole 8 and the secondary pressure relief hole 10 can also be adjusted to complete the adjustment of the pressure relief speed.

[0059] Furthermore, as a preferred implementation, the axial length of the small diameter section of the tubing connector 7 is greater than the axial length of the large diameter section, which can increase the volume of the pressure equalizing cavity 15 while avoiding an increase in the production cost of the tubing connector 7.

[0060] Furthermore, as a preferred implementation, the pressure relief base 9 can also be arranged on the circumferential surface of the tubing connector 7 by a threaded connection method.

[0061] Further, as a preferred embodiment, the axial length of the extending section of the pressure relief set screw 11 is greater than or equal to the axial length of the pressure relief base 9.

[0062] Further, as a preferred embodiment, the secondary pressure relief hole 10 is arranged near the connection position of the pressure relief base 9 and the tubing connector 7.

[0063] Further, as a preferred embodiment, the angle between the axis of the secondary pressure relief hole 10 and the horizontal plane is 30 - 45 degrees.

[0064] Working process: During the normal operation of the blind pipe section of the oil well, the pressure relief set screw 11 extends into the pressure relief base 9, plugs the primary pressure relief hole 8 through the conical head 12, and the extending section 13 plugs the secondary pressure relief hole 10. When performing a pressure relief operation on the blind pipe section, the operator uses a tool to screw the pressure relief set screw 11 through the operating section 14, so that the conical head 12 opens the primary pressure relief hole 8, and at the same time the extending section 13 opens the secondary pressure relief hole 10. At this time, the inside of the blind pipe section of the oil well can be sequentially connected to the external environment through the pressure equalizing cavity 15, the primary pressure relief hole 8, the pressure relief base 9, and the secondary pressure relief hole 10, completing the pressure relief operation on the blind pipe section of the oil well.

[0065] Specific embodiment of the blind pipe section of the oil well of the present utility model: It includes a blind pipe section. A pressure relief device is arranged on the radial circumferential surface of the blind pipe section. The pressure relief device is connected to the blind pipe section by means of snap connection or welding. The specific structure of the pressure relief device is the same as the casing structure in the embodiment of the casing introduced above, and will not be elaborated herein.

[0066] It should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable way without conflict. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods.

[0067] In addition, any combination can be made between various different embodiments of the present utility model, as long as it does not violate the idea of the present utility model, it should equally be regarded as the content disclosed by the present utility model.

[0068] The above is only a preferred embodiment of the present utility model, and it is not used to limit the present utility model. The patent protection scope of the present utility model is subject to the claims. Any equivalent structural changes made by using the description and drawings of the present utility model should equally be included in the protection scope of the present utility model.

Claims

1. A pressure relief device, characterized in that: It includes a tubing connector, a pressure relief base, and a pressure relief set screw. The tubing connector is provided with a pressure equalizing cavity for communicating with the blind pipe section of the oil well. The pressure relief base is arranged on the circumferential surface of the tubing connector. A first-stage pressure relief hole is provided on the side wall of the tubing connector at the installation position of the pressure relief base. A second-stage pressure relief hole is provided on the circumferential surface of the pressure relief base. The pressure relief set screw is assembled in the pressure relief base. The pressure equalizing cavity, the first-stage pressure relief hole, and the second-stage pressure relief hole are communicated with each other.

2. The pressure relief device according to claim 1, wherein: The tubing connector includes a large-diameter section and a small-diameter section. The pressure relief base is arranged at the 1 / 3 position of the small-diameter section close to the large-diameter section.

3. The pressure relief device according to claim 2, characterized in that: The axial length of the small-diameter section is greater than the axial length of the large-diameter section.

4. The pressure relief device according to claim 1, characterized in that: The pressure relief set screw is divided into an inserted section and an operating section. The axial length of the inserted section is greater than or equal to the axial length of the pressure relief base.

5. A pressure relief device according to claim 4, characterized in that: A conical head for plugging the first-stage pressure relief hole is provided at one end of the inserted section away from the operating section.

6. The pressure relief device according to claim 4 or 5, characterized in that: The outer circumferential surface of the operating section is a regular polygon.

7. A pressure relief device according to claim 1, characterized in that: The pressure relief base is connected to the tubing connector by welding or threading.

8. A pressure relief device according to claim 1 or 7, characterized in that: The second-stage pressure relief hole is arranged close to the connection position between the pressure relief base and the tubing connector.

9. A pressure relief device according to claim 1 or 7, characterized in that: The included angle between the axis of the second-stage pressure relief hole and the horizontal plane is 30 - 45 degrees.

10. An oil well blind pipe section, characterized in that: It includes a blind pipe. A pressure relief device is arranged on the radial circumferential surface of the blind pipe. The pressure relief device is connected to the blind pipe section by means of snap connection or welding. The pressure relief device is the pressure relief device described in any one of claims 1 - 9.

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