A pressure relief device and coring tool incorporating the same

Abstract

The present application belongs to the field of drilling coring equipment, and discloses a pressure relief device and a coring tool with the same. The pressure relief device comprises a cylinder, a plug and an elastic member. The cylinder has a cavity and a through hole on the end wall of the cylinder. The plug has a base and a protrusion, the base is installed in the cavity of the cylinder, and the protrusion extends to the outside of the cylinder through the through hole of the cylinder. The elastic member is arranged in the cavity, the first end of the elastic member abuts against the surface of the base away from the protrusion, and the second end of the elastic member is supported by the cylinder. The pressure relief device of the present application is an integral structure which can be independently installed and used, and has the advantages of simple structure, convenient maintenance and easy replacement. When the coring tool with the pressure relief device is used, when the pressure in the inner cylinder is blocked and the pressure reaches the set value, the pressure relief device is automatically opened for pressure relief under the action of the pressure in the cylinder, so that the pressure in the inner cylinder during the sealed coring operation does not exceed the set value of the pressure relief device, thereby ensuring that the core can smoothly enter the inner cylinder.

Description

Technical Field

[0001] This invention relates to the field of drilling coring equipment, and more particularly to a pressure relief device and a coring tool incorporating the pressure relief device. Background Technology

[0002] Closed coring is a unique coring method designed to obtain raw oil and water saturation data of reservoirs, as well as crucial information such as lithology, physical properties, and the correlation between reservoir and electrical properties. This data reveals the true oil-bearing status of the reservoir and is essential for calculating oil geological reserves, optimizing reservoir description, guiding primary and secondary oil recovery operations, and assessing the distribution of remaining oil in older reservoirs.

[0003] Conventional coring can contaminate core samples with drilling fluid, and solid particles from the fluid can penetrate the core pores, affecting the accuracy of porosity data. Simultaneously, the infiltration of drilling fluid filtrate can alter the mineral composition of formation fluids, leading to inaccurate oil-water saturation data. These problems significantly increase the error in core analysis results, thus limiting the effective formulation of exploration and development plans. Sealed coring, on the other hand, involves rotating both the inner and outer cylinders simultaneously with the drill string during core drilling. The inner cylinder is filled with sealing fluid. When the sealing head passes through the core claw and enters the inner cylinder, the sealing fluid flows out from the gaps and evenly covers the core surface, forming a protective layer that effectively prevents drilling fluid intrusion. The core enters the inner cylinder by overcoming the friction of the core claw. During core cutting, the drill string is lifted, causing the core claw to descend along the inner conical surface of the drill bit, generating a radial locking force that firmly holds the core. When the tensile force reaches the ultimate breaking force of the core cross-section, the core is cleanly cut.

[0004] During closed-loop coring, poor fluidity of the sealing fluid can lead to pressure buildup within the inner cylinder. This increased pressure not only hinders core entry and reduces coring efficiency but also poses safety risks during core removal. Therefore, there is an urgent need in this field to research a pressure relief device to address the problem of pressure buildup within the inner cylinder during closed-loop coring operations. Summary of the Invention

[0005] To address the above problems, the present invention provides a pressure relief device and a core extraction tool incorporating the pressure relief device.

[0006] According to one aspect of the present invention, a pressure relief device is provided, the pressure relief device comprising: A cylinder body having a chamber and a through-hole located on the end wall of the cylinder body; A plug having a connected base and a protrusion, the base being movably mounted in the cavity of the cylinder body, the protrusion extending through the through-hole of the cylinder body to the outside of the cylinder body; An elastic element is disposed in the cavity, with a first end abutting against the base surface away from the protrusion, and a second end supported by the cylinder body.

[0007] According to one embodiment of the present invention, the pressure applied to the plug by the elastic element can be adjusted and changed.

[0008] According to one embodiment of the present invention, the device further includes a cylinder head, wherein the cylinder body has an opening at one end opposite to the end wall having the through-hole, and the cylinder head is detachably connected to the cylinder body and closes the opening.

[0009] According to one embodiment of the present invention, the cylinder body is provided with an internal thread at one end that abuts the cylinder head, and the peripheral wall of the cylinder head is provided with an external thread. The engagement position of the internal thread and the external thread can be adjusted to change the compression amount of the elastic element.

[0010] According to one embodiment of the invention, the elastic element can be replaced to adjust the pressure applied by the elastic element to the plug by changing the elastic element.

[0011] According to one embodiment of the present invention, the cylinder body includes an end wall and a circumferential wall, the end wall and the circumferential wall defining a cylindrical chamber, and the inner surface of the end wall is planar.

[0012] According to one embodiment of the present invention, the shape and size of the bump are adapted to the shape and size of the through opening.

[0013] According to one embodiment of the present invention, the end face of the protrusion away from the base and the outer peripheral face are tapered transition surfaces.

[0014] According to one embodiment of the present invention, the elastic element is a helical spring, and the outer diameter of the helical spring is adapted to the radial dimension of the chamber.

[0015] According to another aspect of the present invention, a core-retrieving tool with a pressure relief device is provided, the core-retrieving tool comprising: Pressure relief holes and mounting grooves are provided on the side walls of the upper and / or lower connectors of the inner cylinder of the core-taking tool. The pressure relief holes and the mounting grooves are connected and both penetrate the side walls of the upper and / or lower connectors of the inner cylinder. The pressure relief holes are located on the side closer to the inner wall of the inner cylinder. According to any of the above embodiments of the pressure relief device, the cylinder is constrained in the mounting groove, and a gap is left between the outer wall of the cylinder and the inner wall of the mounting groove. When the pressure in the inner cylinder is lower than a set threshold, the protrusion of the plug is closed by the elastic element and the pressure relief hole is opened when the pressure in the inner cylinder exceeds the set threshold, so that the pressure relief hole communicates with the gap.

[0016] According to an embodiment of the present invention, the mounting groove is further provided with an annular boss and a pressure relief channel. When the cylinder body is assembled into the mounting groove, the annular boss abuts against the end wall of the cylinder body, so that the area enclosed by the annular boss forms an overflow space. The overflow space is connected to the pressure relief hole and the pressure relief channel. The pressure relief channel is connected to the annular space between the inner and outer cylinders of the core-taking tool.

[0017] According to one embodiment of the present invention, the mounting groove is provided with a plurality of pressure relief channels, which are evenly distributed along the circumference of the mounting groove, and each pressure relief channel is radially expanded outward to a position further outward than the peripheral wall of the mounting groove.

[0018] By adopting the above technical solutions, the pressure relief device provided by this invention is an independently installable and usable integrated structure. It is simple in structure, easy to maintain, and easy to replace. When a coring tool equipped with this pressure relief device is in use, if pressure buildup occurs in the inner cylinder and the pressure reaches a set value, the pressure relief device automatically opens under the pressure inside the cylinder to release the pressure. This ensures that the pressure in the inner cylinder will not exceed the set value of the pressure relief device during closed coring operations, thereby ensuring that the core can smoothly enter the inner cylinder, improving coring efficiency and core extraction safety. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 A schematic diagram of the overall structure of a core-harvesting tool with a pressure relief device according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of a pressure relief device assembled on an inner cylinder joint according to an embodiment of the present invention is shown; Figure 3 It shows Figure 2 Enlarged view of a section of the structure; Figure 4 It shows Figure 2 A magnified view of the structure from another perspective.

[0020] List of reference numerals in the attached diagram: 1. Pressure relief device; 10. Cylinder body; 11. End wall; 11a. Through port; 12. Side wall / circumferential wall; 13. Chamber; 14. Opening; 15. Cylinder head; 20. Plug; 21. Base; 22. Protrusion; 30. Elastic element; 100. Inner cylinder upper connector / inner cylinder lower connector; 110. Pressure relief hole; 120. Mounting groove; 121. Annular boss; 122. Mating surface; 123. Pressure relief flow channel. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] The terms "comprising" and "having," and any variations thereof, used in the specification and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0023] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0024] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0025] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] One object of the present invention is to provide a pressure relief device, and also to provide a core extraction tool incorporating the pressure relief device. Figure 1 A schematic diagram of the overall structure of a coring tool with a pressure relief device according to an embodiment of the present invention is shown. Figure 2 A schematic diagram of a pressure relief device assembled on an inner cylinder joint according to an embodiment of the present invention is shown. Figure 3 It shows Figure 2 Enlarged view of a section of the structure.Figure 4 It shows Figure 2 A magnified view of the structure from another perspective.

[0027] like Figures 1-4 As shown, the pressure relief device 1 in this embodiment generally includes a cylinder 10, a plug 20, and an elastic element 30.

[0028] like Figure 3 As shown, the cylinder body 10 has an end wall 11 and a side wall 12, which together form a chamber 13. A through port 11a may be provided on one of the end walls 11.

[0029] The plug 20 is a component used to close and open the pressure relief port 110. The plug 20 may have a connected base 21 and a protrusion 22. The base 21 is movably mounted within the chamber 13 of the cylinder 10, and may be flat and disc-shaped, providing stable support for the protrusion 22. The radial dimension of the base 21 is close to the radial dimension of the chamber 13, and the two are slidably fitted together. A first end of the protrusion 22 is connected to an end face of the base 21, and the body of the protrusion 22 passes through the through-hole 11a of the cylinder 10 and extends to the outside of the cylinder 10. The protrusion 22 may be columnar, smaller than the base 21, and located at the center of the base 21.

[0030] The elastic element 30 applies elastic force to the plug 20, controlling the movement of the plug 20, thereby controlling the plug 20 to close and open the pressure relief hole 110. The elastic element 30 is disposed within the chamber 13. The elastic element 30 may have a first end and a second end disposed opposite each other along its length. The first end of the elastic element 30 may abut against the surface of the base 21 opposite to the protrusion 22, and the second end of the elastic element 30 may be supported by the cylinder body 10.

[0031] The elastic properties of the elastic element 30 can be selected according to the pressure relief requirements, so as to adjust and change the pressure applied by the elastic element 30 to the plug 20.

[0032] For example, in some embodiments, the cylinder body 10 has a through-hole 11a on the end wall 11 at the first end and an opening 14 at the second end opposite to the first end. The cylinder head 15 can be detachably connected to the cylinder body 10 and close the opening 14. The cylinder head 15 can be removed to replace the elastic element 30 in the chamber 13. Different elastic elements 30 have different stiffness coefficients, so the pressure required to overcome the elastic force of the elastic element 30 is also different, thus pressure relief devices with different pressure relief values ​​can be obtained by replacing the elastic element 30.

[0033] Optionally, in other embodiments, the cylinder body 10 may have an internal thread at its second end (i.e., the end where the cylinder head 15 is mounted), and the peripheral wall of the cylinder head 15 (i.e., the wall that engages with the cylinder body 10) may have an external thread. The engagement position of the internal and external threads can be adjusted to change the compression of the elastic element 30. For example, the internal thread on the inner wall of the cylinder body 10 may extend a distance along the axial direction of the cylinder body 10, such that the axial extension range of the internal thread is significantly greater than the axial extension range of the external thread of the cylinder head 15. Tightening the cylinder head 15 changes its axial mounting position within the cylinder body 10, causing a change in the compression of the elastic element 30, thereby providing a pressure relief device with different opening pressures. Furthermore, the cylinder head 15 may also have a structure that facilitates rotation of the cylinder head 15. For example, the outer end wall of the cylinder head 15 may have a hexagonal protrusion, which can be engaged with a hexagonal wrench of a shape and size adapted to the protrusion, allowing the cylinder head 15 to be rotated by tightening the wrench.

[0034] Optionally, in some embodiments, the sidewall 12 of the cylinder body 10 is cylindrical, and the sidewall 12 may also be referred to as the circumferential wall. The end wall 11 and the circumferential wall 12 define a cylindrical chamber, allowing the plug 20 to slide more smoothly along the inner wall of the cylinder body 10. The inner surface of the end wall 11 with the through port 11a can be flat, so that the base 21 of the pressure relief device can be stably supported on the inner surface of the end wall 11 when the pressure relief hole 110 is closed, allowing the protrusion 22 to be aligned with the pressure relief hole 110 without misalignment.

[0035] Optionally, in some embodiments, the shape and size of the protrusion 22 are adapted to the shape and size of the through-hole 11a. That is, the inner contour of the through-hole 11a is adapted to the outer contour of the protrusion 22. Since the inner contour of the through-hole 11a effectively wraps around and supports the outer contour of the protrusion 22, the through-hole 11a can stably guide the movement trajectory of the protrusion 22. This guidance not only ensures that the protrusion 22 can move smoothly along the predetermined path, but also effectively reduces friction and resistance during the movement, limits the deflection and wobbling of the protrusion 22, and enables it to accurately close the pressure relief hole 110.

[0036] Optionally, in some embodiments, the end face of the protrusion 22 furthest from the base 21 (also referred to as the second end of the protrusion 22, which is disposed opposite to the first end of the protrusion 22) and its outer peripheral surface form a tapered transition surface. This tapered transition surface can guide the protrusion 22 when it is inserted into the pressure relief hole 110, facilitating the alignment of the second end of the protrusion 22 with the pressure relief hole 110. Moreover, as the protrusion 22 gradually penetrates deeper into the pressure relief hole 110, the tapered transition surface gradually contacts and compresses the inner wall of the pressure relief hole 110, thereby forming a tight and uniform mating interface. In addition, the tapered transition surface can also disperse stress, uniformly transmitting force to the inner wall of the pressure relief hole 110, avoiding localized stress concentration and potential damage.

[0037] Optionally, in some embodiments, the elastic element 30 can be a helical spring, the outer diameter of which is adapted to the radial dimension of the chamber 13, so that the inner surface of the chamber 13 can serve as a boundary to constrain the compression movement of the helical spring, thereby improving its stability during compression.

[0038] Figure 1 A schematic diagram of the overall structure of a coring tool with a pressure relief device 1 according to an embodiment of the present invention is shown. This coring tool is used for closed-loop coring and includes an upper inner cylinder connector 100 and a lower inner cylinder connector 100, the pressure relief device 1, and other structures required for conventional closed-loop coring tools. Since the present invention does not involve improvements to other structures, these other structures are not described in detail here. It is understood that although the coring tool described in this embodiment includes both the upper inner cylinder connector 100 and the lower inner cylinder connector 100, in some cases, the coring tool may include only one of the upper inner cylinder connector 100 and the lower inner cylinder connector 100. For ease of description, "inner cylinder connector" in the following text can refer to both the "upper inner cylinder connector" and / or the "lower inner cylinder connector".

[0039] like Figures 1-4 As shown, a pressure relief hole 110 and a mounting groove 120 are provided on the side wall of the inner cylinder upper connector 100 and / or inner cylinder lower connector 100 of the coring tool. The pressure relief hole 110 and the mounting groove 120 are connected, and the pressure relief hole 110 is located on the side closer to the inner wall of the inner cylinder. The pressure relief hole 110 and the mounting groove 120 together penetrate the side wall of the inner cylinder connector. The size of the pressure relief hole 110 is significantly smaller than the size of the mounting groove 120.

[0040] The radial dimension of the pressure relief hole 110 is adapted to the radial dimension of the second end of the protrusion 22, so that the second end of the protrusion 22 is suitable for closing the pressure relief hole 110. Optionally, the pressure relief hole 110 may be provided with a tapered surface that matches the tapered transition surface of the second end of the protrusion 22, so that the tapered transition surface of the protrusion 22 can be tightly pressed against the pressure relief hole 110.

[0041] The mounting groove 120 is used to accommodate and receive the cylinder body 10. To ensure that the fluid in the inner cylinder can be discharged after the plug 20 is opened, a gap is left between the outer wall of the cylinder body 10 and the inner wall of the mounting groove 120. When the plug 20 disengages from the pressure relief hole 110, opening the pressure relief hole 110, the gap between the pressure relief hole 110 and the outer wall of the cylinder body 10 and the inner wall of the mounting groove 120 is connected, allowing the fluid to be discharged. Optionally, in some embodiments, the mounting groove 120 is provided with an annular boss 121. Figure 3As shown, the portion of the mounting groove 120 that connects to the pressure relief hole 110 has a mating surface 122. An annular boss 121 is located at the radial outer edge of this mating surface 122 and extends circumferentially, forming a ring shape. The main radial section of the annular boss 121 has an axial dimension (i.e., the dimension in the direction parallel to the axial direction of the mounting groove 120) and a radial dimension (i.e., the dimension in the direction parallel to the radial direction of the mounting groove 120). Axially, the annular boss 121 protrudes from the mating surface 122 toward the opening side of the mounting groove 120, such that the central region of the annular boss 121 is concave relative to the edge region. The axial dimension of the annular boss 121 needs to be set according to the axial length of the protrusion 22 and the thickness of the end wall 11, so that the second end of the protrusion 22 can move to a position that closes the pressure relief hole 110. The radial dimension of the annular boss 121 determines the size of the central gap it encloses, and this dimension can be adjusted according to specific needs.

[0042] Furthermore, such as Figure 4 As shown, the mounting groove 120 is further provided with one or more pressure relief channels 123. When multiple pressure relief channels 123 are provided in the mounting groove 120, they are evenly distributed circumferentially along the mounting groove 120. Each pressure relief channel 123 may have a radially extending portion and an axially extending portion. The radially extending portion is parallel to the radial direction of the mounting groove 120, and the axially extending portion is parallel to the axial direction of the mounting groove 120. The radially extending portion of the pressure relief channel 123 penetrates the radial direction of the annular boss 121 and extends to the central gap region of the annular boss 121. The axially extending portion of the pressure relief channel 123 extends from the mating surface 122 to the opening side of the mounting groove 120. At the same time, the axially extending portion expands radially to a position further outward than the peripheral wall of other positions in the mounting groove 120. The pressure relief channel 123 communicates with the annular space between the inner and outer cylinders of the core-taking tool.

[0043] When the pressure relief device 1 is assembled into the mounting groove 120, the end wall 11 of the cylinder body 10 abuts against the annular boss 121. A gap is left between the outer surface of the end wall 11 of the cylinder body 10 and the mating surface 122. This gap is connected to the pressure relief hole 110 and the pressure relief flow channel 123, thereby connecting the inside of the inner cylinder with the annular space between the inner and outer cylinders.

[0044] The method of using the pressure relief device and the core-taking tool equipped with the pressure relief device of the present invention is as follows: Before construction, the pressure relief device of the present invention is pre-tested and adjusted to a safe pressure relief value. The pressure relief device is installed in the mounting grooves 120 of the upper connector 100 and the lower connector 100 of the inner cylinder, respectively, so that the second end of the protrusion 22 is aligned with the pressure relief hole 110. When the core is taken in a sealed environment, if the fluidity of the sealing fluid is poor, pressure will be generated in the inner cylinder, and the pressure inside the inner cylinder will increase. When the pressure value is greater than the set value of the pressure relief device, that is, when the pressure value can overcome the pressure, the pressure relief device will be activated. When the elastic element 30 applies elastic force to the plug 20, the pressure in the inner cylinder acts on the plug 20. The plug 20 overcomes the elastic force of the elastic element 30 under pressure and moves away from the pressure relief hole 110, compressing the elastic element 30. At this time, the conical surface of the plug 20 leaves the pressure relief hole 110 of the inner cylinder joint, and a gap is generated between the two. The fluid in the inner cylinder is discharged through the pressure relief hole 110 and the pressure relief flow channel 123 of the inner cylinder joint, thereby achieving the effect of safe pressure reduction, so that the core can smoothly enter the inner cylinder and can be safely and risk-free when exiting the core.

[0045] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A pressure relief device, characterized in that, include: The cylinder (10) has a chamber (13) and a through-hole (11a) located on the end wall (11) of the cylinder (10). A plug (20) having a connected base (21) and a protrusion (22), the base (21) being movably mounted in the chamber (13) of the cylinder (10), and the protrusion (22) extending through the through-hole (11a) of the cylinder (10) to the outside of the cylinder (10); An elastic element (30) is disposed in the chamber (13). The first end of the elastic element (30) abuts against the surface of the base (21) away from the protrusion (22), and the second end of the elastic element (30) is supported by the cylinder (10).

2. The pressure relief device according to claim 1, characterized in that, The pressure applied by the elastic element (30) to the plug (20) can be adjusted and changed.

3. The pressure relief device according to claim 2, characterized in that, The device also includes a cylinder head (15), the cylinder body (10) having an opening (14) at one end opposite to the end wall (11) having the through port (11a), the cylinder head (15) being detachably connected to the cylinder body (10) and closing the opening (14).

4. The pressure relief device according to claim 3, characterized in that, The cylinder body (10) has an internal thread at one end that mates with the cylinder head (15), and the circumferential wall of the cylinder head (15) has an external thread. The engagement position of the internal thread and the external thread can be adjusted to change the compression of the elastic element (30).

5. The pressure relief device according to claim 2, characterized in that, The elastic element (30) can be replaced to adjust the pressure applied by the elastic element (30) to the plug (20) by changing the elastic element (30).

6. The pressure relief device according to claim 1, characterized in that, The cylinder (10) includes an end wall (11) and a circumferential wall (12), which define a cylindrical chamber (13), and the inner surface of the end wall (11) is planar.

7. The pressure relief device according to claim 1, characterized in that, The shape and size of the protrusion (22) are adapted to the shape and size of the through opening (11a).

8. The pressure relief device according to claim 1, characterized in that, The end face of the protrusion (22) away from the base (21) and the outer peripheral face are tapered transition surfaces.

9. The pressure relief device according to claim 1, characterized in that, The elastic element (30) is a helical spring, and the outer diameter of the helical spring is adapted to the radial dimension of the chamber (13).

10. A core-retrieving tool with a pressure relief device, characterized in that, include: Pressure relief hole (110) and mounting groove (120) are provided on the side wall of the inner cylinder upper connector (100) and / or inner cylinder lower connector (100) of the core-taking tool. The pressure relief hole (110) and the mounting groove (120) are connected and both penetrate the side wall of the inner cylinder upper connector (100) and / or inner cylinder lower connector (100). The pressure relief hole (110) is located on the side close to the inner wall of the inner cylinder. According to any one of claims 1-9, the cylinder (10) is constrained in the mounting groove (120), and a gap is left between the outer wall of the cylinder (10) and the inner wall of the mounting groove (120). When the pressure in the inner cylinder is lower than a set threshold, the protrusion (22) of the plug (20) is closed by the elastic element (30) to close the pressure relief hole (110), and when the pressure in the inner cylinder exceeds the set threshold, the pressure relief hole (110) is opened, so that the pressure relief hole (110) communicates with the gap.

11. The core-retrieving tool with a pressure relief device according to claim 10, characterized in that, The mounting groove (120) is also provided with an annular boss (121) and a pressure relief channel (123). When the cylinder (10) is assembled into the mounting groove (120), the annular boss (121) abuts against the end wall (11) of the cylinder (10), so that the area enclosed by the annular boss (121) forms an overflow space. The overflow space is connected to the pressure relief hole (110) and the pressure relief channel (123). The pressure relief channel (123) is connected to the annular space between the inner and outer cylinders of the core extractor.

12. The core-removing tool with a pressure relief device according to claim 11, characterized in that, The mounting groove (120) is provided with a plurality of pressure relief channels (123), which are evenly distributed along the circumference of the mounting groove (120). Each pressure relief channel (123) is radially expanded outward along the mounting groove (120) to a position further outward than the circumferential wall of the mounting groove (120).

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