A spiral ball seat

Abstract

The present invention relates to the field of oil well downhole construction, and particularly relates to a spiral ball seat, comprising: a central tube with a conical outer surface, the central tube having an axial through hole; an anchoring and sealing structure, the anchoring and sealing structure being fitted on the outer surface of the central tube, the anchoring and sealing structure having a radially penetrating spiral gap, the anchoring and sealing structure between the spiral gaps including a sealing and anchoring main body and a locking main body, and a locking structure cooperating with the locking main body being provided on the central tube. The sealing surface between the inner surface of the anchoring and sealing structure and the outer surface of the central tube is in surface contact, so as to have a good sealing effect and avoid the problem of sealing failure. At the same time, when locking, only the locking main body retracts and locks radially, and the other parts of the sealing and anchoring main body do not retract, so that the outer surface of the sealing and anchoring main body still maintains reliable anchoring and sealing with the inner wall of the wellbore, and does not affect the overall anchoring and sealing effect of the ball seat.

Description

Technical Field

[0001] The present invention relates to the field of downhole oil construction, and particularly relates to a spiral ball seat. Background Art

[0002] After the ball seat is set in the wellbore, it is necessary to ensure that there is no relative movement between the anchor of the ball seat and the central pipe. Otherwise, the sealing will be affected, and at the same time, ineffective anchoring will occur, posing a safety hazard. In order to ensure that there is no relative movement between the anchor and the central pipe, the existing ball seats are provided with a limiting structure that anchors to the outer surface of the central pipe on the entire inner surface of the anchor or the seal. When this limiting structure locks and limits, since the limiting structure is provided on the entire sealing surface of the outer surface of the central pipe and the inner surface of the anchoring and sealing structure, the sealing surface of the central pipe is not in surface contact, affecting the sealing effect of the outer surface of the central pipe. Moreover, the anchor and the seal will retract radially, resulting in sealing failure. Summary of the Invention

[0003] The present invention provides a spiral ball seat to solve the above technical problems, so as to improve the locking and sealing effects of the anchor and the seal with the outer wall of the central pipe.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: A spiral ball seat, comprising:

[0005] A central pipe with a conical outer surface, the central pipe having an axial through hole;

[0006] An anchoring and sealing structure, the anchoring and sealing structure being fitted on the outer surface of the central pipe, the anchoring and sealing structure having a radially penetrating spiral gap, the anchoring and sealing structure between the spiral gaps including a sealing and anchoring main body and a locking main body, and a locking structure cooperating with the locking main body being provided on the central pipe.

[0007] The working principle and beneficial effects of the present invention are as follows: Since the anchoring and sealing structure is set as a spiral structure, only part of the spiral structure is the locking main body, so that the sealing surface between the inner surface of the sealing and anchoring main body and the outer surface of the central pipe is in surface contact, having a good sealing effect and avoiding the problem of sealing failure. At the same time, when locking, since the locking main body of the spiral structure has a retracting force in the direction of its axis after being radially expanded, the locking main body is directly retracted and locked in the radial direction by its retracting force, and the other parts of the sealing and anchoring main body will not retract, so that the outer surface of the sealing and anchoring main body still maintains reliable anchoring and sealing with the inner wall of the wellbore, and will not affect the overall anchoring and sealing effects of the ball seat. Moreover, since the anchoring and sealing structure is a spiral structure, the spiral structure requires a certain initial force to expand, which can prevent premature setting.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Further, the locking structure is a locking groove, and the width of the locking groove in the axial direction of the central tube is greater than the pitch of the locking body.

[0010] The beneficial effect of adopting the above further solution is that: the width of the locking groove in the axial direction of the central tube is greater than the pitch of the locking body. When the tool completes setting, it is ensured that part of the locking body retracts into the locking groove of the locking structure by its own elastic force, ensuring the limit locking effect of the locking structure.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Further, a plurality of locking teeth that match each other are provided on the surface of the locking groove and the inner surface of the locking body.

[0013] The beneficial effect of adopting the above further solution is that: by setting a plurality of locking teeth, the locking effect between the locking body and the central tube is ensured.

[0014] On the basis of the above technical solution, the present invention can also be improved as follows.

[0015] Further, the locking groove is a locking recess, and the locking recess has a groove side surface in the radial direction of the central tube. The groove side surface far from the small end of the central tube is an inclined side surface, and the opening of the inclined side surface is far from the small end of the central tube.

[0016] The beneficial effect of adopting the above further solution is that: by setting the locking recess, the retracted locking body is directly used to match and lock with the locking recess, simplifying the structure of the locking structure; at the same time, the groove side surface is set as an inclined surface. After the sealing and anchoring body in the anchoring and sealing structure moves to the locking recess, under the action of an external thrust, the sealing and anchoring body can smoothly move out of the locking recess along the inclined surface, ensuring the sealing and locking of the anchoring and sealing structure to the wellbore.

[0017] On the basis of the above technical solution, the present invention can also be improved as follows.

[0018] Further, the anchoring and sealing structure is a variable pitch structure, the locking body is located at the smaller inner diameter end of the anchoring and sealing structure, the pitch of the locking body is less than the width of the locking groove in the axial direction of the central tube, and the width of the locking groove in the axial direction of the central tube is less than the pitch of the sealing and anchoring body.

[0019] The beneficial effects of adopting the above further solution are as follows: Since the width of the lock groove in the axial direction of the central tube is greater than the pitch of the locking body and less than the pitch of the sealing and anchoring body, during the process of the anchoring and sealing structure moving towards the central tube, the sealing and anchoring body will not fall into the lock groove, improving the efficiency of downhole construction of the ball seat.

[0020] Based on the above technical solution, the present invention can be further improved as follows.

[0021] Furthermore, the locking body is located at the smaller inner diameter end of the anchoring and sealing structure.

[0022] The beneficial effects of adopting the above further solution are as follows: The locking position is at the opposite end of the ball seat under pressure, ensuring the effect of limit locking.

[0023] Based on the above technical solution, the present invention can be further improved as follows.

[0024] Furthermore, the sealing and anchoring body has a sealing section and an anchoring section, and the sealing section has a sealing boss.

[0025] The beneficial effects of adopting the above further solution are as follows: The sealing section is set as a sealing boss. When the sealing section is subjected to radial pressure, the surface area of the boss is small. Under the condition of the same pressure, the pressure received at the position of the boss is large, making it easy for the boss to squeeze into the inner wall of the wellbore and form a seal with the inner wall of the wellbore, improving the sealing effect.

[0026] Based on the above technical solution, the present invention can be further improved as follows.

[0027] Furthermore, the sealing section is located at the larger inner diameter end of the anchoring and sealing structure, the spiral gap does not penetrate the sealing section in the axial direction of the anchoring and sealing structure, and the sealing boss has at least one complete circle on the circumferential direction of the outer surface of the sealing section.

[0028] The beneficial effects of adopting the above further solution are as follows: At least one complete circle of sealing bosses ensures the sealing effect in the entire circumferential direction of the ball seat and prevents leakage.

[0029] Based on the above technical solution, the present invention can be further improved as follows.

[0030] Furthermore, both the sealing section and the anchoring section are multi-segment and are alternately arranged with each other.

[0031] The beneficial effects of adopting the above further solution are as follows: It realizes multi-stage sealing and multi-stage anchoring, further improving the sealing and anchoring effect of the ball seat.

[0032] Based on the above technical solution, the present invention can be further improved as follows.

[0033] Furthermore, the surface of the anchoring section is arranged to be wavy.

[0034] The beneficial effect of adopting the above further solution is that: the wave crests in the wavy anchoring surface are under greater pressure, which is convenient for the anchoring of the anchoring section and the inner wall of the wellbore; at the same time, the anchoring section at the wave crest position can also play an auxiliary sealing role.

[0035] Based on the above technical solution, the present invention can also be improved as follows.

[0036] Furthermore, an anchoring layer is provided on the surface of the anchoring section.

[0037] The beneficial effect of adopting the above further solution is that: the anchoring layer further improves the anchoring effect of the anchoring section. Description of the Drawings

[0038] Figure 1 is a three-dimensional structural schematic diagram of the first embodiment of the spiral ball seat of the present invention;

[0039] Figure 2 is a cross-sectional view in one direction of the first embodiment;

[0040] Figure 3 is a schematic diagram of the central pipe structure of the first embodiment;

[0041] Figure 4 is a schematic diagram of the first working state of the first embodiment;

[0042] Figure 5 is a schematic diagram of the second working state of the first embodiment;

[0043] Figure 6 is a cross-sectional view in one direction of the second embodiment;

[0044] Figure 7 is a schematic diagram of the central pipe structure of the second embodiment;

[0045] Figure 8 is a schematic diagram of the first working state of the second embodiment;

[0046] Figure 9 is a schematic diagram of the second working state of the second embodiment;

[0047] Figure 10 is a cross-sectional view in one direction of the third embodiment;

[0048] Figure 11 is a schematic diagram of the central pipe structure of the third embodiment;

[0049] Figure 12 is a schematic diagram of the first working state of the third embodiment;

[0050] Figure 13 It is a schematic diagram of the second working state of the third embodiment;

[0051] Figure 14 It is a sectional view in one direction of the fourth embodiment.

[0052] In the attached drawings, the list of components represented by each reference numeral is as follows:

[0053] 1. Central tube, 2. Anchoring and sealing structure, 21. Spiral gap, 22. Sealing and anchoring main body, 221. Sealing section, 222. Anchoring section, 23. Locking main body, 3. Locking structure, 4. Wellbore Specific implementation manners

[0054] The principles and features of the present invention will be described below with reference to the attached drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0055] For the structural schematic diagram of the first embodiment of the spiral ball seat of the present invention, see Figures 1 to 5 .

[0056] A spiral ball seat includes: a central tube 1 with a conical outer surface, and the central tube 1 has an axial through hole.

[0057] An anchoring and sealing structure 2, which is fitted on the outer surface of the central tube 1. The anchoring and sealing structure 2 has a radially penetrating spiral gap 21. The anchoring and sealing structure 2 between the spiral gaps 21 includes a sealing and anchoring main body 22 and a locking main body 23. A locking structure 3 cooperating with the locking main body 23 is provided on the central tube 1.

[0058] In this embodiment, a plurality of locking teeth that match each other are provided on the surface of the locking groove and the inner surface of the locking main body 23. Among them, the pitch of the sealing and anchoring main body 22 is equal to the pitch of the locking main body 23, and the width of the locking groove in the axial direction of the central tube 1 is 1.5 times the pitch of the locking main body 23.

[0059] The anchoring and sealing structure is set as a spiral structure, and only part of the spiral structure is the locking main body. In this way, the sealing surface between the inner surface of the sealing and anchoring main body and the outer surface of the central tube is surface contact, so that it has a good sealing effect and avoids the problem of sealing failure.

[0060] In the existing limit tooth structure on the entire surface of the tee center pipe, the anchor and the seal will retract radially. The setting tool needs to provide a relatively large setting stroke to ensure sealing and anchoring. If the setting stroke is insufficient, the problem of sealing failure will occur. For the spiral tee provided in this embodiment, when locking, since the locking body 23 of the spiral structure has a retracting force in the direction of its axis after radially expanding, the locking body 23 is directly retracted and locked radially by its retracting force, and the sealing and anchoring bodies of other parts will not retract, so that the outer surface of the sealing and anchoring body still maintains reliable anchoring and sealing with the inner wall of the wellbore, without affecting the overall anchoring and sealing effect of the tee. Moreover, since the anchoring and sealing structure 2 is a spiral structure, the spiral structure requires a certain initial force to expand, which can prevent premature setting.

[0061] Moreover, when the tool completes setting, it is ensured that part of the locking body 23 retracts into the locking groove of the locking structure 3 by its own elastic force. By setting a plurality of locking teeth to lock and limit each other, the limiting and locking effect of the locking structure is ensured.

[0062] In this embodiment, the sealing and anchoring body 22 has a sealing section 221 and an anchoring section 222, and the sealing section 221 has a sealing boss. Among them, there are two sealing sections 221 and two anchoring sections 222, and the sealing sections 221 and the anchoring sections 222 are arranged alternately.

[0063] For the sealing section set as a sealing boss, when the sealing section is subjected to radial pressure, the surface area of the boss is small. Under the condition of the same pressure, the pressure received at the position of the boss is large, so that the boss can easily be extruded into the inner wall of the wellbore and form a seal with the inner wall of the wellbore, improving the sealing effect. The alternately arranged sealing sections 221 and anchoring sections 222 achieve multi-stage sealing and multi-stage anchoring, further improving the sealing and anchoring effect of the tee.

[0064] In this embodiment, the sealing boss is set as a spiral sealing boss with the same spiral direction as the spiral line of the sealing section 221, so there are multiple sealing bosses, further improving the sealing effect of the tee.

[0065] In this embodiment, the surface of the anchoring section 222 is set to be wavy, and an anchoring layer is provided on the surface of the anchoring section 222.

[0066] The wave crest in the wavy anchoring surface receives a relatively large pressure, which is convenient for the anchoring of the anchoring section with the inner wall of the wellbore; at the same time, the anchoring section at the wave crest position can also play an auxiliary sealing role; the anchoring layer further improves the anchoring effect of the anchoring section.

[0067] In this embodiment, the locking body 23 is located at the smaller inner diameter end of the anchoring and sealing structure 2. The locking position is at the opposite end of the tee under pressure, ensuring the limiting and locking effect.

[0068] The working state of this embodiment is as follows Figures 4 to 5 shown. Place the spiral ball seat of this embodiment in the wellbore 4, and use a setting tool to squeeze the anchoring and sealing structure 2 to the outside of the large end of the central pipe 1 (the left end as shown in the figure). Since the anchoring and sealing structure 2 is a spiral structure, it can expand radially, achieving a large radial elongation rate of the anchoring and sealing structure 2, and realizing the sealing of the wellbore at the larger inner diameter end. When the sealing and anchoring main body 22 in the anchoring and sealing structure 2 is unfolded and extended to seal and anchor with the inner wall of the wellbore 4, and a plurality of locking teeth on the inner surface of the locking main body 23 cooperate with a plurality of locking teeth on the outer surface of the central pipe 1 to lock, the limit and anti - detachment are realized (as Figure 5 shown).

[0069] For the structural schematic diagram of the second embodiment of the spiral ball seat of the present invention, see Figures 6 to 9 .

[0070] The difference between this embodiment and the first embodiment is that the locking groove is a locking recess. The locking recess has a groove side surface in the radial direction of the central pipe 1. The groove side surface far from the small end of the central pipe 1 is an inclined side surface, and the opening of the inclined side surface is far from the small end of the central pipe 1.

[0071] By setting the locking recess, directly using the retracted locking main body 23 to match and lock with the locking recess simplifies the structure of the locking structure; at the same time, setting the groove side surface as an inclined surface enables the sealing and anchoring main body to smoothly move out of the locking recess along the inclined surface under the action of an external thrust after the sealing and anchoring main body in the anchoring and sealing structure moves to the locking recess, ensuring the sealing and locking of the anchoring and sealing structure to the wellbore.

[0072] For the structural schematic diagram of the third embodiment of the spiral ball seat of the present invention, see Figures 10 to 13 .

[0073] The difference between this embodiment and the second embodiment is that the anchoring and sealing structure 2 is a variable pitch structure. The locking main body 23 is located at the smaller inner diameter end of the anchoring and sealing structure 2. The pitch of the locking main body 23 is smaller than the width of the locking groove in the axial direction of the central pipe 1, and the width of the locking groove in the axial direction of the central pipe 1 is smaller than the pitch of the sealing and anchoring main body 22. In this embodiment, the locking groove is a locking recess, the pitch of the sealing and anchoring main body 22 is 1.5 times the pitch of the locking main body 23, and the width of the locking groove in the axial direction of the central pipe 1 is 1.2 times the pitch of the locking main body 23.

[0074] With the above - mentioned structure, during the process of the anchoring and sealing structure moving towards the central pipe, the sealing and anchoring main body 22 will not fall into the locking groove (as Figure 12 shown), improving the efficiency of downhole construction of the ball seat. At the same time, there is no need to set an inclined surface on the side surface of the locking groove, and the processing process is relatively simple.

[0075] For the structural schematic diagram of the fourth embodiment of the spiral ball seat of the present invention, refer to Figure 14 .

[0076] The difference between this embodiment and the third embodiment is that the sealing section 221 is located at the larger inner diameter end of the anchoring and sealing structure 2, the spiral gap 21 does not penetrate the sealing section 221 axially in the anchoring and sealing structure 2, and the sealing boss has at least one complete sealing boss in the circumferential direction on the outer surface of the sealing section 221.

[0077] There is one complete sealing boss in the circumferential direction on the outer surface of the sealing section 221 in this embodiment, ensuring the sealing effect of the entire circumference of the ball seat and preventing leakage.

[0078] In a specific embodiment, multiple complete sealing bosses can be arranged in the circumferential direction on the outer surface of the sealing section 221 according to the usage conditions of the ball seat to improve the sealing reliability.

[0079] In a specific embodiment, the locking structure 3 can be set as a spiral structure that matches the spiral direction of the locking main body 23. In this way, most of the locking main body 23 can fall into the locking structure 3 and contact its matching surface, so that the locking main body 23 and the locking structure 3 have a larger contact area in the radial direction, improving the locking and limiting reliability of the locking main body 23 and the locking structure 3. For example: the locking main body 23 and the locking structure 3 are set as a locking tooth structure that locks with each other, a spiral groove structure, etc. It is advisable that the length of the locking structure 3 is greater than half of the whole thread, which can ensure the locking and limiting reliability of the locking main body 23 with the matching spiral structure falling into the locking structure 3.

[0080] In a specific embodiment, in order to make more locking main bodies 23 fall into the locking structure 3, the locking structure 3 can be set wider, such as setting the width of the locking structure 3 in the circumferential direction to 2.5 times the pitch of the locking main body 23, etc.

[0081] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A spiral ball seat, characterized in that, it includes: a central tube (1) with a conical outer surface, and the central tube (1) has an axial through-hole; an anchoring and sealing structure (2), the anchoring and sealing structure (2) is fitted on the outer surface of the central tube (1) in a matching manner, the anchoring and sealing structure (2) is a spiral structure, the anchoring and sealing structure (2) has a radially penetrating spiral gap (21), and the anchoring and sealing structure (2) between the spiral gaps (21) includes a sealing and anchoring body (22) and a locking body (23), and a locking structure (3) matching with the locking body (23) is arranged on the central tube (1); the sealing and anchoring body (22) has a sealing section (221) and an anchoring section (222), and the sealing section (221) has a sealing boss; both the sealing section (221) and the anchoring section (222) are multi-segment and are arranged alternately with each other.

2. A spiral ball seat according to claim 1, characterized in that, the locking structure (3) is a locking groove, and the width of the locking groove in the axial direction of the central tube (1) is greater than the pitch of the locking body (23).

3. A spiral ball seat according to claim 2, characterized in that, a plurality of locking teeth that match each other are provided on the surface of the locking groove and the inner surface of the locking body (23).

4. A spiral ball seat according to claim 2, characterized in that, the locking groove is a locking recess, the locking recess has a groove side surface in the radial direction of the central tube (1), and the groove side surface far from the small end of the central tube (1) is an inclined side surface, and the opening of the inclined side surface is far from the small end of the central tube (1).

5. A spiral ball seat according to claim 2, characterized in that, the anchoring and sealing structure (2) is a variable pitch structure, the locking body (23) is located at the smaller inner diameter end of the anchoring and sealing structure (2), the pitch of the locking body (23) is smaller than the width of the locking groove in the axial direction of the central tube (1), and the width of the locking groove in the axial direction of the central tube (1) is smaller than the pitch of the sealing and anchoring body (22).

6. A spiral ball seat according to any one of claims 1 to 4, characterized in that, the locking body (23) is located at the smaller inner diameter end of the anchoring and sealing structure (2).

7. A spiral ball seat according to claim 1, characterized in that, the sealing section (221) is located at the larger inner diameter end of the anchoring and sealing structure (2), the spiral gap (21) does not penetrate the sealing section (221) in the axial direction of the anchoring and sealing structure (2), and the sealing boss has at least one complete circle of sealing bosses on the circumferential direction of the outer surface of the sealing section (221).

8. A spiral ball seat according to claim 1, characterized in that, the surface of the anchoring section (222) is arranged in a wavy shape.

9. A spiral ball seat according to claim 1, characterized in that, an anchoring layer is provided on the surface of the anchoring section (222).

Images