Open hole anchor and anchoring method

Abstract

The invention provides an open hole anchor which comprises a first connector and an anchoring mechanism, the anchoring mechanism comprises a middle cylinder arranged on the downstream of the first connector, an outer cylinder arranged on the radial outer side of the middle cylinder and fixed to the first connector through a first pin, and a center pipe arranged on the radial inner side of the middle cylinder, and a piston is arranged between the middle cylinder and the central pipe and is fixed on the middle cylinder through a second pin. According to the method, the risk of drill jamming caused by accidental starting of the open hole anchor in the tripping-in process of the open hole section can be effectively prevented, so that the tripping-in safety of the open hole packer is further ensured. In addition, the invention further provides an anchoring method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of horizontal well open hole staged technology in oil and gas well completion engineering, in particular to an open hole anchor and an anchoring method. BACKGROUND

[0002] At present, horizontal well open hole staged fracturing reconstruction has become an important means to improve the producing degree and recovery ratio of low-permeability and ultra-low-permeability reservoirs. This technology not only can increase the production of oil and gas wells, but also can greatly reduce the cost and risk brought by cementing and perforating operations, and can also reduce the pollution and damage to the formation, which is the trend of low-permeability reservoir development.

[0003] In the open hole staged process, in order to protect the packer and its string, a hydraulic anchor or a hanger is generally anchored in the casing near the front end of the open hole section, but for the open hole section, due to the irregularity of the open hole wall, the hydraulic anchor or the slip is prone to accidental opening during running, which may cause sticking accidents, and its adaptability is poor. The open hole packer is completely anchored by the friction force of the rubber tube, and generally has no other anchoring device.

[0004] In high-pressure construction, the string is elongated due to the bulging effect of bearing a large pressure. For example, for 88.9mm tubing, the elongation rate of the string during fracturing can reach 2‰. The elongation of the string, on the one hand, will drive the rubber tube of the packer that has been set on the open hole wall to move axially and be damaged by the rock wall, causing the packer to lose its sealing effect; on the other hand, the elongation of the string due to the hydraulic tension during fracturing directly acts on the tubing and its thread, which may cause the tubing to break or the thread to come off. Therefore, in order to ensure the sealing effect of the open hole packer and the safety of the string, an anchoring means suitable for this process should be provided in the open hole staged string.

[0005] CN106368635B discloses a new type of open hole anchor, which uses a plate bridge assembly as an anchoring element to increase the contact area with the well wall, thereby ensuring the anchoring force without damaging the well wall. A damping folding spring is used to reduce the vibration of the string, thereby prolonging the effective anchoring time. By using a rotating lock sleeve, a one-way lock ring, a sliding bolt and a tension spring, the anchor can be conveniently converted between the states of setting, maintaining and releasing the anchor in one trip. However, the anchoring, maintaining and releasing of the anchor must be controlled by hydraulic pressure, and the anchoring range is limited, which cannot achieve anchoring in the open hole section with large well diameter expansion.

[0006] CN202914000U discloses a righting anchoring device applied to a horizontal open hole well, comprising an upper joint and a lower joint respectively arranged at two ends of an outer side of a central pipe, each of which is limited by a respective positioning ring and each of which is provided with a hydraulic cylinder, and a gap for arranging a hinge type anchor is opened between the two hydraulic cylinders; a piston is arranged in the hydraulic cylinder, and an inner end surface of the piston is connected with the hinge type anchor; a cover plate is arranged on an outer peripheral wall of the hinge type anchor; and a one-way lock ring matched with a sawtooth thread on the central pipe is arranged on an inner side wall of the piston. Under the action of hydraulic pressure, the piston moves relatively, a plurality of anchors composed of hinges arranged in the middle of the two pistons are pressed and raised, the top end of the anchor is embedded into the rock of the well wall from contacting the well wall, thereby playing a righting and anchoring role on the fracturing pipe column, especially the packer. However, the device has the following problems in actual application, for example, the anchor needs to be embedded into the open hole well wall, thereby causing great damage to the well wall, and easily causing the well wall to collapse, and the reliability of the performance cannot meet the application requirements.

[0007] Therefore, it is desirable in the art to provide an open hole anchor to solve the above technical problems. SUMMARY

[0008] The open hole anchor can realize double insurance through the first pin, the second pin and the lock ball, thereby effectively preventing the open hole anchor from being accidentally started during the open hole section lowering process to cause the risk of sticking, and further ensuring the safety of the open hole packer lowering.

[0009] According to a first aspect of the present application, an open hole anchor is provided, comprising a first joint, and

[0010] an anchoring mechanism comprising a middle cylinder arranged downstream of the first joint, an outer cylinder arranged radially outside the middle cylinder and fixed on the first joint through a first pin, and a central pipe arranged radially inside the middle cylinder,

[0011] wherein a piston is arranged between the middle cylinder and the central pipe, and the piston is fixed on the middle cylinder through a second pin.

[0012] In one embodiment, an upper end surface of the piston leaves a gap with the middle cylinder in an initial state, a pressure transmission hole is arranged on the central pipe and communicates with the gap,

[0013] the second pin is configured to be sheared under the pressure from the pressure transmission hole, thereby allowing the piston to move downward along the axial direction.

[0014] In one embodiment, the anchoring mechanism further comprises an anchoring cylinder arranged downstream of the outer cylinder and configured to abut against the piston, and an anchoring slip arranged downstream of the anchoring cylinder,

[0015] The first pin is configured to be sheared under the pushing action of the piston, thereby allowing the anchoring cylinder and the anchoring slip to move axially downward.

[0016] In one embodiment, a plurality of anchoring slips are arranged at intervals along the circumference of the anchoring cylinder, and a connecting rod is arranged between each anchoring slip and the anchoring cylinder, and adjacent anchoring slips are connected by a fin.

[0017] In one embodiment, the outer wall of the anchoring slip is arranged obliquely, and a plurality of anchoring teeth are arranged on the outer wall of the anchoring slip and extend obliquely outward and upward in a radial direction.

[0018] In one embodiment, the open hole anchor further comprises a second joint arranged downstream of the central tube, and a guide slope is arranged on the outer wall of the second joint,

[0019] A guide slope adapted to the guide slope is arranged on the side of the anchoring slip close to the central tube, thereby allowing the anchoring slip to move radially outward and anchor on the open hole wall.

[0020] In one embodiment, the anchoring mechanism further comprises a retainer ring nested on the inner wall of the middle tube, and a retainer tooth adapted to the retainer ring is arranged on the outer wall of the piston.

[0021] In one embodiment, a receiving groove is arranged on the inner wall of the middle tube, and the open hole anchor further comprises a locking ball arranged in the receiving groove and configured to limit the upward movement of the piston.

[0022] In one embodiment, a sealing ring is arranged between the piston and the central tube and the middle tube.

[0023] According to a second aspect of the present application, a method for anchoring an open hole wall using the open hole anchor as described above is provided, comprising the following steps:

[0024] S1, pressurize into the pressure transmission hole, the second pin is sheared under the action of pressure, thereby allowing the piston to move axially downward until abutting against the anchoring cylinder;

[0025] S2, continue to pressurize, the first pin is sheared under the pushing action of the piston, thereby allowing the anchoring cylinder and the anchoring slip to move axially, and the anchoring slip moves radially outward under the action of the second joint and anchors on the open hole wall.

[0026] Compared with the prior art, the present application has the advantages of:

[0027] Firstly, the present application can realize double insurance through the first pin, the second pin and the locking ball, thereby effectively preventing the risk of sticking caused by accidental starting of the open hole anchor during the open hole section lowering process, and further ensuring the safety of the open hole packer lowering.

[0028] Secondly, the present application not only increases the friction between the anchor teeth and the open hole wall by designing the anchor teeth as inverted teeth, but also further increases the contact area between the anchor teeth and the open hole wall by arranging the outer wall surface of the anchor slips to be inclined, thereby improving the anchoring ability of the open hole packer to the open hole wall.

[0029] Thirdly, when the pipe string has an upward moving trend, the anchor teeth in the present application can have a larger opening angle under the action of the second joint, and the anchoring ability of the anchor teeth to the open hole wall can be strengthened, thereby realizing the effect of the more anchoring, the more secure, and further effectively improving the upward moving effect of the pipe string, to further improve the reliability of the open hole anchor.

[0030] Fourthly, the present application divides the anchor slips into two parts, so that when the guide inclined surface of the anchor slip contacts the guide inclined surface of the second joint, each anchor slip can be opened radially outward along a different direction, thereby having a larger anchoring range and being more easily anchored on the open hole wall, to further make the open hole anchor have good adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0031] The present application will be described in detail below with reference to the accompanying drawings, in which:

[0032] Figure 1 schematically shows the structure of the open hole anchor according to the present application;

[0033] Figure 2 schematically shows the structure of the outer cylinder in the open hole anchor according to the present application;

[0034] Figure 3 schematically shows the structure of the middle cylinder in the open hole anchor according to the present application;

[0035] Figure 4 schematically shows the stop ring in the open hole anchor according to the present application;

[0036] Figure 5 schematically shows the connection relationship between the anchor cylinder, the anchor slip and the connecting rod in the open hole anchor according to the present application;

[0037] Figure 6 To Figure 5 cross-sectional view at A-A.

[0038] Figure 7 For Figure 5 a cross-sectional view at B-B.

[0039] In the drawings, like reference numerals refer to like elements throughout. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application. DETAILED DESCRIPTION

[0040] In order to make the technical solutions and advantages of the present application clearer, the exemplary embodiments of the present application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. And the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0041] In the description of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0042] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements.

[0043] The directional term "upstream" or "above" or similar terms refers to the direction close to the wellhead, i.e. the left direction in Figure 1 . The directional term "downstream" or "below" or similar terms refers to the direction away from the wellhead, i.e. the right direction in Figure 1 .

[0044] For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] The present application will be further described below with reference to the accompanying drawings.

[0046] Figure 1 schematically shows the structure of the open hole anchor 100 according to the present application;

[0047] Figure 2 schematically shows the structure of the outer cylinder 22 in the open hole anchor 100 according to the present application;

[0048] Figure 3The structure of the middle cylinder 21 in the barehole anchor 100 according to the present application is schematically shown;

[0049] As Figures 1 to 3 shown, according to the first aspect of the present application, there is provided a barehole anchor 100 comprising a first joint 10 and an anchoring mechanism. Wherein, the anchoring mechanism comprises a middle cylinder 21, an outer cylinder 22 and a central pipe 30.

[0050] In one embodiment, the middle cylinder 21 is arranged downstream of the first joint 10, and the middle cylinder 21 is threadedly connected with the first joint 10 to improve the firmness therebetween; the outer cylinder 22 is arranged radially outside the middle cylinder 21, and the central pipe 30 is arranged radially inside the middle cylinder 21. Preferably, the inner peripheral surface of the outer cylinder 22 is sealingly connected with the outer peripheral surface of the middle cylinder 21, and a sealing ring is arranged between the outer cylinder 22 and the middle cylinder 21, thereby improving the sealing therebetween to facilitate the subsequent anchoring work.

[0051] In the present application, as Figure 1 shown, the outer cylinder 22 is firmly mounted on the first joint 10 by means of the first pin 201, thereby effectively preventing the risk of accidental starting of the barehole anchor 100 during the running-in process of the barehole section to cause the sticking of the drill pipe, so as to further ensure the safety of the running-in of the barehole anchor 100.

[0052] According to the present application, as Figure 1 shown, a piston 23 is arranged between the middle cylinder 21 and the central pipe 30. Preferably, the piston 23 is fixed on the middle cylinder 21 in the initial state by means of the second pin 202, thereby effectively preventing the risk of accidental starting of the barehole anchor 100 during the running-in process of the barehole section to cause the sticking of the drill pipe, so as to further ensure the safety of the running-in of the barehole anchor 100.

[0053] In one embodiment, as Figure 1 shown, the upper end surface of the piston 23 leaves a gap 24 with the middle cylinder 21 in the initial state, and a pressure transmission hole 31 is arranged on the central pipe 30. Preferably, the pressure transmission hole 31 communicates with the gap 24, thus the pressure injected into the central pipe 30 can be transmitted to the gap 24 through the pressure transmission hole 31, thereby facilitating the axial movement of the piston 23 in the annulus between the middle cylinder 21 and the central pipe 30.

[0054] According to one embodiment of the present application, the ball is dropped into the central pipe 30 to pressurize, and the pressure is transmitted to the gap 24 through the pressure transmission hole 31, thus the second pin 202 is sheared under the pressure from the pressure transmission hole 31, thereby allowing the piston 23 to move axially downward in the annulus between the middle cylinder 21 and the central pipe 30 until axially abutting against the anchoring cylinder 25 (to be described below).

[0055] Preferably, the piston 23 is sealingly connected with the middle cylinder 21 and the central pipe 30, and a sealing ring is arranged between the piston 23 and the central pipe 30 and the middle cylinder 21. In this way, the pressure injected through the pressure transmission hole 31 can fully act on the upper end surface of the piston 23, so as to improve the effectiveness of the downhole setting of the open hole anchor 100, which will be described below.

[0056] According to the present application, as shown in Figure 1 and 5 , the anchoring mechanism further comprises an anchoring cylinder 25 arranged downstream of the outer cylinder 22, and an anchoring slip 26 arranged downstream of the anchoring cylinder 25. Preferably, the upper end surface of the anchoring cylinder 25 is fixedly connected with the lower end surface of the outer cylinder 22, so that the outer cylinder 22 can move together with the anchoring cylinder 25.

[0057] Therefore, when the piston 23 axially abuts against the anchoring cylinder 25, the pressure continues to be applied through the pressure transmission hole 31, so that the piston 23 shears the first pin 201 and pushes the anchoring cylinder 25 to move axially downward together with the outer cylinder 22, at the same time, the anchoring slip 26 will also move axially downward together with the anchoring cylinder 25, and finally anchor on the open hole wall, which will be described below.

[0058] In one embodiment, as shown in Figure 1 , 5 , 6 and 7, a plurality of anchoring slips 26 are arranged at intervals along the circumference of the anchoring cylinder 25. Preferably, a connecting rod 263 is arranged between each anchoring slip 26 and the anchoring cylinder 25. In this way, each anchoring slip 26 is arranged independently of each other, and each anchoring slip 26 has a firm connection relationship with the anchoring cylinder 25, thereby improving the anchoring capacity of the open hole anchor 100 on the open hole wall.

[0059] In one embodiment of the present application, as shown in Figure 1 and 5 , the adjacent anchoring slips 26 are connected by flippers 264 in the initial state. Therefore, all the anchoring slips 26 can be integrated into a structure under the action of the flippers 264, so as to improve the overall stability of the open hole anchor 100, thereby effectively preventing the risk of accidental starting of the open hole anchor 100 during the running-in process of the open hole section, so as to further ensure the safety of the running-in of the open hole anchor 100.

[0060] According to the present application, as shown in Figure 1As shown, the open hole anchor further comprises a second joint 41 arranged downstream of the central tube 30. Preferably, a guide slope 411 is arranged on the outer wall of the second joint 41. Correspondingly, a guide slope 262 is arranged on the side of the anchor shoe 26 close to the central tube 30. Preferably, the guide slope 262 of the anchor shoe 26 is adapted to the guide slope 411 of the second joint 41.

[0061] In the present application, when the anchor shoe 26 moves downward along with the anchor barrel 25, the guide slope 262 of the anchor shoe 26 contacts the guide slope 411 of the second joint 41, and all the anchor shoes 26 are broken at the flippers 264 under the action of the second joint 41 and then open radially, thereby smoothly anchoring on the open hole wall.

[0062] In the present application, the anchor shoe 26 is designed to be split, so that when the guide slope 262 of the anchor shoe 26 contacts the guide slope 411 of the second joint 41, each anchor shoe 26 can open radially outward in different directions, thereby having a greater anchoring range (expansion rate > 15%) and being more easily anchored on the open hole wall, to further improve the adaptability of the open hole anchor 100.

[0063] In one embodiment, as shown in Figs. 1 and 2, the anchor shoe 26 is designed to be split, so that when the guide slope 262 of the anchor shoe 26 contacts the guide slope 411 of the second joint 41, each anchor shoe 26 can open radially outward in different directions, thereby having a greater anchoring range (expansion rate > 15%) and being more easily anchored on the open hole wall, to further improve the adaptability of the open hole anchor 100. Figure 1 and 5 As shown in Figs. 1 and 2, a plurality of anchor teeth 261 are arranged on the outer wall of the anchor shoe 26 and extend radially outward and upward. Therefore, when the pipe string has a tendency to move upward, the anchor teeth 261 can have a greater opening angle under the action of the second joint 41, and the anchoring ability of the anchor teeth 261 to anchor on the open hole wall can be strengthened, thereby achieving the effect of the more anchored, the more secure.

[0064] Preferably, under the combined friction of the anchor shoe 26, the second joint 41 and the open hole wall, the upward movement of the pipe string can be effectively prevented.

[0065] In the present application, since the anchor teeth 261 are designed as inverted teeth, the friction between the anchor teeth 261 and the open hole wall is increased, and since the outer wall of the anchor shoe 26 is arranged obliquely, the contact area between the anchor teeth 261 and the open hole wall can be further increased, thereby making the open hole anchor 10 more easily and securely anchored on the open hole wall, and effectively preventing the upward movement of the pipe string, to further improve the reliability of the open hole anchor 100.

[0066] According to the present application, as shown in Figs. 1 and 2, the anchor mechanism further comprises a stop ring 211 nested on the inner wall of the middle tube 21. Preferably, a stop tooth 231 adapted to the stop ring 211 is arranged on the outer wall of the piston 23. Figure 1 and 4 ​

[0067] In this way, the piston 23 can only move axially downward within the annulus between the middle cylinder 21 and the central tube 30, thereby effectively preventing the risk of the open-hole anchor 100 accidentally starting and causing the drill bit to jam during the open-hole section insertion process, so as to further ensure the safety of the open-hole packer 100 insertion.

[0068] In this invention, the anti-reverse ring 211 is constructed as a C-shaped structure.

[0069] In one embodiment, such as Figure 1 As shown, a receiving groove 33 is provided on the inner wall of the middle cylinder 21. Furthermore, the naked eye anchor 100 also includes a locking ball 50 arranged within the receiving groove 33. Preferably, when the piston 23 moves axially downward within the annulus between the middle cylinder 21 and the central tube 30, the locking ball 50 can fall into the annulus between the middle cylinder 21 and the central tube 30, thereby restricting the upward movement of the piston 23.

[0070] In this invention, the first pin 201, the second pin 202 and the locking ball 50 can achieve a double insurance effect, thereby effectively preventing the risk of the open-eye anchor 100 being accidentally activated during the open-eye section insertion process and causing the drill to get stuck, so as to further ensure the safety of the open-eye packer 100 insertion.

[0071] According to a second aspect of the present invention, a method for anchoring the naked eye wall using a naked eye anchor as described above is provided, comprising the following steps:

[0072] First, the closed tubing is pressurized into the central tube 30. The pressure is transmitted to the gap 24 through the pressure transmission hole 31, thus allowing the piston 23 to move axially downward after shearing the second pin 202.

[0073] Then, the locking ball 50 is pressed down and falls into the annular space between the middle cylinder 21 and the central tube 30, pushing the piston 23 to continue moving downward along the axis until the piston 23 axially abuts against the anchoring cylinder 25.

[0074] Then, pressure continues to be applied into the central tube 30, and the first pin 201 is sheared off under the pushing action of the piston 23, thereby allowing the anchoring cylinder 25 and the anchoring slip 26 to move axially downward.

[0075] Finally, the guide ramp 262 of the anchoring slip 26 comes into contact with the guide ramp 411 of the second connector 41, and all the anchoring slips 26 are radially split open after the second connector 41 breaks the fins 264, thus successfully anchoring to the bare eye wall.

[0076] It is worth noting that when the tubing tends to move upward, the combined friction of the anchor slip 26, the second joint 41, and the open hole wall can effectively prevent the tubing from moving upward.

[0077] In addition, since the anchoring tooth 261 is designed as an inverted tooth, the friction with the open hole wall is increased, and since the outer wall surface of the anchoring slip 26 is arranged obliquely, the contact area of the anchoring tooth 261 with the open hole wall is further increased. Therefore, when the pipe string moves upward, the anchoring tooth 261 can have a larger opening angle under the action of the second joint 41, and the anchoring ability of the anchoring tooth 261 on the open hole wall can be strengthened, so that the effect of the more anchoring, the more firm is realized, and the effect of the pipe string moving upward is effectively realized, so as to further improve the reliability of the open hole anchor 100.

[0078] Compared with the prior art, the advantages of the present application are that:

[0079] Firstly, the present application can realize double insurance through the first pin 201, the second pin 202 and the lock ball 50, so as to effectively prevent the risk of sticking caused by accidental starting of the open hole anchor 100 during the open hole section running-in process, so as to further ensure the safety of the open hole anchor 100 running-in.

[0080] Secondly, the present application not only increases the friction with the open hole wall by designing the anchoring tooth 261 as an inverted tooth, but also further increases the contact area of the anchoring tooth 261 with the open hole wall by arranging the outer wall surface of the anchoring slip 26 obliquely, so as to improve the anchoring ability of the open hole anchor 100 on the open hole wall.

[0081] Thirdly, when the pipe string has a tendency to move upward, the anchoring tooth 261 in the present application can have a larger opening angle under the action of the second joint 41, and the anchoring ability of the anchoring tooth 261 on the open hole wall can be strengthened, so that the effect of the more anchoring, the more firm is realized, and the effect of the pipe string moving upward is effectively realized, so as to further improve the reliability of the open hole anchor 100.

[0082] Fourthly, the present application divides the anchoring slip 26 into two parts, so that when the guide inclined surface 262 of the anchoring slip 26 contacts the guide inclined surface 411 of the second joint 41, each anchoring slip 26 can open radially outward in a different direction, so as to have a larger anchoring range and be more easily anchored on the open hole wall, so as to further make the open hole anchor 100 have good adaptability.

[0083] The above is only the preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art can easily make changes or variations within the scope of the present application, and such changes or variations should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A naked-eye anchor, comprising: First connector (10), and The anchoring mechanism includes a middle cylinder (21) disposed downstream of the first joint (10), an outer cylinder (22) disposed radially outside the middle cylinder (21) and fixed to the first joint (10) by a first pin (201), and a central tube (30) disposed radially inside the middle cylinder (21). A piston (23) is provided between the middle cylinder (21) and the central tube (30), and the piston (23) is fixed to the middle cylinder (21) by a second pin (202).

2. The naked-eye anchor according to claim 1, characterized in that, In the initial state, the upper end face of the piston (23) has a gap (24) between it and the middle cylinder (21). A pressure transmission hole (31) communicating with the gap (24) is provided on the central tube (30). The second pin (202) is configured to shear under pressure from the pressure-transmitting hole (31), thereby allowing the piston (23) to move axially downward.

3. The naked-eye anchor according to claim 2, characterized in that, The anchoring mechanism further includes an anchoring cylinder (25) disposed downstream of the outer cylinder (22) and for abutting against the piston (23), and an anchoring slip (26) disposed downstream of the anchoring cylinder (25). The first pin (201) is configured to shear under the pushing action of the piston (23), thereby allowing the anchoring cylinder (25) and the anchoring slip (26) to move axially downward.

4. The naked-eye anchor according to claim 3, characterized in that, Multiple anchoring slips (26) are arranged at intervals along the circumference of the anchoring cylinder (25). Each anchoring slip (26) is connected to the anchoring cylinder (25) by a connecting rod (263), and adjacent anchoring slips (26) are connected by flippers (264).

5. The naked-eye anchor according to claim 4, characterized in that, The outer wall of the anchoring slip (26) is arranged at an angle, and a plurality of anchoring teeth (261) extending radially outward and upward at an angle are provided on the outer wall of the anchoring slip (26).

6. The naked-eye anchor according to claim 5, characterized in that, The naked-eye anchor also includes a second connector (41) located downstream of the central tube (30), and a guide bevel (411) is provided on the outer wall of the second connector (41). The anchoring slip (26) has a guide slope (262) adapted to the guide slope (411) on the side near the central tube (30), thereby allowing the anchoring slip (26) to move radially outward and anchor to the bare eye wall.

7. The naked-eye anchor according to any one of claims 1 to 6, characterized in that, The anchoring mechanism also includes a backstop ring (211) nested on the inner wall of the middle cylinder (21), and a backstop tooth (231) adapted to the backstop ring (211) is provided on the outer wall of the piston (23).

8. The naked-eye anchor according to any one of claims 1 to 6, characterized in that, The inner wall of the middle cylinder (21) is provided with a receiving groove (33), and the naked eye anchor also includes a locking ball (50) arranged in the receiving groove (33) for restricting the upward movement of the piston (23).

9. The naked-eye anchor according to any one of claims 1 to 6, characterized in that, A sealing ring (27) is provided between the piston (23) and the central tube (30) and the middle cylinder (21).

10. A method for anchoring the naked eye wall using the naked eye anchor according to any one of claims 1 to 9, comprising the following steps: S1. Pressing into the pressure transmission hole (31), the second pin (202) is sheared under pressure, thereby allowing the piston (23) to move axially downward until it abuts against the anchoring cylinder (25); S2. Continue pressing, and the first pin (201) is sheared by the piston (23), thereby allowing the anchoring cylinder (25) and the anchoring slip (26) to move axially downward. The anchoring slip (26) moves radially outward under the action of the second joint (41) and is anchored on the bare eye wall.

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